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Let’s dive into one of those cosmic curiosities that’s bound to blow your mind: how we might chat with aliens. And no, I’m not talking about elaborate coded messages or flashy signals. We’re talking about something incredibly fundamental—21cm radiation.

If you’re planning on having a conversation across the vastness of space, using light waves (electromagnetic radiation) is pretty much your go-to option. It’s fast, reliable, and, well, it’s the most practical way to shout out to other civilizations in the universe. But why specifically 21 centimeters? That’s where things get juicy.

This 21cm radiation isn’t just some random frequency we picked out of a hat. It’s tied to something very essential, known as the hydrogen spin flip. Hydrogen atoms consist of one proton and one electron, and these tiny particles have a property called “spin.” Think of spin like a little arrow pointing up or down. Every so often, in the vast reaches of space, a hydrogen atom’s electron can flip its spin, going from a state where its spin is aligned with the proton to one pointing in the opposite direction. This flip releases energy in the form of radiation at—you guessed it—a wavelength of 21 centimeters.

So, why does this matter? Well, any smart civilization, whether they have blue skin, tentacles, or something more bizarre, will eventually discover hydrogen, understand spin, dabble in quantum mechanics, and figure out this whole 21cm radiation thing. They’ll call it something different (they won’t have “21” or “cm”) but the concept remains universal. It’s like the cosmic Rosetta Stone.

What makes 21cm radiation perfect for long-distance interstellar chats is its ability to cut through interstellar dust. Space is filthy, with dust clouds that block out other forms of light. However, 21cm waves are like the VIPs of the universe, slipping through the velvet ropes of cosmic debris to carry their message far and wide.

Here’s a fun fact: NASA’s Pioneer spacecraft, launched in the early 1970’s, carry plaques. On these plaques there’s a handy diagram of the hydrogen spin flip transition. All other measurements on the plaque, including the height of humans, are made in reference to this fundamental distance. So the hope is that aliens can recognize the hydrogen spin-flip transition and use that to unlock the rest of our message.

Now imagine this scenario: One day, astronomers on Earth detect an unusual surge of 21cm radiation. It’s not coming from a random hydrogen cloud; it’s directional, purposeful. That could very well be an alien civilization sending us a “What’s up?” across the cosmos – 21cm radiation makes for a great calling card.

Using 21cm radiation to communicate with extraterrestrial beings leverages a basic, universal constant. And who knows? Maybe one day, when we finally hear that signal, we’ll know that somewhere out there, another intelligent species figured out the same galactic hack we did.

So keep your eyes—or rather, your telescopes—peeled. The next big discovery could be just a spin flip away!

The post If You’re Going to Call Aliens, Use This Number appeared first on Universe Today.

The majority of the universe remains unmapped, but we have a potential window into it through a peculiar light emitted by nothing other than neutral hydrogen.

Before stars and galaxies lit up the universe, the cosmos was a dark place filled mostly with neutral hydrogen. This was right after the Big Bang and the formation of the CMB—Cosmic Microwave Background. The CMB is like a baby picture of the universe when it was just 380,000 years old. But what came next was a long period called the “Dark Ages.” During this time, the universe didn’t have much going on in terms of visible light because there were no stars or galaxies yet. Frustratingly, most of the volume of the visible universe exists in these Dark Ages, which makes it a very valuable resource to learn about the nature of dark matter and dark energy. But…it was dark, so we can’t just make a bigger telescope and observe it.

Thankfully, the neutral hydrogen that filled the universe during this epoch does emit a feeble kind of light. Due to the quantum mechanical spin flip transition, neutral hydrogen emits radiations with a wavelength of 21 centimeters. However, the Dark Ages were so long ago at this 21cm radiation is redshifted to a wavelength of two meters or more, putting it firmly in the radio band of the electromagnetic spectrum.

In fact, a tiny fraction of the static you hear in your car radio is due to this ancient radiation.

Astronomers can use slightly different wavelengths to map out the extent and evolution of the Dark Ages. Different pockets of neutral gas will emit their radiation at different times, which will correspond to different redshifts.

We expect to see an enormous amount of 21cm radiation at the very longest wavelengths, right at the beginning of the Dark Ages. That’s when the universe was filled with an almost uniform distribution of neutral hydrogen. Then as the first stars and galaxies wake up, they ionize their surrounding gas with powerful blasts of high-energy radiation. So a 21cm map of this era should show holes and pockets in the overall signal. Finally, once most of the neutral hydrogen is wiped away and confined only to cool regions of galaxies, we should see the signal disappear – only to be replaced with the light of galaxies themselves.

However, observing this radiation is a daunting task. That’s because humans are also quite fond of radio emissions, and this signal from the Dark Ages is at least a million times weaker than terrestrial radio broadcasts. Observatories around the world, like the Murchison Wide-field Array in Western Australia and the Hydrogen Epoch of Reionization Array in South Africa have so far failed to find a conclusive signal.

To nail this detection and open up the Dark Ages to exploration, we may have to go off planet. The Lunar Crater Radio Telescope hopes to turn the far side of the Moon into a pristine radio observatory, using the Moon itself to shield the observatory from radio interference. The idea is a long way off, but it might be our only way to to draw a complete map of the cosmos’ past, present, and future.

The post Neutral Hydrogen: The Next Big Game in Cosmology appeared first on Universe Today.

NASA engineers are pressing ahead with preparations for the Artemis II mission unless someone tells them otherwise. The ambitious flight will send four astronauts on a trajectory similar to Apollo 8’s historic lunar journey, with the crew traveling around the Moon in an Orion Capsule before returning to Earth. A crucial milestone in the mission preparations was reached as technicians completed the assembly of the Space Launch System’s twin solid rocket boosters inside the Vehicle Assembly Building. The stacking process began in late November 2024 and concluded on February 19th.

In a significant step forward for our return to the Moon, NASA engineers at Kennedy Space Center have finished assembling the massive solid rocket boosters that will power the Artemis II mission. The stacking operation, completed on 19 February 2025, marks a key milestone in preparation for the first crewed lunar mission since Apollo. As someone who never saw the Apollo Moon landings, I’m excited. 

Aldrin on the Moon. Astronaut Buzz Aldrin walks on the surface of the moon near the leg of the lunar module Eagle during the Apollo 11 mission. Mission commander Neil Armstrong took this photograph with a 70mm lunar surface camera. While astronauts Armstrong and Aldrin explored the Sea of Tranquility region of the moon, astronaut Michael Collins remained with the command and service modules in lunar orbit. Image Credit: NASA

The assembly process began on 20 November 2024, inside Kennedy’s amazing Vehicle Assembly Building (VAB), where generations of Moon rockets have been built. Using techniques that have been refined over decades of spaceflight experience, technicians employed one of the facility’s overhead cranes to carefully position each segment of the twin boosters.

These solid rocket boosters represent modern engineering at its best, being assembled on Mobile Launcher 1, a huge structure standing 380 feet tall – roughly the height of a 38-story building. This launch platform serves a number of different functions, acting as both the assembly base for the Space Launch System (SLS) rocket and Orion spacecraft, and the launch platform from which the mission will eventually depart for the Moon.

NASA’s Space Launch System (SLS) rocket with the Orion spacecraft aboard is seen at sunset atop the mobile launcher at Launch Pad 39B as preparations for launch continue, Wednesday, Aug. 31, 2022, at NASA’s Kennedy Space Center in Florida. Credit: (NASA/Joel Kowsky)

The completed boosters will form part of the most powerful rocket ever built by NASA, more powerful even than Saturn V that took Apollo astronauts to the Moon. When ignited, these twin rockets will generate millions of pounds of thrust, working in together with the SLS core stage to lift the Orion spacecraft and its four-person crew toward the Moon.

Apollo 11 launch using the Saturn V rocket

Artemis II represents a historic moment in space exploration as the first time humans will venture beyond low Earth orbit since 1972. The mission profile calls for a crew of four astronauts to journey around the Moon in the Orion spacecraft, testing critical systems and procedures before future missions attempt lunar landings.

The successful completion of booster stacking demonstrates the expertise of NASA’s engineering teams. Each segment had to be perfectly aligned and secured, with no room for error in a process that demands accuracy. The boosters will eventually help propel the spacecraft to speeds exceeding 17,000 miles per hour – fast enough to break free of Earth’s gravity and get to the Moon.

With this milestone achieved, NASA continues toward launch, carefully checking and testing each system to ensure the safety of the crew and the success of this ambitious mission to return humans to deep space.

Moon, here we come, once again. 

Source : Artemis II Rocket Booster Stacking Complete

The post The Artemis II Boosters are Stacked appeared first on Universe Today.

It’s not uncommon for space missions to be tested here on planet Earth. With the plethora of missions that have been sent to Mars it  is becoming increasingly likely that the red planet was once warmer, wetter and more habitable than it is today. To find evidence of this, a new paper proposes that Deception Island in Antarctica is one of the best places on Earth to simulate the Martian environment. The paper identifies 30 sites on the island that correspond well to places on Mars.

The exploration of Mars has been a focus of space agencies worldwide, driven by the desire to understand the its geology, climate, possibility of past life, and excitingly the potential for future human colonisation. Early missions, such as NASA’s Mariner 4 in 1965, provided the first close-up images of Mars, while the Viking landers of the 1970s conducted the first successful surface experiments. In the 1990s and 2000s, orbiters like Mars Global Surveyor and rovers like Spirit and Opportunity helped us to understand more about the Martian terrain and atmospheric conditions. As we explore the red planet, and with more projects on the horizon, Mars remains a key target for exploration. 

Three Generations of Mars Rovers in the ‘Mars Yard’ at the Jet Propulsion Laboratory. The Mars Pathfinder Project (front) landed the first Mars rover – Sojourner – in 1997. The Mars Exploration Rover Project (left) landed Spirit and Opportunity on Mars in 2004. The Mars Science Laboratory Curiosity rover landed on Mars in August 2012. Credit: NASA/JPL-Caltech.

The world that has been revealed following the multitude of missions is of a surface that is cold, dry, and exposed to high radiation. Evidence exists that liquid water once flowed on Mars, bringing the tantalising possibility that microbial life may have existed in the past. Today, underground water reserves and seasonal methane emissions hint at the possibility of present-day life BUT and it is a strong BUT, no evidence has been found yet.   Further exploration is required and it is at times like this that researchers turn to planetary analogues to explore further. 

Image taken by the Viking 1 orbiter in June 1976, showing Mars thin atmosphere and dusty, red surface. Credits: NASA/Viking 1

A planetary analogue is a location on Earth that is similar or identical to places found on alien worlds. In the case of Mars, a new paper has been published that suggests that Deception Island in Antarctica is a great ‘analogue’ for parts of Mars. Exploring life that is found in these locations enables us to better understand the locations on Mars and helps inform future exploration. 

The paper, that was authored by a team led by María Angélica Leal Leal identifies 30 locations on the island that are an excellent match for locations on Mars. The locations have been divided into four categories; geologically similar to areas of Mars, environmental conditions are similar to Mars, biological interest due to the existence of extremophiles on Earth and various engineering applications enabling hardware testing in Mars-like environment. 

It concludes that Deception Island in Antarctica serves as a valuable Mars analogue site due to the combination of extreme environmental conditions and geological features that mirror those found on Mars. It’s a volcanic island too offering a natural (and significantly closer) laboratory where it might reveal how life adapts to harsh conditions including low temperatures and high radiation. 

The island’s particularly unique features include the presence of perchlorate (chemical compounds that contain salts made up of chlorine and oxygen atoms,) glaciovolcanic processes, permafrost, and microbial mats (layers of complex microorganisms) that survive in extreme conditions. This all makes for an excellent terrestrial alternative for studying potential past or present life on Mars. However, the researchers note that further detailed studies of the island’s geochemistry, extremophile organisms, and mission simulations are needed to fully confirm its validity as a Mars analogue for specific Martian regions and time periods.

Source : The potential of Deception Island, Antarctica, as a multifunctional Martian analogue of astrobiological interest

The post Antarctica’s Deception Island is the Perfect Place to Practice Exploring Mars appeared first on Universe Today.

Some of our Solar System’s moons have become very enticing targets in the search for life. There’s growing evidence that some of them have oceans under layers of ice and that these oceans are warm and rich in prebiotic chemistry. NASA’s Europa Clipper is on its way to examine Jupiter’s moon Europa, and the ESA’s Jupiter Icy Moons Explorer is also on its way to the Jovian system to explore some of its icy moons.

While the presence of an ocean on Europa is becoming widely accepted, there’s more uncertainty about the other Galilean moons. However, new evidence suggests that Callisto is very likely an ocean moon, too.

Callisto is Jupiter’s second-largest moon, the third-largest moon in the Solar System, and the outermost Galilean moon. The Voyager probes gave us our first close looks at Callisto in 1979, and the Galileo spacecraft gave us our best images and science data during flybys between 1996 and 2001. Galileo provided the first evidence that Callisto may harbour a subsurface ocean.

Callisto has a different appearance than other suspected ocean moons like Europa and Saturn’s Enceladus. Europa clearly has a white, icy surface, although it has other brownish colours, too. Enceladus has an extremely bright, icy surface and has the highest albedo of any object in the Solar System. Callisto, on the other hand, has a dark, icy surface and is covered in craters.

Europa (L), Enceladus (M), and Callisto (R) have distinctly different surfaces, yet all likely have subsurface oceans.

However, the evidence for its ocean is unrelated to its surface appearance and any visible ice.

The main evidence supporting an ocean on Callisto comes from the moon’s magnetic field. Unlike Earth’s internally generated magnetic field, Callisto’s is induced. That means the field is created from Callisto’s interactions with Jupiter and its extremely powerful magnetic field. For Callisto to induce a magnetic field, it has to have a layer of conductive material.

This illustration shows Jupiter’s powerful magnetic field and the four Galilean moons. Image Credit: ESA.
Licence: ESA Standard Licence

The question is, is the layer an ocean or something else?

Different researchers have been trying to answer that question since Galileo gathered its data. One of the spacecraft’s instruments was a magnetometer, a type called a Dual-Technique Magnetometer (DTM). There are multiple types of magnetometers, and each one works differently. Galileo’s DTM provided redundancy and allowed for cross-checking, which increased the accuracy and reliability of its data. It was especially good at detecting the subtle magnetic fields of Jupiter’s moons, including Callisto. It also collected data continuously, which let scientists gain insights into how the magnetic fields of Jupiter and its moons varied over time due to different interactions.

In a 2017 paper, researchers pointed to the ionosphere as the primary cause of Callisto’s magnetic fields. “We find that induction within Callisto’s ionosphere is responsible for a significant part of the observed magnetic fields,” the authors wrote. “Ionospheric induction creates induced magnetic fields to some extent similar as expected from a subsurface water ocean.”

New research in AGU Advances based on Galileo data strengthens the idea that Callisto has a subsurface ocean and that it’s responsible for the moon’s magnetic field rather than its ionosphere. The paper is titled “Stronger Evidence of a Subsurface Ocean Within Callisto From a Multifrequency Investigation of Its Induced Magnetic Field.” The lead author is Corey Cochrane, a scientist at JPL who studies planetary interiors and geophysics. An important part of this research is that they considered data from multiple Galileo flybys (C03, C09, and C10).

“Although there is high certainty that the induced field measured at Europa is attributed to a global-scale subsurface ocean, there is still uncertainty around the possibility that the induced field measured at Callisto is evidence of an ocean,” Cochrane and his co-researchers write. “This uncertainty is due to the presence of a conductive ionosphere, which will also produce an induction signal in response to Jupiter’s strong time-varying magnetic field.”

Observations acquired from the Galileo spacecraft indicate that Callisto (left) reacts inductively to Jupiter’s (right) time-varying magnetic field. New research suggests that this reaction and its results are indicative of the moon hosting a subsurface salty ocean. Image Credit: Corey J. Cochrane, NASA/JPL-Caltech

In short, Callisto’s magnetic field could be caused by its ionosphere, an ocean, or a combination of both. The problem is that Callisto’s conductive ionosphere creates a magnetic field that can mask the presence of an ocean. To get to the truth, the authors used previously published simulations of the moon’s interactions combined with “both an inverse and an ensemble forward modeling method.” The authors write that this brings some clarity about the possible range of Callisto’s interior properties.

The researchers created a four-layer model of Callisto, including its ionosphere. “Among these models, we vary the thickness of the ice shell, the thickness of the ocean, and the conductivity,” the authors write. They also varied the seafloor depth and the ionosphere’s conductance.

This schematic diagram from the study shows the variable parameters in some of the researchers’ modelling. (Left) D is seafloor depth, T is ocean thickness, and Rc is conductance. (R) The ocean parameter space in the study has 8 linear steps for ocean thickness and 10 steps for ocean conductivity. Image Credit: Cochrane et al. 2025.

The researchers concluded that the moon’s ionosphere alone cannot explain the magnetic field. Instead, it “more likely arises from the combination of a thick conductive ocean and an ionosphere rather than from an ionosphere alone.”

They also concluded that the ocean is tens of kilometres thick from the seafloor to the ice shell, and the ice shell could also be tens of kilometres thick. “As our results demonstrate, both the inverse and forward modelling approaches support the presence of an ocean when considering data acquired from flyby C10 alongside C03 and C09,” the researchers explain. “Our analysis, the first to simultaneously fit C03, C09, and C10 flyby data together, favours the presence of a thick and deep ocean within Callisto.”

The models also favour a thick ice shell “consistent with Callisto’s heavily cratered geology,” they explain.

Galileo wasn’t dedicated to studying Callisto, so there is a dearth of data in all research into its magnetic fields. “It is challenging to place tighter constraints on the properties of Callisto’s ocean because of the limited number of close Galileo flybys that produced reliable data and because of the uncertainty associated with the plasma interaction,” the authors write in their conclusion.

Better and more complete data is in the future, though. Both NASA’s Europa Clipper and the ESA’s JUICE mission will gather more data, some of it from very close to Callisto’s surface.

The Europa Clipper is scheduled to make nine flybys of Callisto. Seven will be within 1800 km of the surface, and four of those will be within 250 km. Its magnetometer will operate continuously during those flybys. The ESA’s JUICE mission is scheduled to perform 21 flybys of Callisto. All of them will be within 7000 km of the surface, and most will be below 1000 km.

The Europa Clipper’s elliptical orbit will allow it to perform flybys of Jupiter’s moons, including Callisto. Image Credit: NASA/JPL-Caltech

Both the Europa Clipper and JUICE have instruments that Galileo didn’t have. Though Galileo came within about 1100 km of Callisto’s surface, it simply could not provide the same kind of data that these newer missions will. The Clipper and JUICE are scheduled to reach the Jovian system in 2030 and 2031, respectively.

As their data starts to arrive and reaches scientists, we will likely determine for sure if Callisto is yet another of the Solar System’s ocean moons.

• Press Release: Jupiter’s Moon Callisto Is Very Likely an Ocean World
• Research: Stronger Evidence of a Subsurface Ocean Within Callisto From a Multifrequency Investigation of Its Induced Magnetic Field

The post Does Jupiter’s Moon Callisto Have an Ocean? The Evidence is Mounting appeared first on Universe Today.

Gateway’s HALO module heads to the U.S., on its long path to orbiting the Moon.

Preparations for Lunar Gateway are starting to come together. Thales Alenia Aerospace engineers recently began a series of checks on the HALO (Habitation Logistics Outpost) core module. Currently at the company’s Turin, Italy facility, the module is set to head to the U.S. to contractor Northrop Grumman’s Gilbert, Arizona site next month, aboard an Antonov AN-124-100 aircraft.

The HALO segment is the crucial core of what will become Lunar Gateway. Along with environmental and stress tests, the Thales Alenia team will install valves, carry out leak checks, and prepare for integrating secondary structures with HALO. One airlock, the Emirates Crew and Science Module was built and provided by the United Arab Emirates’ Mohammed bin Rashid Space Centre. The airlock will be used for space walks outside of Gateway. In exchange, the UAE will receive an astronaut slot on an Artemis expedition.

The first welding of the ring and cylinder segments for HALO occurred at Thales Alenia Space in 2021, marking the first major milestone for assembly of the module’s primary structure.

The HALO core module on the move. Credit: Thales Alenia Space.

Northrop Grumman was awarded the $935 million dollar contract to develop the Gateway HALO module in 2021. NASA’s FY2025 budget allocates over $817 million for the continued construction of Gateway.

Looking inside the HALO module. Credit: Thales Alenia Space. What’s Next for HALO and Gateway

“To ensure all flight hardware is ready to support Artemis IV—the first crewed mission to Gateway—NASA is targeting the launch of HALO and the Power and Propulsion Element no later than December 2027,” Laura Rochon (NASA-Johnson Spaceflight Center) told Universe Today in a recent email. “These modules will launch together aboard a SpaceX Falcon Heavy rocket and spend about a year traveling uncrewed to lunar orbit, while providing scientific data on solar and deep space radiation during transit.”

Once the module arrives at Northrop Grumman’s Arizona facility, it will undergo more tests and integration with the propulsion stage prior to launch. As one of four pressurized modules, HALO will support crew, experiments and internal and external payloads. Gateway will serve as a staging point, supporting lunar research and crews on the surface. One big advantage for Gateway is that it would act as a reusable ‘command module’ for expeditions to the Moon, allowing for longer stays on the surface.

Part of the propulsion element for Gateway. Credit: NASA/JSC/Maxar Space Systems. A Deep Space Station

Like the International Space Station, Gateway is an international effort. The European Space Agency is designing its Lunar Link (part of ESA’s larger LunaNet DTN framework initiative) for the station. The Canadian Space Agency (CSA) is supplying a robotic arm, its Small Orbital Replacement Unit Robotic Interface. Gateway will be approximately a fifth the size and volume of the ISS. Unlike the permanently crewed ISS, Gateway will only host temporary expeditions, and will spend much on its time vacant and running in autonomous mode.

An artist’s conception of Gateway in orbit around the Moon. Credit: NASA-JSC.

“The ISS has been a cornerstone of space research in low-Earth orbit for more than two decades,” says Rochon. “Gateway expands this legacy into the deep space environment. Gateway will operate in orbit around the Moon, where radiation is a greater concern due to lack of a protective shield. It took 40 launches and over 13 years to build the ISS. Gateway will be fully constructed in four launches using advanced technology and capabilities focused on what is needed to support long-term human lunar exploration.”

Science and research will still happen on Gateway… even when humans are absent. “Gateway will focus on pushing the boundaries of remote and autonomous operations,” says Rochon. “This will enable Gateway to conduct science investigation and support missions, even when crew are not present.”

Putting Gateway together. Credit: NASA. Artemis at a Crossroads

This all happens at a time of change and uncertainty for NASA. A layoff of 1,000 employees announced earlier this week was put on hold…for now. Many pundits have also questioned the burgeoning complexity and cost overruns for the Artemis initiative, and if Gateway is still needed.

NASA’s large Space Launch System (SLS) rocket finally got off the ground with Artemis I in November 2022. The first crewed lunar flyby on Artemis II has been pushed back to April 2026. The first lunar landing mission on Artemis III relies heavily on SpaceX’s Starship Heavy and Starship HLS (Human Landing System) as part of its architecture. Starship has another suborbital launch coming up on February 26th. The first possible orbital flight of Starship is planned for this April. SpaceX still has lots of hurdles to overcome prior to the Artemis III lunar landing, set for 2027.

Gateway will orbit the Moon in a unique, Near-rectilinear halo orbit (NRHO). This unique type of orbit is necessary for astronauts to access the entirety of the lunar surface. This is especially true for a landing in the south polar regions. The Cis-Lunar Autonomous Positioning System Technology Operations Navigations Experiment (CAPSTONE) mission launched in 2022 on a Rocket Lab Electron rocket is pioneering this type of orbit. An NRHO path also affords the station a near-continuous line-of-sight communications link with controllers on Earth.

Despite the hurdles it faces, it would be great to finally see humans living and working around the Moon. Imagine the view! For now, we can watch as the pieces come together, and the core HALO module for Gateway takes ‘one small step’ closer to the launch pad.

The post Lunar Gateway’s Core HALO Module Enters the Clean Room appeared first on Universe Today.

What if I told you there was a secret window, and if you looked through this window you could see the entire history of the universe unfold before your very eyes?

It sounds too good to be true. But this is science, and if we’ve learned anything in our four centuries of scientific exploration of nature, its that science can produce miracles. Or in this case, science can take advantage of nature’s own miracles.

I’m talking about a curious little feature of the humble hydrogen atom. One proton, one electron. Done, the simplest atom possible. You can throw a neutron in there if you’re feeling generous. It’s not necessary but adds a little bit of fiber.

Now this proton and this electron are particles, which means they have a list of properties, like mass and charge. Those properties tell us how the particles respond to the gravitational force and the electric force. And then there’s this other property, a property we call spin. When I say “spin” everybody, including myself, thinks of the obvious: something spinning, like a Harlem globetrotter spinning a basketball on their pinky finger. But these are particles, which means they take up no volume in space, so how do they…spin?

The answer is they don’t. But they kind of do. It’s really weird and complicated and it’s one of those many quantum things that we just have to learn to live with, because there’s no getting around it and quantum mechanics doesn’t really care if we understand it or not. The spin of a particle refers to, essentially, how it responds to magnetic fields. If you were to take a metal ball and charge it up with electricity, and then set it spinning and throw it into a magnetic field, there’s a natural response of that spinning metal charged ball to the magnetic field. If it’s spinning one way, the ball gets deflected in one direction. If it’s spinning the other way, it goes the other way.

Particles like electrons and protons do that: they respond to magnetic fields exactly as if they were charged metal balls. They’re not, but they still act like they are, so we call it spin because that’s the closest thing we can call this, and we have to move on.

And particles like protons and electrons can have one of two choices for their spin. We call these choices up and down, because when we shoot these particles through a magnetic field that points up-and-down, the up-pointing particles go up and the down-spinning particles go down. We could have called these spin states left and right or a and b or alice and bob, but we went with up and down.

In a hydrogen atom, the electron and proton can either have the same direction of spin (both up or both down) or they can have opposite spins. For various quantum mechanical reasons having to do with overlap of the wavefunctions, when the proton and electron have the exact same spin, that configuration has ever so slightly more energy than the situation than when they’re the opposite.

That means that when they find themselves in that same-spin situation, because quantum mechanics allows all sorts of randomness like that, they can realign themselves to reach a lower energy state.

This takes a long time. If you found a hydrogen atom all by its lonesome in the middle of empty space with parallel spins, and you waited and watched for it to flip back to its normal configuration, the average wait time is around 11 million years.

But here’s the kicker. Last time I checked there are way more than 11 million hydrogen atoms in the universe, which means if you have a whole bunch of hydrogen atoms all sitting around, chances are one of them is going to realign and release that pent-up energy.

And if you have, say, a galaxy’s worth of hydrogen atoms, then they’re emitting this energy pretty much all the time.

Now it’s not a lot of energy, around 5.8 micro electron-volts. That energy comes out in a very specific way, in the form of a single photon of electromagnetic radiation. And we can compute the wavelength of that radiation, and that comes out to 21 cm.

Every galaxy is glowing in this very special kind of light, all thanks to the humble hydrogen atom.

The post How Humble Hydrogen Lights Up the Universe appeared first on Universe Today.

Every Martian year (which last 686.98 Earth days), the Red Planet experiences regional dust storms that coincide with summer in the southern hemisphere. Every three Martian years (five and a half Earth years), these storms grow so large that they encompass the entire planet and are visible from Earth. These storms are a serious hazard for robotic missions, causing electrostatic storms that can mess with electronics and cause dust to build up on solar panels. In 2018 and 2022, the Opportunity Rover and InSight Lander were lost after dust storms prevented them from drawing enough power to remain operational.

But what about crewed missions? In the coming decades, NASA and the Chinese Manned Space Agency (CMS) plan to send astronauts and taikonauts to Mars. These missions will include months of surface operations and are expected to culminate in the creation of long-duration habitats on the surface. According to new research by the Keck School of Medicine at the University of Southern California (USC), Martian dust storms can potentially cause respiratory issues and elevated risk of disease, making them yet another health hazard space agencies need to prepare for.

The research was led by Justin L. Wang, a Doctor of Medicine at USC, along with several of his colleagues from the Keck School of Medicine. They were joined by researchers from the UCLA Space Medicine Center, the Ann and HJ Smead Department of Aerospace Engineering and the Laboratory for Atmospheric and Space Physics at UC Boulder, and the Astromaterials Acquisition and Curation Office at NASA’s Johnson Space Center. The paper detailing their findings appeared on February 12th in the journal GeoHealth.

Sending crewed missions to Mars presents many challenges, including logistics and health hazards. In the past 20 years, the shortest distance between Earth and Mars was 55 million km (34 million miles), or roughly 142 times the distance between the Earth and the Moon. This was in 2003 and was the closest the two planets had been in over 50,000 years. Using conventional methods, it would take six to nine months to make a one-way transit, during which time astronauts will experience physiological changes caused by long-term exposure to microgravity.

These include muscle atrophy, loss of bone density, a weakened cardiovascular system, etc. Moreover, a return mission could last as long as three years, during which time astronauts would spend at least a year living and working in Martian gravity (36.5% that of Earth). There’s also the risk of elevated radiation exposure astronauts will experience during transits and while operating on the surface of Mars. However, there are also the potential health effects caused by exposure to Martian regolith. As Wang described to Universe Today via email:

“There are many potential toxic elements that astronauts could be exposed to on Mars. Most critically, there is an abundance of silica dust in addition to iron dust from basalt and nanophase iron, both of which are reactive to the lungs and can cause respiratory diseases. What makes dust on Mars more hazardous is that the average dust particle size on Mars is much smaller than the minimum size that the mucus in our lungs is able to expel, so they’re more likely to cause disease.”

During the Apollo Era, the Apollo astronauts reported how lunar regolith would stick to their spacesuits and adhere to all surfaces inside their spacecraft. Upon their return to Earth, they also reported physical symptoms like coughing, throat irritation, watery eyes, and blurred vision. In a 2005 NASA study, the reports of six of the Apollo astronauts were studied to assess the overall effects of lunar dust on EVA systems, which concluded that the most significant health risks included “vision obscuration” and “inhalation and irritation.”

Artist’s depiction of a dust storm on Mars. Credit: NASA

“Silica directly causes silicosis, which is typically considered an occupational disease for workers that are exposed to silica (i.e., mining and construction),” said Wang. “Silicosis and exposure to toxic iron dust resemble coal worker’s pneumoconiosis, which is common in coal miners and is colloquially known as black lung disease.”

Beyond causing lung irritation and respiratory and vision problems, Martian dust is known for its toxic components. These include perchlorates, silica, iron oxides (rust), gypsum, and trace amounts of toxic metals like chromium, beryllium, arsenic, and cadmium – the abundance of which is not well understood. On Earth, the health effects of exposure to these metals have been studied extensively, which Wang and his team drew upon to assess the risk they pose to astronauts bound for Mars in the coming decades:

“It’s significantly more difficult to treat astronauts on Mars for diseases because the transit time is significantly longer than other previous missions to the ISS and the Moon. In this case, we need to be prepared for a wide array of health problems that astronauts can develop on their long-duration missions. In addition, [microgravity and radiation] negatively impact the human body, can make astronauts more susceptible to diseases, and complicate treatments. In particular, radiation exposure can cause lung disease, which can compound the effects that dust will have on astronauts’ lungs.”

In addition to food, water, and oxygen gas, the distance between Earth and Mars also complicates the delivery of crucial medical supplies, and astronauts cannot be rushed back to Earth for life-saving treatments either. According to Wang and his colleagues, this means that crewed missions will need to be as self-sufficient as possible when it comes to medical treatment as well. As with all major health hazards, they emphasize the need for prevention first, though they also identify some possible countermeasures to mitigate the risks:

“Limiting dust contamination of astronaut habitats and being able to filter out any dust that breaks through will be the most important countermeasure. Of course, some dust will be able to get through, especially when Martian dust storms make maintaining a clean environment more difficult. We’ve found studies that suggest vitamin C can help prevent diseases from chromium exposure and iodine can help prevent thyroid diseases from perchlorate.”

Austin Langton, a researcher at NASA’s Kennedy Space Center in Florida, creates a fine spray of the regolith simulant BP-1. Credits: NASA/Kim Shiflett

They also stressed that these and other potential countermeasures need to be taken with caution. As Wang indicated, taking too much vitamin C can increase the risk of kidney stones, which astronauts are already at risk for after spending extended periods in microgravity. In addition, an excess of idione can contribute to the same thyroid diseases that it is meant to treat in the first place. For years, space agencies have been actively developing technologies and strategies to mitigate the risks of lunar and Martian regolith.

Examples include special sprays, electron beams, and protective coatings, while multiple studies and experiments are investigating regolith to learn more about its transport mechanisms and behavior. As the Artemis Program unfolds and missions to Mars draw nearer, we are likely to see advances in pharmacology and medical treatments that address the hazards of space exploration as well.

Further Reading: GeoHealth

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If Intermediate-Mass Black Holes (IMBHs) are real, astronomers expect to find them in dwarf galaxies and globular clusters. There’s tantalizing evidence that they exist but no conclusive proof. So far, there are only candidates.

The Dark Energy Spectroscopic Instrument (DESI) has found 300 additional candidate IMBHs.

Logic says that IMBHs should exist. We know of stellar-mass black holes, and we know of supermassive black holes (SMBHs). Stellar-mass black holes have between five and tens of solar masses, and SMBHs have at least hundreds of thousands of solar masses. Their upper limit is not constrained. Astrophysicists think these black holes are linked in an evolutionary sequence, so it makes sense that there’s an intermediate step between the two. That’s what IMBHs are, and their masses should range from about 100 to 100 thousand solar masses. IMBHs could also be relics of the very first black holes to form in the Universe and the seeds for SMBHs.

The problem is that there are no confirmed instances of them.

Omega Centauri, the brightest globular cluster in the Milky Way, is one of the prime candidates for an IMBH. There’s an ongoing scientific discussion about the cluster and the potential IMBH in its center. Stars in the cluster’s center move faster than other stars, indicating that a large mass is present. Some scientists think it’s an IMBH, while others think it’s a cluster of stellar-mass black holes.

This is Omega Centauri, the largest and brightest globular cluster that we know of in the Milky Way. An international team of astronomers used more than 500 images from the NASA/ESA Hubble Space Telescope spanning two decades to detect seven fast-moving stars in the innermost region of Omega Centauri. These stars provide compelling new evidence for the presence of an intermediate-mass black hole. Image Credit: ESA/Hubble & NASA, M. Häberle (MPIA)

Other evidence for IMBHs comes from a gravitational wave detection in 2019. The wave was generated by two black holes merging. The pair of black holes had masses of 65 and 85 solar masses, and the resulting black hole had 142 solar masses. The other 8 solar masses were radiated away as gravitational waves.

By adding 300 more IMBH candidates to the list, DESI may be nudging us toward a definitive answer about the existence of these elusive black holes.

The 300 new candidates are presented in a paper soon to be published in The Astrophysical Journal. It’s titled “Tripling the Census of Dwarf AGN Candidates Using DESI Early Data” and is available at arxiv.org. The lead author is Ragadeepika Pucha, a postdoctoral researcher at the University of Utah.

The 300 candidate IMBHs are the largest collection to date. Until now, there were only 100 to 150 candidates. This is a massive leap in the amount of available data, and future research will no doubt rely on it to make progress on the IMBH issue.

“Our wealth of new candidates will help us delve deeper into these mysteries, enriching our understanding of black holes and their pivotal role in galaxy evolution.”

Ragadeepika Pucha, University of Utah

The new candidates were identified in DESI’s early data release, which contains data from 20% of DESI’s first year of operations. The data included more than just IMBH candidates. DESI also found about 115,000 dwarf galaxies and spectra from about 410,000 galaxies, a huge number.

This mosaic shows a series of images featuring candidate dwarf galaxies hosting an active galactic nucleus, captured with the Subaru Telescope’s Hyper Suprime-Cam. Image Credit: Legacy Surveys/D. Lang (Perimeter Institute)/NAOJ/HSC Collaboration/D. de Martin (NSF NOIRLab) & M. Zamani (NSF NOIRLab)

The data allowed lead author Pucha and her colleagues to explore the relationship between the evolution of dwarf galaxies and black holes.

Despite their extreme masses, black holes are difficult to find. Their presence is inferred from their effect on their environment. In their presence, stars are accelerated to high velocities. Fast-moving stars were one of the clues showing that the Milky Way has an SMBH.

Astronomers are pretty certain that all massive galaxies like ours host an SMBH in their centers, but this certainty fades when it comes to dwarf galaxies. Dwarf galaxies are so small that our instruments struggle to observe them in detail. Unless the black hole is actively feeding.

When a black hole is actively consuming material, it is visible as an active galactic nucleus (AGN.) AGNs are like beacons that alert astronomers to the presence of a black hole.

“When a black hole at the center of a galaxy starts feeding, it unleashes a tremendous amount of energy into its surroundings, transforming into what we call an active galactic nucleus,” lead author Pucha said in a press release. “This dramatic activity serves as a beacon, allowing us to identify hidden black holes in these small galaxies.”

The team found 2,500 dwarf galaxies containing an active galactic nucleus, an astonishing number. Like the new IMBH candidates, this is the largest sample ever discovered. The researchers determined that 2% of the dwarf galaxies hosted AGN, a big step up from the 0.5% gleaned from other studies.

“This increase can be primarily attributed to the smaller fibre size of DESI compared to SDSS <Sloan Digital Sky Survey>, which aids with the identification of lower luminosity AGN within the same magnitude and redshift range,” the authors explain in their paper.

This artist’s illustration depicts a dwarf galaxy that hosts an active galactic nucleus — an actively feeding black hole. In the background are many other dwarf galaxies hosting active black holes, as well as a variety of other types of galaxies hosting intermediate-mass black holes. Image Credit: NOIRLab/NSF/AURA/J. da Silva/M. Zamani

Astronomers think that black holes found in dwarf galaxies should be within the intermediate-mass range. However, only 70 of the newly discovered IMBH candidates overlap with dwarf AGN candidates. This is unexpected and raises yet more questions about black holes, how they form, and how they evolve within galaxies.

This scatter plot, adapted from the research, shows the number of candidate dwarf galaxies hosting active galactic nuclei (AGN) from previous surveys compared with the number of new dwarf galaxy AGN candidates discovered by the Dark Energy Spectroscopic Instrument (DESI). Image Credit: NOIRLab/NSF/AURA/R. Pucha/J. Pollard

“For example, is there any relationship between the mechanisms of black hole formation and the types of galaxies they inhabit?” Pucha said. “Our wealth of new candidates will help us delve deeper into these mysteries, enriching our understanding of black holes and their pivotal role in galaxy evolution.”

DESI is only getting started. These discoveries were made with only a small portion of data from the instrument’s first year of operation, and there are several more years of operation to come.

“The anticipated increase in the sample of dwarf AGN candidates over the next five years with DESI will accelerate studies of AGN in dwarf galaxies,” the authors write in their research. “The statistical sample of dwarf AGN candidates will be invaluable for addressing several key questions related to galaxy evolution on the smallest scales, including accretion modes in low-mass galaxies and the co-evolution of galaxies and their central BHs,” they conclude.

• Press Release: DESI Uncovers 300 New Intermediate-Mass Black Holes Plus 2500 New Active Black Holes in Dwarf Galaxies
• Research: Tripling the Census of Dwarf AGN Candidates Using DESI Early Data
• Research: Properties and Astrophysical Implications of the 150 M? Binary Black Hole Merger GW190521
• Research: New constraints on the central mass contents of Omega Centauri from combined stellar kinematics and pulsar timing

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There are plenty of types of stars out there, but one stands out for being just a little weirder than the others. You might even say it’s strange. According to a paper from researchers at Guangxi University in China, the birth of one might have recently been observed for the very first time.

A strange star is a (so far theoretical) compact star that is so dense it literally breaks down regular parts of atoms (like neutrons) into their constituent quarks. Moreover, even those quarks (the up and down that comprise a neutron) get compressed into an even rarer type of quark called a strange quark – hence the name strange star.

Technically, the “strange” matter that a strange star would be composed of is a combination of up, down, and strange quarks. But, at least in theory, this mix of sub-hadronic particles could even be more stable than a traditional neutron star, which is similar to a strange star but doesn’t have enough gravity to break down the neutrons.

Fraser discusses strange stars.

Strange stars, though they exist in theory, are exceedingly rare. No one has ever proven that one exists. But Xiao Tian and his co-authors think they might have found evidence of one.

Their paper describes a recent gamma-ray burst known as GRB 240529A that they think holds the clues to finding a strange star. Gamma-ray bursts, the gigantic implosions that sometimes result from creating a black hole, could also have other causes – or “central engines,” as they are called in the literature. One such central engine is the creation of a magnetar.

Magnetars are another type of neutron star that is even more extreme. Their magnetic fields could be up to 1,000 times that of a typical neutron star, giving them the largest magnetic fields in the known universe. In them, electrons and protons are forced together to create neutrons, hence the name neutron star.

Fraser discusses magnetars, the type of star that would theoretically collapse into a strange star.

However, they could also collapse upon themselves, as a part of cosmological theory allows for a magnetar to collapse into an even more dense form, which would be something akin to a strange star with the requisite mix of quarks. Doing so would undoubtedly produce a gamma-ray burst, which Dr. Tian and his co-authors believe they found in GRB 240529A.

The details of that particular GRB hold the clues. There were three distinct “emission episodes” that represented different phases of the collapse to a magnetar, then to a strange star, and then the spin-down of the strange star. A different spectrum of gamma rays represents each as part of the burst, and each episode was separated by a few hundred seconds of relative calm, which seems like an exceedingly short time considering how massive the objects were collapsing. 

Moreover, in the X-ray spectrum, another part of the light curve could be described as containing “plateaus.” According to the authors, each of these plateaus could represent a stage in the birth of the strange star, with the first representing its cooling and the second representing its “pin down” phase.

According to their calculations, the observed data best matches the theoretical values that would be seen if GRB represented the birth of a strange star. So it seems likely that, for the first time, astronomers have garnered some evidence to support a theory that was initially developed in the 1980s. But, as always, more testing is needed, and other researchers should confirm the authors’ calculations. But if they do, it would be a significant leap forward in experimental astrophysics – and may herald many more strange findings to come.

Learn More:
Tian et al – Signature of strange star as the central engine of GRB 240529A
UT – It Takes Very Special Conditions to Create This Bizarre Stellar Spectacle
UT – SLS Hurricanes, James Webb Fixed, Strange Quark Star
UT – The Mysterious Case of the Resurrected Star

Lead Image:
Illustration of the interior of a neutron star and a strange quark star
Credit – NASA/SAO/CXC/J.Drake et al.

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As far as we can tell, life needs water. Cells can’t perform their functions without it. Some have suggested that other exotic liquids, like liquid methane, could do the job on worlds like Saturn’s moon Titan. That idea is highly speculative, though.

So, it makes sense that NASA is launching a spacecraft dedicated to the search for water.

SPHEREx stands for Spectro-Photometer for the History of the Universe, Epoch of Reionization, and Ices Explorer. It’s scheduled to launch on February 27th. It has a single instrument and one observing mode. Part of its mission is to map the sky in near-infrared and measure the spectra of 450 million galaxies. The results will help scientists understand the expansion of the Universe and the origin and evolution of galaxies.

This image shows a semi-frontal view of the SPHEREx observatory during integration and testing at BAE Systems (Boulder, CO). Image Credit: NASA/JPL-Caltech.

Its other scientific goal is to probe molecular clouds for water ice and other frozen pre-biotic molecules. These ices are frozen onto the surface of dust grains in molecular clouds, and somehow, through a long journey, they become part of planets, where they can form oceans and potentially foster the appearance of life.

Infrared observations show that in cold, dense regions of space in molecular clouds, chemicals critical to life are locked into dust grains. Water is the primary one, of course, but there are other pre-biotic molecules as well: carbon dioxide (CO2), carbon monoxide (CO), methanol (CH3OH), the nitrogen-bearing molecule ammonia (NH3) plus various carbon-nitrogen stretch molecules (XCN), and the important sulphur-bearing molecule, carbonyl sulphide (COS). Carbon-nitrogen stretch molecules are everywhere in organic and biological molecules and play critical roles in biological processes. Carbonyl-sulphide plays a role in the formation of peptides, which are the building blocks of proteins.

There’s a vast amount of water frozen in dust grains in molecular clouds, and scientists think this is where the bulk of the water in the galaxy and even in the Universe resides. These grains are the source of water for Earth’s oceans and for any exoplanets or moons that might harbour oceans.

SPHEREx will examine molecular clouds and try to understand how much water they contain. It will also examine stars in those clouds and the rings of material that form around them, out of which planets form.

Put succinctly, SPHEREx is trying to answer this question: How does ice content evolve from diffuse clouds to dense clouds to planetary disks and then to planets?

This photo by renowned astrophotographer Rogelio Bernal Andreo shows the Orion constellation and the surrounding nebulas of the Orion Molecular Cloud complex. The clouds in the complex hold frozen water and other chemicals critical to life. Image Credit: By Rogelio Bernal Andreo – http://deepskycolors.com/astro/JPEG/RBA_Orion_HeadToToes.jpg, CC BY-SA 3.0, https://commons.wikimedia.org/w/index.php?curid=20793252

There’s little doubt that ices play an important role in the formation of planetesimals in disks around young stars. Likewise, there’s little doubt that these ices are sources of water and organic molecules, too. But how does it all happen? Ice’s journey from translucent to dense molecular clouds and then to protoplanetary disks is not well understood. Scientists want to know if the ices in the disks are simply inherited from the interstellar medium or if they’re altered in the disks somehow.

The SPHEREx mission hopes to answer this question and others with its infrared absorption spectroscopy.

SPHEREx will generate spectra for between 8 and 9 million sources and should transform our understanding of ices in molecular clouds, young stellar objects, and protoplanetary disks.

In infrared wavelengths, ices have unique spectral signatures. Prior to the JWST, scientists had only about 200 ice absorption spectra available. The JWST is changing that, but it has lots of other important work to do.

The JWST is already advancing our understanding of these ices. Like other infrared observatories, it can see through dust, but it is far more powerful and sensitive. A key to SPHEREx’s design and performance is its ability to be as accurate as the JWST.

The black line is the JWST spectrum of a source seen through a thick molecular cloud of interstellar dust, showing the strong features of the interstellar ice species H2O, CO2, and CO at wavelengths of 3.05, 4.27, and 4.67 microns (McClure et al. 2023, Nature Astronomy, 7, 431). Overlaid in red is a simulated spectrum, taken with SPHEREx’s lower spectral resolving power, of a background source with 100x the JWST brightness in the SPHEREx range that shows the same absorption features as seen by JWST. Note that SPHERE reproduces almost all of the spectral structure apparent in the JWST spectrum. Image Credit: NASA/JPL

There is no shortage of targets for SPHEREx. Some research shows that there are over 8,000 molecular clouds in the Milky Way. Not all of them are great targets for SPHEREx, but many are.

SPHEREx has a catalogue of targets that includes molecular clouds in the Large and Small Magellanic Clouds and several constellations, including Monoceros, home of the Monoceros R2 Molecular Cloud.

The Monoceros R2 Molecular Cloud is one of SPHEREx’s targets. This image shows only a portion of the cloud, which is a large cloud with lots of active star formation. Star formation is particularly active in the location of the bright red nebula just below the center of the image. This image was obtained with the wide-field view of the Mosaic II camera on the Blanco 4-meter telescope at Cerro Tololo Interamerican Observatory on January 11th, 2012. Image Credit: T.A. Rector (University of Alaska Anchorage) and N.S. van der Bliek (NOIRLab/NSF/AURA)

It’s axiomatic that stars and planets have the same compositions as the molecular clouds that fostered them. But the specifics of planet formation are mysterious and the study of the processes has produced some surprises.

In 1998, NASA launched the Submillimeter Wave Astronomy Satellite (SWAS). Similar to SPHEREx, it studied the chemical composition of interstellar clouds and surveyed the galaxy to determine how much water vapour was present in molecular clouds. Surprisingly, it found far less than expected.

“This puzzled us for a while,” said Gary Melnick, a senior astronomer at the Center for Astrophysics | Harvard & Smithsonian and a member of the SPHEREx science team. “We eventually realized that SWAS had detected gaseous water in thin layers near the surface of molecular clouds, suggesting that there might be a lot more water inside the clouds, locked up as ice.”

The SWAS team figured out that hydrogen and oxygen atoms were being frozen onto the surfaces of ice grains where they formed water ice. Subsequent research confirmed their suspicions. On the unprotected surfaces of molecular clouds, cosmic radiation can break the H2O molecules apart, but protected inside molecular clouds, the molecules persisted.

The water ice and other ices create spectroscopic signatures separate from their liquid counterparts, and SPHEREx is designed to detect them.

It will do more than detect them, though. The spacecraft will also determine how deep inside the clouds the ices form, how their abundance changes with cloud density, and how the abundance changes when a star forms.

SPHEREx will also cooperate with other telescopes, including the JWST, which will perform more powerful follow-up observations when merited.

“If SPHEREx discovers a particularly intriguing location, Webb can study that target with higher spectral resolving power and in wavelengths that SPHEREx cannot detect,” said Melnick. “These two telescopes could form a highly effective partnership.”

SPHEREx will launch on February 27th in a Falcon Heavy rocket from Vandenberg Air Base. It will follow a Sun-Synchronous orbit at about 700 km altitude. In its nominal 25-month mission, SPHEREx will map the entire sky four times.

• Press Release: NASA’s SPHEREx Space Telescope Will Seek Life’s Ingredients
• CalTech SPHEREx Science
• An All-Sky Spectral Survey
• The Astrophysical Journal: The SPHEREx Target List of Ice Sources (SPLICES)
• JPL: The Origin of Water – and Other Pre-biotic Molecules – in Planetary Systems

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Dubbed CADRE, a trio of lunar rovers are set to demonstrate an autonomous exploration capability on the Moon.

An exciting Moon mission launching in the next year will perform a first, deploying multiple rovers. These will talk to each other and a remote base station, demonstrating an autonomous exploration capability.

The three Cooperative Autonomous Distributed Robotic Exploration (CADRE) rovers were recently packaged and shipped from their home at NASA’s Jet Propulsion Laboratory in Pasadena, California. Each about the size of a small suitcase, the CADRE rovers will launch from LC-39A at the Kennedy Space Center in Florida on a SpaceX Falcon-9 rocket with Intuitive Machines’ IM-3 mission in late 2025 or early 2026. The ultimate destination is the enigmatic Reiner Gamma region in the Oceanus Procellarum (Ocean of Storms) region on the lunar nearside.

Robotic lunar rovers go all the way back to the late Soviet Union’s Lunokod-1 rover on the Luna 17 mission in 1970. CADRE, however, will demonstrate that three rovers can work in unison for lunar exploration. This sort of rover network could come in handy, allowing astronaut controllers to one day explore regions too dangerous to venture into.

A CADRE rover undergoes a vibration test ahead of launch. Credit: NASA/JPL A Robotic Lunar Trio

To this end, the Nova-C lander will lower the solar-powered rovers to the surface shortly after touchdown. Engineers equipped each rover with cameras and ground-penetrating radars for exploration. Controllers expect the rovers to last two weeks (14 days) on the surface, from local sunrise to sunset.

“Our small team worked incredibly hard constructing these robots and putting them to the test,” says Coleman Richdale (NASA-JPL) in a recent press release. “We are all genuinely thrilled to be taking this next step in our journey to the Moon, and we can’t wait to see the lunar surface through CADRE’s eyes.”

This will mark Intuitive Machines’ third delivery to the lunar surface. Part of NASA’s CLPS (Commercial Lunar Payload Services) initiative, The company’s IM-1 mission and Nova-C lander Odysseus made an askew landing at the Malapert A crater early last year. The company will make another attempt with the launch of IM-2 next week on February 26th. The mission will carry NASA’s PRIME-1 (Polar Resources and Ice Mining Experiment) with The Regolith and Ice Drill for Exploring New Terrain (TRIDENT) 1-meter drill. The mission is headed to the Shackleton connecting ridge site in the lunar South Pole region.

A Mars rover twin versus a CADRE rover at JPL’s ‘Mars Yard’. Credit: NASA/JPL

Meanwhile, another CLPS mission, Firefly Aerospace’s Blue Ghost will land on the Moon on March 2nd.

The Reiner Gamma landing site is a high priority target for exploration. Astronomers recognize the feature as one of the best known examples of a ‘lunar swirl’. It’s also a known site for localized magnetic anomalies. What causes swirls on the lunar surface isn’t entirely clear. They definitely stand out in stark contrast to the typical pockmarked, cratered surface of the Moon.

The location of the Reiner Gamma landing site on the lunar nearside. Credit: Dave Dickinson (inset: NASA/LRO). What Else is Aboard IM-3?

In addition to CADRE, several other experiments are hitching a rideshare trip to the Moon aboard IM-3. These include Lunar Vertex (LVx), a joint lander-rover also looking to explore the magnetic anomalies of Reiner Gamma, and the Korea Astronomy Space Science Institute (KASI)’s Lunar Space Environment Monitor (LUSEM) which will monitor the near-surface space environment on the Moon. Also on board is a pointing actuator experiment for the European Space Agency’s MoonLIGHT network. This is a precursor to the agency’s Lunar Geophysical Network for laser ranging and pinpoint measurements.

The CADRE Team plus the trio of rovers, headed to the Moon. Credit: NASA/JPL-Caltech

The Moon is about to become a busy place. It’ll be exciting to see CADRE and other missions resume lunar exploration in the coming years.

The post CADRE’s Three Adorable Rovers Are Going to the Moon appeared first on Universe Today.

Astronomers have identified sulfur as a potentially crucial indicator in narrowing the search for life on other planets. While sulfur itself is not necessarily an indication of habitability, significant concentrations of sulfur dioxide in a planet’s atmosphere can suggest that the planet is likely uninhabitable, allowing researchers to eliminate it from further consideration.

The discovery of extraterrestrial life remains one of the most sought-after objectives in modern astronomy. However, this is a formidable challenge. The James Webb Space Telescope is unlikely to detect biosignatures—atmospheric gases produced by living organisms—in nearby planets. Similarly, the upcoming Habitable Worlds Observatory will only be able to assess a limited number of potentially habitable exoplanets.

One of the primary obstacles astronomers face is the typically faint nature of biosignature spectra. To address this, they focus on the potential for planets to host life, particularly through the presence of water vapor in their atmospheres. A planet with substantial water vapor may be more likely to support life.

This concept is encapsulated in the “Habitable Zone,” the region around a star where a planet receives just the right amount of radiation: not too little to freeze all water, and not too much to boil it away. In our solar system, Venus lies near the inner edge of the Habitable Zone with surface temperatures exceeding 800 degrees Fahrenheit beneath a dense atmosphere, while Mars resides primarily outside the zone, its water largely trapped in polar ice caps and subsurface reservoirs.

However, detecting water alone poses challenges. For instance, distinguishing between Earth and Venus based solely on atmospheric spectra is difficult due to their similarities when only searching for water vapor.

Recently, a team of astronomers has identified another potentially useful indicator gas for differentiating uninhabitable from possibly habitable worlds: sulfur dioxide. Warm, wet planets like Earth contain minimal sulfur dioxide because it is washed out of the atmosphere by rain. Conversely, Venus also has little detectable sulfur dioxide, as ultraviolet radiation from the Sun converts it into hydrogen sulfide in the upper atmosphere, driving it downwards.

Planets orbiting red dwarf stars present another scenario. These stars emit minimal ultraviolet radiation, allowing sulfur dioxide to persist in the upper atmospheres of dry, uninhabitable planets. Red dwarfs are of particular interest because they are the most common type of star in the galaxy, and many nearby systems, such as Proxima Centauri and TRAPPIST-1, host planets around red dwarfs, making them prime targets for future searches for life.

This new approach involving sulfur dioxide does not identify planets that might harbor life but helps exclude those that likely do not. If significant sulfur dioxide is detected in the atmosphere of a rocky planet orbiting a red dwarf, it suggests a dry, hot world with a thick atmosphere and little to no water, akin to Venus. Such planets can be deprioritized in the search for life.

Conversely, the absence of significant sulfur dioxide may indicate a planet worth further observation for signs of water vapor and potential life.

The quest to find life on other planets will require extensive investigative efforts and unwavering determination. Any method, including the analysis of sulfur dioxide levels to streamline candidate lists, is highly valuable in this endeavor.

The post What’s That Smell? It’s Sulfur – A New Tool For Finding Alien Life appeared first on Universe Today.

Biologists identified a series of “hard steps” on the journey from abiogenesis – that life evolved naturally from non-living matter – to modern civilisation. These steps, such as the evolution of multi-cellular organisms or even language make the stark suggestion that intelligent life is highly improbable! Instead, the researchers propose that human-like life could be a natural outcome of planetary evolution, increasing the likelihood of intelligent life elsewhere. 

The hard-steps model of the evolution of life suggests that the development of complex life depends on a series of highly improbable events, or “hard steps,” that must occur in a specific order. Each step marks a major evolutionary transition—such as complex cells, multicellularity, and intelligence. These steps are rare and require precise conditions, according to the theory, making complex life an unlikely outcome. This model explains why intelligent life seems so scarce, despite the vast number of potentially habitable planets, as the long timescales for each step contribute to its rarity.

An artist’s conception of Tau Ceti e, a possible ‘exo-Earth’ in the habitable zone. Ph03nix1986/Wikimedia Commons/CCA 4.0

The model was originally developed in 1983 by Brandon Carter, an Australian theoretical physicist. It’s conclusion has now been challenged by a team of scientists including astrophysicists and astrobiologists. They argue that the inhospitable young Earth would have gone through environmental changes and it was these that facilitated the ‘hard-steps.’ An example of this is the requirement for complex animal life on a certain level of oxygen in the atmosphere. Before the atmosphere could sustain the levels of oxygenation it was difficult for complex life to evolve, after the event, the liklihood was for greater. 

A view of Earth’s atmosphere from space. Credit: NASA

In their new study, the researchers suggested that the evolution of humans can be associated to the gradual emergence of “windows of habitability” throughout Earth’s history. These windows are thought to have been influenced by shifts in nutrient availability, sea surface temperatures, ocean salinity, and atmospheric oxygen levels. They explained that, considering all these factors, Earth has only recently become suitable for human life.

The collaborative paper between disciplines was effective due to the learning gained from each other’s fields. It developed a new picture of how life evolved on the Earth. The team plan to test their new model which even questions the ‘hard steps’ theory. They suggest other pieces of work that will help to corroborate – or otherwise – their theory such as the search for biosignatures in exoplanetary atmospheres. They also suggest it would be suitable to test the requirements for the so called ‘hard steps’ and try to understand just how hard they really are. Using unicellular and multicellular forms of life, the team want to explore the impact of specific environmental conditions. 

The team are keen to explore other innovations within multicellular Homo sapiens, photosynthesis and eukaryotic cellular environment. It’s possible that similar innovations may have evolved independently in the past. Although the researchers acknowledge that extinction events may have eradicated such evidence. 

Source : Does planetary evolution favor human-like life? Study ups odds we’re not alone

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The supermassive black hole at the center of our Milky Way galaxy may not be as voracious as the gas-gobbling monsters that astronomers have seen farther out in the universe, but new findings from NASA’s James Webb Space Telescope reveal that its surroundings are flaring with fireworks.

JWST’s readings in two near-infrared wavelengths have documented cosmic flares that vary in brightness and duration. Researchers say the accretion disk of hot gas surrounding the black hole, known as Sagittarius A*, throws off about five or six big flares a day, and several smaller bursts in between.

The observations are detailed today in The Astrophysical Journal Letters.

“In our data, we saw constantly changing, bubbling brightness. And then boom! A big burst of brightness suddenly popped up. Then, it calmed down again,” study lead author Farhad Yusef-Zadeh of Northwestern University in Illinois said in a news release. “We couldn’t find a pattern in this activity. It appears to be random. The activity profile of this black hole was new and exciting every time that we looked at it.”

Yusef-Zadeh and his colleagues observed Sagittarius A* using JWST’s Near-Infrared Camera, or NIRCam, for a total of 48 hours, broken up into eight- to 10-hour increments over the course of a year. They expected to see flares, but they didn’t expect the black hole’s surroundings to be as active as they are.

The researchers suggest that two separate processes are sparking the light show. The smaller flares may be due to turbulence in the accretion disk, compressing the disk’s hot, magnetized gas. Such disturbances could throw off brief bursts of radiation that Yusef-Zadeh likens to solar flares.

“It’s similar to how the sun’s magnetic field gathers together, compresses and then erupts a solar flare,” he explained. “Of course, the processes are more dramatic because the environment around a black hole is much more energetic and much more extreme.”

The bigger bursts could be due to magnetic reconnection events. That would occur when two magnetic fields collide, throwing off bright blasts of particles that travel at velocities near the speed of light. “A magnetic reconnection event is like a spark of static electricity, which, in a sense, also is an ‘electric reconnection,’” Yusef-Zadeh said.

Another unexpected finding has to do with how the flares brighten and dim when seen in two different wavelengths. Events observed at the shorter wavelength changed brightness slightly before the longer-wavelength events.

“This is the first time we have seen a time delay in measurements at these wavelengths,” Yusef-Zadeh said. “We observed these wavelengths simultaneously with NIRCam and noticed the longer wavelength lags behind the shorter one by a very small amount — maybe a few seconds to 40 seconds.”

Those observations could serve as clues to the physical processes at work in the disk swirling around the black hole. It could be that the particles thrown off by the flares lose energy more quickly at shorter wavelengths than at longer wavelengths. That’s the pattern you’d expect for particles spiraling around magnetic field lines in a cosmic synchrotron.

Now researchers are hoping to get a longer stretch of time on JWST, which should help them reduce the noise in their observations and produce a more detailed picture of what’s going on at the center of our home galaxy.

“When you are looking at such weak flaring events, you have to compete with noise,” Yusef-Zadeh said. “If we can observe for 24 hours, then we can reduce the noise to see features that we were unable to see before. That would be amazing. We also can see if these flares repeat themselves, or if they are truly random.”

In addition to Yusef-Zadeh, the authors of the study in The Astrophysical Journal Letters, “Nonstop Variability of Sgr A* Using JWST at 2.1 and 4.8 ?m Wavelengths: Evidence for Distinct Populations of Faint and Bright Variable Emission,” include H. Bushouse, R.G. Arendt, M. Wardle, J.M. Michail and C.J. Chandler.

The post Webb Space Telescope Tracks Fireworks Around Our Galaxy’s Black Hole appeared first on Universe Today.

For those who missed the memo, UFOs (Unidentified Flying Objects) are now called UAPs (Unidentified Aerospace-Undersea Phenomena). The term UFO became so closely tied to alien spacecraft and fantastical abduction stories that people dismissed the idea, making any serious discussion difficult. The term UAP is a broader term that encompasses more unexplained objects or events without the alien spaceship idea truncating any useful or honest discussion.

While the name change is helpful, it’s just the beginning. We need a way to study UAPs scientifically, and new research shows us how.

Though the idea of alien spacecraft visiting us isn’t always taken very seriously, the effort to document UAP and understand them goes back decades. In current times, governments around the world have made more serious efforts to understand what’s behind the phenomena. Most notably, NASA recently initiated a study into UAP called the Unidentified Anomalous Phenomena Independent Study and released its final report in September 2023.

New research aims to explore past efforts, dispel some misunderstandings, and enable future research into UAP.

The research is titled “The New Science of Unidentified Aerospace-Undersea Phenomena (UAP).” The lead author is Kevin Knuth from the Department of Physics at the State University of New York at Albany. The research is available on the pre-press site arxiv.org.

“After decades of dismissal and secrecy, it has become clear that a significant number of the world’s governments take Unidentified Aerospace-Undersea Phenomena (UAP), formerly known as Unidentified Flying Objects (UFOs), seriously–—yet still seem to know little about them,” the authors write. “As a result, these phenomena are increasingly attracting the attention of scientists around the world, some of whom have recently formed research efforts to monitor and scientifically study UAP.”

Many UAP have good explanations, like this image from the Apollo 16 mission to the moon that shows what may look like a flying saucer. In 2004, NASA said it was the spacewalk floodlight/boom that was attached to the Apollo spacecraft. Image Credit: NASA

The authors review about 20 historical studies, some done by governments and others by private researchers, between 1933 and the present. Countries include the USA, Canada, France, Russia, and China. Their goal is to summarize and clarify the scientific narrative around UAPs. “Studies range from field station development and deployment to the collection and analysis of witness reports from around the world,” the authors write.

The main obstacle to studying UAPs is that they’re neither repeatable nor controllable. Another problem is that witness reports are unreliable, often explained away as natural phenomena, or dismissed outright by citizens, scientists, and governments. This has dissuaded serious discussion and study and left us in “a rather disconcerting state of ignorance,” the authors write.

Ignorance is seldom desirable, though it can sometimes provide a false sense of relief. Being disconcerted is likewise undesirable. What can be done?

“The problem and opportunity that we face today is that the situation has changed dramatically,” according to the authors. We now know that the US Defense Intelligence Agency (DIA) conducted a covert, six-year program called the Advanced Aerospace Threat Identification Program (AATIP) to study UAP. With 50 full-time investigators, the AATIP dwarfed other UAP efforts. The AATIP focused on military-only encounters and considered things like psychic and paranormal phenomena correlated with UAP events. The AATIP created a massive amount of data on UAP that encompassed more than 200,00 cases. (Alarmingly, the effort also produced more than 200 research papers, some over 100 pages long, and none of them have ever been seen by the public or by the US Congress.)

This proves that the effort to study and understand UAP has gained traction and moved from the fringe to the mainstream. It’s a signal that UAP research could see increased funding and resources. According to the researchers, that means there needs to be a coordinated effort. The effort needs to be scientific, and data needs to be shared among researchers.

The geographic distribution of UFO sightings. One of the puzzling things about sightings is that they’re not distributed in any way that makes sense. Does culture play a role? Image Credit: sammonfort3

Enough research has been done to make the next steps clear.

“It is generally agreed that the optimal methodology to study UAP relies on many different types of instruments, spatially separated, to dramatically reduce the possibility of error,” the authors write. “This is the only way in which the scientific community will recognize truly anomalous data.” The authors say that multi-messenger astronomy, in which objects are studied across wavelengths with multiple telescopes, is a good model for the future study of UAP.

Rigor is required for UAP studies and data to be taken seriously. One group arguing in favour of more UAP scientific research is the UAlbany-UAPx Collaboration, an organization that the lead author of this research, Kevin Knuth, is involved with. They developed rigorous definitions of what detections constitute a UAP and recommended that “at least two of each type of sensor and 2+ distinct sensor types” be used in the effort to study UAP.

The future effort to understand UAP must migrate in from the fringes and adhere to scientific standards in other disciplines. “This way, one rigorously quantifies the meaning of extraordinary evidence, in the same way it has been done historically by particle physicists, who have established a very high bar to clear,” the authors write.

The researchers also explain how our burgeoning fleet of satellites could play a larger role in the study of UAP. “UAP researchers are now considering the air and space domains as open-air laboratories, utilizing these vast environments for systematic scientific inquiry,” they write.

Throughout most of history, satellite data has been restricted to large governments and their defence and military organizations. But their monopoly on the data is withering away. Satellite imagery and data are routinely shared with the public and are freely available for scientific use. Coinciding with greater accessibility is greater quality. “Thanks to significant technological advancements and the proliferation of commercial satellite services, access to satellite data has expanded dramatically. In addition, rapid advances in information and communication technologies have opened new avenues for many more actors,” the authors explain.

This image shows one of the NOAA’s Geostationary Operational Environmental Satellites (GOES)–R Series. It’s the Western Hemisphere’s most sophisticated weather-observing and environmental monitoring system. The GOES-R Series provides advanced imagery and atmospheric measurements, real-time mapping of lightning activity, and monitoring of space weather. Could satellites like it be used in the scientific study of UAPs? Image Credit: NOAA

Though current satellites aren’t aimed at studying UAP, their sensors can be used to examine environments near reported UAP. This brings up another parallel between astronomy and UAP. We have telescopes that scan the sky for transients and when they detect one, they send out urgent messages to other telescopes suited for follow-up observations. The same arrangement could work in the study of UAP.

Advancements in science and astronomy can also benefit the study of UAP. Tools such as cloud computing, artificial intelligence (AI), and machine learning (ML) now enable scientists to gather, store, transmit, and analyze data more efficiently than ever before,” the authors write. There’s an ongoing democratization of data sharing that can be leveraged in the study of UAP.

UAP are not one thing. Only a dedicated, serious effort to understand them as they appear can determine if there’s something there deserving of deeper study. The authors argue that a “paradoxical loop of dismissal in mainstream science” is preventing progress. The paper outlines a way to cancel that paradox based on the sound methods of the scientific method.

The problem is that detecting them scientifically requires a very wide net of detectors and significant resources over long periods of time. That, again, parallels how we do other science. “Only long-term, transgenerational research programs, such as enjoyed by many research programs well established and stabilized within academic science now for many decades, can possibly yield the proper data on which a potential resolution to UAP can be founded,” the authors write.

However, we’re not starting from scratch.

“Our aim here is to enable future studies to draw on the great depth of prior documented experience,” the researchers explain.

Research: The New Science of Unidentified Aerospace-Undersea Phenomena (UAP)

The post What Would Actual Scientific Study of UAPs Look Like? appeared first on Universe Today.

The Phoenix Cluster is one of the most massive galaxy clusters known. Astronomers have identified 42 member galaxies so far, yet there could be as many as 1,000 in the cluster. Because of its size and its age, it should be finished with the vigorous star formation characteristic of young galaxies.

But it’s not.

Star formation needs cold, dense gas. Hot gas resists collapsing into stellar cores, which become protostars and then main sequence stars. Old galaxies and clusters have either used up their cold gas or had it stripped away. These are called ‘quenched’ galaxies. In terms of star formation, galaxies can be classified as red sequence, meaning old and quenched, or blue cloud, meaning there’s more active star formation.

The Phoenix Cluster’s central galaxy is about 5.8 billion light-years away and should be mostly done with star formation. Many galaxy clusters have a region of hot gas in the intracluster medium (ICM). In a typical galaxy, this gas cools down and feeds star formation. However, observations show that the rate of star formation in these galaxies is remarkably low, and there’s no evidence of the cold gas. Astronomers call this discrepancy the “cooling flow problem,” and it leads to this question: Why isn’t the ICM cooling and forming new stars?

The dominant answer to this is that black hole jets from active galactic nuclei are heating the gas and preventing it from forming stars.

The Phoenix Cluster’s central galaxy should be mostly done with star formation. Yet it has an intensely bright core typical of vigorous star formation. Somehow, the Phoenix Cluster has a source of cold gas that’s fuelling the star birth. Did it generate itself somehow? Is it funnelling in from younger galaxies?

In new research, scientists used the JWST to probe the cluster’s heart. They did so because previous observations with other telescopes showed that the core was extraordinarily bright, indicating ferocious star birth. Since this contradicted what astronomers think they know about clusters like this, their curiosity was piqued.

The research, published in Nature, is titled “Directly imaging the cooling flow in the Phoenix cluster.” The lead author is Michael Reefe, a physics graduate student at MIT’s Kavli Institute for Astrophysics and Space Research.

This older image of the Phoenix Cluster (SPT-CLJ2344-4243) combines Chandra and Hubble’s X-ray, ultraviolet, and optical wavelengths. In this new research, the team of scientists used the JWST’s infrared capabilities to try to understand Phoenix better. Image Credit: By X-ray: NASA/CXC/MIT/M.McDonald et al; Optical: NASA/STScI – https://chandra.harvard.edu/photo/2015/phoenix/ (image link), Public Domain, https://commons.wikimedia.org/w/index.php?curid=45952066

Michael McDonald, associate professor of physics at MIT and co-author of this research, led the research team that discovered the Phoenix Cluster in 2010 using the South Pole Telescope. Two years later, they observed it again with multiple telescopes. They found that the central galaxy in the cluster was unexpectedly bright due to extreme star formation. The researchers said that up to 1,000 stars could be forming each year, an astounding number compared to the Milky Way, which forms fewer than 10 stars per year according to some research.

In previous observations, astronomers have found some very hot gas and some very cold gas in the Phoenix Cluster. They have observed pockets of ultrahot gas measuring about 1 million degrees Fahrenheit and regions of extremely cold gas measuring only 10 kelvins, or 10 degrees above absolute zero. Hot gas is not unusual since supermassive black holes (SMBHs) can emit extremely energetic jets that can heat gas. When a galaxy is young, some of this gas cools and forms stars. The Phoenix Cluster’s central galaxy also has some cool gas. Previous observations showed that there was no in-between warm gas, which is odd. Is there an answer to the cooling flow problem in the Phoenix Cluster?

The researchers reasoned that if the Phoenix central galaxy is somehow generating the detected cold gas, then there must be warm gas that’s intermediate between the hot gas and the cold gas. This is where the JWST enters the picture.

The JWST, with its powerful infrared capabilities, did find some warm gas. That shows that the cluster is able to generate the cold gas needed for star formation because the warm gas is evidence of a transition between temperature extremes.

New JWST observations, based on neon emissions, provided the first large-scale map of gas at temperatures between 100,000 and 1,000,000 Kelvin in the Phoenix Cluster. They used the Medium-Resolution Spectrometer on MIRI and collected 12 hours of infrared data. They were looking for a specific wavelength of light emitted by neon at around 300,000 K, or 540,000 F. This shows the presence of the intermediate warm gas that would be evidence of cooling.

Critically, the neon is co-spatial with other features like the coolest gas and the sites of active star formation. This is evidence supporting a direct link between intermediate gas, its cooling, and star formation.

“This 300,000-degree gas is like a neon sign that’s glowing in a specific wavelength of light, and we could see clumps and filaments of it throughout our entire field of view,” lead author Reefe said in a press release. “You could see it everywhere.”

The three panels in this figure from the study go to the heart of the research. They’re maps of the [Ne VI]-emitting coronal gas in the central galaxy of the Phoenix cluster overlaid with the hotter and colder gas phases and starlight. (a) shows Ne VI flux, which indicates cooling gas. (b) shows an [O II] image of the central galaxy of the Phoenix cluster in the greyscale using data from the HST Advanced Camera for Surveys. It indicates star formation. (c) shows young, actively star-forming regions in blue. Image Credit: Reefe et al. 2025

“For the first time, we have a complete picture of the hot-to-warm-to-cold phase in star formation, which has really never been observed in any galaxy,” said Reefe. “There is a halo of this intermediate gas everywhere that we can see.”

The fact that astronomers were unable to see the telltale warm gas in the Phoenix Cluster doesn’t mean it wasn’t there. The JWST gives researchers their best look at galaxies, uncovering details that were previously hidden. Still, the question that has to be asked is whether Phoenix is special. Will the JWST find the telltale warm gas in other galaxies?

“The question now is, why this system?” added co-author McDonald. “This huge starburst could be something every cluster goes through at some point, but we’re only seeing it happen currently in one cluster. The other possibility is that there’s something divergent about this system, and the Phoenix went down a path that other systems don’t go. That would be interesting to explore.”

“Previous to the Phoenix, the most star-forming galaxy cluster in the universe had about 100 stars per year, and even that was an outlier. The typical number is one-ish,” McDonald said. “The Phoenix is really offset from the rest of the population.”

This brings us to one of the unanswered questions about old galaxies. They should be quenched or “red and dead,” but all of them aren’t. Where did this cold gas come from? Did it come from outside these galaxies?

“The question has been: Where did this cold gas come from?” McDonald said. “It’s not a given that hot gas will ever cool, because there could be black hole or supernova feedback. So, there are a few viable options, the simplest being that this cold gas was flung into the center from other nearby galaxies. The other is that this gas somehow is directly cooling from the hot gas in the core.”

The fact that the [Ne VI] emissions are cospatial with the sites of active star formation suggests a recent episode of rapid gas cooling, creating a spike in cooling. The researchers say this extreme cooling us generating 20,000 solar masses of cold gas each year. That shows that the galaxy is able to supply its own cold gas for star formation and that it’s not coming from elsewhere. The question is, how?

The results suggest that somehow, the central black hole is actually promoting cooling the gas rather than heating it. “These data provide a large-scale map of gas at temperatures between 105 kelvin and 106 kelvin in a cluster core and highlight the critical role that black hole feedback has in not only regulating cooling but also promoting it,” the authors write. “

An artist’s conception of a supermassive black hole’s jets. These jets may play a role in cooling gas rather than heating it. Image Credit: NASA / Dana Berry / SkyWorks Digital

The research answers part of the question that the Phoenix Cluster poses.

“If short-lived cooling episodes are common in the galaxy cluster population, providing the necessary fuel for ongoing AGN feedback, then Phoenix provides a unique window into this critically important, but rarely captured, process for understanding the formation of the most massive galaxies in the Universe,” the authors write in their conclusion.

“I think we understand pretty completely what is going on, in terms of what is generating all these stars,” McDonald said. “We don’t understand why. But this new work has opened a new way to observe these systems and understand them better.”

• Press Release: Study reveals the Phoenix galaxy cluster in the act of extreme cooling
• Research: Directly imaging the cooling flow in the Phoenix cluster

The post This Ancient Galaxy Cluster is Still Forming Stars When it Should be ‘Red and Dead’ appeared first on Universe Today.

We typically think of the Oort cloud as scattered ice balls floating far from the Sun, yet still tied to it gravitationally. Occasionally, some wayward gravitational perturbation will knock one of them a weird way and create a long-period comet, which might briefly delight us lowly humans by providing something interesting in the sky to look at. But what the Oort cloud actually looks like and how it is affected by forces greater than just our solar system has remained somewhat of a mystery. A new paper from researchers at the Southwest Research Institute and the American Museum of Natural History tries to shine a light on what this invisible part of the solar system looks like – at least the part that is only 1,000 to 10,000 times farther away from the Sun as Earth is.

That part called the “inner” Oort cloud is considered slightly more populated than the “outer” Oort cloud, which ranges from 10,000 AU to 100,000 AU. Overall, potentially trillions of icy bodies are thought to be floating deep in space, though we only ever see the ones that show up in the inner solar system as long-period comets. 

Estimating the cloud’s structure requires more than understanding the planet’s gravitational forces. While they still have an impact, there is a larger player in the orbital mechanics of these icy rocks—the galaxy itself.

There’s a concept known as the “Galactic tide”. As our solar system moves through the galaxy, it is subjected to gravitational forces of other objects, like stars and black holes, that are closer or farther away from it. Like Earth’s Moon forces the water on the surface towards it due to its gravity, the galactic center, where most of the galaxy’s mass is, affects large objects in our solar system.

Fraser discusses the Oort cloud, the mysterious region where comets come from.

For the planets, this influence is drowned out by their gravitational bond to the Sun. But for Oort cloud objects, it plays a major role in determining their positioning. New long-period comets are formed when a nuance in the galactic tide either forces them into the inner solar system itself or causes them to collide with one another, sending one off on a trajectory toward the Sun.

Modeling this complex dynamic is hard, and the researchers, including lead author David Nesvorný, had to rely on a supercomputer at NASA to run their analytical model and compare it to previous simulations of the structure of the Oort cloud. They found something intriguing hiding in the data.

According to their model, the Oort cloud looks like a spiral disk about 15,000 au across, offset by the ecliptic by about 30 degrees. But more interestingly, it has two spiral arms that almost make it look like a galaxy.

Spiral arms of the Oort cloud in relation to the ecliptic and galactic planes.
Credit – Nesvorný et al.

These spiral arms, which are located nearly perpendicular to the galaxy’s center, resulting from the influence of the Galactic tide, are represented in the mathematical model by a phenomenon known as the Kozai-Lidov effect. In this quirk of celestial mechanics, large bodies are affected by “Kozai oscillations” that result from the gravitational influence of objects that are much farther away but, in the aggregate, still have an impact on the mechanics of a body.

The changes those oscillations make take a long time, but according to the researcher’s analysis, they almost solely determine the shape of the inner Oort cloud. The gravitational pull of the solar system’s planets or nearby passing stars doesn’t seem to have much effect.

According to the paper, taking a picture of this two-armed spiral will be exceedingly difficult. The authors suggest doing so would either require direct observation of a large number of objects in that space (which is unlikely in the near term) or separation of radiation from those objects that eliminates background and foreground sources so it could track the specific structure.

As of now, neither observational method has any resources dedicated to it. But, if we want to learn more about the home of any potential new comets and their impact on us, it wouldn’t be a bad idea to start planning how to look.

Learn More:
Nesvorný et al – A Spiral Structure in the Inner Oort Cloud
UT – The Oort Cloud Might be More Active Than We Thought
UT – A Star Passed Through the Oort Cloud Less Than 500,000 Years Ago. It Wasn’t the Only One.
UT – There Could Be Captured Planets in the Oort Cloud

Lead Image:
Illustration of the Oort Cloud.
Credit – NASA

The post A Spiral Structure in the Inner Oort Cloud appeared first on Universe Today.

When it comes to telescope mirrors, larger is generally better. The larger your main mirror, the more light you can capture and the more faint and distant objects you can see. The problem is that large mirrors are difficult to manufacture. They also deform under their own weight, which means you need an expensive support structure to keep it in alignment. The most common way to get around these challenges is to make telescopic mirrors in segments, but another solution is to simply use a liquid mirror.

The basic idea for a liquid mirror telescope is to use a thin layer of mercury, then spin it slowly. The rotation of the frame causes the liquid to form a parabolic surface. Combined with secondary mirrors or lenses, you then have a working telescope. Liquid mirror telescopes are dirt cheap compared to other telescopes of a similar size. The 6-meter Large Zenith Telescope (LZT), for example, was built for a fiftieth of the cost of a similar-sized telescope. The reason liquid mirror telescopes aren’t more common is that they have a couple of major drawbacks. The first is that mercury is extremely toxic, but the second is that they can only observe the sky directly above them. They can’t be used to track objects in the sky like other telescopes. But we might be able to address these challenges, as a recent paper in Acta Astronautica shows.

A proposed liquid mirror telescope on the Moon. Credit: Comstock, et al

Rather than using mercury, the study proposes using a ferrofluid. Ferrofluid mirrors have been used in some liquid mirror telescopes, but this study takes the idea further by adding electromagnets. Rotation could be used to shift the mirror into a parabolic shape, which could then be held in place by magnetic currents. This way, some degree of orientation could be used without the mirror losing its shape. On Earth, this wouldn’t be overly effective since our gravity is relatively strong. But this method could be quite effective for space telescopes. Magnetic currents could shape a space-telescope mirror effectively regardless of its orientation. The design could also be quite effective on the Moon, where gravity is 1/6 that of Earth and costs are at a premium.

The study looks at various coil arrangements and current levels needed to shape a large ferrofluid mirror and finds that it would be feasible for a wide range of wavelengths. At least in theory. The problem at the moment is that our tolerance levels for current electric circuitry are too large to provide the necessary precision. While the idea has some potential, it won’t be a solution for the foreseeable future.

Reference: Comstock, Eric A., et al. “On the feasibility of spherical magnetic liquid mirror telescopes.” Acta Astronautica (2025).

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One planet was missing from the sunset lineup… until now.

Perhaps you’ve seen the news headlines admonishing sky watchers to ‘See All Naked Eye Planets…at Once!’ in January. While this was basically true, it was also missing one key player: Mercury. This week, the swift inner planet joins the scene at dusk.

It’s certainly rare to see all the planets in the solar system in one sweep. This sort of lineup depends mainly on slow moving Jupiter and Saturn, which have parted ways since the rare conjunction of the two on December 21st, 2020.

The planetary lineup on February 22nd, looking westward, up to the zenith. Credit: Stellarium. A Planetary Dusk Tour

Seeing all the naked eye planets at once is set to become a rarity in coming years. In any event, here’s a tour of the planets at dusk for the remainder of February into early March from the inner solar system outward, with ready-made star party facts for each:

Fresh off solar conjunction on February 9th, the vigil is now on the week to recover Mercury low to the west after sunset. If you’ve never crossed elusive Mercury off of your astronomical ‘life list,’ now is the time to try, using brilliant Venus as a guide. Mercury passes 1.5 degrees north of Saturn on February 25th, and the waxing crescent Moon joins the scene on February 28th, and occults Mercury on March 1st for Hawai’i and the Pacific.

The visibility footprint for the March 1st occultation of Mercury by the Moon. Credit: Occult 4.1.2

Though the oft told tale that astronomer Nicolaus Copernicus never saw Mercury is probably apocryphal, it does speak to just how elusive the fleeting world is. Mercury reaches greatest elongation for the first of six times in 2025 on March 8th, 18 degrees east of the Sun shining at magnitude -0.35 and displaying a half illuminated disk in the telescope, just 7” across.

Moon versus Mercury, looking westward at dusk on February 28th. Credit: Stellarium.

The crescent Moon then passes 5.7 degrees south of Venus on March 2nd, marking a good time to see the two in the daytime. Fun fact this President’s Day week: attendants of Lincoln’s second inauguration on March 4th 1865 actually noticed the Venus in the daytime sky as the midday clouds cleared.

Venus in the daytime sky on Inauguration Day, 1865. Credit: Stellarium. A Planetary Race

Venus and Mercury both go on to race each other towards inferior conjunction next month, passing the Sun just 24 hours apart on March 23 and 24th. Both will then reemerge into the dawn sky in late March. Spotting Venus through inferior conjunction is tricky but not impossible, as the -4.2 magnitude slender 1% crescent passes just over 8 degrees north of the Sun at its closest. Be sure to try this feat visual athletics before sunrise, or after sunset.

A crescent Venus on January 28th. Credit: Efrain Morales Rivera. Into the Outer Solar System

Mars leads up the back of the pack, shining at -0.58 magnitude in Gemini the Twins. Look for ruddy Mars high to the east at dusk, fresh off of opposition on January 16th. The waxing gibbous Moon meets up with Mars on March 9th. NASA’s ESCAPADE Mars mission is set to launch for the Red Planet this year.

Onward and outward, Jupiter rides high to the south in Taurus the Bull at dusk. The waxing near First Quarter Moon meets Jupiter on March 6th, and the planet reaches quadrature 90 degrees east) of the Sun on March 2nd. Danish astronomer Ole Rømer noticed that predictions for phenomena for Jupiter’s moons (transits, ingress/egress times, etc) were off from opposition versus quadrature, and correctly deduced it was because the time it took light to traverse the two different distances was not factored in. Sometimes, scientific inspiration doesn’t stem as much from a ‘eureka!’ moment, but simply from a patient observer saying ‘that’s funny…’

Meanwhile, the outermost of the classical planets presents a challenge, as Saturn sits in the murk low to the west. Once you’ve found Mercury, sweep the horizon with binoculars and scoop up +1.1 magnitude Saturn, just over three times fainter than Mercury. The rings of Saturn pass edge on as seen from our Earthly vantage point on March 23rd, just two weeks after solar conjunction.

The shrinking tilt of Saturn’s rings, from 2016 to 2024. Credit: Roger Hutchison. …And Something More

Finally, completists will want to also pick off the outer ice giant worlds Uranus and Neptune. +5.8 magnitude Uranus is an easy binocular catch in Taurus (not far from Jupiter), while +7.8 magnitude Neptune is more of a challenge, hanging out in the murk low to the horizon with Mercury and Saturn in Pisces the Fishes.

Uranus’ current position in Taurus. Credit: Stellarium.

Both planets have the distinction of being discovered in the telescopic era, and Neptune is the only planet discovered using the power of math and deduction.

Neptune’s current position in Pisces at dusk. Credit: Stellarium.

The celestial drama sorts itself out in March, with Saturn leaving the scene and Mercury and Venus reappearing in the dawn sky. But hey, we have the first of two eclipse seasons for 2025 coming right up next month, with a partial solar eclipse on March 29th and a total lunar eclipse on 14th.

Let’s hope that the fickle Spring weather cooperates. Good skywatching, and clear skies in your planetary quest.

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