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Ever since the advent of space exploration we have seen some amazing images of the planets. New technology often brings with it a new perspective and we have been reminded of this again just recently with images from the Hubble Space Telescope (HST)  and New Horizons spacecraft. The two objects simultaneously imaged Uranus from different perspectives in an attempt to predict what astronomers would see when they look at exoplanets orbiting other stars. 

Uranus is the 7th planet from the Sun and is recognisable for its wonderful blue-green colour. It was discovered by William Herschel in 1781 and since then we have been probing its secrets with telescopes and space probes alike. Like the other outermost planets, Uranus is a giant ball of gas and its the presence of methane in its atmosphere that gives it the striking colour. It’s unusual among the other planets since it seems to rotate around the Sun with an axial tilt of 98 degrees so it has really quite extreme seasons. 

This zoomed-in image of Uranus, captured by Webb’s Near-Infrared Camera (NIRCam) Feb. 6, 2023, reveals stunning views of the planet’s rings. Credit: NASA, ESA, CSA, STScI IMAGE PROCESSING: Joseph DePasquale (STScI).

HST and New Horizons have recently turned their gaze on Uranus but for a somewhat unusual project, to help develop imaging techniques for exoplanets. Directly imaging the distant alien worlds is tricky simply due to their distance and often due to their proximity to the host star. It’s of great importance to be able to study them directly to be able to learn more about their nature and possible habitability. Directly imaging exoplanets often just reveals pinpoints of light so researchers have used Uranus as a ‘proxy’ exoplanet to explore new imaging methods. 

The New Horizons instrument payload that is currently doing planetary science, heliospheric measurements, and astrophysical observations. Credit: NASA/Johns Hopkins University Applied Physics Laboratory/Southwest Research Institute

Uranus was chosen because the majority of exoplanets are gas giants and similar in nature. It was also chosen as New Horizons was on the far side of Uranus at the time of observation placing it 10.5 billion kilometres away. From its vantage point, New Horizons would see a crescent Uranus, a phase often seen on exoplanets when they are at their furthermost point from their star. They used the Multispectral Visible Imaging Camera to grab the images with Uranus covering just a few pixels, much like an exoplanet when viewed from Earth. 

While New Horizons was taking its images, HST which was just 2.7 billion km away and with its high quality cameras could capture a fabulous amount of detail in the atmosphere. By comparing the two images, the researchers have been able to see how atmospheric features appear in the New Horizon data to help learn about exoplanet observations. The team found that both HST and New Horizons saw that the brightness did not vary as the planet rotated which revealed that the cloud features were not changing with the rotation of the planet.

This image of NASA’s Hubble Space Telescope was taken on May 19, 2009 after deployment during Servicing Mission 4. NASA

They also found that New Horizons showed exoplanets are likely to seem dimmer than predicted at partial and high phase angles. This means that a gas planet like Uranus reflects light differently at partial phases when compared to others. The results are a testimony to the wonderfully insightful approach to cracking an existing challenge in modern astronomy; The direct study of exoplanets. Over the coming years telescopes like Nancy Grace Roman Space Telescope which is due for launch in 2027 has the ability to block out light to enable direct observations of exoplanets. This latest study will help to interpret the data revealed in future studies.

Source : NASA’s Hubble, New Horizons Team Up for a Simultaneous Look at Uranus

The post Hubble and New Horizons Look at Uranus at the Same Time appeared first on Universe Today.

A group of frogs from Madagascar have mating calls that sound like Star Trek sound effects – now their species names honour captains from the series

This buried rock wall found throughout Rockwall County has people wondering about its origin.

Hangovers: a problem with only one solution.

The post Hungover first appeared on Science-Based Medicine.

From brighter TV screens to better medical diagnostics and more efficient solar panels, new research has discovered how to make more molecules stick to the surface of tiny nanocrystals, in a breakthrough that could lead to improvements in everyday technology.

From brighter TV screens to better medical diagnostics and more efficient solar panels, new research has discovered how to make more molecules stick to the surface of tiny nanocrystals, in a breakthrough that could lead to improvements in everyday technology.

The future of wireless technology -- from charging devices to boosting communication signals -- relies on the antennas that transmit electromagnetic waves becoming increasingly versatile, durable and easy to manufacture. Researchers believe kirigami, the ancient Japanese art of cutting and folding paper to create intricate three-dimensional designs, could provide a model for manufacturing the next generation of antennas.

The future of wireless technology -- from charging devices to boosting communication signals -- relies on the antennas that transmit electromagnetic waves becoming increasingly versatile, durable and easy to manufacture. Researchers believe kirigami, the ancient Japanese art of cutting and folding paper to create intricate three-dimensional designs, could provide a model for manufacturing the next generation of antennas.

At high altitudes, global warming is having its strongest effect on winter temperatures – and that might mean soils there store can less carbon than we expected

NASA’s Europa Clipper spacecraft today began its six-year cruise to the Jupiter system, with the goal of determining whether one of the giant planet’s moons has the right stuff in the right setting for life.

The van-sized probe was sent into space from NASA’s Kennedy Space Center atop a SpaceX Falcon Heavy rocket at 12:06 p.m. ET (16:06 UTC). A little more than an hour after launch, the spacecraft separated from its launch vehicle to begin a roundabout journey of 1.8 billion miles (2.9 billion kilometers) from Earth orbit to Europa.

For decades, scientists have been collecting evidence that Europa harbors a hidden ocean of salty water beneath its icy shell. Or are they hidden lakes? Europa Clipper is built to characterize the moon’s surface, and what’s beneath that surface, to an unprecedented degree.

The spacecraft won’t actually land on Europa. Instead, it will document the moon’s chemical composition, magnetic field, gravity field and subsurface structure over the course of four years, during 49 flybys that will pass as close as 16 miles (25 kilometers) above the surface.

“Europa Clipper carries the most sophisticated suite of instruments that we’ve ever sent to the outer solar system,” mission project scientist Bob Pappalardo said during today’s webcast.

“It carries a radar that can penetrate through ice like a CAT scan to find liquid water,” he said. “Super-high-resolution imaging will be able to look for warm spots, plumes at Europa — all these wonderful techniques that combine together to tell us, ‘Could Europa be the kind of place that could support life today?'”

Europa Clipper is the most massive interplanetary probe built for NASA, with a fueled-up weight of 13,000 pounds (6,000 kilograms). Putting the spacecraft on its proper trajectory required so much oomph that there wasn’t enough propellant left over for the recovery of SpaceX’s rocket afterward.

Getting the spacecraft off the pad was an odyssey in itself: This summer, mission planners worried that the probe’s radiation shielding wasn’t strong enough to protect its electronics, but those concerns were eased. Last week, Hurricane Milton forced a postponement of the Florida launch, but after the storm passed, NASA and SpaceX gave the all-clear for today’s attempt. During the countdown, the launch team detected — and successfully resolved — a last-minute temperature anomaly on the Falcon Heavy’s second stage.

On its way to the Jupiter system, Europa Clipper will rely on gravity boosts provided during a flyby of Mars next March, and during an Earth flyby at the end of 2026.

Once the spacecraft gets to its destination in 2030, it will fly over Europa repeatedly, following a flight path that’s meant to minimize exposure to the intense emissions from Jupiter’s radiation belts.

Europa Clipper’s science instruments include visible-light, ultraviolet and infrared cameras that will map the ridges and cracks in Europa’s surface — and check for thermal clues that could point to upwellings of liquid water.

Spectrometers will determine the chemical composition of the surface ice and “sniff” Europa’s thin atmosphere. Ice-penetrating radar and a gravity field detector will map Europa’s internal structure. Two instruments will chart the magnetic field, producing data that could confirm the depth and salinity of Europa’s subsurface ocean. A dust analyzer will sample the material that’s thrown up from the surface, to track down its composition and figure out where it’s coming from.

The spacecraft is also carrying a radiation-shielding plate that is decorated with graphical representations of the word “water” in 103 languages — in recognition of Europa’s status as a water world — plus a poem for Europa, celestial equations and other tributes. The names of 2.6 million people around the world have been etched in microscopic letters onto a silicon chip that’s attached to the plate, thanks to a “Message in a Bottle” campaign organized by NASA.

Is there life in Europa’s hidden ocean? Scientists say the $5.2 billion Europa Clipper mission shouldn’t be expected to answer that question definitively. “We’re not looking for life itself. We’re just looking for an environment in which life could thrive,” Kate Craft, a staff scientist at Johns Hopkins University’s Applied Physics Laboratory, said in a video about the mission from NASA’s Jet Propulsion Laboratory. Nevertheless, the data could produce some surprises.

NASA has already started looking into the possibility of sending a robotic lander to Europa to follow up on findings from the Europa Clipper mission. Such a lander could sample the ice to a depth of, say, 4 inches (10 centimeters) — and look for signs of life in those samples using a microscope and other lab instruments.

The post Europa Clipper Begins Odyssey to Assess Jovian Moon’s Habitability appeared first on Universe Today.

NASA's Europa Clipper has embarked on its long voyage to Jupiter, where it will investigate Europa, a moon with an enormous subsurface ocean that may have conditions to support life. The largest spacecraft NASA ever built for a mission headed to another planet, Europa Clipper also is the first NASA mission dedicated to studying an ocean world beyond Earth.

The early Universe continues to offer surprises and the latest observations of infant galaxies are no exception. Astronomers found a surprisingly Milky Way-like galaxy that existed more than 13 billion years ago. That was a time when the Universe was really just an infant and galaxies should still be early in their formation. A well-formed one in such early history is a bit of a surprise.

The newly discovered galaxy is called REBELS-25. It was found as part of the “Reionization Era Bright Emission Line Survey (REBELS) survey using the Atacama Large Millimeter Array (ALMA) in Chile. The idea of the survey is to search out and measure early galaxies.

REBELS-24 is a massive disc-like galaxy with structures that look like spiral arms. That’s pretty similar to our Milky Way Galaxy. It’s more than 13 billion years old and took billions of years to evolve into its present shape. Like REBELS-25, the Milky Way began as a clumpy, disorganized proto-galaxy not long after the Universe began. It merged with other protogalaxies and evolved into a beautiful spiral shape. It appears to be actively forming stars and is incredibly massive for such a young galaxy.

Early Spirals Aren’t New

So, REBELS-25 raises a big question: why is it so massive and well-evolved at a time when the infant Milky Way was still a clump? That’s what astronomers are working to figure out. “According to our understanding of galaxy formation, we expect most early galaxies to be small and messy looking,” said Jacqueline Hodge, an astronomer at Leiden University, the Netherlands. The fact that REBELS-25 looks so “modern” after less than a billion years does—in a sense—rebel against the generally accepted theories about galaxy formation and evolution.

This isn’t the first time that astronomical observations uncovered early spirals. JWST observations suggest that perhaps a third of early galaxies are already spirals in the infant Universe. Its Cosmic Evolution Early Release Science Survey (CEERS) found many of these in the first 700 million years of cosmic history. So, finding this one looking almost “modern” some 13 billion years ago just adds to the mystery of their formation.

REBELS-25 showed up in ALMA observations, which also gave hints that it had a rotating disk. A set of follow-up observations confirmed the rotation of this galaxy and its spiral arm structures. In addition, the ALMA data found hints of a central bar (just like our Milky Way galaxy has). “ALMA is the only telescope in existence with the sensitivity and resolution to achieve this,” said Renske Smit, a researcher at Liverpool John Moores University in the UK and part of the team that worked on this discovery.

The ALMA data produced an image of REBELS-25 (left) and a map of gas motions in this galaxy which lies more than 13 billion light-years away. Blue coloring indicates movement towards Earth. Red indicates movement away from Earth, with a darker shade representing faster movement. In this case, the red-blue divide of the image shows clearly that the object is rotating, making REBELS-25 the most distant and early (13 billion years old) rotating disc galaxy ever discovered. Courtesy ESO.

Surprisingly, the ALMA data also hinted at more developed features similar to those of the Milky Way. It looks like there’s a central elongated bar, and even spiral arms in REBELS0-25. “Seeing a galaxy with such similarities to our own Milky Way, that is strongly rotation-dominated, challenges our understanding of how quickly galaxies in the early Universe evolve into the orderly galaxies of today’s cosmos,” said Lucie Rowland, a doctoral student at Leiden University who led the research into REBELS-25. “Finding further evidence of more evolved structures would be an exciting discovery, as it would be the most distant galaxy with such structures observed to date.”

What Does This Mean for Galaxy Evolution?

As astronomers discover more of these well-evolved galaxies in the early Universe, they’ll have to adjust the working model of galactic birth and evolution. In that model, the baby galaxies are clumps of stars and gas that come together in collisions and cannibalism to form larger galaxies. It’s typically considered a messy and turbulent time in cosmic history. Infant galaxies collided and grew. They combined their stars and gases to make larger structures. Over time they begin to rotate, which also influences the formation of structures inside the galaxy. Further collisions add more mass to the galaxy, and they also spur bursts of star formation. All of this takes billions of years to accomplish. Or so astronomers always thought.

REBELS-25 and other early spirals challenge that general model. For one thing, REBELS-25 looks like a galaxy that’s evolving at an accelerated pace. Compared to the Milky Way’s ponderous billions of years of evolution, REBELS-25 is going at warp speed. That implies something is pushing that acceleration. T he big thing now will be to explain its advanced evolution at a very young age.

The REBELS program should help astronomers understand more about the processes at work only a few hundred million years after the Big Bang. That survey will supply large enough amounts of data about high-mass galaxies in the early Universe. Those samples should allow astronomers to do targeted studies of more galaxies using both ALMA and JWST. Both observatories are powerful enough to give detailed looks at individual galaxies in those very early epochs of cosmic history.

For More Information

Space Oddity: Most Distant Rotating Disc Galaxy Found (PR)
Space oddity: Most Distant Rotating Disc Galaxy Found (the paper)
About REBELS

The post It’s Like Looking into a Mirror, 13 Billion Years Ago appeared first on Universe Today.

According to the National Post, Canada has a new med school (Torontoo Metropolitan University, or TMU), slated to open next year, has bought into the full DEI ideology that seems to be waning in the U.S.

This is an op-ed piece, and of course reflects a conservative opinion with statements like the first one below one, but read the facts for yourself. At any rate, I’m not keen on the paragraph below, as we don’t know how admissions will work (the “sob stories” bit is somewhat invidious):

All considered, most of TMU’s prospective med students will be getting in on student personal statements, sob stories and extracurriculars — factors that actually tend to bias admissions in favour of those who are well-off, but perhaps less competent. That’s who many of these diversity doctors will likely be.

The particulars (indented) and remember this is a conservative partisan view, so the language is inflammatory. Look at the links to ensure that their conclusions are supported.

Canada’s newest medical school is slated to be one of the most discriminatory programs of its kind when it opens in 2025. Straight, white, “privileged” men won’t be warmly welcomed as MD candidates at Toronto Metropolitan University (formerly Ryerson), as only a quarter of seats will be open to their kind.

It’s the exact kind of over-the-top, explicit, proud racism that diversity advocates assured us would never happen. Well, it’s here, and it’s vile, and in another decade, it might be the reason you switch to a medical AI for general needs and a Mexico-based private specialist for anything more complex.

You see, 75 per cent of spots in the Ryersonian med program will be reserved for “equity-deserving” folk: Indigenous people, admitted through their own stream, Black people, who also get their own stream, and everyone else who can check a diversity box, who get lumped into a final catch-all admissions pathway.

That list of diversity boxes is long, including LGBT people, disabled people, non-white people, children of non-white immigrants, poor-upbringing people, people over the age of 26, and people who have “faced familial and/or socio-cultural barriers such as loss of both parents, long term involvement with the child welfare system, and/or precarious housing.”

The standards for acceptance into the program, you should know, are quite lax. Applicants are required to have a degree and have achieved a GPA of at least 3.3 on a 4.0 scale, or a high B, but even that’s a soft floor — diversity candidates (i.e. most candidates) are eligible for consideration below that 3.3. No MCAT results are required, because the faculty is still under the false impression that standardized testing isn’t inclusive. Not all demographics perform as proficiently on these tests, but the data overwhelmingly show that it is predictive of academic ability across all backgrounds, which is what matters when we’re selecting future doctors.

But here is one thing I really object to (bolding is mine):

The administrators overseeing the place won’t be much better: as we speak, the faculty is searching for a “social accountability” associate dean to lead social justice and decolonization initiatives. They’re also looking for an “other ways of knowing” lead to ensure non-scientific perspectives are represented.

Seriously? What other “way of knowing” is there besides science construed broadly: empirical observation, experiment, doubt, replication, and all the stuff that enables us to understand the universe. Here’s from that page:

This is a bow to indigenous ways of knowing related to medicine but if that knowledge has been supported using modern scientific tests, it becomes “modern medicine”. I hope they won’t teach any indigenous “way of knowing” that haven’t been tested to see if they’re medically efficacious.

More from the article:

Hence, TMU Med aims to “Intentionally recruit diverse faculty and staff and those with a demonstrated commitment to (DEI)“; “include (DEI), intersectionality, health equity, human rights and the social determinants of health in curriculum.” That’s code for more courses about racist, systemic biases in health care more medical academics positioned to churn out bogus scholarly articles about microaggressions and race grievances, and the addition of political capacities, such as the ability to diagnose patients with “climate change”.

. . . Especially concerning for a program that should be rooted in reality is its rejection of absolute truth with regard to health: the school was designed with sensitivity to “ageism,” “fatphobia,” and “anti-madness.” It was also designed clearly to generate activist-doctors: “we work to acknowledge, understand, and challenge systems of power that privilege some groups over others,“ reads one planning document. “We take a race-conscious approach that recognizes the way racism is perpetuated in the healthcare system and that encompasses perspectives like Critical Race Theory.”

The rest of the article is more or less a conservative diatribe against these standards, but of course there is a concern when one prizes diversity over merit in a field like medicine: lives are at stake.  So the $64 question is this: would you be hesitant to go to a doctor who got their degree from this school? Would you vet them more carefully than usual?  Check out the links and weigh in below.

Cosmology has had several ground-breaking discoveries over the last 100+ years since Einstein developed his theory of relativity. Two of the most prominent were the discovery of the Cosmic Microwave Background (CMB) in 1968 and the confirmation of gravitational waves in 2015. Each utilized different tools, but both lent credence to the Big Bang Theory, which relates to the universe’s formation. However, we still don’t understand a vital part of that formation, and a new review paper by Rishav Roshan and Graham White at the University of Southampton suggests that we might be able to make some headway on our one-second “gap” in knowledge by using our newfound understanding of gravitational waves.

First, let’s look at what problem physicists are trying to solve. The Big Bang theory of cosmology is currently the one most widely accepted by scientists. There are different stages in it, including the earliest stage, known as “inflation,” and a stage where atoms begin to form, known as Big Bang Nucleosynthesis (BBN). However, there was a one-second gap between the end of inflation and the beginning of BBN that scientists have been unable to see into.

It’s difficult to see what happened in that second because that specific period was opaque to electromagnetic waves, such as the CMB that helped prove the Big Bang theory in the first place. While one second may not seem like a whole lot of time, the universe might have dropped something like twenty-two orders of magnitude in temperature in that one second. How that temperature change played out is critical to understanding what happened in BBN and, therefore, in creating the universe as we know it today.

Fraser discusses using existing missions as gravitational wave detectors.

Luckily, gravitational waves are here to save the day. They could permeate even that one-second gap, allowing cosmologists for the first time to peer into the previously mysterious time and try to glean any information they could about the imbalance between matter and antimatter or the expansion rate of the universe itself at that point. But to do so, they need a new set of tools.

Now that gravitational waves have officially been found, after a search that lasted more than 100 years, scientists have plenty of new ideas for novel ways to detect them. The paper breaks down three methods, each of which could find waves of different frequencies.

First are more advanced systems similar to LIGO that detected the first wave. Known as interferometers, these precise tools use synced lasers to detect any minute differences between two locations that gravitational waves might have caused. Scientists have drawn up plans for the future, including more enormous interferometers based on the ground and some based in space, which wouldn’t be subject to disturbances like earthquakes. These solutions promise to look into gravitational waves in the microhertz to kilohertz range of frequencies.

Fraser describes gravitational waves in detail.

Astrometry and pulsar timing array are the two other techniques. Both are useful in other parts of cosmology but can also detect lower-frequency gravitational waves if the instruments monitoring them are sensitive enough. Astrometry is more commonly used for exoplanet detection, whereas pulsar timing arrays are a typical measure of distance in cosmology. However, both could be affected by slow gravitational waves that could be detectable by the same instruments already used to monitor them.

These different techniques will search for the Stochastic Gravitational-Wave Background (SGWB). This operates similarly to the CMB in that it’s a leftover remnant of the beginning phase of the universe. Still, in this case, the SGWB comprises gravitational waves that would allow astronomers to see back to the very beginning of the universe.

If these new instruments do detect it, they could potentially detect some massively energetic events that happened during that one-second temperature de-escalation. One of the most commonly considered creation theories for gravitational waves is an “acoustic” source. This isn’t sound as we would traditionally consider it, but it describes massive shockwaves that would happen from two “sound shells” surrounding early, hot matter running into each other. Creation theories like this are commonly grouped in the paper as “cosmic phase transitions.”

Gravitational wave astronomy has the potential to change our understanding of the universe, as Fraser discusses.

Another grouping in the paper surrounds events known as “topological defects.” Topology is a common theme in physics, and a “defect,” in this case, represents an actual break in space-time as we know it. Those events could have obvious gravitational implications, some of which should be detectable in the frequencies tracked by the new detectors.

A final set of events that could induce gravitational waves is called “scalars.” Instead of representing a “break,” like the defects mentioned above, these events are just giant-scale versions of known physics. Gravitational waves can be caused by large masses moving together, though equations better describe such a”scalar” event than words.

Other, even more exotic events could form gravitational waves during this time period, but detecting them would require higher-frequency detectors than are currently available. Designs for some that could detect high-frequency gravitational waves are currently on the drawing board, but no solid commitment or experimental proof of their efficacy is forthcoming at the time of writing.

Fraser discusses LISA, one of the proposed space-based interferometers that might one day detect gravitational waves from space.

Cosmologists will undoubtedly have enough to chew on even without detecting higher-frequency GWs. We’ve talked before about the coming age of gravitational wave astronomy – and every day, it’s getting closer to reality—papers like those from Drs. Roshan and White are what help light the way.

Learn More:
Roshan & White – Using gravitational waves to see the first second of the Universe
UT – Future Gravitational Wave Observatories Could See the Earliest Black Hole Mergers in the Universe
UT – Gravitational Waves Could Show us the First Minute of the Universe
UT – Gravitational Wave Observatories Could Detect Primordial Black Holes Speeding Through the Solar System

Lead Image:
Representation of gravitational waves in the CMB.
Credit – Harvard-Smithsonian Center for Astrophysics

The post How Gravitational Waves Could Let Us See the First Moments After the Big Bang appeared first on Universe Today.

Netflix’s Ancient Apocalypse peddles the idea that we have overlooked an extraordinary ancient civilisation. Flint Dibble explains why that is wrong, and why real archaeology is more exciting

There are four fundamental forces in the Universe. These forces govern all the ways matter can interact, from the sound of an infant’s laugh to the clustering of galaxies a billion light-years away. At least that’s what we’ve thought until recently. Things such as dark matter and dark energy, as well as a few odd interactions in particle physics, have led some researchers to propose a fifth fundamental force. Depending on the model you consider, this new force could explain dark matter and cosmic expansion, or it could interact with elemental particles we haven’t yet detected. There are lots of theories about this hypothetical force. What there isn’t a lot of is evidence. So a new study is looking for evidence in the orbits of asteroids.

Many of the fifth-force models focus on what are known as Yukawa-type interactions. Back in the early days of nuclear physics, Hideki Yukawa proposed a potential interaction to describe how protons and neutrons could bind together in the nuclei of atoms. The resulting force was similar to the inverse-square forces of gravity and electromagnetism but had an exponential decay aspect, so it only affected nucleons. Over time, as we began to better understand nuclear interactions, the Yukawa potential model was replaced by the strong nuclear force, though it remains a good approximation for low-energy nucleons. Similar to the way Newtonian gravity is a good approximation for general relativity.

As scientists started to develop fifth-force models, the Yukawa interaction gained attention once again. For example, the Higgs boson generates mass in particles through a Yukawa interaction. Dark energy is often described as a part of the fundamental aspects of spacetime, but it can also be described as a Yukawa-type fundamental force. If there is such a fifth force, then it would have an effect on things such as planetary motion. But the effect would be so tiny that we haven’t had a chance of detecting it until recently, which is where this new study comes in.

The potential impact on the orbit of Bennu from other forces. Credit: Tsai, et al

The team considered the effects of a Yukawa-type fundamental force mediated by a massive scalar field. In other words, just as the electromagnetic field is mediated by the massless bosons known as photons, the fifth force is mediated by a similar boson, but one with mass. The mass of these new bosons would determine how strongly the force would affect orbital motions. Given how well orbital motions agree with Newtonian gravity, any Yukawa boson would need to have an extremely tiny mass. With standard optical observations and radar observations of planets, we know that the mass of these bosons couldn’t be more than about 10-16 eV. That’s really tiny, but still large enough to measure with an asteroid-visiting spacecraft.

In this work, the team looked at data from the OSIRIS-REx mission, which gathered sample material from the asteroid 101955 Bennu. Since we get radio signals directly from OSIRIS-REx, we know its motion with extreme precision. And since it orbited and landed on Bennu, we know the orbital motion of the asteroid extremely well. Based on this data, the team found no evidence of a fifth force, but they did put even further constraints on the mass of any fifth-force particle. We now know these hypothetical dark bosons can’t have a mass greater than 10-18 eV, roughly a factor of 100 stronger than previous limits.

So as far as we can tell, when it comes to fundamental forces, five is right out.

Reference: Tsai, Yu-Dai, et al. “Constraints on fifth forces and ultralight dark matter from OSIRIS-REx target asteroid Bennu.” Communications Physics 7.1 (2024): 311.

The post Can an Asteroid's Movements Reveal a New Force in the Universe? appeared first on Universe Today.

A new way to store numbers in computers can dynamically prioritise accuracy or range, depending on need, allowing software to quickly switch between very large and small numbers

It’s been quite a week… Spectacular northern lights for hours on Thursday night. A great comet in the evening skies (though so far I’ve have only caught glimpses, thanks to atrocious viewing conditions.) And now, I’m at CERN (the pan-European particle physics laboratory) for the first time since the pandemic began. I’ll be giving a talk at a conference of CMS experimenters. (CMS and ATLAS are the two general purpose experiments at the Large Hadron Collider [LHC].)

The topic of the workshop is a novel technique called “Level-1 Scouting” — though it isn’t really about “scouting” for anything. It has to do with evading the strait-jacket of the trigger, an essential feature of data gathering at each of the LHC experiments. With tens of millions of collisions per second, the data flood at CMS is too great, and only a tiny fraction of these collisions can be stored. The trigger decides real-time which ones to keep and which ones to discard forever. That’s been the basic rule since the LHC began running.

But this rule no longer applies, thanks to new technology and human ingenuity. CMS now uses level-1 scouting to record sketchy information about every single collision that happens in their detector. LHCb, with a smaller detector, was the first to try something along these lines. ATLAS is on a parallel track. These developments have the potential, looking ahead, to substantially enhance the capability of these detectors. More about this after I’ve given my talk.

Auroras after sunset. (These were as bright to the naked eye) Comet A3 after sunset. (Brighter than to the naked eye.)

Post-sunset light over CERN. (As to the naked eye.)

SpaceX has conducted their most successful test launch of a Starship system to date. The system they tested has three basic components – the Super Heavy first stage rocket booster, the Starship second stage (which is the actual space ship that will go places), and the “chopsticks”, which is a mechanical tower designed to catch the Super Heavy as it returns. All three components apparently functioned as hoped.

The Super Heavy lifted Starship into space (suborbital), then returned to the launch pad in Southern Texas where it maneuvered into the grasping mechanical arms of the chopsticks. The tower’s arms closed around the Super Heavy, successfully grabbing it. The engines then turned off and the rocket remained held in place. The idea here is to replicate the reusable function of the Falcon rockets, which can return to a landing pad after lifting their cargo into orbit. The Falcons land on a platform one the water. SpaceX, however, envisions many Starship launches and wants to be able to return the rockets directly to the launch pad, for quicker turnaround.

The Starship, for its part, also performed as expected. It came back down over the designated target in the Indian Ocean. Once it got to the surface it rolled on its side and exploded. They were never planning on recovering any of the Starship so this was an acceptable outcome. Of course, eventually they will need to land Starship safely on the ground.

The system that SpaceX came up with reflects some of the realities and challenges of space travel. The Earth is a massive gravity well, and it is difficult to get out of and back into that gravity well. Getting into orbit requires massive rockets with lots of fuel, and falls prey to the rocket equation – you need fuel to carry the fuel, etc. This is also why, if we want to use Starship to go to Mars, SpaceX will have to develop a system to refuel in orbit.

Getting back down to the ground is also a challenge. Orbital velocity is fast, and you have to lose all that speed. Using the atmosphere for breaking works, but the air compression (not friction as most people falsely believe) causing significant heat, so reentering through the atmosphere requires heat shielding. You then have to slow down enough for a soft landing. You can use parachutes. You can splash down in the water. You can use bouncy cushions on a hard landing. Or you can use rockets. Or you can land like a plane, which was the Shuttle option. All of these methods are challenging.

If you want to reuse your rockets and upper stages, then a splashdown is problematic as salt water is bad. No one has gotten the cushion approach to work on Earth, although we have used it on Mars. The retro-rocket approach is what SpaceX is going with, and it works well. They have now added a new method, by combining rockets with a tower and mechanical arms to grab the first stage. I think this is also the planned method for Starship itself.

On the Moon and Mars the plan is to land on legs. These worlds have a lower gravity than Earth, so this method can work. In fact, NASA is planning on using the Starship as their lunar lander for the Artemis program. We apparently can’t do this on Earth because the legs would have to be super strong to handle the weight of the Super Heavy or Starship, and therefore difficult to engineer. It does seem amazing that a tower with mechanical arms grabbing the rocket out of the air was considered to be an easier engineering feat than designing strong-enough landing legs, but there it is. Needing a tower does limit the location where you can land – you have to return to the landing pad exactly.

SpaceX, however, is already good at this. They perfected the technology the the Falcon rocket boosters, which can land precisely on a floating landing pad in the ocean. So they are going with technology they already have. But it does seem to me that it would be worth it to have an engineering team work on the whole strong-landing-legs problem. That would seem like a useful technology to have.

All of this is a reminder that the space program, as mature as it is, is still operating at the very limits of our technology. It makes it all the more amazing that the Apollo program was able to send successful missions to the Moon. Apollo solved these various issues also by going with a complex system. As a reminder, the Saturn V used three stages to get into space for the Apollo program (although only two stages for Skylab). You then had the spaceship that would go to the moon, which consisted of a service module, a command module, and a lander. On approach to the Moon, it would have to undergo, “transposition, docking, and extraction”. The command module would detach from the service module, turn around, then dock with the lunar lander and extract it from the service module. The pair would then go into lunar orbit. The lander would detach and land on the lunar surface, and eventually blast off back into orbit around the Moon. There it would dock again with the command module for return to Earth.

This was considered a crazy idea at first within NASA, and many of the engineers were worried they couldn’t pull it off. Docking in orbit was considered the most risk aspect, and if that failed it would have resulted in astronauts being stranded in lunar orbit. This is why they perfected the procedure in Earth orbit before going to the Moon.

All of this complexity is a response to the the physical realities of getting a lot of mass out of Earth’s gravity well, and having enough fuel to get to the Moon, land, take off again, return to Earth, and then get back down to the ground. The margins were super thin. It is amazing it all worked as well as it did. Here we are more than 50 years later and it is still a real challenge.

Spaceflight technology has not fundamentally changed in the last 50 years – rockets, fuel, capsules are essentially the same in overall design, with some tweaks and refinements. Except for one thing – computer technology. This has been transformative, make no mistake. SpaceX’s reusable rockets would not be possible without advanced computer controls. Modern astronauts have the benefits of computer control of their craft, and are travelling with the Apollo-era equivalent of supercomputers. Computer advances have been the real game-changing technology for space travel.

Otherwise we are still using the same kinds of rocket fuel. We are still using stages and boosters to get into orbit. Modern capsule design would be recognizable to an Apollo-era astronaut, although the interior design is greatly improved, again due to the availability of computer technology. There are some advanced materials in certain components, but Starship is literally built out of steel.

Again, I am not downplaying the very real advances in the aerospace industry, especially in getting down costs and in reusability. My point is more that there haven’t been any game-changing technological advances not dependent on computer technology. There is no super fuel, or game-changing material. And we are still operating at the limits of physics, and have to make very real tradeoffs to make it work. If I’m missing something, feel free to let me know in the comments.

In any case, I’m glad to see progress being made, and I look forward the the upcoming Artemis missions. I do hope that this time we are successful in building a permanent cis-lunar infrastructure. That, in turn, would be a stepping stone to Mars.

The post Latest Starship Launch first appeared on NeuroLogica Blog.

A 6000-kilogram spacecraft will embark on a six-year journey to Jupiter to explore whether its icy moon Europa has the conditions to support life