News Feeds

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.

Yesterday I posted an animation of a quantum wave function, and as a brain teaser, I asked readers to see if they could interpret it. Here it is again:

Yesterday’s wave function, showing an interesting interference phenomenon.

Admittedly, it’s a classic trap — one I use as a teaching tool in every quantum physics class. The wave function definitely looks, intuitively, as though two particles are colliding. But no. . . the wave function describes only one particle.

And what is this particle doing? It’s actually in the midst of a disguised version of the famous double slit experiment! This version is much simpler than the usual one, and will be super-useful to us going forward. It will make it significantly easier to see how all the puzzles of the double-slit experiment play out, both from the old, outdated but better known perspective of 1920’s quantum physics and from the modern perspective of quantum field theory.

You can read the details about this wave function — why it can’t possibly describe two particles, why it shows interference despite there being only one particle, and why it gives us a simpler version of the double-slit experiment — in an addendum to yesterday’s post.

Physicists use mathematical assumptions in many situations that forbid time from moving backwards – but that isn’t necessarily a reflection of quantum reality

I am fascinated by the technologies that live largely behind the scenes. These are not generally consumer devices, but they may be components of consumer products, or may largely have a role in industry – but they make our modern world possible, or make it much better. In addition I think that material science is largely underrated in terms of popular appeal, but it is material science that often make all other technologies possible or feasible. There is another aspect of technology that I have been increasingly interested in – solid state technology. These are, generally speaking, devices that use electricity rather than moving parts. You are likely familiar with solid state drives, that do not have spinning discs and therefore are smaller, use less power, and last longer. One big advantage of electric vehicles is that they are largely solid state, without the moving parts of an engine.

There is a technology that combines all three of these features – it is a component technology, dependent on material science, and solid state: thermoelectric devices. This may not sound sexy, but bear with me, this is cool (pun intended) technology. Thermoelectric materials are those that convert electricity into a temperature difference across a material, or convert a temperature difference into electricity. In reality, everything is a thermoelectric material, but most materials have insignificant thermoelectric effects (so are functionally not thermoelectric).

Thermoelectric devices can be used to harvest energy, from any temperature difference. These are generally not large amounts of energy – we don’t have thermoelectric power plants connected to the grid – and they are currently not practical and cost effective enough for a large scale. This may be possible in the future, but not today. However, for applications that require small amounts of energy, harvesting that energy from ambient sources like small temperature differences is feasible.

There are likely many more applications for the reverse – using electricity to cause temperature changes. This is basically a refrigerator, and in fact y0u can buy small solid state thermoelectric refrigerators. A traditional refrigerator uses a compressor and a refrigerant. This is a liquid that turns into a gas at low temperature, absorbing heat when it transitions to gas and then letting off heat when it transitions back to liquid. But this requires a compressor with moving parts and pipes to carry the refrigerant. Refrigerants are also not good for the environment or the ozone. Thermoelectric coolers can be smaller, use less electricity, are quiet, and have more precise temperature control. But their size is limited because they are not powerful enough for full-sized refrigerators.

As an aside, I see that Samsung is coming out this year with a hybrid full-size refrigerator. I still uses a compressor, but also has a thermoelectric cooler to reduce temperature variation throughout the refrigerator.

Thermoelectric cooling is also useful for electronics, which having an increasing problem with heat dissipation as we make them smaller, more compact, and more powerful. Heat management is now a major limiting factor for high end computer chips. This is also a major limiting factor for bio-electronics – implanting chips in people for various potential applications. Having a small and efficient solid state cooling device that just requires electricity would enable this technology.

But – the current state of the art for thermoelectric cooling is limited. Devices have low overall efficiency, and their manufacture is expensive and generates a lot of waste.  In other words – there is a huge opportunity to improve this technology with massive and far ranging potential benefits. This is an area ripe for investment with clear benefits. This can also be a significant component of our current overall goal to electrify our technology – to accomplish with electricity what currently requires moving parts and fossil fuels.

All this is why I was very interested in this latest advance – Interfacial bonding enhances thermoelectric cooling in 3D-printed materials. This incorporates yet another technology that has my interest – 3D printing, or additive manufacturing. This does not represent an improvement in the thermoelectric devices themselves, but an improvement in the cost and efficiency of making them (again, and often neglected by very important aspect of any technology). As one of the authors says:

“With our present work, we can 3D print exactly the needed shape of thermoelectric materials. In addition, the resulting devices exhibit a net cooling effect of 50 degrees in the air. This means that our 3D-printed materials perform similarly to ones that are significantly more expensive to manufacture,” says Xu.”

The innovation has to do with the molecular bonding of the materials in the 3D printing process. As Xu says, the performance is the same as existing materials, but with much lower cost to manufacture. As always, shifting to a new technology often means that there is room for further incremental advances to make the advantages even better over time. It may take years for this technology to translate to the market, but it is very possible it may lead directly to a slew of new products and applications.

It may seem like a small thing, but I am looking forward to a future (hopefully not too distant) with full-sized thermoelectric refrigerators, and with computers that don’t need fans or water cooling. Having a silent computer without fans is nice for podcasting, which I know is a particular interest of mine, but is also increasingly common.

In general, quality of life will be better if we are surrounded by technology that is silent, small, efficient, cost-effective, and long-lasting. Thermoelectric cooling can make all of that increasingly possible.

The post Thermoelectric Cooling – It’s Cooler Than You Think first appeared on NeuroLogica Blog.

By fusing different human organoids, researchers have created “mini-brains” containing most of the cell types found in fetal brains

New observations have dramatically reduced the chances of asteroid 2024 YR4 hitting Earth in 2032, lowering the risk to minimal levels, but its extraordinarily close approach will offer astronomers the chance to examine it in detail

A new AI-based method can accurately recover digital data from DNA strands nearly 90 times faster than older techniques, raising the possibility of practical DNA storage for computing

There is no doubt the "studies" in this journal will conclude We Want Them Infected doctors were right about everything the whole time; mitigation measure were an epic catastrophe while COVID was a harmless cold for everyone but grandma.

The post Misinformation Doctors Start a Misinformation Journal to Spread Misinformation first appeared on Science-Based Medicine.

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.

Researchers developed a low-cost, scalable terahertz amplifier that could be used to make antenna arrays that can steer and focus high-frequency terahertz waves, for applications like high-resolution radar, high-speed communications, and medical imaging.

After a cyber attack or natural disaster, a backup network of decentralized devices -- like residential solar panels, batteries, electric vehicles, heat pumps, and water heaters -- could restore electricity or relieve stress on the grid, engineers find.

A novel system that chases larval zebrafish around an arena with predator robots is enabling scientists to understand how these days-old fish quickly learn in the real world.

A novel system that chases larval zebrafish around an arena with predator robots is enabling scientists to understand how these days-old fish quickly learn in the real world.

In a leap forward for quantum computing, physicists unveiled an eight-qubit topological quantum processor, the first of its kind. The chip, built as a proof-of-concept for the scientists' design, opens the door to the development of the long-awaited topological quantum computer.

In a leap forward for quantum computing, physicists unveiled an eight-qubit topological quantum processor, the first of its kind. The chip, built as a proof-of-concept for the scientists' design, opens the door to the development of the long-awaited topological quantum computer.

Chemical engineers have discovered that adding nickel atoms to silver catalysts could revolutionize the production of ethylene oxide by eliminating the need for toxic chlorine while maintaining efficiency. The breakthrough could significantly reduce greenhouse gas emissions from the $40 billion global ethylene oxide industry, which currently produces this crucial chemical used in plastics, textiles, antifreeze, and disinfectants through a process that emits millions of tons of carbon dioxide annually.

Safety critical components for aircraft and Formula 1 racing cars could one day be 3D printed via a new technique that substantially reduces imperfections in the manufacturing process.

Rapid, localized heat management is essential for electronic devices and could have applications ranging from wearable materials to burn treatment. While so-called thermoelectric materials convert temperature differences to electrical voltage and vice versa, their efficiency is often limited, and their production is costly and wasteful. Researchers have now used a 3D printing technique to fabricate high-performance thermoelectric materials, reducing production costs significantly.

A research team has unveiled a new artificial intelligence (AI) system that uses satellite imagery to track urban green spaces more accurately than prior methods, critical to ensuring healthy cities.