Science

Dark matter may have to go on a diet, according to new research.

By now we have a vast abundance of evidence for the existence of dark matter. That’s because cosmological observations just aren’t adding up. All our measures of luminous matter fall far short of the total gravitational effects we see in galaxies, clusters, and the universe as a while.

Dark matter far outweighs the regular matter in the cosmos, but we still don’t know the identity of this mysterious particle. Because of that, it could have a wide variety of masses, anything from a billionth of the mass of the lightest known particles to mass ranges far, far heavier.

Most searches for dark matter have focused on masses roughly in the range of the heavier known particles, because several extensions to known physics predict particles like that. But those searches have thus far come up short, making physicists wonder if the dark matter might be much lighter than expected…or much heavier.

But heavier dark matter runs into some serious issues, according to a new paper appearing on the preprint server arXiv.

The problem is that we expect to dark matter to at least sometimes, rarely, interact with normal matter. In the extremely early universe, dark matter and regular matter talked to each other much more often. But as the cosmos expanded and cooled, the interactions broke down, freezing out dark matter and leaving it behind as a relic background.

Almost all models of dark matter predict that it talks to normal matter through some interaction involving the Higgs boson, the famous particle finally detected by the Large Hadron Collider in 2012. The Higgs boson is responsible for the mass of many particles.

But interactions in physics are two-way streets. Many particles acquire their mass through their interaction with the Higgs, and in turn the mass of the Higgs is modified by its interaction with the other particles. But those particles are so light that the back-reaction isn’t very strong, so usually we don’t have to worry about it.

But if the dark matter is much heavier, somewhere around ten times the mass of the heaviest known particles, then its own interactions will cause the Higgs to balloon up in mass, making it far heavier than measurements suggest.

There are possibilities to get around this restriction. The dark matter might not interact with regular particles at all, or through some exotic mechanism that doesn’t involve the Higgs. But those models are few are far between, and require a lot of fine-tuning and extra steps.

This means that the dark matter, whatever it is, might just be an ultra-light particle, rather than an ultra-heavy one.

The post Dark Matter Can’t Be Too Heavy appeared first on Universe Today.

According to new research, the earliest seeds of structures may have been laid down by gravitational waves sloshing around in the infant universe.

Cosmologists strongly suspect that the extremely early universe underwent a period of exceptionally rapid expansion. Known as inflation, this event expanded the universe by a factor of at least 10^60 in less than a second. Powering this event was a new ingredient in the cosmos known as the inflaton, a strange quantum field that ramped up, drove inflation, and then faded away.

Inflation didn’t just make the universe big. It also laid down the seeds of the first structures. It did so by taking the quantum foam, the subatomic fluctuations in spacetime itself, and expanding that along with everything else. Slowly over time those fluctuations grew, and hundreds of millions of years later they became the first stars and galaxies, ultimately leading to the largest structure in the universe, the cosmic web.

But mysteries remain. We do not know the identity of the inflaton, or what powered it, or why it turned off when it did. And we have no conclusive evidence that inflation actually happened.

So researchers are always looking for alternatives, especially ones that don’t invoke some new and mysterious ingredient. In a recent paper, a team of astrophysicists describe a model where inflation happens, leading to the large-scale structure of the universe, all without an inflaton.

The model described by the researchers is set in the backdrop of an expanding universe that is accelerating in its expansion, just like the modern-day universe is. In that expanding universe, the quantum foam releases gravitational waves. Those ripples in space spread outwards, colliding with each other and amplifying themselves.

Gravitational waves usually can’t create structures on their own, but the researchers found that in certain special cases the gravitational waves can amplify each other in just the right way. When that happens, the imprints they make in space are nearly the same at a wide variety of length scales.

This is precisely what cosmologists observe in the cosmic microwave background, the leftover light from the early universe. This radiation contains a faint impression of the echoes of inflation, and it shows that whatever set the seeds of structure, it had to have that kind of pattern.

There are slight differences between the kinds of structures generated in this inflation-without-inflaton scenario and traditional inflation. In this first paper, the researchers did not yet calculate how strong those differences are, but an important next step is to explore the observational consequences of this model and see if it’s worth investigating further.

The post Space Itself May Have Created Galaxies appeared first on Universe Today.

Researchers have discovered how to make a new kind of metamaterial reconfigure itself without tangling itself up in knots, opening up the possibility of a broad array of space applications.

Metamaterials are a hot topic in engineering. These are materials inspired from biological systems. Many living structures start from simple, repeatable patterns that then grow into large, complex structures. The resulting structures can then have properties that the small subcomponents don’t. For example, individual bone cells or coral polyp skeletons aren’t very strong, but when they work together they can support huge animals or gigantic underwater colonies.

One promising kind of metamaterial is known as a Totimorphic lattice. This lattice starts from a triangular shaped structure. On one side is a fixed beam with a ball joint in the center. An arm attaches to that ball joint, and the other end of the arm is attached to the ends of the fixed beam with two springs. Many of these shapes attached together can morph into a wide variety of shapes and structures, all with very minimal input, giving the Totimorphic lattice incredible flexibility.

In a recent paper, scientists with the European Space Agency’s Advanced Concepts Team found a way to reconfigure Totimorphic lattices without having them tangle up on themselves. They discovered this using a series of computer simulations, creating an optimization problem for the algorithm to solve. With the algorithm in hand, they could then take any configuration of the lattice and change it to another in an optimal, efficient way.

The researchers showed off their technique with two examples. The first was a simple habitat structure that could change its shape and stiffness, which could allow future astronauts to deploy the same kind of metamaterial to build a variety of structures, and reconfigure them as mission needs changed.

The second example was a flexible space telescope that could change its focal length by adapting the curvature of its lens. This would enable a single launch, with a single vehicle, to serve a variety of observing needs.

As of right now, this is all hypothetical. Totimorphic lattices don’t exist in practice, only as curious mathematical objects. But this research is crucial for advancing humanity into space. The cost and difficulty of launching materials into space mean that we need flexible, adaptable structures that are cheap to launch and easy to deploy.

This research is yet another example of how we can draw inspiration from nature, in this case investigating the surprising properties of metamaterials, to bring ourselves into a future in space.

The post A Flexible, Adaptable Space Metamaterial appeared first on Universe Today.

SpaceX’s seventh flight test of its massive Starship launch system brought good news as well as not-so-great news.

The good news? The Super Heavy booster successfully flew itself back to the Texas launch site and was caught above the ground by the launch tower’s chopstick-style mechanical arms. That’s only the second “Mechazilla” catch to be done during the Starship test program. The bad news is that the upper stage, known as Ship 33, was lost during its ascent.

“Starship experienced a rapid unscheduled disassembly during its ascent burn. Teams will continue to review data from today’s flight test to better understand root cause,” SpaceX said in a post-mission posting to X. “With a test like this, success comes from what we learn, and today’s flight will help us improve Starship’s reliability.”

Today’s test marked the first use of an upper stage that was upgraded with a redesign of the avionics, the propulsion system and the forward control flaps. Ship 33’s heat shield featured next-generation protective tiles as well as a backup layer of heat-resistant material. SpaceX had removed some of the tiles for this flight as a stress test for the heat shield.

During the webcast, an onscreen graphic suggested that Ship experienced engine problems during its ascent. “We saw engines dropping out on telemetry,” launch commentator Dan Huot said.

In a posting to X, SpaceX founder Elon Musk said preliminary indications were that there was “an oxygen/fuel leak in the cavity above the ship engine firewall that was large enough to build pressure in excess of the vent capacity.”

“Apart from obviously double-checking for leaks, we will add fire suppression to that volume and probably increase vent area,” Musk wrote. “Nothing so far suggests pushing next launch past next month.”

After Ship’s breakup, eyewitnesses posted videos showing a glittering hail of debris falling to Earth. Reuters reported that at least 20 commercial aircraft had to divert to different airports or alter their course to dodge the debris.

In response to an emailed inquiry, the Federal Aviation Administration said it was aware of the anomaly that occurred during today’s flight test and would be assessing the operation. “The FAA briefly slowed and diverted aircraft around the area where space vehicle debris was falling,” the agency said via email. “Normal operations have resumed.”

Just saw the most insane #spacedebris #meteorshower right now in Turks and Caicos ?@elonmusk? what is it?? pic.twitter.com/a7f4MbEB8Q

— Dean Olson (@deankolson87) January 16, 2025

A view of Starship as seen from an airplane ?pic.twitter.com/MfmavSCKUa

— Jenny Hautmann (@JennyHPhoto) January 17, 2025

If Ship had made it to space, it would have deployed 10 Starlink simulators that were about the same size and weight as SpaceX’s Starlink broadband satellites. This was meant to test the procedure that SpaceX plans to use to put scores of Starlink satellites into low Earth orbit during a single Starship mission.

At the end of the flight test, Ship would have made a controlled re-entry and splashdown into the Indian Ocean.

Starship is the world’s most powerful launch system, with the booster’s 33 methane-fueled Raptor engines providing liftoff thrust of 16.7 million pounds. That’s more than twice the thrust of the Apollo-era Saturn V rocket, and almost twice the thrust of NASA’s Space Launch System, which was first launched in 2022 for the uncrewed Artemis I moon mission.

When fully stacked, Starship stands 403 feet (123 meters) tall. The system is meant to be fully reusable. Flight tests began in 2023, and SpaceX has made gradual progress. The first successful catch of the Super Heavy booster thrilled observers last October — and like that catch, today’s catch drew cheers from SpaceX employees watching the launch.

This year, SpaceX aims to demonstrate full reuse of Super Heavy and Ship, and promises to fly “increasingly ambitious missions.” The Starship system would be used for large-scale satellite deployments — and eventually for missions beyond Earth orbit. A customized version of Starship is slated to serve as a crewed lunar landing system for NASA’s Artemis III mission, which is currently scheduled for no earlier than mid-2027.

Musk envisions sending Starships on missions to Mars, perhaps starting in 2026. “These will be uncrewed to test the reliability of landing intact on Mars,” he said last September in a posting to X.

“If those landings go well, then the first crewed flights to Mars will be in 4 years,” Musk said. “Flight rate will grow exponentially from there, with the goal of building a self-sustaining city in about 20 years.”

The post SpaceX Catches Booster But Loses Ship in Starship Test Flight appeared first on Universe Today.

Wildfires and fossil fuel burning in 2024 contributed to the biggest annual rise in atmospheric CO2 levels ever recorded at the Mauna Loa Observatory in Hawaii

We can judge the value of any scientific endeavour based on how much of our knowledge it overturns or transforms. By that metric, the ESA’s Gaia mission is a resounding success. The spacecraft gave us a precise, 3D map of our Milky Way galaxy and has forced us to abandon old ideas and replace them with compelling new ones.

Currently, we’re marking the end of the Gaia mission, our best effort to understand the Milky Way. Gaia is an astrometry mission that’s built an impressive map of the Milky Way by taking three trillion observations of two billion individual objects in the galaxy, most of them stars, over an 11-year period. Measuring the same objects repeatedly means Gaia’s map is 3D and shows the proper motion of stars throughout the galaxy. Rather than a static map, it reveals the galaxy’s kinetic history and some of the changes it’s gone through.

Gaia showed us our galaxy’s turbulent history, including the streams of stars stemming from past disruptive events. Image Credit: ESA/Gaia/DPAC, Stefan Payne-Wardenaar

We’ve waited a long time for such a detailed look at our galaxy.

Radio astronomy, which gained momentum in the 1950s, helped us understand the structure of the Milky Way. Radio telescopes could see through intervening dust clouds and detect the distribution of hydrogen in the galaxy. In 1952, astronomers began the first major radio survey of the Milky Way. Astronomers theorized that the galaxy had a spiral structure, and finally, they detected the spiral arms, revealing the Milky Way’s basic structure.

In a 1958 paper, the authors wrote that “The distribution of the hydrogen evidently shows great irregularities. Nevertheless, several arms can be followed over considerable lengths.”

This figure shows the hydrogen distribution in the plane of the Milky Way’s disk. Though it appears outdated to our modern eyes and isn’t visually intuitive, it was exciting at the time. Image Credit: From “The galactic system as a spiral nebula” by Oort et al. 1958.

Astronomers also used RR Lyrae and Cepheids, two types of variable stars with known intrinsic brightnesses (standard candles), to calculate their distances. This allowed them to trace the Milky Way’s structure. Globular clusters also helped astronomers map the Milky Way.

In the 1980s, infrared telescopes like NASA’s IRAS peered through cosmic dust to help find features like the Milky Way’s central bar. Then, in 1989, the ESA’s Hipparcos mission was launched. Hipparcos was an astrometry mission and was Gaia’s predecessor. Though not nearly as precise, and though it only measured 100,000 stars, it was finally able to measure their proper motions. It revealed more details of the Milky Way and helped confirm its barred spiral form. It also provided some insights into our galaxy’s history and evolution.

But astronomers craved more detailed knowledge. Gaia was launched in 2013 to meet this need, and it’s been a total success.

Gaia is a tribute to ingenuity. We’re effectively trapped inside the Milky Way, and no spacecraft can get beyond it to capture an external view of the galaxy. Gaia has given us that view without ever leaving L2.

While many prior efforts to trace the Milky Way’s structure depended on sampling select stellar populations, Gaia precisely measured the position and motion of almost two billion stars throughout the galaxy.

Gaia’s map of the Milky Way has become iconic. This image is constructed from Gaia data that’s mapping two billion of the galaxy’s stars. It also mapped stars in the Large and Small Magellanic clouds. Image Credit: ESA/Gaia/DPAC

Gaia’s work has culminated in artist impressions of the Milky Way based on its voluminous data. These impressions show that the Milky Way has multiple arms and that they’re not as prominent as we thought.

Gaia’s observations have given us a much more detailed and precise look at the Milky Way’s spiral arms. It has identified previously unknown structures in the arms, including fossil arms in the outer disk. These could be remnants of past tidal arms or distortions in the disk, or remnants of ancient interactions with other galaxies. Gaia has also found many previously unknown filamentary structures at the disk’s edge.

The Gaia mission has also allowed us to finally see our galaxy from the side. We’ve learned that the galactic disk has a slight wave to it. Astronomers think this was caused by a smaller galaxy interacting with the Milky Way. The Sagittarius Dwarf Spheroidal galaxy could be responsible for it.

The Sagittarius Dwarf Spheroidal Galaxy has been orbiting the Milky Way for billions of years. According to astronomers, the three known collisions between this dwarf galaxy and the Milky Way have triggered major episodes of star formation, one of which may have given rise to our Solar System. Image Credit: ESA/Gaia

Alongside the compelling science, artists have created illustrations based on Gaia data that really hit home. The stunning side view of our galaxy is one of the most accurate views of the Milky Way we’ve ever seen.

This artist’s reconstruction of Gaia data shows the Milky Way’s central bulge, galactic disk, and outer reaches. Image Credit: ESA/Gaia/DPAC, Stefan Payne-Wardenaar

Gaia has updated our understanding of the galaxy we live in and brought its history to life. Even if it had no more to offer beyond today, it would still be an outstanding, successful mission. But even though its mission is over, we still don’t have all of its data.

Its final data release, DR5, will be available by the end of 2030.

Who knows what else the mission will show us about our home, the Milky Way galaxy.

The post The Most Accurate View of the Milky Way appeared first on Universe Today.

As apparent acts of sabotage cut undersea data cables around the world, NATO held its first demonstration of a project to quickly reroute crucial communications to satellite internet

Two new articles document progress in neuroprosthetic technology that lets people feel the shape and movement of objects moving over the 'skin' of a bionic hand.

Two new articles document progress in neuroprosthetic technology that lets people feel the shape and movement of objects moving over the 'skin' of a bionic hand.

Resembling the interlocking links in chainmail, novel nanoscale material is incredibly strong and flexible. The interlocked material contains 100 trillion mechanical bonds per 1 square centimeter -- the highest density of mechanical bonds ever achieved. Small amounts of the mechanically interlocked polymer added to Ultem fibers increased the high-performance material's toughness.

Scientists use devices known as frequency comb lasers to search for methane in the air above oil and gas operations and to screen for signs of infection in human breath. A new study could help make these sensors even more precise.

Researchers have developed an adhesive polymer that is stronger than current commercially available options while also being biodegradable, tunable, and reusable. The findings show how the common, naturally occurring polymer P3HB can be chemically re-engineered for use as a strong yet sustainable bonding agent.

Leo P, a small galaxy and a distant neighbor of the Milky Way, is lighting the way for astronomers to better understand star formation and how a galaxy grows. Scientists have reported finding that Leo P 'reignited,' reactivating during a significant period on the timeline of the universe, producing stars when many other small galaxies didn't.

Galaxies like the Milky Way grow by merging with smaller galaxies over billions of years, unlike dwarf galaxies, which have long been thought to lack the heft to attract mass and grow in the same way. New observations challenge this view, suggesting that even dwarf galaxies can accrete mass from other small galaxies.

Engineering researchers have developed carbon capture systems that use molecules called quinones, dissolved in water, as their capturing compounds. A new study provides critical insights into the mechanisms of carbon capture in these safer, gentler, water-based electrochemical systems, paving the way for their further refinement.

One of the most exciting developments in modern astronomy is how astronomers can now observe and study the earliest galaxies in the Universe. This is due to next-generation observatories like the James Webb Space Telescope (JWST), with its sophisticated suite of infrared instruments and spectrometers, and advances in interferometry – a technique that combines multiple sources of light to get a clearer picture of astronomical objects. Thanks to these observations, astronomers can learn more about how the earliest galaxies in the Universe evolved to become what we see today.

Using Webb and the Atacama Large Millimeter/submillimeter Array (ALMA), an international team led by researchers from the National Astronomical Observatory of Japan (NAOJ) successfully detected atomic transitions coming from galaxy GHZ2 (aka. GLASS-z12), located 13.4 billion light-years away. Their study not only set a new record for the farthest detection of these elements This is the first time such emissions have been detected in galaxies more than 13 billion light-years away and offers the first direct insights into the properties of the earliest galaxies in the Universe.

The galaxy was first identified in July 2022 by the Grism Lens-Amplified Survey from Space (GLASS) observing program using the JWST’s Near-Infrared Camera (NIRCam). A month later, follow-up observations by ALMA confirmed that the galaxy had a spectrographic redshift of more than z = 12, making it one of the earliest and most distant galaxies ever observed. The exquisite observations by both observatories have allowed astronomers to gain fresh insights into the nature of the earliest galaxies in the Universe.

The Atacama Large Millimeter/submillimeter Array (ALMA). Credit: C. Padilla, NRAO/AUI/NSF

Jorge Zavala, an astronomer at the East Asian ALMA Regional Center at the NAOJ, was the lead author of this study. As he explained in an ALMA-NAOJ press release:

“We pointed the more than forty 12-m antennas of the Atacama Large Millimeter/submillimeter Array (ALMA) and the 6.5-m James Webb Space Telescope (JWST) for several hours at a sky position that would appear totally empty to the naked human eye, aiming to catch a signal from one of the most distant astronomical objects known to date. And [we] successfully detected the emission from excited atoms of different elements such as Hydrogen and Oxygen from an epoch never reached before.”

Confirming and characterizing the physical properties of distant galaxies is vital to testing our current theories of galaxy formation and evolution. However, insight into their internal physics requires detailed and sensitive astronomical observations and spectroscopy – the absorption and emission of light by matter- allowing scientists to detect specific chemical elements and compounds. Naturally, these observations were challenging for the earliest galaxies, given that they are the most distant astronomical objects ever studied.

Nevertheless, the ALMA observations detected the emission line associated with doubly ionized oxygen (O III), confirming that the galaxy existed about 367 million years after the Big Bang. Combined with data obtained by Webb’s Near-Infrared Spectrograph (NIRSpec) and Mid-Infrared Instrument (MIRI) instruments, the team was able to characterize this object effectively. Based on their observations, the team discovered that GHZ2 was experiencing extreme bursts of star formation 13.4 billion years ago under conditions that differ considerably from what astronomers have seen in star-forming galaxies over the past few decades.

For instance, the relative abundance of heavier elements in this galaxy (metallicity) is significantly lower than that of most galaxies studied. This was expected given the dearth of heavier elements during the early Universe when Population III stars existed, which were overwhelmingly composed of hydrogen and helium. These stars were massive, hot, and short-lived, lasting only a few million years before they went supernova. Similarly, the team attributed GHZ2’s high luminosity to its Population III stars, which are absent from more evolved galaxies.

The scattered stars of the globular cluster NGC 6355 are strewn across this image from the NASA/ESA Hubble Space Telescope. Credit: ESA/Hubble & NASA, E. Noyola, R. Cohen

This luminosity is amplified by the fact that GHZ2, which is a few hundred million times the mass of the Sun, occupies a region of around 100 parsecs (~325 light-years). This indicates that the galaxy has a high stellar density similar to that of Globular Clusters observed in the Milky Way and neighboring galaxies. Other similarities include low metallicity, the anomalous abundances of certain chemicals, high star formation rates, high stellar mass surface density, and more. As such, studying galaxies like GHZ2 could help astronomers explain the origin of globular clusters, which remains a mystery.

Said Tom Bakx, a researcher at Chalmers University, these observations could pave the way for future studies of ancient galaxies that reveal the earliest phases of galaxy formation:

“This study is a crown on the multi-year endeavor to understand galaxies in the early Universe. The analysis of multiple emission lines enabled several key tests of galaxy properties, and demonstrates the excellent capabilities of ALMA through an exciting, powerful synergy with other telescopes like the JWST.”

Further Reading: ALMA, AJL

The post Webb and ALMA Team Up to Study Primeval Galaxy appeared first on Universe Today.

By using MRI brain scans to identify regions linked to hand movements and sensations, researchers were able to restore a sense of touch to two people with paralysis – and one was able to control and feel a robot arm using his thoughts

Droughts lasting multiple years are becoming more common and extreme around the globe, expanding by about 50,000 square kilometres annually

Pandora, a small satellite mission poised to provide in-depth study of at least 20 known planets orbiting distant stars to determine the composition of their atmospheres cleared an important milestone by completing the spacecraft bus, which acts as the spacecraft's 'brains.'

The chemical composition of a material alone sometimes reveals little about its properties. The decisive factor is often the arrangement of the molecules in the atomic lattice structure or on the surface of the material. Materials science utilizes this factor to create certain properties by applying individual atoms and molecules to surfaces with the aid of high-performance microscopes. Using artificial intelligence, a new research group now wants to take the construction of nanostructures to a new level.