Science

What happens when one galaxy shoots a bigger galaxy right through the heart? Like a rock thrown into a pond, the smashup creates a splash-up of starry ripples. At least that’s what happened to the Bullseye galaxy, which is the focus of observations made by NASA’s Hubble Space Telescope and the Keck Observatory in Hawaii.

In a study published today by The Astrophysical Journal Letters, a research team led by Yale University’s Imad Pasha identifies nine visible ring-shaped ripples in the structure of the galaxy, formally known as LEDA 1313424. The galaxy is 567 million light years from Earth in the constellation Pisces.

The Bullseye now holds the record for the most rings observed in a galaxy. Previous observations of other galaxies showed a maximum of two or three rings.

“This was a serendipitous discovery,” Pasha said in a news release. “I was looking at a ground-based imaging survey and when I saw a galaxy with several clear rings, I was immediately drawn to it. I had to stop to investigate it.”

Eight separate rings could be spotted in the image captured by Hubble’s Advanced Camera for Surveys. The ninth ring was identified in data from the Keck Observatory. Follow-up observations also helped the team figure out which galaxy plunged through the Bullseye’s core. It’s the blue dwarf galaxy visible to the center-left of LEDA 1313424 in the Hubble image.

This illustration pinpoints the nine rings in the Bullseye galaxy. Credit: NASA, ESA, Ralf Crawford (STScI)

Researchers say the current view captures the state of the Bullseye about 50 million years after the blue dwarf blasted through its core. Even though the two galaxies are separated by 130,000 light-years, a thin trail of gas still links them together. “We’re catching the Bullseye at a very special moment in time,” said Yale Professor Pieter G. van Dokkum, a study co-author. “There’s a very narrow window after the impact when a galaxy like this would have so many rings.”

The multi-ringed shape conforms to the mathematical models for a headlong galaxy-on-galaxy collision. The blue dwarf’s impact caused galactic material to move both inward and outward, sparking multiple waves of star formation along the lines of the ripples — almost exactly as the models predicted.

“It is immensely gratifying to confirm this longstanding prediction with the Bullseye galaxy,” van Dokkum said.

The models suggest that the first two rings in the Bullseye formed quickly and spread out in wider circles. The timing for the formation of additional rings was staggered as the blue dwarf plowed through the bigger galaxy’s core. The research team suspects that there was once a 10th ring to the galaxy, but that it faced out and is no longer detectable. That ring might have been as much as three times farther out than the widest ring seen in the Hubble image.

This artist’s conception shows our Milky Way galaxy at left, and the Bullseye galaxy at right. Credit: NASA, ESA, Ralf Crawford (STScI)

Compared to our own Milky Way galaxy, the Bullseye is a big target. It’s about 250,000 light-years wide, as opposed to 100,000 light-years for the Milky Way.

Billions of years from now, the Milky Way and the neighboring Andromeda galaxy are due to collide, but computer simulations suggest that the dynamics of that collision will be more complex than merely dropping a cosmic rock into a pond, or shooting an arrow through a bull’s-eye.

Fortunately, astronomers won’t have to wait billions of years to see more spot-on galactic collisions. “Once NASA’s Nancy Grace Roman Space Telescope begins science operations, interesting objects will pop out much more easily,” van Dokkum said. “We will learn how rare these spectacular events really are.”

In addition to Pasha and van Dokkum, the authors of the Astrophysical Journal Letters study, “The Bullseye: HST, Keck/KCWI, and Dragonfly Characterization of a Giant Nine-Ringed Galaxy,” include Qing Liu, William P. Bowman, Steven R. Janssens, Michael A. Keim, Chloe Neufeld and Roberto Abraham.

The post Bullseye! Hubble Spots Ripples in Space From a Galaxy Collision appeared first on Universe Today.

The ESA’s Gaia mission mapped the positions and velocities of stars with extreme precision by measuring about one billion stars multiple times. It created a massive 3D map of the Milky Way that will pay scientific dividends for years to come. Gaia is based on astrometry, the study of the positions and movements of celestial objects.

Gaia also tentatively detected some planets, and new radial velocity studies have now confirmed the existence of one of them. The planet is an important outlier in exoplanet science.

Gaia wasn’t designed to be a planet finder, but it found some anyway. Since the spacecraft was built to measure stars, the planets it found are massive, and they orbit low-mass stars. These planets tug on their stars, and Gaia can detect the way the stars wobble. However, follow-up observations were required to confirm them.

Now, researchers have used the NEID spectrograph on the WIYN 3.5-meter Telescope at the NSF’s Kitt Peak National Observatory to measure these stellar wobbles and the planet and brown dwarf that cause them via radial velocity. Their results are in a paper published in The Astronomical Journal. Its title is “Gaia-4b and 5b: Radial Velocity Confirmation of Gaia Astrometric Orbital Solutions Reveal a Massive Planet and a Brown Dwarf Orbiting Low-mass Stars.” The lead author is Gudmundur Stefansson from the Anton Pannekoek Institute for Astronomy at the University of Amsterdam.

“Gaia is more than living up to its promise of detecting planetary companions to stars with highly precise astrometry…”

Jayadev Rajagopal, co-author, NSF NOIRLab

The most recent Gaia data release contains a list of Gaia AStrometric Objects of Interest (Gaia-ASOIs). They’re stars that appear to be moving as if influenced by an exoplanet.

In a press release, lead author Stefansson said, “However, the motion of these stars is not necessarily due to a planet. Instead, the ‘star’ might be a pair of stars that are too close together for Gaia to recognize them as separate objects. The tiny shifts in position that appear to be due to a planet might actually result from the nearly perfect cancellation of the larger shifts in position of the two stars.”

Follow-up spectroscopy can do what Gaia can’t and determine if the objects are binary stars or stars and their orbiting planets. The researchers used the NEID spectrograph and two others—the Habitable-zone Planet Finder and the FIES Spectrograph to perform follow-up observations. In radial velocity, spectrographs measure the blue-shifted and red-shifted light from stars as nearby planets tug on them and make them wobble. It takes extreme precision to do this, and all three spectrographs are capable of it.

Astronomers used the NEID spectrograph on the WIYN 3.5-meter Telescope at Kitt Peak National Observatory (KPNO) to confirm the existence of an exoplanet and a brown dwarf first detected by the ESA’s Gaia spacecraft. Image Credit: KPNO/NOIRLab/NSF/AURA/T. Matsopoulos

The researchers examined 28 separate star systems where Gaia detected candidate exoplanets.

According to the results, 21 of the systems have no substellar companions. Instead, these 21 are binary star systems. Five others are inconclusive and require more observations and data before they can be confirmed or refuted.

However, two of the 21 are confirmed: one is an exoplanet now named Gaia-4b, and one is a brown dwarf named Gaia-5b.

Gaia-4b is a massive exoplanet with about 11.8 Jupiter masses. It follows a 571-day orbit around a star with a mass of 0.644 solar masses. It has the distinction of being the first confirmed exoplanet found by Gaia. It’s also one of the most massive planets that have ever been detected orbiting a low-mass star, reflecting the observational bias inherent in Gaia’s method.

Gaia-4b orbits the star Gaia-4, which is around 244 light-years away. It is about twelve times more massive than Jupiter and has an orbital period of 570 days. It is a relatively cold gas giant planet. This artist’s impression visualizes a portion of the orbital motion as determined by Gaia’s astrometric data. The star and planet are not to scale. Image Credit: ESA/Gaia/DPAC/M. Marcussen

“It is an exciting time for both NEID and Gaia,” said Jayadev Rajagopal, a scientist at NSF NOIRLab and a co-author of the paper. “Gaia is more than living up to its promise of detecting planetary companions to stars with highly precise astrometry, and NEID is demonstrating that its long-term radial velocity precision is capable of detecting low-mass planets around those stars. With more candidate planets to come as roughly the last year of data is analyzed, this work is a harbinger of the future where Gaia discoveries of planets and brown dwarfs will need to be confirmed, or rejected, by NEID data.”

Gaia-5b is a brown dwarf, an object in between planetary mass and stellar mass. Gaia-5b has about 21 Jupiter masses and follows a highly eccentric 358-day orbit around a star with a mass of about 0.34 solar masses.

This study highlights how effective Gaia’s astrometric capabilities are for detecting exoplanets and brown dwarfs. It also exemplifies how different observational techniques—astrometry and radial velocity spectrometry—can work together for more robust results. The combined methods can find a wider range of substellar companion masses and orbital characteristics compared to the transit method, for example.

“If we want to understand how planets are formed, it is necessary to have a vision of how the whole planetary system is composed,” said the ESA’s Ana Heras in a separate press release. “Currently, our vision of most systems is only partial because each detection technique is efficient for a certain range of planet sizes and orbital periods. Being able to combine all techniques and data is critical to understand what planetary systems look like and to put our Solar System in context.”

Gaia-4b is an outlier in exoplanet discoveries. Finding such a massive planet around such a low-mass star is a big test for our planet formation theories. “With respect to stellar host-star mass, the occurrence of massive planets is known to decrease with decreasing stellar mass,” the authors write in their paper. “This has been connected to the fact that less massive stars tend to have less massive protoplanetary disks.” If Gaia and the NEID spectrograph and other facilities can find and confirm more of these massive planets, maybe researchers can make progress in understanding how they form.

This figure from the published study shows the masses of planets and brown dwarfs as a function of stellar host mass for stars with <0.7 solar masses and orbital periods <10,000 days. (a) Companion mass as a function of host-star mass. (b) Histogram of the points in panel (a). (c) Mass ratio as a function of host-star mass. As the figure shows, Gaia-5b and Gaia-4b straddle the Brown Dwarf Limit Line. The Jupiter Desert Region highlights the absence of planets with 1 to 10 Jupiter masses orbiting stars with 0.3 solar masses or less. Image Credit: Stefansson et al. 2025.

Astronomers expect to find more massive exoplanets and brown dwarfs in Gaia data and confirm some of them with spectrographs like NEID. Due to Gaia’s observational method, there will likely be more “outliers” in the data. These outliers are needed to help us understand planet formation and solar system architecture.

“These detections represent the tip of the iceberg of the planet and brown dwarf yield expected with Gaia in the immediate future, enabling key insights into the masses and orbital architectures of numerous massive planets at intermediate orbital periods,” the authors conclude.

The post Gaia Was Right. It Did Find a Planet. appeared first on Universe Today.

At first glance the large scale structure of the Universe may seem to be a swarming mass of unconnected galaxies. Yet somehow, they are! The ‘cosmic web’ is the largest scale structure of the Universe and consists of vast networks of interconnected filamentary structures that surround empty voids. A team of astronomers have used hundreds of hours of telescope time to capture the highest resolution image ever taken of a single cosmic filament that connects to forming galaxies. It’s so far away from us that we see it as it was when the Universe was just 2 billion years old! 

Dark matter is largely invisible to us, only detectable through its interaction with other phenomenon. It makes up about 85% of the matter in the universe and plays a crucial role in shaping the large-scale structure of the cosmos. It doesn’t emit, absorb, or reflect light hence its name and its gravitational influence holds galaxies together and forms the cosmic web—a vast, interconnected network of filaments composed of dark matter, gas, and galaxies. Scientists have been studying the cosmic web using simulations and gravitational lensing techniques to understand the nature of dark matter and its role in evolution of the universe.

A massive galaxy cluster named MACS-J0417.5-1154 is warping and distorting the appearance of galaxies behind it, an effect known as gravitational lensing. This natural phenomenon magnifies distant galaxies and can also make them appear in an image multiple times, as NASA’s James Webb Space Telescope saw here. Two distant, interacting galaxies — a face-on spiral and a dusty red galaxy seen from the side — appear multiple times, tracing a familiar shape across the sky. NASA, ESA, CSA, STScI, V. Estrada-Carpenter (Saint Mary’s University).

One of the biggest challenges that faces astronomers studying the cosmic web is that the gas has mainly been detected through its absorption of light from a more distant object. The results of such studies however do not help us to understand the distribution of gas in the web. Studies that focus on hydrogen which is the most common element in the universe, can only be detected from a very faint glow so that previous attempts to map its distribution have failed. 

In this new paper that was published by a team of researchers that were led by scientists from the University of Milano-Bicocca and included members from the Max Planck Institute for Astrophysics. The team employed the use of the Multi-Unit Spectroscopic Explorer (MUSE) on the Very Large Telescope at the European Southern Observatory in Chile. The instrument was designed to capture 3D data of astronomical objects by combining images and spectroscopic observations across thousands of wavelengths simultaneously. Even with the capabilities of MUSE, the team had to capture data over hundreds of hours to reveal sufficient detail in the filaments of the cosmic web. 

ESO’s Very Large Telescope is composed of four Unit Telescopes (UTs) and four Auxiliary Telescopes (ATs). Seen here is one of the UTs firing four lasers which are crucial to the telescope’s adaptive optics systems. To the right of the UT are two ATs, these smaller telescopes are moveable and work in tandem with the other telescopes to create a unique and powerful tool for observing the Universe.

The team was led by PhD student at the University of Milano-Bicocca Davide Tornotti and they used MUSE to study a filament that measures 3 million light years in length. The filament connects two galaxies, each with a supermassive black hole deep in their core. They were able to demonstrate a new way of mapping the intergalactic filaments, helping to understand more about galactic formation and the evolution of the universe.

Before they were able to start collecting the data, the team were able to run simulations of the emissions from filaments based upon the current model of the universe. They were then able to compare the results and both were remarkably similar. The discovery can help us to learn how galaxies in the cosmic web are fuelled but the team assert that they still need more data. More structures are now being uncovered as the techniques are repeated with the goal to finally reveal how gas is distributed among the cosmic web. 

Source : Researchers capture direct high-definition image of the “Cosmic Web”

The post Our Best Look at the Cosmic Web appeared first on Universe Today.

New research shows grain yields critical to India's food security are dragged down 10% or more in many parts of the country by nitrogen dioxide pollution from power stations that run on coal. Economic losses from crop damages exceed $800 million per year.

Combining two semiconductor thin films into a tandem solar cell can achieve high efficiencies with a minimal environmental footprint. Teams have now presented a CIGS-perovskite tandem cell that sets a new world record with an efficiency of 24.6%, certified by an independent body.

Running out of gas in a remote area far from a gas station is every driver's worst nightmare. A similar stressor, known as "range anxiety," exists for owners of electric vehicles who worry about how far their EV's can drive without running out of battery. As EVs become more common on roadways -- annual EV sales are estimated to reach 7.2 million by 2030 -- innovative new methods are being developed to more easily charge them.

Revelations from the past can seem quaint once we’ve been living with them for a generation or two. That’s true of the realization in the past that spawned SETI: the Search for Extraterrestrial Intelligence. Humanity realized that if we’re blasting radio signals out into the cosmos haphazardly, then other ETIs, if they exist, are probably doing the same.

It seems obvious now, but back then, it was a revelation. So, we set up our radio antennae and began scanning the skies.

The realization that other ETIs are probably sending out radio noise leads to the obvious question: How easily can hypothetical ETIs detect our radio signals and other technosignatures?

A fledgling space-travelling civilization similar to ours may be out there somewhere in the Milky Way. Maybe they have their own fledgling SETI program, complete with radiotelescope arrays scanning the sky for the telltale signs of another technological civilization.

If there is, and if they do, from how far away could they detect our technosignatures? New research is asking that question.

The research is titled “Earth Detecting Earth: At What Distance Could Earth’s Constellation of Technosignatures Be Detected with Present-day Technology?” It’s published in The Astronomical Journal, and Sofia Sheikh is the lead author. Sheikh is affiliated with the SETI Institute, the Penn State Extraterrestrial Intelligence Center, and Breakthrough Listen at UC Berkeley.

Nikola Tesla was one of the first to suggest communicating with beings on other planets. In 1899, Tesla thought he had detected a signal from Mars. In the early part of the 20th century, Guglielmo Marconi also thought he had heard signals from Mars. These potential signals were serious enough that when Mars was closest to Earth in 1924, the USA promoted a Radio Silence Day in order to better detect signals from Mars.

We know better now. The only signals we’ll detect will be from our own Martian rovers and orbiters. However, the basic idea of searching for radio signals from other worlds was planted, and people started taking it more seriously.

In 1971, NASA considered Project Cyclops, a plan to build an array of 1500 radio dishes to scan the cosmos for signals. Although it was never funded, it helped lead to the modern SETI.

It’s a simple matter to imagine that other civilizations followed a similar path and are now searching the sky for signals. In the new research in The Astronomical Journal, Sheikh and her co-researchers try to understand how one of these civilizations could detect our technosignatures if they had the same technology as we do in 2024.

“In SETI, we should never assume other life and technology would be just like ours, but quantifying what ‘ours’ means can help put SETI searches into perspective.”

Macy Huston, co-author, Dept. of Astronomy, UC Berkeley

This is important because similar research looks for advanced ETIs that are further along the Kardashev Scale, which many researchers think is probable. However, this means researchers have to do a lot of technological extrapolation. “In this paper, we instead turn our gaze Earthward, minimizing the axis of extrapolation by only considering transmission and detection methods commensurate with an Earth 2024 level,” the authors write.

It all boils down to simple questions: Can an ETI with our current technology detect our technosignatures? If the answer is yes, which of our signatures would they detect, and from how far away?

The researchers considered multiple types of different technosignatures, including radio transmissions, microwave signals, atmospheric technosignatures like NO2, satellites, and even city lights. They used a theoretical, modelling-based method in their effort, and they say they’re the first to analyze these technosignatures together rather than separately.

“Our goal with this project was to bring SETI back ‘down to Earth’ for a moment and think about where we really are today with Earth’s technosignatures and detection capabilities,” said Macy Huston in a press release. Huston is a co-author and postdoc at the University of California, Berkeley, Department of Astronomy. “In SETI, we should never assume other life and technology would be just like ours, but quantifying what ‘ours’ means can help put SETI searches into perspective.”

This table is a rough timeline of human technologies across different wavelengths and multimessenger approaches. Image Credit: Sheikh et al. 2025.

Imagine a hypothetical space probe travelling toward us from this hypothetical, technologically equivalent ETI. According to the researchers, the first technosignature they’d detect would come from our effort to detect potentially hazardous asteroids that might be headed for Earth. This is our planetary radar, like the signals coming from the now-defunct Arecibo Radio Observatory. These are detectable out to about 12,000 light years from Earth. That’s about the same distance away as the Tadpole Nebula.

The hypothetical space probe would have a long way to travel before it could detect our next technosignature. When it was about 100 light-years away, it would detect signals from NASA’s Deep Space Network that’s used to communicate with spacecraft we send out into the Solar System. 100 light-years away is about the same distance away as Alpha Pictoris, the brightest star in the Pictor constellation.

The alien spacecraft would hit paydirt at about four light-years away, around the same distance as our closest stellar neighbour, Proxima Centauri. At that distance, it would detect lasers, our atmospheric NO2 emissions, and even LTE signals.

The figure below illustrates how our current technology would detect our own technosignatures and at what distances.

This figure from the research shows the maximum distances that each of Earth’s modern-day technosignatures could be detected at using modern-day receiving technology. Image Credit: Sheikh et al. 2025.

“One of the most satisfying aspects of this work was getting to use SETI as a cosmic mirror: what does Earth look like to the rest of the galaxy? And how would our current impacts on our planet be perceived,” said Sheikh. “While, of course, we cannot know the answer, this work allowed us to extrapolate and imagine what we might assume if we ever discover a planet with, say, high concentrations of pollutants in its atmosphere.”

The research also illustrates how our own technosignature footprint is growing. According to the authors, it highlights “the growing complexity and visibility of the human impact upon our planet.”

It also shows that despite some second-guessing among the SETI community, it’s probably wise to focus our search on radio waves. “In this framework, we find that Earth’s space-detectable signatures span 13 orders of magnitude in detectability, with intermittent, celestially targeted radio transmission (i.e., planetary radar) beating out its nearest nonradio competitor by a factor of 103 in detection distance,” the authors write in their paper.

The authors also point out that we can begin to understand what an ETI might surmise about us based on our technosignatures. That can also serve as a mirror through which we can see ourselves. “It is possible for ETIs to hypothesize about our culture, society, biosphere, etc., from our unintentional technosignatures, and thinking through those possible hypotheses can help us interrogate how we are presenting ourselves to the galaxy: how we organize socially, how we relate to the world around us, how we perceive and experience things, and perhaps even what we value,” the authors explain in their research.

For example, they could correctly surmise that our species has no biological capacity to detect radio signals; otherwise, our world would be an unimaginably noisy cacophony of competing signals. Or, they may infer the reverse. “Conversely, our reliance on radio waves could make it natural for an alien species to wonder if it is because we can detect them biologically!” the authors write.

As in all things SETI and technosignature related, we’re left wondering.

However, with their “Earth detecting Earth” paradigm, Sheikh and her co-authors are at least giving us another way to examine one of our most quintessential questions: Are we alone?

Press Release: Earth Detecting Earth

Research: Earth Detecting Earth: At What Distance Could Earth’s Constellation of Technosignatures Be Detected with Present-day Technology?

The post How Far Away Could We Detect… Ourselves? appeared first on Universe Today.

Engineers took on the well-known battery challenge of degradation in a real-world technology that many of us use daily: wireless earbuds.

I am not particularly keen on seeing fish catching birds—or, indeed, seeing any animals eaten by others—but of cours that’s the way Nature works.  So here we see a 6½-minute BBC Earth video showing  terns in the Indian Ocean becoming possible meals for giant trevally (Caranx ignobilis).  It’s natural selection, Jake! But I’m still glad that the bird in the last segment escapes.

Reductions in air pollution have helped warm the planet by cutting down on reflective particles in the atmosphere – but researchers still disagree on the size of this effect

A research team has developed a novel multidimensional sampling theory to overcome the limitations of flat optics. The study not only identifies the constraints of conventional sampling theories in metasurface design but also presents an innovative anti-aliasing strategy that significantly enhances optical performance.

Photosynthesis -- mainly carried out by plants -- is based on a remarkably efficient energy conversion process. To generate chemical energy, sunlight must first be captured and transported further. This happens practically loss-free and extremely quickly. A new study shows that quantum mechanical effects play a key role in this process.

Physicists have achieved a breakthrough in data processing by employing an 'inverse-design' approach. This method allows algorithms to configure a system based on desired functions, bypassing manual design and complex simulations. The result is a smart 'universal' device that uses spin waves ('magnons') to perform multiple data processing tasks with exceptional energy efficiency. This innovation marks a transformative advance in unconventional computing, with significant potential for next-generation telecommunications, computing, and neuromorphic systems.

Physicists have achieved a breakthrough in data processing by employing an 'inverse-design' approach. This method allows algorithms to configure a system based on desired functions, bypassing manual design and complex simulations. The result is a smart 'universal' device that uses spin waves ('magnons') to perform multiple data processing tasks with exceptional energy efficiency. This innovation marks a transformative advance in unconventional computing, with significant potential for next-generation telecommunications, computing, and neuromorphic systems.

Synthetic biologists have developed a prototype for an innovative biosensor that can detect rare earth elements and be modified for a range of other applications.

A research team presents an AI assessor for Hall-effect ion thrusters, the engines of satellites and space probes.

A research team presents an AI assessor for Hall-effect ion thrusters, the engines of satellites and space probes.

A research team presents an AI assessor for Hall-effect ion thrusters, the engines of satellites and space probes.

Physicists have performed a groundbreaking simulation they say sheds new light on an elusive phenomenon that could determine the ultimate fate of the Universe.

Recyclers, battery manufacturers, and electric vehicle manufacturers must work together to revolutionize lithium-ion battery (LIB) recycling processes to meet ever-growing demand for electric vehicles (EVs) and energy storage systems.