Category: 7. Science

What dinosaurs ate has long fascinated scientists. Now, fossilized teeth tell the story in surprising detail. By analyzing chemical traces in tooth enamel, researchers have uncovered distinct diets among Late Jurassic dinosaurs.

A study from The University of Texas at Austin shows that different species did not just live side by side. They also had unique food preferences. These eating habits helped them thrive together without competing for the same plants.

Calcium isotopes in enamel carry chemical fingerprints from ancient meals. Different plants, and even plant parts like bark or buds, leave different traces. This evidence reveals which dinosaurs ate what and how their diets shaped their ecosystem.

“The idea is that they were all eating different things, and now we have found proof of that,” said study lead author Liam Norris, a recent doctoral graduate from UT’s Jackson School of Geosciences.

How dinosaurs lived together

Norris studied fossils from a single deposit at Carnegie Quarry in northeast Utah. This site, rich with bones from herbivorous and carnivorous species, likely formed during an intense drought. Its rapid fossil preservation made it ideal for comparing diets across species living at the same time and place.

The herbivores in the study included Camarasaurus, Camptosaurus, and Diplodocus. Carnivores included the Allosaurus and the croc-like Eutretauranosuchus.

Norris collected enamel samples from 17 individual animals, either accessed in the field or loaned by local museums. At the Jackson School, he conducted isotope analysis with support from co-authors John Lassiter and Aaron Satkoski.

Professor Rowan Martindale called the site “a unique paleontological gem.” The research deepens our understanding of ancient ecosystems and dietary preferences.

Plant-eating dinosaurs had different diets

Earlier theories assumed large herbivores ate from different vertical zones of the forest canopy. But Norris found that diet separation was more nuanced. For example, Camptosaurus favored soft, nutritious plant parts like leaves and buds.

Camarasaurus preferred conifers and tougher, woody plant tissues. Diplodocus had a more varied menu of low-lying ferns, horsetails, and coarse materials.

“This differentiation in diet makes sense with what we see from the morphology of these animals: the different height, the different snout shape. Then, we bring in this geochemical data, which is a very concrete piece of evidence to add to that pot,” said Norris.

These findings support the idea that long-necked dinosaurs had flexible necks allowing them to reach different plant levels. Instead of competing, they targeted specific vegetation patches suited to their anatomy and energy needs.

Diet choices of carnivore dinosaurs

The two carnivores in the study, Allosaurus and Eutretauranosuchus, showed overlapping isotope values, suggesting some dietary similarities. But subtle differences hinted at distinct prey choices and ecological roles.

Allosaurus, a large bipedal predator, likely hunted herbivorous dinosaurs, including Camptosaurus and other smaller or juvenile plant-eaters within the same region. Its size, jaw structure, and teeth suggest active predation or scavenging of large-bodied prey.

Eutretauranosuchus, in contrast, was smaller and more crocodile-like. Its isotope signature indicates it may have consumed fish or small terrestrial vertebrates, likely along rivers or shallow wetlands.

The hunting strategy and habitat of Eutretauranosuchus likely differed greatly from the Allosaurus, reducing competition between the two carnivores despite their coexistence.

These dietary contrasts reflect ecological separation shaped by behavior, anatomy, and environment. Such distinctions help reconstruct predator-prey dynamics within this Jurassic ecosystem.

The overlapping yet diversified food chain reveals how balance existed even during environmental stress, such as the severe drought that led to the rapid fossil preservation at Carnegie Quarry.

Many dinosaurs shared one ecosystem

The fact that so many massive animals thrived together points to a lush, productive ecosystem teeming with plant life. Their dietary specialization hints at a world where resource use was efficient and competition was minimal.

“It’s really just more proof that this ecosystem was as spectacular as we thought it was,” Norris said.

The study offers not just a clearer view of dinosaur life and diet but also a method for understanding other prehistoric ecosystems through geochemistry.

The study is published in the journal Palaeogeography, Palaeoclimatology, Palaeoecology.

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Italy’s Minister for Enterprises and Made in Italy, Adolfo Urso, has announced that Italy will build a residential module for astronauts on the Moon. Here’s what you need to know.

Decoding the news. With the MPH module (Multi-Purpose Habitat), Italy will deliver the first real surface habitat for sustained astronaut presence on the Moon — a mobile, pressurised unit designed to support scientific research and human exploration in extreme environments.

• “This is the result of a clear political vision: establishing Italy as a space power,” Urso said.

What’s on the table? On July 25, Thales Alenia Space — a joint venture between Thales and Leonardo — signed a contract with the Italian Space Agency (ASI) to initiate the preliminary design phase of MPH, under the bilateral cooperation between NASA and ASI within the Artemis program.

• The agreement includes early development of enabling technologies and the concept study of the lunar hardware. Launch is currently scheduled for 2033 from NASA’s Kennedy Space Center.
• MPH is expected to operate for at least ten years and support both crewed and uncrewed missions. It will serve as a permanent lunar base, offering safe shelter for astronauts, enabling scientific experiments, and providing mobility across the lunar surface.

Fly me to the Moon. The module represents Italy’s first direct contribution to the surface architecture of Artemis and NASA’s broader Moon to Mars strategy. It builds on decades of transatlantic cooperation and positions Italy as a key player in future human missions beyond Earth.

• ASI President Teodoro Valente: “MPH reflects our international leadership in space habitability and confirms Italy’s long-term vision in the new space race.”
• The announcement also comes just days after the Italian Parliament passed the country’s first national Space Law, underscoring growing institutional support for the sector.

Industry lead. Thales Alenia Space Italia will act as prime contractor during the two-year design phase, working with ALTEC — a Turin-based aerospace centre co-owned by ASI and Thales Alenia Space — and other Italian industrial partners.

• Core technology development will focus on adapting systems to harsh lunar conditions: temperature extremes, radiation, micrometeorites, lunar dust, and low gravity.
• “We are proud to lead the design of Italy’s first human outpost on the Moon,” said Giampiero Di Paolo, CEO of Thales Alenia Space Italia.

(Photo: ASI, the today’s signature moment)

For years, NASA has monitored a strange anomaly in Earth’s magnetic field: a giant region of lower magnetic intensity in the skies above the planet, stretching out between South America and southwest Africa.

This vast, developing phenomenon, called the South Atlantic Anomaly, has intrigued and concerned scientists for years, and perhaps none more so than NASA researchers.

The space agency’s satellites and spacecraft are particularly vulnerable to the weakened magnetic field strength within the anomaly, and the resulting exposure to charged particles from the Sun.

The South Atlantic Anomaly (SAA) – likened by NASA to a ‘dent’ in Earth’s magnetic field, or a kind of ‘pothole in space’ – generally doesn’t affect life on Earth, but the same can’t be said for orbital spacecraft (including the International Space Station), which pass directly through the anomaly as they loop around the planet at low-Earth orbit altitudes.

During these encounters, the reduced magnetic field strength inside the anomaly means technological systems onboard satellites can short-circuit and malfunction if they become struck by high-energy protons emanating from the Sun.

Related: Humanity Has Dammed So Much Water It’s Shifted Earth’s Magnetic Poles

These random hits may usually only produce low-level glitches, but they do carry the risk of causing significant data loss, or even permanent damage to key components – threats obliging satellite operators to routinely shut down spacecraft systems before spacecraft enter the anomaly zone.

Mitigating those hazards in space is one reason NASA is tracking the SAA; another is that the mystery of the anomaly represents a great opportunity to investigate a complex and difficult-to-understand phenomenon, and NASA’s broad resources and research groups are uniquely well-appointed to study the occurrence.

“The magnetic field is actually a superposition of fields from many current sources,” geophysicist Terry Sabaka from NASA’s Goddard Space Flight Centre in Greenbelt, Maryland explained in 2020.

The primary source is considered to be a swirling ocean of molten iron inside Earth’s outer core, thousands of kilometers below the ground. The movement of that mass generates electrical currents that create Earth’s magnetic field, but not necessarily uniformly, it seems.

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A huge reservoir of dense rock called the African Large Low Shear Velocity Province, located about 2,900 kilometers (1,800 miles) below the African continent, is thought to disturb the field’s generation, resulting in the dramatic weakening effect – which is aided by the tilt of the planet’s magnetic axis.

“The observed SAA can be also interpreted as a consequence of weakening dominance of the dipole field in the region,” said NASA Goddard geophysicist and mathematician Weijia Kuang in 2020.

“More specifically, a localized field with reversed polarity grows strongly in the SAA region, thus making the field intensity very weak, weaker than that of the surrounding regions.”

Satellite data suggesting the SAA is dividing. (Division of Geomagnetism, DTU Space)

While there’s much scientists still don’t fully understand about the anomaly and its implications, new insights are continually shedding light on this strange phenomenon.

For example, one study led by NASA heliophysicist Ashley Greeley in 2016 revealed the SAA slowly drifts around, which was confirmed by subsequent tracking from CubeSats in research published in 2021.

It’s not just moving, however. Even more remarkably, the phenomenon seems to be in the process of splitting in two, with researchers in 2020 discovering that the SAA appeared to be dividing into two distinct cells, each representing a separate center of minimum magnetic intensity within the greater anomaly.

Just what that means for the future of the SAA remains unknown, but in any case, there’s evidence to suggest that the anomaly is not a new appearance.

A study published in July 2020 suggested the phenomenon is not a freak event of recent times, but a recurrent magnetic event that may have affected Earth since as far back as 11 million years ago.

If so, that could signal that the South Atlantic Anomaly is not a trigger or precursor to the entire planet’s magnetic field flipping, which is something that actually happens, if not for hundreds of thousands of years at a time.

A more recent study published in 2024 found the SAA also has an impact on auroras seen on Earth.

Obviously, huge questions remain, but with so much going on with this vast magnetic oddity, it’s good to know the world’s most powerful space agency is watching it as closely as they are.

“Even though the SAA is slow-moving, it is going through some change in morphology, so it’s also important that we keep observing it by having continued missions,” said Sabaka.

“Because that’s what helps us make models and predictions.”

An earlier version of this article was published in August 2020.

For years, NASA has monitored a strange anomaly in Earth’s magnetic field: a giant region of lower magnetic intensity in the skies above the planet, stretching out between South America and southwest Africa.

This vast, developing phenomenon, called the South Atlantic Anomaly, has intrigued and concerned scientists for years, and perhaps none more so than NASA researchers.

The space agency’s satellites and spacecraft are particularly vulnerable to the weakened magnetic field strength within the anomaly, and the resulting exposure to charged particles from the Sun.

The South Atlantic Anomaly (SAA) – likened by NASA to a ‘dent’ in Earth’s magnetic field, or a kind of ‘pothole in space’ – generally doesn’t affect life on Earth, but the same can’t be said for orbital spacecraft (including the International Space Station), which pass directly through the anomaly as they loop around the planet at low-Earth orbit altitudes.

During these encounters, the reduced magnetic field strength inside the anomaly means technological systems onboard satellites can short-circuit and malfunction if they become struck by high-energy protons emanating from the Sun.

Related: Humanity Has Dammed So Much Water It’s Shifted Earth’s Magnetic Poles

These random hits may usually only produce low-level glitches, but they do carry the risk of causing significant data loss, or even permanent damage to key components – threats obliging satellite operators to routinely shut down spacecraft systems before spacecraft enter the anomaly zone.

Mitigating those hazards in space is one reason NASA is tracking the SAA; another is that the mystery of the anomaly represents a great opportunity to investigate a complex and difficult-to-understand phenomenon, and NASA’s broad resources and research groups are uniquely well-appointed to study the occurrence.

“The magnetic field is actually a superposition of fields from many current sources,” geophysicist Terry Sabaka from NASA’s Goddard Space Flight Centre in Greenbelt, Maryland explained in 2020.

The primary source is considered to be a swirling ocean of molten iron inside Earth’s outer core, thousands of kilometers below the ground. The movement of that mass generates electrical currents that create Earth’s magnetic field, but not necessarily uniformly, it seems.

A huge reservoir of dense rock called the African Large Low Shear Velocity Province, located about 2,900 kilometers (1,800 miles) below the African continent, is thought to disturb the field’s generation, resulting in the dramatic weakening effect – which is aided by the tilt of the planet’s magnetic axis.

“The observed SAA can be also interpreted as a consequence of weakening dominance of the dipole field in the region,” said NASA Goddard geophysicist and mathematician Weijia Kuang in 2020.

“More specifically, a localized field with reversed polarity grows strongly in the SAA region, thus making the field intensity very weak, weaker than that of the surrounding regions.”

Satellite data suggesting the SAA is dividing. (Division of Geomagnetism, DTU Space)

While there’s much scientists still don’t fully understand about the anomaly and its implications, new insights are continually shedding light on this strange phenomenon.

For example, one study led by NASA heliophysicist Ashley Greeley in 2016 revealed the SAA slowly drifts around, which was confirmed by subsequent tracking from CubeSats in research published in 2021.

It’s not just moving, however. Even more remarkably, the phenomenon seems to be in the process of splitting in two, with researchers in 2020 discovering that the SAA appeared to be dividing into two distinct cells, each representing a separate center of minimum magnetic intensity within the greater anomaly.

Just what that means for the future of the SAA remains unknown, but in any case, there’s evidence to suggest that the anomaly is not a new appearance.

A study published in July 2020 suggested the phenomenon is not a freak event of recent times, but a recurrent magnetic event that may have affected Earth since as far back as 11 million years ago.

If so, that could signal that the South Atlantic Anomaly is not a trigger or precursor to the entire planet’s magnetic field flipping, which is something that actually happens, if not for hundreds of thousands of years at a time.

A more recent study published in 2024 found the SAA also has an impact on auroras seen on Earth.

Obviously, huge questions remain, but with so much going on with this vast magnetic oddity, it’s good to know the world’s most powerful space agency is watching it as closely as they are.

“Even though the SAA is slow-moving, it is going through some change in morphology, so it’s also important that we keep observing it by having continued missions,” said Sabaka.

“Because that’s what helps us make models and predictions.”

An earlier version of this article was published in August 2020.

Related News

Recent NASA budget uncertainties could make one space agency endeavor up for grabs — defending Earth from incoming space rocks.

That effort, undertaken by NASA for many years, could be given to the U.S. Space Force, which has a much bigger new budget.

In a discovery that feels ripped from the pages of cosmic poetry, astronomers have found a galaxy shaped like the infinity symbol, and nestled at its heart may be something even more extraordinary: a newborn supermassive black hole.

Yale astronomer Pieter van Dokkum and his team stumbled upon this celestial oddity while combing through images from NASA’s James Webb Space Telescope. What they saw was jaw-dropping: two galaxies amid a collision, their swirling stars forming a glowing figure eight. And right in the center, not in either galactic nucleus, but between them, sat a black hole, embedded in a cloud of gas and actively feeding.

“This is as close to a smoking gun as we’re likely ever going to get,” van Dokkum said.

This isn’t just a cool-shaped galaxy. It could rewrite our understanding of how black holes form.

Scientists detected a chirp of a baby black hole

Traditionally, scientists believed that black holes formed from the remnants of dying stars, small “light seeds” that slowly merged over time. But Webb has already spotted massive black holes too early in the universe’s timeline for that theory to hold up.

Enter the ‘heavy seeds’ theory, championed by Yale astrophysicist Priyamvada Natarajan. It suggests black holes can form directly from collapsing gas clouds, skipping the star stage entirely. The Infinity galaxy might be the first real-world example of that process in action.

According to van Dokkum, the two disk galaxies collided, compressing their gas into dense knots. One of those knots may have collapsed into the black hole now visible as a glowing region between the galactic cores. It’s a rare event, but similar conditions were likely common in the early universe.

As the evidence builds, one detail stands out with cosmic clarity: the black hole isn’t situated within the core of either galaxy. Instead, it occupies a curious position between them, a gravitational outsider lodged at their center. What’s more, it’s not idle.

This black hole is voraciously feeding, pulling in surrounding material and growing larger with each passing moment. Enveloping it is a cloud of ionized gas, signaling the kind of intense compression astronomers associate with high-energy, transformative cosmic events. Altogether, these signs suggest something rare and spectacular.

The team used data not just from Webb but also from the Keck Observatory, Chandra X-ray Observatory, and the Very Large Array to confirm their findings. Still, they say more research is needed to be sure this is truly a black hole being born.

But if it is? We may be witnessing something no one has ever seen before: the birth of a cosmic giant.

Journal References:

1. Pieter van Dokkum, Gabriel Brammer, Josephine F. W. Baggen, Michael A. Keim, Priyamvada Natarajan, Imad Pasha. The Infinity Galaxy: a Candidate Direct-Collapse Supermassive Black Hole Between Two Massive, Ringed Nuclei. The Astrophysical Journal Letters. DOI: 10.48550/arXiv.2506.15618
2. Pieter van Dokkum, Gabriel Brammer, Connor Jennings, Imad Pasha, Josephine F. W. Baggen. Further Evidence for a Direct-Collapse Origin of the Supermassive Black Hole at the Center of the Milky Way. The Astrophysical Journal Letters. DOI: 10.48550/arXiv.2506.15619

The Earth has been spinning unusually fast recently. Last year on July 4, our planet set a record by completing a full spin 1.66 milliseconds (0.00166 seconds) faster than usual, according to timeanddate.com. One year later, on July 10, 2025, Earth completed a daily rotation that scientists estimate was 1.36 milliseconds faster than usual, giving us another particularly short day. Other shorter (but ever-so-slightly longer) days occurred on July 9 and July 22, although the exact margins have yet to be confirmed.

Losing a couple milliseconds may seem insignificant to most of us—perhaps justifiably so. But tiny error margins in time can mess up systems that depend on extremely precise calculations, such as high-speed communication networks, GPS, or banking systems. As such, scientific timekeepers use highly sophisticated atomic clocks to set the standard via the Coordinated Universal Time (UTC). But with the recent acceleration in Earth’s rotation, the need for a “negative” leap second has re-emerged among some timekeeping experts. 

Scientists regularly apply a leap second to keep UTC synchronized with astronomical time, which they base on Earth’s rotation. A full day on Earth—the time it takes our planet to complete one full rotation on its axis—lasts for 86,400 seconds. But factors such as the Sun’s position, the Moon’s orbit, and Earth’s gravitational field influence how quickly the Earth completes its daily cycle. As a result, Earth’s rotation ends up being irregular, and slight differences between UTC and astronomical time can add up in the long run, causing a mismatch between the two.

Leap seconds correct for this deviation. By the same logic, a negative leap second would subtract an extra second from UTC to account for the milliseconds we’re losing from Earth’s faster rotation. Now, this may seem perfectly reasonable, but not all scientists agree. In fact, some scientists found the leap second so problematic that, in 2020, an international group of experts voted to phase out the practice by 2035. 

As computing networks became more globally interconnected, the leap second began to cause “failures and anomalies in computing systems,” Patrizia Tavella, director of the International Bureau of Weights and Measures’ time department, told Live Science in a 2022 interview. Moreover, countries account for leap seconds in different ways, causing major complications for airlines scheduling international flights, she said.

Critics of the proposed negative leap second cite similar concerns. To be clear, no formal institution or body is currently advocating for the negative leap second. But should that happen, squeezing in the negative leap second to our timekeeping system will be difficult given the increasingly interconnected nature of our society, Darryl Veitch, a computer networking expert, explained to Live Science in a recent interview. 

“There are continuing problems with the insertion of positive leap seconds even after 50 years,” Judah Levine, a physicist at the University of Colorado, told Live Science. “And this increases the concerns about the errors and problems of a negative leap second.”

It seems unlikely, therefore, that scientists will actually adopt the negative leap second, especially since they’ve already decided to retire the positive leap second. But given Earth’s recent shorter daily spins, astronomical time might eventually fall behind UTC, forcing the need for negative leap seconds. Levine puts the likelihood of this happening at 30% in the next decade or so, although last year, Duncan Carr Agnew, an oceanographer at the Scripps Institution of Oceanography, argued in a paper from last year that this could occur as early as 2029. However, Veitch also believes our planet might slow down soon, which would be consistent with longer-term trends on record.

But we’ll just have to see—and you can, too! Timekeepers estimate that our next “short” day will fall on August 5.

• New research shows that metasurfaces could be used as strong linear quantum optical networks
• This approach could eliminate the need for waveguides and other conventional optical components
• Graph theory is helpful for designing the functionalities of quantum optical networks into a single metasurface

In the race toward practical quantum computers and networks, photons — fundamental particles of light — hold intriguing possibilities as fast carriers of information at room temperature. Photons are typically controlled and coaxed into quantum states via waveguides on extended microchips, or through bulky devices built from lenses, mirrors, and beam splitters. The photons become entangled – enabling them to encode and process quantum information in parallel – through complex networks of these optical components. But such systems are notoriously difficult to scale up due to the large numbers and imperfections of parts required to do any meaningful computation or networking.

Could all those optical components could be collapsed into a single, flat, ultra-thin array of subwavelength elements that control light in the exact same way, but with far fewer fabricated parts?

Optics researchers in the Harvard John A. Paulson School of Engineering and Applied Sciences (SEAS) did just that. The research team led by Federico Capasso, the Robert L. Wallace Professor of Applied Physics and Vinton Hayes Senior Research Fellow in Electrical Engineering, created specially designed metasurfaces — flat devices etched with nanoscale light-manipulating patterns — to act as ultra-thin upgrades for quantum-optical chips and setups.

The research was published in Science and funded by the Air Force Office of Scientific Research (AFOSR).

Capasso and his team showed that a metasurface can create complex, entangled states of photons to carry out quantum operations – like those done with larger optical devices with many different components.

“We’re introducing a major technological advantage when it comes to solving the scalability problem,” said graduate student and first author Kerolos M.A. Yousef. “Now we can miniaturize an entire optical setup into a single metasurface that is very stable and robust.”

Metasurfaces: Robust and scalable quantum photonics processors

Their results hint at the possibility of paradigm-shifting optical quantum devices based not on conventional, difficult-to-scale components like waveguides and beam splitters, or even extended optical microchips, but instead on error-resistant metasurfaces that offer a host of advantages: designs that don’t require intricate alignments, robustness to perturbations, cost-effectiveness, simplicity of fabrication, and low optical loss. Broadly speaking, the work embodies metasurface-based quantum optics which, beyond carving a path toward room-temperature quantum computers and networks, could also benefit quantum sensing or offer “lab-on-a-chip” capabilities for fundamental science

Designing a single metasurface that can finely control properties like brightness, phase, and polarization presented unique challenges because of the mathematical complexity that arises once the number of photons and therefore the number of qubits begins to increase. Every additional photon introduces many new interference pathways, which in a conventional setup would require a rapidly growing number of beam splitters and output ports.

Graph theory for metasurface design

To bring order to the complexity, the researchers leaned on a branch of mathematics called graph theory, which uses points and lines to represent connections and relationships. By representing entangled photon states as many connected lines and points, they were able to visually determine how photons interfere with each other, and to predict their effects in experiments. Graph theory is also used in certain types of quantum computing and quantum error correction but is not typically considered in the context of metasurfaces, including their design and operation.

The resulting paper was a collaboration with the lab of Marko Loncar, whose team specializes in quantum optics and integrated photonics and provided needed expertise and equipment.

“I’m excited about this approach, because it could efficiently scale optical quantum computers and networks — which has long been their biggest challenge compared to other platforms like superconductors or atoms,” said research scientist Neal Sinclair. “It also offers fresh insight into the understanding, design, and application of metasurfaces, especially for generating and controlling quantum light. With the graph approach, in a way, metasurface design and the optical quantum state become two sides of the same coin.”

The research received support from federal sources including the AFOSR under award No. FA9550-21-1-0312. The work was performed at the Harvard University Center for Nanoscale Systems

Imagine you’re watching a balloon inflate, but instead of slowing down as it gets bigger, it keeps expanding faster and faster. That’s essentially what scientists discovered about our universe in 1998 using exploding stars called supernovae. They found that some unknown force, which was subsequently named “dark energy” was pushing space itself apart at an accelerating rate. Now, after analyzing over 2,000 of these stellar explosions, researchers have found hints that dark energy might not be as constant as we thought. It may actually be changing, and possibly weakening over time.

A supernova was captured in the Pinwheel Galaxy in 2011 and named SN2011fe (Credit : Thunderf00t)

Type Ia supernovae are incredibly bright explosions that occur when a specific type of dead star, called a white dwarf, accumulates too much material and explodes. They’re so bright that they can be seen across billions of light years, and crucially, they all shine with roughly the same brightness.

This predictability of the brightness makes them perfect “standard candles” for measuring distances in space. Just like you could estimate how far away a streetlight is based on how bright it appears, astronomers can calculate how far these supernovae are from Earth. But here’s the key, by also measuring how much the light from these explosions has been stretched or redshifted by the expansion of space, it’s possible to figure out how fast the universe was expanding at different times in the past.

Since that Nobel Prize winning discovery in 1998, astronomers have spotted more than 2,000 Type Ia supernovae using different telescopes and techniques. But there was a problem, comparing data from different sources was like trying to compare measurements taken with different rulers. Each telescope and survey had its own calibrations and differences.

Schematic of the Type 1a supernova process (Credit : NASA, ESA and A. Feild (STScI))

To solve this, an international team called the Supernova Cosmology Project spent years creating something called “Union3”, the largest standardised dataset of supernovae ever assembled. They painstakingly analysed 2,087 supernovae from 24 different datasets, adjusting for all the differences between telescopes and surveys to put everything on the same scale. When the team analysed this massive, standardised dataset using statistical methods, they found something intriguing. The data suggests that dark energy might not have stayed constant throughout history.

“Dark energy makes up almost 70% of the universe and is what drives the expansion, so if it is getting weaker, we would expect to see expansion slow over time” – David Rubin, the study’s lead author from the University of Hawaii.

This potential change in dark energy has huge implications for the ultimate fate of our universe. Currently, researchers work with a model called Lambda CDM, where dark energy (Lambda) stays constant over time and counteracts the gravitational pull of matter (cold dark matter, or CDM). But if dark energy is actually weakening then the model could play out very differently. If dark energy wins over gravity, the universe continues expanding forever, potentially leading to a “Big Rip” where space expands so fast that even atoms get torn apart. If gravity wins, the expansion could slow down, stop, or even reverse into a “Big Crunch” where everything collapses back together. If they balance, the universe might reach a steady state.

What makes this discovery particularly exciting is that it’s not coming from just one source. A separate study called the Dark Energy Spectroscopic Instrument (DESI), which studies how galaxies cluster together, is seeing similar hints that dark energy might be evolving.

The researchers aren’t ready to definitively declare that dark energy is changing—the evidence, while intriguing, isn’t quite strong enough yet. Over the next year, they plan to add several hundred more supernovae to their dataset, which should provide even more precise measurements. Looking further ahead, new telescopes like the Vera C. Rubin Observatory and the Nancy Grace Roman Space Telescope are expected to discover tens of thousands of additional supernovae over the coming decade.

Source : Largest supernova dataset hints dark energy may be changing over time