Category: 7. Science

Impact craters exist on every continent on Earth. While many have eroded away or been buried by geologic activity, some remain visible from the ground and from above. This week, we revisit stories featuring some of our most captivating satellite images of impact sites around the planet. The images and text on this page were originally published on September 1, 2018.

About two billion years ago, an asteroid measuring at least 10 kilometers across hurtled toward Earth. The impact occurred southwest of what is now Johannesburg, South Africa, and temporarily made a 40-kilometer-deep and 100-kilometer-wide dent in the surface. Almost immediately after impact, the crater widened and shallowed as the rock below started to rebound and the walls collapsed. The world’s oldest and largest known impact structure was formed.

Scientists estimate that when the rebound and collapse ceased, Vredefort Crater measured somewhere between 180 and 300 kilometers wide. But more than 2 billion years of erosion has made the exact size hard to pin down.

“If you consider that the original impact crater was a shallow bowl like you would serve food in, and you were able to slice horizontally through the bowl progressively, you would see that the bowl’s diameter will decrease with each slice you take off,” said Roger Gibson of University of the Witwatersrand and an expert on impact processes. “For this reason, we are unable to categorically fix where the edge now lies.”

According to Gibson, the uplift at the center of the impact was so strong that a 25-kilometer section of Earth’s crust was turned on end. The various layers of upturned rock eroded at different rates and produced the concentric pattern still visible today. Vredefort Dome, which measures about 90 kilometers across, was observed on June 27, 2018, by the Operational Land Imager (OLI) on Landsat 8.

Notice that only part of the ring is visible. That’s because areas to the south have been paved over by rock formations that are less than 300 million years old. The young rock formations have begotten fertile soils that are intensely cultivated.

The darker ring in the center of this image, known as the Vredefort Mountainland, has shallow soils with steep terrain not suitable for farming, so the area remains naturally forested. Along the ridges in the Mountainland you can see white lines: these are the hardest layers of rock, such as quartzite, which resist erosion. The outer part of Mountainland has exposed rocks that are roughly 2.8 billion years old; this is the Central Rand Group, the source of more than one-third of all gold mined on Earth.

Visitors to the impact site today can witness geologic time by traversing just 50 kilometers from Potchefstroom toward Vredefort. The journey would take you from shallow crustal sedimentary rocks deposited between 2.5 and 2.1 billion years ago, ending with 3.1- to 3.5-billion-year-old granites and remnants of ocean crust that were once about 25 kilometers below Earth’s surface.

“Such exposed crustal sections are incredibly rare on Earth,” Gibson said. “The added bonus here is that the rocks preserve an almost continuous record spanning almost one-third of Earth’s history.”

NASA Earth Observatory image by Lauren Dauphin, using Landsat data from the U.S. Geological Survey. Story by Kathryn Hansen.

Research at the University of Wisconsin-Madison drives innovation, saves lives, creates jobs, supports small businesses, and fuels the industries that keep America competitive and secure. It makes the U.S.-and Wisconsin-stronger. Federal funding for research is a high-return investment that’s worth fighting for. Learn more about the impact of UW-Madison’s federally funded research and how you can help.

Lingjun Li, a professor in the University of Wisconsin-Madison School of Pharmacy and Department of Chemistry, has spent decades developing powerful new ways to measure and map the molecular machinery of life.

Recently, Li and her collaborators at UW-Madison and the Howard Hughes Medical Institute introduced a new imaging technology that has the power to reveal biomolecular detail in tissues like cancer tumors in their native environments and at unprecedented resolution. That technology, recently reported in Nature Methods, has been described as a potential game-changer for biomedical researchers.

Li’s track record for advancing mass spectrometry and other techniques earned her a spot on The Analytical Scientist’s 2024 Power List, and she recently received a Kellett Mid-Career Award from the UW-Madison Office of the Vice Chancellor for Research. The award honors mid-career tenured faculty who have made key research contributions in their field.

Here, Li reflects on her lab’s interdisciplinary research, the importance of spatial molecular imaging, and how tools like AI and mass spectrometry are shaping the future of biomedical science.

Can you describe your research background and what brought you to UW-Madison?

I’m a bioanalytical chemist by training – my background is in analytical and biomolecular chemistry. I did a unique postdoc, spending a year at Pacific Northwest National Lab working on high-end mass spectrometry-based proteomics, and another year at Brandeis University in a neurobiology lab using crabs and lobsters as model organisms. I joined UW-Madison in December 2002 to combine mass spectrometry technology development with fundamental neuroscience research, always with the goal of improving human health.

How has your lab’s focus evolved since then?

Initially, we aimed to discover nervous system biomolecules called neuropeptides and understand their function. Over time, we’ve expanded to studying a wide variety of biomolecules – proteins, peptides, lipids, metabolites, glycans – and their spatial distributions in tissues. Mass spectrometry allows us to look at all of these molecules with high specificity. A major focus now is understanding how these molecules contribute to diseases like Alzheimer’s, work that we’re doing in collaboration with the Wisconsin Alzheimer’s Disease Research Center.

What makes mass spectrometry a powerful tool for your work?

Mass spectrometry measures the mass of molecules and can provide structural information about them. For proteins, we can determine amino acid sequences and their modifications. For lipids and metabolites, we can distinguish structural isomers – molecules with the same mass but different chemical bonds. That structural detail can be crucial, for example, in distinguishing cancer cells from healthy cells.

What’s the significance of spatial context in molecular imaging?

Cells, even adjacent neurons, can use different chemical messengers. Without spatial information, you lose context about how molecules function in specific areas. In cancer, for instance, being able to see tumor heterogeneity at a fine level could influence treatment strategies. That’s why we’re focused on imaging techniques that retain spatial resolution.

Your lab recently helped develop a new mass spectrometry imaging technique that’s been described as a game-changer. What’s new about it?

We integrated tissue expansion microscopy with mass spectrometry imaging. Traditional imaging mass spectrometry lacks spatial resolution and loses the important context of how molecules behave in their natural environment within tissue. By physically expanding the tissue under mild conditions, we preserve its molecular composition and native structure while achieving higher resolution without needing fancy or expensive new hardware. That makes this approach, led by Hua Zhang in my lab, both powerful and accessible.

Why is making this new technique accessible important to you?

We want this to be open and available to biomedical researchers everywhere. Anyone with a commercial mass spectrometer can use the technique, and tissue expansion itself follows a straightforward protocol. What’s exciting is that you can achieve higher resolution without expensive new equipment or long acquisition times. That opens up mass spectrometry imaging to more biologists – helping them investigate molecular detail down to the single-cell level.

How do you see analytical science contributing to broader research and societal needs?

Analytical science is central to so many disciplines. It’s not just about supporting other research – it’s a science of measurement. Whether it’s environmental pollutants like PFAS or biomarkers in human disease, we need tools that are sensitive and precise. Mass spectrometry-based approaches are increasingly seen as foundational tools in biological discovery. Analytical science enables system-level investigations that not only uncover new biological mechanisms but also inspire the development of innovative hypotheses and transformative technologies.

How is your lab thinking about AI and machine learning in this space?

We’re generating huge volumes of data. Machine learning can help us translate these data into biological and clinical insights. We already use clustering and algorithmic tools for things like neuropeptide identification and single-cell analysis. Collaborating with statisticians and developing new software is key to managing this complexity. AI has great potential for biomarker discovery and predictive modeling in precision medicine.

What makes your lab environment unique?

We’re very interdisciplinary. My group includes students and postdocs from analytical chemistry, pharmaceutical sciences and biophysics. That diversity helps us tackle big, meaningful problems. And analytical science is very practical – it not only advances health-related research but also prepares our trainees for real-world careers in academia, industry and public health.

What motivates your continued focus on technology development?

Our goal is always to develop tools that can improve human health. We don’t build technology for its own sake – it’s always about enabling discovery. Whether it’s understanding disease mechanisms, identifying early biomarkers, or informing treatment strategies, analytical science has the potential to make a real difference.

The research that led to the new technology recently described in Nature Methods was supported in part by the National Institutes of Health (grants R01AG078794, R01DK071801, R01AG052324, P01CA250972 and DP1DK113644) and the U.S. Department of Agriculture (2018-67001-28266).

Ocean health is moving into a danger zone, with rampant human-caused carbon dioxide emissions having already pushed ocean acidification levels beyond safe limits in large swaths of the marine environment, according to a recent study. The new findings underline the urgent need to ramp up protection of the world’s oceans, while simultaneously slashing CO₂ emissions, say experts.

But from a scientific perspective, worsening ocean acidification is not an overly surprising finding, considering that carbon dioxide emissions remain high, says lead author Helen Findlay, a biological oceanographer at the Plymouth Marine Laboratory in the UK

Researchers have known for decades that humanity’s CO₂ emissions are being absorbed by seawater, triggering chemical reactions that release hydrogen ions, in turn reducing the abundance of carbonate ions. This ocean acidification process — which has escalated in tandem with atmospheric emissions — has implications for a large number of ocean-dwelling calcifying species that rely on calcium carbonate for their shells, with harm to those species potentially reverberating throughout marine ecosystems.

“We have really good data sets, and the data sets and this paper really just emphasise that we’re just watching the system crash.… [W]e need to be making real change now so that we don’t make things worse,” Findlay says.

“In my assessment, [this new paper] confirms what we’ve been expecting,” agrees Johan Rockström, director of the Potsdam Institute for Climate Impact Research in Germany, who was not involved in the current study. “[W]e are unfortunately moving beyond the safe boundary on ocean acidification.”

Rockström’s international team — known for their groundbreaking planetary boundary research — is working on an updated Planetary Health Check, due out in September. Last year’s inaugural report found ocean acidification on the cusp of transgression. But evidence from multiple sources is now pointing to this boundary being crossed, he says. “It’s too early to say conclusively, but I think this [new] paper is important in that context.”

Mounting evidence of worsening ocean acidification should trigger a “much more ambitious level of ocean protection,” along with rapid climate action, Rockström says. “When you add one additional stressor, like ocean acidification, you have an even stronger argument to protect [marine systems] because they’re getting weaker under the pressure of multiple stressors.”

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For all efforts to protect the ocean, it would be beneficial to stop emissions. The way forward is… to stop CO₂ emissions, and then the natural systems over time, over a long time, will help us bring things back into balance.

Hans-Otto Pörtner, marine biologist, Alfred Wegener Institute

Acidification widespread, and runs deep

Findlay’s team found that four of seven ocean basins have crossed the planetary boundary for ocean acidification — with polar waters and ocean upwelling areas particularly affected.

They also found that this acidification picture becomes worse when one looks deep below the ocean’s surface. The authors found that 60 per cent of the world’s ocean has crossed the safe limit down to 200 meters (656 feet) depth, compared to 40 per cent of surface waters.

That’s concerning for marine life, Findlay says, as this part of the water column is where much of Earth’s marine biodiversity thrives.

Rockström and an international team of planetary boundary scientists working out of Sweden’s Stockholm Resilience Centre previously set the safe limit for ocean acidification at 20 per cent aragonite saturation (aragonite being a form of calcium carbonate). But Findlay and her team, after assessing the acidification tolerances of a wide range of species and inspecting regional data, propose a 10 per cent aragonite saturation safe limit to ensure functional integrity of ocean ecosystems.

Concerningly, that would push the crossing of the safe space back to 2000.

The researchers found that rising ocean acidification levels have already caused “significant declines” in habitat for some calcifying creatures. According to their study, tropical and subtropical coral reefs have lost 43 per cent of their suitable habitat. Polar pteropods, a free-swimming form of planktonic marine snail, and a key part of the food chain, have lost 61 per cent of their suitable habitat, while coastal bivalves have lost 13 per cent.

“It’s quite frustrating to now be at a point where we’re saying, well actually, if we wanted a really good system — to be healthy and safe [for] all these ecosystems — we need to have gone back and kept [ocean acidification] at year 2000 levels,” Findlay says.

However, experts emphasise that current levels of acidification are not an immediate death knell for ocean life. But they do note that these rising levels are greatly concerning when factoring in the bombardment of the world’s oceans by other stressors including climate change-induced marine heatwaves, declining ocean oxygen levels, eutrophication, and more direct anthropogenic impacts such as overfishing and pollution from far-ranging sources including microplastics and raw sewage.

We need to see ocean acidification “as a component of other challenges that can make things worse,” says Hans-Otto Pörtner, a marine biologist at Germany’s Alfred Wegener Institute, former co-chair of the Intergovernmental Panel on Climate Change (IPCC) Working Group II who wasn’t involved in the recent study.

He emphasises that the risks posed by interactions between acidification, heating and oxygen loss are all driven by human carbon emissions. “My more holistic view would be that the interaction of these three [factors], in terms of Earth history … have been a driver for evolutionary mass extinctions.”

“The findings are certainly concerning for coral reefs and bivalves and many other organisms that rely on calcium for their shells and their skeletons,” adds Helen Fox, a senior scientist at the Coral Reef Alliance, California, who wasn’t involved in the recent research. “Corals are already suffering from an onslaught of impacts. We are still in the midst of the fourth global bleaching event. So there has already been a lot of death and habitat loss from bleaching.”

Urgency for ocean protection

Globally, marine protection lags far behind land efforts, say conservationists. But there is building momentum on the back of the just-concluded 2025 UN Ocean Conference. In recent weeks, a raft of new Marine Protected Areas (MPAs) and ocean protection commitments were announced, as nations moved toward ratifying the Agreement on Marine Biological Diversity of Areas beyond National Jurisdiction, also known as the High Seas Treaty.

This international agreement aims to push forward protection of 30 per cent of the world’s oceans by 2030 while establishing legal mechanisms for protection of high seas areas. Fifty countries have ratified the treaty so far, but 60 are needed for it to come into force.

Findlay says her team’s acidification findings should add impetus for nations who have yet to ratify the accord. “Any additional protection that’s placed on the ocean, provides an opportunity for ecosystem resilience against harder-to-solve issues, such as [ocean acidification],” she says. “However, [our findings] should also be a motivation to cut emissions, given that [acidification] and climate change are a [dual] threat to marine biodiversity, which this treaty aims to protect.”

In a June 2025 Nature commentary, Rockström and other scientists, including eminent marine biologist Sylvia Earle, warned that the high seas treaty, though important, will likely take years to put into action. They argue that urgent steps are needed immediately to protect the world’s oceans from all forms of exploitation.

“Given the urgency of addressing the climate and biodiversity crises, the world can’t wait another decade to fix the problems humans have created,” they write. “Ocean life is too precious and important to lose, and shifts in the chemical and physical environments of the sea, once made, will be irreversible on timescales of centuries to millennia.”

“For the high seas, 30 by 30 is not enough,” Rockström tells Mongabay. “We should halt 100 per cent of the high seas overexploitation with industrial fishing [and] industrial trawling and forbid all forms of deep-sea mining.”

Others say ocean protection must become far more adaptive in the face of rapidly changing ocean chemistry. That includes identifying and targeting conservation action in marine areas that could act as climate refugia for particularly vulnerable ecosystems.

“We talk about refugia in terms of heat. We do not talk about them in terms of other aspects, such as ocean chemistry, and we need to,” says Daniela Shmidt, a professor at the School of Earth Science at the University of Bristol, England, who wasn’t involved in the recent study. In-depth metrics on ocean acidification, warming and other marine changes could help identify key areas to protect, she adds. “We can’t protect all the world. So we need to know where our efforts are best placed.”

Addressing the root cause: Fossil fuels

All experts Mongabay interviewed for this story agree: The number one solution to address ocean acidification is to aggressively tackle its root cause — the continuing carbon emissions driving the uptake of CO₂ in the oceans.

Researchers recently warned that the window to keep warming below the 1.5°C (2.7°F) Paris Agreement target is rapidly closing, with only three years left. Several analyses have concluded that, barring a drastic course correction, the world is rushing toward a catastrophic 2-3°C (3.6-5.4°F) rise in temperature over preindustrial levels by 2100.

But even if atmospheric CO₂ levels were reduced today, the consequences of ocean acidification will remain with us for centuries as the oceans continue to soak up the CO₂ altering the sea chemistry and pH.

Experts stress that net zero and net negative approaches will be needed to protect oceans, including some geoengineering solutions that involve CO₂ removal (CDR) on land and sea — even though these technologies remain in their infancy, requiring much testing and scaling up.

Reducing ocean acidification will likely require novel methods, such as ocean alkalinity enhancement or electrochemical approaches. But these techniques come with still poorly understood consequences for marine life and ecosystems.

“We all know that reduction in CO₂ [emissions] is … the most important step. But maybe for some of the … really critical [marine] ecosystems, we might need additional adaptation or mitigation approaches,” says Nina Bednarsek, assistant professor of senior research at Oregon State University and a co-author on the recent paper.

CDR technologies will be necessary to a degree, agrees Rockström. “There’s not one climate scenario that you see that can hold 1.5° Celsius [2.7° Fahrenheit] and still giving us a little sliver of a remaining carbon budget for an orderly phase out of coal, oil and gas, without assuming very optimistic scaling of CDR.”

But he draws the line at more aggressive geoengineering approaches. “These are technologies that involve such a large-scale manipulation of the Earth system, with not well-understood and potentially catastrophic side effects, that they should, under all circumstances, be avoided,” he says. “Many of them will not even solve the problem, because [while] they could temporarily reduce the temperature, they wouldn’t get rid of the stress of acidification in the ocean.”

Pörtner is sceptical of geoengineering methods that add material to the ocean at a global scale, and instead emphasises the need to slash emissions and raise ocean protections. “For all efforts to protect the ocean, it would be beneficial to stop emissions,” he says. “The way forward is … to stop CO₂ emissions, and then the natural systems over time, over a long time, will help us bring things back into balance.”

“This doesn’t have to be all doom and gloom in terms of all ocean life … dying,” says Bednarsek. Instead, the passing of the safe threshold for ocean acidification should be viewed as an “early warning” spurring us to act. “This sort of knowledge is absolutely critical. It’s not just… to be alarmist. It’s … so we can do something about this.”

This story was published with permission from Mongabay.com.

Most people will never see Antarctic sea ice up close, but its presence or absence affects our day-to-day lives.

Now scientists are questioning whether a ‘regime shift’ to a new state of diminished Antarctic sea-ice coverage is underway, due to recent record lows.

If so, it will have impacts across climate, ecological and societal systems, according to new research published in PNAS Nexus.

These impacts include ocean warming, increased iceberg calving, habitat loss and sea-level rise, and effects on fisheries, Antarctic tourism, and even the mental health of the global human population.

Led by Australian Antarctic Program Partnership oceanographer Dr Edward Doddridge, the international team assessed the impacts of extreme summer sea-ice lows, and the challenges to predicting and mitigating change.

“Antarctic sea ice provides climate and ecosystem services of regional and global significance,” Dr Doddridge said.

“There are far reaching negative impacts caused by sea-ice loss.

“However, we do not sufficiently understand the baseline system to be able to predict how it will respond to the dramatic changes we are already observing.

“To predict future changes, and to potentially mitigate the negative impacts of climate change on Antarctica, we urgently need to improve our knowledge through new observations and modelling studies.”

What’s at stake?

While sea-ice loss affects many things, the research team identified three key impacts:

• Reduced summer sea-ice cover exposes more of the ocean to sunlight. This leads to surface water warming that promotes further sea-ice loss. Ocean warming increases melting under glacial ice shelves, which could lead to increased iceberg calving. Warmer water also affects the flow of deep-water currents that help move ocean heat around the globe, influencing the planet’s climate.
• Sea-ice loss exposes the ice shelves that fringe the Antarctic continent to damaging ocean swells and storms. These can weaken the ice shelves, leading to iceberg calving. As ice shelves slow the flow of ice from the interior of the Antarctic continent to the coast, iceberg calving allows this interior ice flow to speed up, contributing to sea-level rise.
• Sea ice provides breeding habitat for penguin and seal species, and a refuge for many marine species from predators. It is also an important nursery habitat and source of food (sea-ice algae) for Antarctic krill – an important prey species for many Southern Ocean inhabitants. Adverse sea-ice conditions that persist over several seasons could see population declines in these sea-ice dependent species.

The research team also identified socio-economic and wellbeing impacts, affecting fisheries, tourism, scientific research, ice-navigation, coastal operations, and the mental health (climate anxiety) of the global population.

For example, shorter sea-ice seasons will reduce the window for over-ice resupplies of Antarctic stations. There could also be increased shipping pressures on the continent, including from alien species incursions, fuel spills and an increase in the number and movement of tourist vessels to and from new locations.

Research co-author and sea-ice system expert, Dr Petra Heil, from the Australian Antarctic Division, said the paper highlighted the need for ongoing, year-round, field-based and satellite measurements of circumpolar sea-ice variables (especially thickness), and sub-surface ocean variables.

This would allow integrated analyses of the Southern Ocean processes contributing to the recent sea-ice deficits.

“As shown in climate simulations, continued greenhouse gas emissions, even at reduced rate, will further accelerate persistent deficits of sea ice, and with it a lack of the critical climate and ecosystem functions it provides,” Dr Heil said.

“To conserve and preserve the physical environment and ecosystems of Antarctica and the Southern Ocean we must prioritise an immediate and sustained transition to net zero greenhouse gas emissions.

“Ultimately our decison for immediate and deep action will provide the maximum future proofing we can have in terms of lifestyle and economic values.”

Learn more about Antarctic sea ice in our feature Sea ice in crisis.

New research has for the first time tracked ice shelf, sea ice and ocean swell wave conditions over multiple years in the lead-ups to three large-scale iceberg ‘calving’ events in Antarctica, revealing common patterns.

Iceberg calving is the process where chunks of ice break off from glaciers, ice shelves, or icebergs, and fall into the surrounding water.

Published in Nature Geoscience, the study, led by the Universities of Melbourne and Adelaide, found long periods of sea ice loss surrounding the ice shelves in the six to 18 months prior to calving, as well as the collapse of the ‘landfast’ sea ice attached to the ice shelves only weeks prior to the calving events.

University of Melbourne Professor Luke Bennetts explained that the researchers also developed a novel mathematical model to quantify the ice shelf flexing caused by the huge Southern Ocean swells.

“Sea ice is retreating at an unprecedented rate all around Antarctica and our work suggests this will put further pressure on already thinned and weakened ice shelves,” Professor Bennetts said.

“This could lead to more large-scale calving events, with profound implications for the future of global sea levels.”

The Antarctic Ice Sheet is the thick layer of ice that sits on top of Antarctica. It holds enough fresh water to raise current sea levels by over 50 metres.

Ice shelves are floating platforms formed as glaciers flow off the Antarctic continent onto the ocean, whereas sea ice forms when the surface of the ocean freezes.

“Except for a relatively short period around summer, sea ice creates a protective barrier between the ice shelves and the potentially damaging swells of the Southern Ocean,” Professor Bennetts said.

“Without this barrier, the swells can bend and flex pre-weakened ice shelves until they break.”

Professor Bennetts said previous research has shown that warming temperatures are causing more rapid melting and more frequent ‘calving’ of icebergs from some ice shelves.

“Increased melting and calving does not directly increase sea levels as the ice shelves are already floating on the ocean, but it reduces the ability of the ice shelves to push back against the glacial flow into the ocean – which does raise sea levels,” he said.

There is currently no observation system for routinely recording ocean waves in Antarctic sea ice and ice shelves, so mathematical modelling is essential to quantify the connection between the observed ocean swells, sea ice conditions and the response of the ice shelves.

The research was funded by the Australian Antarctic Science Program and the Australian Research Council and collaborators included the University of Melbourne, the University of Adelaide, the Australian Bureau of Meteorology, the University of Tasmania, and the Australian Antarctic Division.

Using the Mid-InfraRed Instrument (MIRI) aboard the NASA/ESA/CSA James Webb Space Telescope, astronomers have captured a stunning infrared image of central part of Messier 82, an edge-on starburst galaxy located about 12 million light-years away.

Messier 82 appears high in the northern spring sky in the direction of the constellation of Ursa Major.

First discovered by the German astronomer Johann Elert Bode in 1774, this galaxy is approximately 40,000 light-years across.

Messier 82 is also called the Cigar Galaxy because of the elongated elliptical shape produced by the tilt of its starry disk relative to our line of sight.

The galaxy is famous for its extraordinary speed in making new stars, with stars being born 10 times faster than in our Milky Way Galaxy.

“Despite being smaller than the Milky Way, Messier 82 is five times as luminous as our home Galaxy and forms stars ten times faster,” Webb astronomers said in a statement.

“Messier 82 is classified as a starburst galaxy because it is forming new stars at a rate much faster than expected for a galaxy of its size, especially at its center.”

In visible-light images of Messier 82, the central hotbed of activity is obscured by a network of thick and dusty clouds, but Webb’s infrared eyes are designed to peer through this cloudy veil and reveal the activity behind them.

“What caused Messier 82’s burst of star formation? The answer likely lies with its neighbor, the larger spiral galaxy Messier 81,” the astronomers said.

“We suspect that the two galaxies have interacted gravitationally, sending gas pouring into Messier 82’s center millions of years ago.”

“The influx of gas provided the raw material for new stars to form — and form they did! Messier 82 is home to more than 100 super star clusters, some of which are still in the process of forming and are blanketed with dense, dusty gas.”

“Super star clusters are more massive and luminous than typical star clusters; these ones each contain around 100,000 stars.”

A previous Webb image of Messier 82, featuring data from the telescope’s Near-InfraRed Camera (NIRCam), was released in 2024.

It focused on the very core of the galaxy, where individual clusters of young stars stand out against the clumps and tendrils of gas.

The new image, captured by Webb’s MIRI instrument, provides a remarkable, mostly starless view of Messier 82.

“The image is instead dominated by the emission from warm dust and intricate clouds of sooty organic molecules called polycyclic aromatic hydrocarbons or PAHs,” the researchers said.

“The emission from the PAH molecules traces the galaxy’s broad outflows, which are launched by the intense radiation and winds from the hot young stars of the central super star clusters.”

“Though super star clusters are the source of Messier 82’s powerful galactic winds, the winds may spell the end for the galaxy’s starburst era: as the winds billow into intergalactic space, they likely carry with them the cool gas needed to form even more stars.”

A SpaceX Falcon 9 rocket just launched an advanced European weather satellite and aced its landing on a ship at sea.

The Falcon 9 lifted off from historic Pad 39A at NASA’s Kennedy Space Center in Florida today (July 1) at 5:04 p.m. EST (2104 GMT), carrying the MTG-Sounder (MTG-S1) satellite toward geostationary transfer orbit.

The rocket’s first stage came back to Earth as planned about 8.5 minutes later, touching down on the SpaceX drone ship “Just Read the Instructions,” which was stationed in the Atlantic Ocean.

It was the ninth launch and landing for this particular booster (which is designated B1085), according to a SpaceX mission description. Among the booster’s previous flights were the Fram2 private astronaut mission, the Crew-9 flight to the International Space Station for NASA and a January 2025 launch that sent two private landers toward the moon: Firefly Aerospace’s Blue Ghost and ispace’s Resilience.

The James Webb Space Telescope’s (JWST) latest target is Messier 82 (M82), also known as the Cigar Galaxy. The nearby galaxy is five times more luminous than the Milky Way. It has previously been photographed by the Hubble Space Telescope, providing a great way to measure the two active space telescopes against each other.

While both JWST and Hubble have unique strengths, it is always fascinating to see how they see the same cosmic targets. In the case of M82, Webb’s excellent infrared camera technology can peer through the galaxy’s thick, dusty clouds, showing a remarkably bright, jaw-dropping hotbed of activity.

In Hubble’s visible light image, which is still spectacular, shows a lot of detail, but it’s impossible to see the stellar nursery where M82’s many young stars are formed. Webb, on the other hand, peels back the curtain, exposing a hotbed of activity.

Researchers are fascinated by M82’s relatively fast rate of new star formation, which far outpaces the expected rate based on its mass. Thanks to images like what JWST can capture, scientists can work to unravel the Universe’s cosmic mysteries. The leading theory now is that M82’s neighbor, the large spiral galaxy M81, interacted with M82 and sent the galaxy an influx of gas. This gas has the raw materials required for star formation.

M82 has more than 100 super star clusters, some of which are still forming, per the European Space Agency (ESA). Super star clusters, as evidenced by the name, are more massive and brighter than regular star clusters and can have hundreds of thousands of stars each.

Researchers have used Webb’s new data to identify plumes of material, including polycyclic aromatic hydrocarbons (PAHs). These PAH molecules can be used to trace star formation.

“Each plume is only about 160 light-years wide, and the Webb images show that these plumes are made up of multiple individual clouds that are 16–49 light-years across — an incredible level of detail enabled by Webb’s sensitive instruments,” ESA explains.

Image credits: Webb image by ESA/Webb, NASA & CSA, A. Bolatto. Hubble image by ESA/Hubble & NASA.

Hundreds of millions of years ago, long before the first plants and animals evolved, the planet was almost entirely covered in ice.

During this period known as Snowball Earth, temperatures across the planet repeatedly plummeted to well below freezing. But the cellular life that had already evolved managed to endure.

New research suggests that our ancient microscopic ancestors may have survived this icy period by sheltering in pools of water that formed on top of the relatively shallow ice sheets near the Earth’s equator.

To test these theories, scientists have been exploring meltwater ponds on the McMurdo Ice Shelf in Antarctica. They believe that the conditions here are likely similar to those that occurred in the equatorial regions during the Snowball Earth event.

Dr Anne Jungblut, a microbial researcher at the Natural History Museum, was involved in this latest research.

“We analysed samples from a variety of these ponds and found that they can support diverse communities of microorganisms,” says Anne.

“Each pond had clear traces of eukaryotic life, which are complex organisms whose cellular ancestors eventually gave rise to the huge diversity of life, including animals and plants, that we see today.”

“We can see from fossils that eukaryotes were around before and after Snowball Earth, so we know they made it through this period of intense freezing, and meltwater ponds might be how they did it!”

The study, which has been published in Nature Communications, was led by researchers at the Massachusetts Institute of Technology with co-authors from Cardiff University and University of Waikato in New Zealand.

How did life survive during Snowball Earth?

Snowball Earth is often used to refer to two consecutive glaciation events that took place between 635 and 720 million years ago, during a time known as the Cryogenian Period.

During these events the global average temperature plummeted to below -50°C, but conditions at the equator may have been somewhat more variable.

The slightly warmer temperatures around the middle of the Earth melted the top layers of ice to form meltwater ponds that hovered around 0°C. This stable, warmer temperature could have served as a habitable refuge for some forms of complex life.

The diverse communities of microorganisms that lived in these ponds would have created their own ecosystems that allowed life to survive. It is these communities that Anne and her colleagues have been studying in Antarctica.

“In Antarctic meltwater ponds, the bottom is often covered with microbial mats,” says Anne. “These mats contain colonies of microorganisms, including bacteria and eukaryotes such as amoeba, fungi and ciliates.”

Microbial mats form from the build-up of multiple layers of bacteria, such as cyanobacteria. Cyanobacteria evolved before the Snowball Earth event, so these mats may have been present in the meltwater ponds during this time.

“These mats are super exciting to study because they are entire ecosystems of microscopic life,” explains Anne. “They are almost like forests where the cyanobacteria are the trees that provide shelter and resources for other microorganisms. Some eukaryotes graze on the bacteria, while others are predatory. We can see so many interactions going on that can tell us a lot about how life interacted during early Earth.”

How can this help with the search for life on other planets?

The study of microorganisms in extreme environments not only provides insight into early Earth but can aid in the search for life on other icy worlds in the solar system.

This is because the way in which the scientists detect the presence of life in Antarctic ponds. Rather than looking for the microorganisms themselves, they can search for biosignatures. These biosignatures include molecules like DNA and lipids. The latter are a group of organic compounds that make up the cell walls and are useful for energy storage in living organisms.

One type of these lipids that occurs in all eukaryotes are called Sterols. The research team were able to use these to detect the presence of complex eukaryotic life in these ponds.

By using the same method of detecting and interpreting biosignatures, scientists think this could help in the search for life on other objects in the solar system.

“The more we understand about these biosignatures, the more we can learn about how they differ between organisms and how they might be affected by their environment,” says Anne. “This work can help us understand the signatures to look for during the search for life elsewhere in the solar system.”

For instance, Saturn’s moon Enceladus is a small world with liquid water beneath an icy crust that scientists believe could potentially support life.

Enceladus also has geyser-like jets that spew water vapour and ice particles into space. Future missions could include an orbiter that will pass through these geysers and capture liquid which could then be analysed for biosignatures of life.

You can learn more about the search for life on the icy moons of Jupiter and Saturn in our latest exhibition, Space: Could Life Exist Beyond Earth?