Category: 7. Science

NASA’s Hubble Space Telescope and NASA’s Chandra X-ray Observatory have teamed up to identify a new possible example of a rare class of black holes. Called NGC 6099 HLX-1, this bright X-ray source seems to reside in a compact star cluster in a giant elliptical galaxy.

Just a few years after its 1990 launch, Hubble discovered that galaxies throughout the universe can contain supermassive black holes at their centers weighing millions or billions of times the mass of our Sun. In addition, galaxies also contain as many as millions of small black holes weighing less than 100 times the mass of the Sun. These form when massive stars reach the end of their lives.

Far more elusive are intermediate-mass black holes (IMBHs), weighing between a few hundred to a few 100,000 times the mass of our Sun. This not-too-big, not-too-small category of black holes is often invisible to us because IMBHs don’t gobble as much gas and stars as the supermassive ones, which would emit powerful radiation. They have to be caught in the act of foraging in order to be found. When they occasionally devour a hapless bypassing star — in what astronomers call a tidal disruption event— they pour out a gusher of radiation.

The newest probable IMBH, caught snacking in telescope data, is located on the galaxy NGC 6099’s outskirts at approximately 40,000 light-years from the galaxy’s center, as described in a new study in the Astrophysical Journal. The galaxy is located about 450 million light-years away in the constellation Hercules.

Astronomers first saw an unusual source of X-rays in an image taken by Chandra in 2009. They then followed its evolution with ESA’s XMM-Newton space observatory.

“X-ray sources with such extreme luminosity are rare outside galaxy nuclei and can serve as a key probe for identifying elusive IMBHs. They represent a crucial missing link in black hole evolution between stellar mass and supermassive black holes,” said lead author Yi-Chi Chang of the National Tsing Hua University, Hsinchu, Taiwan.

X-ray emission coming from NGC 6099 HLX-1 has a temperature of 3 million degrees, consistent with a tidal disruption event. Hubble found evidence for a small cluster of stars around the black hole. This cluster would give the black hole a lot to feast on, because the stars are so closely crammed together that they are just a few light-months apart (about 500 billion miles).

The suspected IMBH reached maximum brightness in 2012 and then continued declining to 2023. The optical and X-ray observations over the period do not overlap, so this complicates the interpretation. The black hole may have ripped apart a captured star, creating a plasma disk that displays variability, or it may have formed a disk that flickers as gas plummets toward the black hole.

“If the IMBH is eating a star, how long does it take to swallow the star’s gas? In 2009, HLX-1 was fairly bright. Then in 2012, it was about 100 times brighter. And then it went down again,” said study co-author Roberto Soria of the Italian National Institute for Astrophysics (INAF). “So now we need to wait and see if it’s flaring multiple times, or there was a beginning, there was peak, and now it’s just going to go down all the way until it disappears.”

The IMBH is on the outskirts of the host galaxy, NGC 6099, about 40,000 light-years from the galaxy’s center. There is presumably a supermassive black hole at the galaxy’s core, which is currently quiescent and not devouring a star.

Black Hole Building Blocks

The team emphasizes that doing a survey of IMBHs can reveal how the larger supermassive black holes form in the first place. There are two alternative theories. One is that IMBHs are the seeds for building up even larger black holes by coalescing together, since big galaxies grow by taking in smaller galaxies. The black hole in the middle of a galaxy grows as well during these mergers. Hubble observations uncovered a proportional relationship: the more massive the galaxy, the bigger the black hole. The emerging picture with this new discovery is that galaxies could have “satellite IMBHs” that orbit in a galaxy’s halo but don’t always fall to the center.

Another theory is that the gas clouds in the middle of dark-matter halos in the early universe don’t make stars first, but just collapse directly into a supermassive black hole. NASA’s James Webb Space Telescope’s discovery of very distant black holes being disproportionately more massive relative to their host galaxy tends to support this idea.

However, there could be an observational bias toward the detection of extremely massive black holes in the distant universe, because those of smaller size are too faint to be seen. In reality, there could be more variety out there in how our dynamic universe constructs black holes. Supermassive black holes collapsing inside dark-matter halos might simply grow in a different way from those living in dwarf galaxies where black-hole accretion might be the favored growth mechanism.

“So if we are lucky, we’re going to find more free-floating black holes suddenly becoming X-ray bright because of a tidal disruption event. If we can do a statistical study, this will tell us how many of these IMBHs there are, how often they disrupt a star, how bigger galaxies have grown by assembling smaller galaxies.” said Soria.

The challenge is that Chandra and XMM-Newton only look at a small fraction of the sky, so they don’t often find new tidal disruption events, in which black holes are consuming stars. The Vera C. Rubin Observatory in Chile, an all-sky survey telescope from the U.S. National Science Foundation and the Department of Energy, could detect these events in optical light as far as hundreds of millions of light-years away. Follow-up observations with Hubble and Webb can reveal the star cluster around the black hole.

In a startling revelation that could rewrite our understanding of the cosmos, scientists have proposed that the universe may not expand forever, but could instead meet a dramatic end in a colossal “Big Crunch.”

A new study, based on data from the Dark Energy Survey (DES) and the Dark Energy Spectroscopic Instrument (DESI), suggests that dark energy — the mysterious force believed to be pushing the universe apart — might not be constant as once thought. If true, this finding could have universe-shattering implications.

According to the researchers, who have published their findings in a preprint paper (awaiting peer review), dark energy may evolve over time, potentially turning negative in the distant future. Their work supports the axion-dark energy model (aDE), a newer theory that allows dark energy to fluctuate, unlike the long-accepted “cosmological constant” model.

If the cosmological constant becomes negative, as the data hints, gravity would ultimately win the tug-of-war with expansion. The universe’s outward growth would reverse, contracting until all matter, space, and time collapse into a dense singularity — the Big Crunch, the mirror image of the Big Bang.

The prediction paints a stark timeline: the universe, now 13.8 billion years old, might live for a total of 33.3 billion years. That means we’re already nearing the halfway point of cosmic history. In approximately 20 billion years, the entire universe could implode.

Astrophysicists stress that this scenario, while dramatic, isn’t set in stone. More observations and evidence are needed to validate the aDE model and confirm whether dark energy truly changes over time.

Still, the findings mark a profound shift in how scientists understand the future of everything. For the first time, the universe may not be running on an eternal timeline, but on a ticking cosmic clock. 

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Researchers have demonstrated that microscopic drug delivery containers can be magnetically steered to their targets, advancing the development of precision medicine for treating diseases such as cancer.

A multi-university team led by Jie Feng, a professor of mechanical science and engineering in The Grainger College of Engineering at the University of Illinois Urbana-Champaign, demonstrated that magnetic particles encapsulated in lipid vesicles can be used to steer the vesicles through fluids.

This work, published in the Royal Society of Chemistry journal Nanoscale, builds on earlier results showing that lipid vesicles can be engineered to release drugs when illuminated with laser light. The resulting system, combining both results, is a comprehensive prototype for precision and targeted drug delivery.

“The appeal of lipid vesicles for drug delivery is that their structure is similar to a cell, so they can be made to interact only with particular kinds of cells – a significant advantage for cancer treatment. One of the challenges to realizing such vehicles is knowing how to steer them to the correct site. We have shown how to do this using magnetic fields, solving the last big problem before we begin demonstrations ex vivo.”

Jie Feng, Professor, Mechanical Science and Engineering, The Grainger College of Engineering, University of Illinois Urbana-Champaign

Feng noted that existing medical technologies such as MRI could be repurposed to steer drug delivery vehicles with their magnetic fields, especially since these fields are designed to penetrate the human body. This can be achieved by encapsulating a superparamagnetic particle within the drug delivery vehicle, so it interacts with the externally controlled magnetic field.

The first step in creating magnetically steerable lipid vesicles was developing a reliable method to encapsulate magnetic particles in the vesicles. Vinit Malik, an Illinois Grainger Engineering graduate student in Feng’s laboratory and the study’s lead author, used the method of “inverted emulsion,” in which magnetic particles are added to a solution of dissolved lipids, leading to lipid droplets forming around the particles.

“It was not obvious what the best way to encapsulate lipid particles would be, so there was a large literature search and some trial and error,” Malik said. “We had to determine what the best magnetic particle size is, and then we had to figure out that the inverted emulsion method has the highest yields for encapsulated particles.”

Next, the researchers demonstrated that magnetic fields could direct the lipid vesicles. Malik developed a 3D-printable platform to mount the magnets securely on a microscope and to place the vesicles in a solution between the magnets. By observing the resulting motion, the researchers observed how speed varied with the ratio of magnetic particle size to vesicle size. They also confirmed that the vesicles only release their cargo when illuminated with laser light after moving to the end of the microfluidic channel.

While these experiments showed that the lipid vesicles moved as expected in magnetic fields, it was necessary to also understand how the magnetic particle pushes the vesicle from within to understand the behavior of the whole device.

The Illinois researchers partnered with investigators at Santa Clara University to computationally study the internal dynamics of the vesicle to predict the motion speed. Using the lattice Boltzmann method, they observed how the magnetic particle drags the whole vesicle when moving through a magnetic field.

“It allowed us to expand on our experiments, since it is otherwise difficult to observe or predict the response of such a vesicle system,” Malik said. “It gives us predictive power that will enhance design guidelines and allow us to understand the physical mechanisms governing the motion.”

Armed with experimental demonstrations of light-induced drug release and magnetic steering, Feng’s laboratory now aims to begin in vitro studies demonstrating that the lipid vesicles can be magnetically steered to specific locations through fluids like human blood.

“Our combined results lay the foundation for a comprehensive precision drug delivery system, and we’re ready to explore the potential uses in treatment,” Feng said. “We’re working towards the next step: using a real drug and performing an in vitro study in a microfluidic system that simulates features of biological environments.”

Our daily lives have increasingly become dependent upon advanced space technology satellites like GPS, communication satellites, and weather systems. So understanding the invisible forces coming from the Sun is also important.NASA has taken a major step in this direction by launching a pair of satellites known as TRACERS, which means Tandem Reconnection and Cusp Electrodynamics Reconnaissance Satellites. These twin spacecraft are on a mission to better understand one of space’s most energetic and mysterious processes, which is also known as magnetic reconnection.The satellites were lifted off from Vandenberg Space Force Base in California aboard a SpaceX Falcon 9 rocket at 11:13 a.m. EDT, according to NASA. This twin satellite system is set to study the constant stream of solar wind and charged particles flowing from the Sun, which interacts with Earth’s magnetic shield, also known as the magnetosphere.

What is magnetic reconnection

When the solar wind hits this magnetic field, it can lead to magnetic reconnection, which also releases a huge amount of energy. “As the solar wind collides with Earth’s magnetic field, this interaction builds up energy that can cause the magnetic field lines to snap and explosively fling away nearby particles at high speeds. This is magnetic reconnection,” explained John Dorelli, TRACERS mission science lead at NASA’s Goddard Space Flight Center.

What is special about the mission?

These reconnection events can cause beautiful light shows like auroras, but also cause problems for satellites, astronauts, and GPS systems. That’s why TRACERS is an important mission.Over the first year alone, the mission is expected to get information on more than 3,000 such reconnection events. The twin satellites will do this while orbiting through Earth’s polar cusp region, funnel-like openings in the magnetic field where the solar wind has a direct path into our atmosphere.

How will the data from these satellites help the scientists

The data gathered from TRACERS will help scientists improve space weather forecasting and better protect critical technology here on Earth. NASA says that once the satellites are in their sun-synchronous orbit, they’ll fly in tandem, sometimes just seconds apart, to study these high-energy events in real-time.“This is going to help us keep our way of life safe here on Earth,” said Joe Westlake, director of NASA’s heliophysics division.

Newswise — Autophagy is essentially the ‘rubbish collection’ of our cells. If there are problems in this process, which is so important for our health, diseases such as Parkinson’s can result. In their latest study, leading cell biologists at the Max Perutz Labs at the University of Vienna investigated mitophagy – a form of autophagy – and came to a remarkable conclusion: the researchers have described a new trigger for mitophagy. This discovery has led to a reassessment of the hierarchy of factors that trigger autophagy. The newly discovered signalling pathways could also open up novel therapeutic options. The study has been published in the renowned journal Nature Cell Biology.

Autophagy is a self-cleaning process of the cell and is crucial for cell health in the human body. A sophisticated molecular surveillance command identifies suspicious substances – broken cell components, clumped proteins or even pathogens – and initiates their removal. Finally, defective cell components are broken down and recycled. Mitophagy is a form of autophagy in which mitochondria within a cell are specifically degraded. Dysregulation of mitophagy is particularly associated with Parkinson’s disease. A better understanding of this process is therefore important for combating Parkinson’s.

In a new study led by postdoctoral researcher Elias Adriaenssens from Sascha Martens’ group at the Max Perutz Labs at the University of Vienna, the scientists reveal a new mechanism for triggering mitophagy. Until now, research has focused heavily on the ‘PINK1/Parkin signalling pathway’. Signalling pathways are used to transmit information within cells. These complex networks of molecules control critical cellular functions such as growth, division, cell death and, indeed, mitophagy.

“When we looked at the big picture, it became clear that, apart from the much-studied ‘PINK1/Parkin pathway’, there were huge gaps in our knowledge of other mitophagy pathways,” explains study leader Elias Adriaenssens. “Our laboratory has explored these neglected areas by using biochemical reconstitutions to gain fundamental mechanistic insights.”

Newly discovered pathways are no exception

“We found that NIX and BNIP3 – two known mitophagy receptors – can trigger autophagy without binding to FIP200 (a protein), which was quite unexpected,” explains Adriaenssens. FIP200 is considered essential for triggering autophagy. “This presented us with a puzzle. Despite extensive testing, we were unable to detect any interaction between FIP200 and either of the two receptors – which raises the crucial question of how they function without this supposedly crucial component,” he adds. However, mass spectrometry revealed that other autophagy components, known as WIPI proteins, bind to these mitochondrial receptors. Since WIPI proteins were previously thought to act later in the signalling pathway, their involvement in triggering autophagy was surprising. Follow-up experiments confirmed these interactions and suggested that WIPI-mediated recruitment is not an exception, but may mediate previously unknown pathways in selective autophagy.

“This is an exciting discovery – it reveals a parallel trigger for selective autophagy. Instead of a single, universal mechanism, cells appear to use different molecular strategies depending on the receptor and context. Until now, no one has considered WIPI proteins to be key players in triggering autophagosome formation, but our discovery could change that view,” explains Adriaenssens.

Potential for new therapies for Parkinson’s disease

Looking ahead, the study raises an important question: How do cells decide between alternative mitophagy signalling pathways – why do some receptors use one and others the other, and what factors determine which pathway is used? Distinguishing between selective mitophagy signalling pathways could pave the way for therapies that specifically activate one pathway to compensate for defects in the other, which has long-term potential for the treatment of Parkinson’s disease.

Original publication in Nature Cell Biology

More information and video in the press room

 

Every year, lightning kills around 320 million trees across the globe, not with raging wildfires but through direct strikes that often go unseen. The trees don’t always fall dramatically; many die slowly from internal damage, their trunks fried from the inside out. In dense forests, these deaths blend into the background, unnoticed by satellites or the human eye. While wildfires make headlines and scar landscapes, lightning-induced tree deaths are scattered and silent, but the impact is anything but small. Now, for the first time, researchers have created a global model to calculate the scale of this damage. The results suggest we’ve been drastically underestimating lightning’s role in shaping forest ecosystems and climate dynamics.

How lightning quietly kills millions of trees

Most people think of lightning as a momentary spectacle—a flash, a thunderclap, and it’s over. But in forests, lightning is an invisible predator. When it strikes a tree, the damage isn’t always external. The bolt can superheat the sap, explode tissue from within, and trigger a slow decline. In tropical and temperate forests alike, these slow deaths often escape detection. Without charred scars or visible damage, the impact is difficult to trace. For decades, scientists lacked the tools to measure how many trees were being lost this way—until now.A research team from the Technical University of Munich set out to fill the data gap. They developed the world’s first global model of lightning-induced tree deaths by combining satellite data, field studies, and global lightning distribution patterns. The result was eye-opening: 320 million trees per year are killed directly by lightning. That number does not include additional trees lost in fires started by lightning. The researchers also identified high-risk regions, particularly in the Amazon and Congo Basin, while warning of growing threats in Canada, Russia, and parts of the United States as climate change increases lightning frequency.

Tree deaths from lightning are a major carbon emission source

When trees die and decompose, they release carbon dioxide—and lightning is a growing contributor. The study found that these deaths emit between 0.77 and 1.09 billion tons of CO₂ per year, nearly matching the 1.26 billion tons emitted annually by wildfires burning live vegetation. Considering total wildfire emissions (including deadwood and soil carbon) reach around 5.85 billion tons, lightning’s contribution is far more significant than previously recognized. As lightning strikes increase and trees struggle to regenerate, the planet’s ability to store carbon is threatened.

Climate change is supercharging lightning and risking forest health

Climate models project that lightning will become more frequent in the coming decades. While tropical forests currently suffer the most from lightning strikes, northern forests in temperate and boreal zones are also at risk. These ecosystems, already weakened by drought, pests, and warming, may face longer recovery times since trees in colder regions grow more slowly. The shift could permanently alter forest composition and resilience in areas not historically adapted to high lightning activity.Unlike wildfires, which leave visible scars, lightning strikes kill trees quietly. A single bolt may take out one tree at a time, with no smoke, no char, and no sign. These deaths are dispersed, subtle, and easy to overlook—making it harder for scientists and satellite systems to track. Yet the ecological consequences are vast. Trees are foundational to biodiversity, climate stability, and carbon storage. Losing hundreds of millions of them annually to an invisible force means rethinking how we model and manage forests worldwide.The death of 320 million trees each year due to lightning strikes is equivalent to the loss of about 8,000 square kilometers of forest approximately — an area larger than Sikkim, over five times the size of Delhi, and nearly ten times that of New York City. And still, these losses go largely unrecorded. As the planet warms and lightning becomes more frequent, this overlooked threat is likely to grow. Forests are dying in silence, and unless we start paying attention, we risk losing one of our most vital defenses against climate change—one bolt at a time.