Latest news with #InstituteofScienceandTechnologyAustria
Yahoo
17-02-2025
- Science
- Yahoo
Researchers issue warning after discovering worrying trend in weather patterns — here's what the next 40 years could look like
Don't take that rainfall for granted. A study has detailed that as the Earth's temperature rises, extreme droughts will become more severe, farther-reaching, and increasingly common. Research from the Swiss Federal Institute for Forest, Snow, and Landscape Research, shared by Science, looked at 40 years of drought data from across the globe. It determined that as the Earth's temperature continues to rise, multi-year droughts will become more intense and will stretch to more areas of the planet. According to study participant professor Francesca Pellicciotti from the Institute of Science and Technology Austria, "Each year since 1980, drought-stricken areas have spread by an additional fifty thousand square kilometers on average—that's roughly the area of Slovakia, or the US states of Vermont and New Hampshire put together." Pellicciotti observed that the increasing severity of droughts and the possibility that they will affect greater global areas could lead to serious damage to "ecosystems, agriculture, and energy production." One of the main causes of increased mega-drought risk is a warming climate, exacerbated by the human-caused production of pollution. Gases like carbon dioxide and methane released from the transportation, energy, manufacturing, and agricultural sectors, among others, trap heat in the atmosphere and cause temperatures to rise. This increases the likelihood of drought conditions — and, counterintuitively, deadly storms and hurricanes. These extreme weather conditions have always occurred, but warmer weather is making them longer, stronger, and more likely. What's more, as the study detailed, extreme weather — like droughts — is extending to previously unaffected regions. For example, the Northeastern United States, not known for wildfires, was at risk due to a lack of rainfall toward the end of 2024. When these intense weather conditions occur, they can result in the displacement of people and animal habitat loss, as well as fatalities. They can also decimate crops, which impacts the food supply and increases grocery store prices. The study documented a 15-year mega-drought in Chile — the longest in 1,000 years — that saw water reserves almost completely depleted. The Congo rainforest also suffered from this problem from 2010 to 2018. Do you think our power grid needs to be upgraded? Definitely Only in some states Not really I'm not sure Click your choice to see results and speak your mind. "We hope that the publicly available inventory of droughts we are putting out will help orient policymakers toward more realistic preparation and prevention measures," remarked Pellicciotti. These incidents can feel overwhelming, but many people and organizations are already doing what they can to help. The Extreme Weather Survivors group was formed to support people impacted by such events. Any action we can take to cut pollution will help in the cooling of our planet, hopefully allowing it to heal while reducing the risk of extreme weather. For example, making your home more energy efficient by converting from air conditioning units to heat pumps can lessen our reliance on grid-provided power and dirty fuels that produce planet-warming pollution. Regarding droughts, saving water when possible is also important to reduce risks. Capturing rainwater to use in your yard and shutting off the tap while brushing your teeth are small but effective changes to conserve an increasingly precious resource. Join our free newsletter for good news and useful tips, and don't miss this cool list of easy ways to help yourself while helping the planet.
Yahoo
28-01-2025
- Science
- Yahoo
Supermassive black holes in 'little red dot' galaxies are 1,000 times larger than they should be, and astronomers don't know why
When you buy through links on our articles, Future and its syndication partners may earn a commission. Using the James Webb Space Telescope (JWST), astronomers have discovered distant, overly massive supermassive black holes in the early universe. The black holes seem way too massive compared to the mass of the stars in the galaxies that host them. In the modern universe, for galaxies close to our own Milky Way, supermassive black holes tend to have masses equal to around 0.01% of the stellar mass of their host galaxy. Thus, for every 10,000 solar masses attributed to stars in a galaxy, there is around one solar mass of a central supermassive black hole. In the new study, researchers statistically calculated that supermassive black holes in some of the early galaxies seen by JWST have masses of 10% of their galaxies' stellar mass. That means for every 10,000 solar masses in stars in each of these galaxies, there are 1,000 solar masses of a supermassive black hole. "The mass of these supermassive black holes is very high compared to the stellar mass of the galaxies that host them," team leader Jorryt Matthee, a scientist at the Institute of Science and Technology Austria (ISTA), told "At face value, our measurements imply that the supermassive black hole mass is 10% of the stellar mass in the galaxies we studied." "In the most extreme scenario, this would imply that the black holes are 1,000 times too heavy." The discovery could bring astronomers a step closer to solving the mystery of how supermassive black holes with masses millions or even billions of times that of the sun grew so quickly in the early universe. "Rather than saying this discovery is 'troubling,' I would say it is 'promising,' as the large discrepancy suggests that we are about to learn something new," Matthee added. Related: Black holes: Everything you need to know Since JWST started beaming data back to Earth in the summer of 2022, the $10 billion telescope has helped astronomers refine their understanding of the early cosmos. This has included the discovery of supermassive black holes with millions of solar masses when the universe was less than one billion years old. This is problematic, because scientists have estimated that the merger chains of progressively larger black holes and the voracious feeding on surrounding matter that leads black holes to supermassive sizes are thought to take more than a billion years. Another significant aspect of this investigation of the early universe by JWST has been the discovery of "little red dot galaxies," some of which existed just 1.5 billion years after the Big Bang, when the universe was around 11% of its current age. The red coloration of these surprisingly bright early galaxies is thought to come from gas and dust in a flattened cloud of matter around supermassive black holes called an accretion disk. As the giant black holes feed on this matter, they emit huge amounts of electromagnetic energy, from a compact region known as an active galactic nucleus (AGN). "In 2023 and 2024, we and other groups discovered a previously hidden population of AGNs in the early universe in the first data sets from the JWST," Matthee said. "The light that we see from these objects, in particular the redder light, originates from accretion disks around supermassive black holes. "These objects became known as 'little red dots' because that's how they appear in JWST images." Currently, this early galactic population is very exciting, albeit poorly understood. For instance, in the early universe, little red dots seem to be far more numerous compared to previously known populations of AGNs seen from Earth as supermassive black hole-powered quasars. Related: What is the Big Bang theory? "The little red dots also show some very remarkable properties, such as the faintness in X-ray emission, which is pretty unusual for AGNs, and the infrared emission is also unusual," Matthee said. "Due to these complications, we are struggling to interpret the light that we observe from the little red dots, which means that it is very difficult to study their properties." This is where Matthee and colleagues' new work comes in. Using a data set from the JWST year 2 (cycle 2) 'All the Little Things (ALT)' survey, the team built a precise 3D map of all galaxies in a specific region in the sky. "Within that region, we have identified seven little red dots, similar to previous studies, but now we have been able to compare the locations of these little red dots in the 3D galaxy map," Matthee said. The team's little red dots are located so far away that their light has been traveling to us for around 12.5 billion years. They are clustered in the so-called cosmic web of galaxies, with their positioning being of paramount importance. The position of galaxies in the cosmic web depends on the type of galaxy. More evolved, massive galaxies are found in over-dense regions such as the nodes where the strands of the web connect. Younger and lower-mass galaxies tend to be found in less dense regions of the cosmic web, along the length of individual strands away from nodes. "We have found that the little red dots are in environments that resemble low-mass, young galaxies," Matthee said. "This implies that the little red dot galaxies are also low-mass young galaxies." The fact these little red dot galaxies contain AGNs has provided evidence that early black holes are actively growing in galaxies with stellar masses as low as around 100 million times that of the sun. One possible explanation for this is that supermassive black holes in the early universe managed to form and grow much more efficiently than those in the present-day universe. This could be due to the more rapid consumption of surrounding gas and matter. "In my opinion, the most likely explanation is the extremely rapid growth of supermassive black holes nurtured by the high gas densities of galaxies in the early universe," Matthee said. "These densities simultaneously lead to high stellar densities, which promotes supermassive black hole formation through facilitating runaway collisions of remnant black holes." If that's true, then the formation of stars and supermassive black holes in galaxies are intrinsically linked, with these processes depending on each other. Though supermassive black holes grow faster in early galaxies, star formation catches up, leading to the 1:100 mass ratio seen today. This doesn't yet confirm rapid growth theories over other supermassive black hole growth explanations, such as the idea that these cosmic titans grow from massive black hole seeds created by the direct collapse of huge clouds of gas and dust. However, Matthee added that it will now be hard for theorists to get around low host galaxy masses when competing theories are considered. Related Stories: —James Webb Space Telescope sees little red dots feeding black holes: 'This is how you solve a universe-breaking problem' — James Webb Space Telescope spots record-breaking collection of stars in far-flung galaxy — Black holes can squash star formation, James Webb Space Telescope finds Matthee explained that the next steps for both the team and for the wider astronomical community are to eliminate the possibility that the stellar mass/black hole mass ratio they found is not the result of inaccurate measurements or a selection bias that may have favored the most active and thus massive supermassive black holes. This will likely involve the discovery of more little red dot galaxies, a hunt that the JWST will undoubtedly be at the heart of. "The JWST has been important for two main reasons: Without it, we would not have discovered those populations of faint AGNs," Matthee concluded. "Also, without the JWST, we would not have been able to make the accurate 3D map of galaxy distributions that we used to infer the properties of the galaxies hosting the faint AGNs. "It's a very exciting research field at the moment!" The team's research has not yet been published in a peer-reviewed journal. It has been posted on the paper repository site arXiv.
