
3 'City-Killer' Asteroids Could Strike Earth In Weeks, Say Scientists
At least three large asteroids, powerful enough to destroy an entire city, could be on a collision course with Earth in the coming weeks, a new study has warned.
Published in the journal Astronomy and Astrophysics, the study highlights the threat posed by three space rocks-named 2020 SB, 524522, and 2002 CL1-which currently share an orbit with Venus. According to the international research team led by Valerio Carruba from Sao Paulo State University in Brazil, these asteroids are hidden in the Sun's glare, making them nearly impossible to detect with telescopes on Earth.
While their current paths don't bring them close to Venus, researchers caution that even a minor gravitational disturbance could shift their orbits toward Earth, with potentially catastrophic consequences. If one were to strike, the impact could create a crater more than 3 kilometres wide and release energy up to a million times greater than the atomic bomb dropped on Hiroshima, Fox News reported.
"These co-orbital asteroids are protected from close encounters with Venus, but not with Earth," the researchers said, as quoted by The Daily Galaxy. The objects are especially dangerous because their position relative to the Sun acts like a cosmic blind spot, making last-minute detection extremely difficult.
The Rubin Observatory in Chile, which monitors such threats, would have just two to four weeks' notice before any potential impact. The study suggests that only a dedicated space-based mission near Venus could effectively detect these hidden, potentially hazardous asteroids.
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Time of India
10 hours ago
- Time of India
Astronomers witness supermassive black hole tear star apart during violent galactic collision—here's what exactly happened in this rare tidal disruption event
Black hole rips apart star in rare galactic collision: Astronomers witness violent tidal disruption event- A supermassive black hole ripping a star apart during a galaxy merger has given astronomers a rare and violent spectacle to study—one that could unlock new insights into how black holes influence their galaxies. This cosmic event, called a tidal disruption event (TDE), happened about 700 million light-years from Earth in a merging pair of galaxies. The event, named AT 2022wtn, is only the second TDE ever seen in interacting galaxies, making it an extraordinary discovery. Scientists say it sheds light—quite literally—on how massive black holes feed, evolve, and possibly impact galactic development. What exactly is a tidal disruption event and why is AT 2022wtn so rare? A tidal disruption event occurs when a star strays too close to a supermassive black hole—an object millions or even billions of times heavier than the Sun. The black hole's gravitational pull is so intense that it rips the star apart, stretching and squeezing it in a process astronomers call spaghettification. by Taboola by Taboola Sponsored Links Sponsored Links Promoted Links Promoted Links You May Like Giao dịch vàng CFDs với sàn môi giới tin cậy IC Markets Tìm hiểu thêm Undo In the case of AT 2022wtn, this violent dismemberment took place in a galaxy called SDSSJ232323.79+104107.7. This galaxy is currently colliding with a larger neighboring galaxy, at least ten times its size, in the early stages of a galactic merger. The merging process is believed to stir up activity near black holes, possibly triggering TDEs like this one. The discovery of AT 2022wtn is crucial because, although galaxy mergers are common, seeing a TDE in one is extremely rare. That's what makes this observation so special. Live Events How did astronomers find out about this cosmic disaster? The TDE was first spotted by the Zwicky Transient Facility (ZTF), which scans the sky for sudden bursts of light and unusual activity. From there, teams across the globe dug deeper, observing the event across the entire spectrum of light—from radio waves to X-rays. The black hole at the center of this event is estimated to have a mass around 1 million times that of the Sun, and the unlucky star it consumed was a low-mass star. Researchers saw a massive burst of light when the star was torn apart, which temporarily outshone the entire galaxy it lived in. What makes AT 2022wtn different from other star-eating events? According to Francesca Onori from Italy's National Institute for Astrophysics (INAF), this event showed features never seen this clearly before. She called it 'a peculiar event' and noted that its light curve stayed at peak brightness for about 30 days—a long time in TDE terms. During that time, the temperature dropped sharply, and scientists detected specific emission lines in the light from the event—namely helium and nitrogen. This suggests very complex chemical activity and possibly a rapid formation of an accretion disk, a spinning cloud of material forming around the black hole from the remains of the star. Onori added, 'We found clear traces of the dynamics of the surrounding material,' showing that stellar debris was being pushed outward rapidly, creating a kind of expanding bubble of gas. What happens when a star becomes 'spaghetti'? When a star ventures too close to a black hole, the difference in gravity between the side closest to the black hole and the side furthest away becomes extreme. This causes the star to be squeezed and stretched into long, thin strands—hence the term spaghettification. In AT 2022wtn, this shredded material formed a whirling disk of plasma. Some of the star's material spiraled into the black hole, while other parts were blasted away into space as jets and high-speed outflows. The team also detected a brief burst of radio waves, confirming these explosive emissions. Why is this discovery so important for science? This rare black hole-star interaction not only gave scientists a detailed view of how TDEs form, but also helped them understand the physical conditions around black holes during galaxy mergers. According to the research team, the study provides new evidence that supports the idea that galaxy collisions can trigger black holes to become more active. It also adds crucial data on how TDEs evolve, how accretion disks form, and how the resulting radiation is produced. Their findings were published on May 23 in the Monthly Notices of the Royal Astronomical Society. A cosmic warning and a clue to galaxy growth? While Earth is safe from such destruction (our Sun isn't near any massive black holes), these events serve as important reminders of the raw power of gravity and the extreme physics happening in deep space. More importantly, they give us clues about how black holes grow, how they interact with their environment, and how they may even shape the galaxies around them. For astronomers, AT 2022wtn is more than a violent end for one star—it's a rare and valuable opportunity to study the life cycle of galaxies and the monstrous forces that control them. FAQs: Q1: What is a tidal disruption event in a galaxy merger? A tidal disruption event is when a star gets torn apart by a supermassive black hole during a galactic collision. Q2: Why is AT 2022wtn important for black hole research? It's a rare case of a black hole eating a star during a galaxy merger, offering new insights into black hole behavior.


Hans India
11 hours ago
- Hans India
Astronomers uncover distant dwarf planet candidate, challenging planet nine theory
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Time of India
2 days ago
- Time of India
Solar storms are killing SpaceX's Starlink satellites and making them re-enter Earth sooner; says NASA
Source: A recent NASA-led study, highlighted by New Scientist, reveals that this accelerated re-entry is caused by increased solar activity during the solar maximum—a period of intense solar storms and radiation. These storms heat and expand Earth's upper atmosphere, increasing atmospheric drag on satellites and hastening their descent. This shift poses new challenges for satellite operators, especially those managing large constellations, as space weather increasingly influences satellite lifespans and orbital dynamics. The Sun also has an about 11-year cycle characterised by varying degrees of activity. At its peak, known as the solar maximum, solar storms intensify and become more intense. The last solar maximum was achieved in late 2024 when the Sun was most active in more than a decade. The Sun releases powerful outbursts of charged particles and electromagnetic radiation during this time, causing geomagnetic storms on Earth. These storms have long-range impacts beyond the northern lights. They disrupt the upper atmosphere of Earth and greatly enhance atmospheric drag, which is now being recognised as an essential factor speeding up the re-entry of satellites. NASA scientist explains geomagnetic storms speeding up satellite re-entry Dr. Denny Oliveira, a scientist at NASA who conducted the research, confirmed that satellites in LEO are re-entering the Earth's atmosphere much more rapidly during geomagnetic storms. "We found that when we have geomagnetic storms, satellites re-enter faster than expected [without solar activity]," Oliveira said. by Taboola by Taboola Sponsored Links Sponsored Links Promoted Links Promoted Links You May Like Lifetime Office 2024 License for Thane [Order] prime software Undo Usually, a decommissioned Starlink satellite can sit in orbit for about 15 days before atmospheric drag pulls it down. But over the past few months, that timeframe has been significantly reduced. In one reported incident, 37 Starlink satellites re-entered Earth's atmosphere just five days after launch—well short of the expected orbital lifetime. This hastened decay presents special challenges for massive satellite constellations like SpaceX 's Starlink initiative. Already more than 7,000 Starlink satellites occupy space, with tens of thousands more planned for launch, the impacts of heightened solar activity may become amplified operational challenges and risk. NASA has followed 523 Starlink satellite re-entries from 2020 to 2024—a figure set to increase dramatically. "For the first time ever, we are experiencing so many satellites re-entering at once," Oliveira commented. "Soon, we'll be observing satellites re-entering on a daily basis." Environmental scientists warn of long-term effects from satellite re-entry Although the removal of malfunctioning satellites through a quick de-orbiting can decrease space debris in the short term, it poses another group of problems. When satellites re-enter, not everything is totally burned away. Pieces from heavier materials will survive and penetrate lower atmospheric layers. Environmental scientists are also sounding the alarm over the possible chemical effect. Satellite combustion emits substances such as aluminum oxide, which may build up in the mesosphere and potentially affect atmospheric chemistry and climate control over a period of time. Aside from the environmental concerns, more satellite activity also raises the threat of collisions in orbit. With more satellites being launched into comparable orbital lanes, the room for mistake closes in. There was one reported incident in 2019 when the European Space Agency performed a maneuver to move one of its Earth-monitoring satellites out of the way of an imminent collision with a Starlink satellite. Space agencies and industry players are now being called upon to create more resilient traffic management systems and to take space weather forecasting into account in operational planning. Also Read | Sunita Williams and Butch Wilmore emerge stronger following recovery from Starliner mission extended until March