Free Republic

Gamma-ray bursts: the most powerful explosions in the Universe Gamma-ray bursts are the most powerful explosions ever detected in the Universe. They are also one of the greatest mysteries of modern astronomy, since so far no clear evidence has existed to prove what causes them. Until now, there have been two 'prime suspects' for what makes gamma-ray bursts, the collision of neutron stars - dead, ultra-dense stars - or the death of very massive stars in supernova explosions. The new results from the XMM-Newton X-ray space telescope rule out the first hypothesis and confirm the second, at least for the...

These ultrabright flashes have recently been tracked for days, upending ideas about the cataclysms that create them. The Cherenkov Telescope Array, currently under construction, will use a network of more than 100 ground-based telescopes such as this one to monitor the long afterglows of ultrahigh-energy gamma-ray bursts.In July 1967, at the height of the Cold War, American satellites that had been launched to look for Soviet nuclear weapons tests found something wholly unexpected. The Vela 3 and 4 satellites observed brief flashes of high-energy photons, or gamma rays, that appeared to be coming from space. Later, in a 1973...

[T]he study of GRBs have been complicated by two major issues. On the one hand, GRBs are very short lived, lasting for only seconds at a time. Second, all detected events have occurred in distant galaxies, some of which were billions of light-years away. Nevertheless, there are a few theories as to what could account for them, ranging from the formation of black holes and collisions between neutron stars to extra-terrestrial communications. ... With the assistance of their collaborators in the US, France, the UK and Sweden, the team from Queen’s University Belfast relied on the Gemini laser, located at...

A DEVASTATING burst of gamma-rays may have caused one of Earth's worst mass extinctions, 443 million years ago. A team of astrophysicists and palaeontologists says the pattern of trilobite extinctions at that time resembles the expected effects of a nearby gamma-ray burst (GRB). Although other experts have greeted the idea with some scepticism, most agree that it deserves further investigation. GRBs are the most powerful explosions known. As giant stars collapse into black holes at the end of their lives, they fire incredibly intense pulses of gamma rays from their poles that can be detected even from across the universe...

A brilliant burst of gamma rays may have caused a mass extinction event on Earth 440 million years ago—and a similar celestial catastrophe could happen again, according to a new study. Most gamma-ray bursts are thought to be streams of high-energy radiation produced when the core of a very massive star collapses. Such a disaster may have been responsible for the mass die-off of 70 percent of the marine creatures that thrived during the Ordovician period (488 to 443 million years ago), suggests study leader Brian Thomas, an astrophysicist at Washburn University in Kansas. The simulation also shows that a...

A stellar explosion has smashed the record for most distant object in the known universe. The gamma-ray burst came from about 13 billion light-years away, and represents a relic from when the universe was just 630 million years old. "It easily surpassed the most distant galaxies and quasars," said Edo Berger, an astrophysicist at Harvard University and a leading member of the team that first demonstrated the burst's origin. "In fact, it showed that we can use these spectacular events to pinpoint the first generation of stars and galaxies." "The burst most likely arose from the explosion of a massive...

Explanation: Why would x-ray rings appear around a gamma-ray burst? The surprising answer has little to do with the explosion itself but rather with light reflected off areas of dust-laden gas in our own Milky Way Galaxy. GRB 221009A was a tremendous explosion -- a very bright gamma-ray burst (GRB) that occurred far across the universe with radiation just arriving in our Solar System last week. Since GRBs can also emit copious amounts of x-rays, a bright flash of x-rays arrived nearly simultaneously with the gamma-radiation. In this case, the X-rays also bounced off regions high in dust right here...

Strange Long-Lasting Pulse of High-Energy Radiation Swept Over Earth Record Breaking Gamma Ray Burst Astronomers think GRB 221009A represents the birth of a new black hole formed within the heart of a collapsing star. In this illustration, the black hole drives powerful jets of particles traveling near the speed of light. The jets pierce through the star, emitting X-rays and gamma rays as they stream into space. Credit: NASA/Swift/Cruz deWildeNASA’s Swift and Fermi Missions Detect Exceptional Cosmic BlastAn unusually bright and long-lasting pulse of high-energy radiation swept over Earth Sunday, October 9, captivating astronomers around the world. The intense emission...

Initially dubbed Swift J1913.1+1946...now re-named GRB221009A. 2.4 billion light-years away...18 teraelectronvolts. [T]hough this proximity happens to be 20 times closer than the average long gamma-ray burst, it poses absolutely no danger to life on Earth. Rather, it's tremendously exciting – an event that could These bursts mark the end of the life of a massive star – a supernova or hypernova. They can also emerge from a collision between two neutron stars. Different gamma-ray burst profiles mean different kinds of explosions, which fade in different ways. When astronomers observed a collision between two neutron stars in 2017, it produced a...

Astronomers think some of these explosions occur when a massive star — five or 10 times the mass of our sun — detonates, abruptly becoming a black hole. Gamma-ray bursts may also occur when two superdense stellar corpses called neutron stars collide, often forming a black hole. And conveniently, a gamma-ray burst that scientists watched during a few nights in 2019 likely occurred only about 1 billion light-years away from Earth, relatively close by for these dramatic events. Two NASA space-based observatories, Fermi and Swift, first detected the event, which is known as GRB 190829A because it was detected on...

Explosions In Space May Have Initiated Ancient Extinction On Earth Scientists at NASA and the University of Kansas say that a mass extinction on Earth hundreds of millions of years ago could have been triggered by a star explosion called a gamma-ray burst. The scientists do not have direct evidence that such a burst activated the ancient extinction. The strength of their work is their atmospheric modeling -- essentially a "what if" scenario. The scientists calculated that gamma-ray radiation from a relatively nearby star explosion, hitting the Earth for only ten seconds, could deplete up to half of the atmosphere's...

When the Swift Gamma Burst Mission spacecraft first detected the flash within the constellation Draco, astronomers thought it was a gamma-ray burst from a collapsing star. On March 31, however, UC Berkeley's Joshua Bloom sent out an email circular suggesting that it wasn't a typical gamma-ray burst at all, but a high-energy jet produced as a star about the size of our sun was shredded by a black hole a million times more massive. Careful analysis of the Swift data and subsequent observations by the Hubble Space Telescope and the Chandra X-ray Observatory confirmed Bloom's initial insight. The details are...

A beautiful pinwheel in space might one day blast Earth with death rays, scientists now report. Unlike the moon-sized Death Star from Star Wars, which has to get close to a planet to blast it, this blazing spiral has the potential to burn worlds from thousands of light-years away. "I used to appreciate this spiral just for its beautiful form, but now I can't help a twinge of feeling that it is uncannily like looking down a rifle barrel," said researcher Peter Tuthill, an astronomer at the University of Sydney. The fiery pinwheel in space in question has at its...

Scientists have seen the afterglow of a gamma-ray burst just nine minutes after the explosion, a result of precision coordination and fast slewing of ground-based telescopes upon detection of the burst by NASA's High-Energy Transient Explorer (HETE) satellite. The quick turnaround has so far allowed scientists to determine a minimum distance to the explosion, which likely marks the creation of a black hole. Results continue to pour in, as nearly 100 telescopes in 11 countries have tracked the burst. The burst was detected on Friday, Oct. 4, at 8:06 a.m. EDT. NASA's Hubble Space Telescope and Chandra X-ray Observatory observed...