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The History Channel...has been running a popular series on so-called mega-disasters that threaten to do serious damage to life on earth. From super volcanoes to super asteroids, to exotic space phenomena and more mundane, down-to-earth threats, we count down the top ten mega disasters and tell you which ones to worry about. Number 10: Global Warming No phenomenon in recent memory has been more over-hyped than global warming... Number 9: Pole Shift Pole shift is so far “out there” as a credible disaster scenario that it just barely straddles the line between science fiction and science. The fact that we...

Explanation: An expansive nebula of dust is seen to surround red supergiant star Betegeuse in this remarkable high resolution composite, an infrared VLT image from the European Southern Observatory. Betelgeuse itself is outlined by the small, central red circle. If found in our own solar system its diameter would almost encompass the orbit of Jupiter. But the larger envelope of circumstellar dust extends some 60 billion kilometers into space, equivalent to about 400 times the Earth-Sun distance. The dust is likely formed as the swollen atmosphere of the supergiant sheds material into space, a final phase in the evolution of...

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...

An Indian theoretical physicist who questioned the existence of black holes and thereby challenged Stephen Hawking of Britain at last feels vindicated. But he is sad. Abhas Mitra, at the Bhabha Atomic Research Centre (BARC) in Mumbai, was perhaps the first and the only scientist who had the guts to openly challenge Hawking of Cambridge University who is regarded by many as the modern-day Einstein. For over 30 years Hawking and his followers were perpetuating the theory that black holes -- resulting from gravitational collapse of massive stars -- destroy everything that falls into them preventing even light or information...

American space agency, the NASA had recently observed flares of X-rays from a black hole, which goes against the conventional notion that they are compact particles with such huge gravity that even light can't escape. Last month NASA announced that two of its space telescopes caught a huge burst of X-ray spewing out of a super massive black hole. These flairs appeared to be be triggered by the eruption of a charged particle from the black hole, which according to conventional belief doesn't let anything out. The latest findings are in accordance with the theory of Indian astrophysicist Abhas Mitra...

Fermi Catalogs the Gamma-ray Sky Credit: NASA, DOE, International Fermi LAT Collaboration Explanation: What shines in the gamma-ray sky? The most complete answer yet to that question is offered by the Fermi Gamma-ray Space Telescope's first all-sky catalog. Fermi's sources of cosmic gamma-rays feature nature's most energetic particle accelerators, ultimately producing 100 MeV to 100 GeV photons, photons with more than 50 million to 50 billion times the energy of visible light. Distilled from 11 months of sky survey data using Fermi's Large Area Telescope (LAT), the 1,451 cataloged sources include energetic star burst galaxies and active galactic nuclei...

Supergiant star Betelgeuse has been getting dimmer at an unprecedented pace over the past few months, leading some astronomers to wonder if it might be in the process of the collapse that precedes a supernova explosion. But there are other possible explanations, and we should have a better idea of what's happening to the massive star by the end of the month. Betelgeuse has no more than about 100,000 years left to burn and could start its death throes just about anytime between now and then. When it does go supernova, it's expected to result in a dramatic light show...

The most distant objects in the universe are also the oldest -- or at least that is how they appear to us, because their light has had to travel for billions of years to get here. They are also extraordinarily faint since they are so far away, and only in the last decade have astronomers been able to stretch their vision using the newest telescopes and clever techniques. One such innovation occurred with the launch of the NASA Swift satellite in 2004; it searches for bursts of gamma-ray emission, called GRBs. These flashes, thought to result from the especially spectacular...

Scientists have new theory on ice age KU researchers believe gamma-ray burst caused extinctions, cooling By Alea Smith - Special to the Journal-World Monday, December 29, 2003 Researchers now believe a cosmic explosion 440 million years ago may have decimated life on Earth. Kansas University scientists are attracting international attention with their research into the possibility a massive gamma ray explosion caused an ice age that wiped out much of the life on Earth. "It appears that the (gamma ray) bursts are a serious danger, although not something you would expect to hit us very often, maybe every few hundred...

ANN ARBOR — Astrophysicists have detected, for the first time, the oscillating signal that heralds the last gasps of a star falling victim to a previously dormant supermassive black hole. Led by researchers at the University of Michigan, the team documented the event with the Suzaku and XMM-Newton orbiting X-ray telescopes. These instruments picked up semi-regular blips in the light from a numerically-named galaxy 3.9 billion light years away in the northern constellation Draco the dragon. The blips, scientifically known as “quasiperiodic oscillations,” occurred steadily every 200 seconds, but occasionally disappeared. Such signals have often been detected at smaller black...

On 15 June 2015, V404 Cygni (V404 Cyg), a binary system comprising a sun-like star orbiting a black hole, woke up. A huge outburst of energy across the electromagnetic spectrum 'lit up' the sky. The last such outburst was 1989. Dr Kunal Mooley, a Hintze Research Fellow at the University's Centre for Astrophysical Surveys works on cutting-edge research based on the discovery and detailed study of transients at radio and optical wavelengths using a wide range of telescope facilities such as the Jansky Very Large Array, the Arcminute Microkelvin Imager (AMI), the Palomar Transient Factory, and the Giant Meterwave Radio...

An intense blast of high-energy protons from the Sun pummelled the Earth in about 660 BC and left a distinct record of cosmogenic nuclei in the Greenland ice sheet. The discovery was made by an international team of scientists who say the event was one most powerful solar storms known to have struck Earth. The team calculates that the storm was about ten times more intense than any event that has occurred in the past 70 years. “If that solar storm had occurred today, it could have had severe effects on our hi-tech society”, says Raimund Muscheler of Sweden’s University...

Three supermassive black holes found lurking in one galaxy NGC 6240 is a well-studied example of a galaxy merger. But the discovery that it hides three supermassive black holes makes it a stunning example of a galaxy formed through a triple merger. By Alison Klesman  |  Published: Friday, November 22, 2019 RELATED TOPICS: BLACK HOLES | GALAXIES The strange galaxy NGC 6240 is an ultra-rare example of a galaxy harboring three supermassive black holes near its core. Astronomers already knew of the galaxy's active, northern black hole (N), but thanks to cutting-edge 3D-mapping techniques, they've now identified two more —...

WASHINGTON (AFP) – A massive bright reddish star in the Orion constellation has mysteriously shrunk by over 15 percent in the last 15 years and astronomers have not yet determined why, according to a study released Tuesday. Betelgeuse, considered a supergiant star, is so large that it would reach to Jupiter's orbit in our solar system. But at a radius of about five astronomical units, the star has shrunk in size since 1993 by a distance equivalent to Venus's orbit. "To see this change is very striking," University of California, Berkley professor Charles Townes, who whon the 1964 Nobel Prize...

Intense pressure can force neutrons into cubes rather than spheres, say physicistsInside atomic nuclei, protons and neutrons fill space with a packing density of 0.74, meaning that only 26 percent of the volume of the nucleus in is empty. That's pretty efficient packing. Neutrons achieve a similar density inside neutron stars, where the force holding neutrons together is the only thing that prevents gravity from crushing the star into a black hole. Today, Felipe Llanes-Estrada at the Technical University of Munich in Germany and Gaspar Moreno Navarro at Complutense University in Madrid, Spain, say neutrons can do even better. These...

The quasar OJ287 contains two black holes (this slightly dated illustration lists the larger black hole's mass as 17 billion Suns, though researchers now estimate it is 18 billion Suns). The smaller black hole crashes through a disc of material around the larger one twice every orbit, creating bright outbursts (Illustration: VISPA) The most massive known black hole in the universe has been discovered, weighing in with the mass of 18 billion Suns. Observing the orbit of a smaller black hole around this monster has allowed astronomers to test Einstein's theory of general relativity with stronger gravitational fields than ever...

[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...

Phil PlaitNovember 16, 2015 A new study says that violent space weather that could cost $2 trillion in damage is more common than previously thought In the years 774 and 993, the Earth was attacked from space. Not by aliens, but by a natural event—and it was very, very powerful. Whatever it was, it subtly altered the chemistry of our planet’s atmosphere, creating trace amounts of radioactive elements like chlorine-36, beryllium-10, and carbon-14. And those provide the clue to what the event was: Those isotopes are created when high-energy protons slam into our air. That means the source must have...

Imagine what our night sky would look like if its stellar density was a million times greater than it is now. Remarkably, such places actually exist: They’re called “Ultracompact Dwarfs,” and astronomers are calling them an entirely new kind of galaxy. Undergraduate astronomy students Michael Sandoval and Richard Vo from San José University discovered a pair of record-breaking compact galaxies buried within data contained in the Sloan Digital Sky Survey. These exotic objects are similar to ordinary globular clusters, but upwards of a hundred to a thousand times brighter. Advertisement Image: The two ultra-dense compact galaxies were discovered orbiting...

Explanation: The Great Nebula in Orion is an intriguing place. Visible to the unaided eye, it appears as a small fuzzy patch in the constellation of Orion. But this image, an illusory-color four-panel mosaic taken in different bands of infrared light with the Earth orbiting WISE observatory, shows the Orion Nebula to be a bustling neighborhood or recently formed stars, hot gas, and dark dust. The power behind much of the Orion Nebula (M42) is the stars of the Trapezium star cluster, seen near the center of the above wide field image. The orange glow surrounding the bright stars pictured...