What was the bright explosion astronomers spotted 1,600 years ago? Mystery of the strange flash deepens as a supernova is ruled out

Daily Mail - Science & tech

Chinese astronomers witnessed a bright explosion in the sky 1,600 years ago. The flash of light had been identified as a supernova remnant, but new observations have shown it could not have been this particular star. The explosion would not have been bright enough to be seen from Earth, research shows, which leaves astronomers with a question to answer – what exactly did the fourth century astronomers see? Astronomers witnessed an explosion in the sky 1,600 years ago. Astronomers still think the event, which happened in the constellation Sagittarius, was probably a supernova.

Superluminous 'Heavy Metal' Supernova 420 Million Light-Years Away Likely Powered By Magnetar

International Business Times

Thousands of supernovae have been detected by humankind, making these explosions of collapsing stars almost commonplace in the universe. However, there is a subset of particularly powerful supernovae, called superluminous supernova, that is rare and far more energetic than its regular counterpart. About 50 superluminous supernovae have been identified so far among the thousands of supernovae detected, but astronomers have now observed one that is unusual even for its kind. Called SN 2017egm, the event took place at a distance of only 420 million light-years from Earth, which is about three times closer than any other superluminous supernova ever observed. Even more remarkably, the explosion took place in a large spiral galaxy which has a relatively high presence of heavier elements.

Supernova explosion defies the laws of physics

Daily Mail - Science & tech

'A better understanding could provide insight into the evolution of the most massive stars, the production of the brightest supernovae and possibly the birth of black holes that have masses near 40 solar masses, such as those associated with the first direct detection of gravitational waves. 'For now, the supernova offers astronomers their greatest thrill: something they do not understand.' One explanation offered by the researchers for the unusual activity of iPTF14hls could be to do with its size. Adding to the puzzle, telescope imagery uncovered by the team suggests explosions may have taken place at the same location before.

This unusually long-lasting supernova may force astronomers to rethink how stars die

Los Angeles Times

Astronomers at Las Cumbres Observatory have discovered a supernova that has defied expectations, lasting far longer than anticipated. The strange and still-going stellar explosion, described in the journal Nature, defies scientists' understanding of dying stars and may force them to rethink their ideas of how stars evolve. "The supernova offers astronomers their greatest thrill: something they do not understand," Stan Woosley of UC Santa Cruz, who was not involved in the study, wrote in a commentary. The supernova known as iPTF14hls didn't seem like anything out of the ordinary when it was picked up in September 2014 by the Intermediate Palomar Transient Factory telescope near San Diego. The supernova sits some 500 million light-years away in the constellation Ursa Major.

Could supernovas have altered the development of life on Earth?

Los Angeles Times

Scientists sifting through rare isotopic signatures in Earth's crust beneath the sea have found a signal from the heavens: evidence of nearby supernova explosions in just the last few million years. The discoveries, described in the journal Nature, shed light on the impact that such stellar deaths can have on our home planet, and may help scientists understand whether or not these events have affected the course of life on Earth. Supernovas are the powerful, violent deaths of massive stars, whose deaths seed the rest of the universe with heavy elements that aren't made otherwise. So while supernovas have helped seed other stars and their planets with rarer elements, astronomers have long wondered what would happen if such fireworks went off a little too close to our planetary home. "For more than half a century, astronomers have speculated that supernovae have occurred close enough to Earth to affect the planet, possibly contributing to mass extinctions or climate," Adrian Melott of the University of Kansas, who was not involved in the study, wrote in a commentary on the paper.