Scientists Report Biggest Star Explosion Ever Seen
2020-04-18
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1Scientists have just seen the biggest star explosion observed to date. Star explosions are often called supernovas.
2The supernova was up to 100 times larger than our sun and happened in a galaxy far away.
3It released two times as much energy as any star explosion ever observed and happened about 4.6 billion light years from Earth, scientists said.
4A light year is the distance light travels in one year, which is 9.5 trillion kilometers.
5The scientists said this explosion might represent a kind of supernova that has only been known in theory until now.
6Matt Nicholl is an astrophysicist with the University of Birmingham in England.
7He told Reuters news agency that two very large stars - each about 50 times the sun's mass - may have joined to make one huge star.
8He thinks this took place about 1,000 years before the explosion.
9The stars had been part of a binary system -- two stars pulled toward each other through gravity.
10The joined star exploded in a supernova that has been named SN2016aps.
11"We found that the supernova was able to become so bright because of a powerful collision" between the matter thrown by the explosion and a shell of gas shaken off by the star a few years before, Nicholl explained.
12He is lead writer of the study published this week in the journal Nature Astronomy.
13Stars die in many different ways, depending on their size and other properties.
14When a massive star - more than eight times the mass of our sun - uses up its fuel, it cools off and its center collapses.
15This launches shock waves that cause its outer layer to explode so violently that it can shine brighter than whole galaxies.
16The researchers observed the explosion for two years until it lowered to one percent of its highest brightness.
17They said it may have been an example of an extremely rare "pulsational pair-instability" supernova.
18Peter Blanchard explains what that means.
19He said pulsational pair-instability is when very large stars experience pulsations which throw material away from the star.
20Blanchard, who co-wrote the study, is an astrophysicist at Northwestern University in Illinois.
21He said the discovery shows there are many new and exciting things that remain uncovered in the universe.
22Very massive stars like this one were probably more common early in the universe's history, Nicholl said.
23"The nature of those first stars is one of the big questions in astronomy," Nicholl added.
24"Seeing things further away means looking back further and further in time.
25So we might actually be able to see the very first stars if they explode in a similar manner to this one.
26Now we know what to look for."
27I'm Alice Bryant.
1Scientists have just seen the biggest star explosion observed to date. Star explosions are often called supernovas. 2The supernova was up to 100 times larger than our sun and happened in a galaxy far away. 3It released two times as much energy as any star explosion ever observed and happened about 4.6 billion light years from Earth, scientists said. A light year is the distance light travels in one year, which is 9.5 trillion kilometers. 4The scientists said this explosion might represent a kind of supernova that has only been known in theory until now. 5Matt Nicholl is an astrophysicist with the University of Birmingham in England. He told Reuters news agency that two very large stars - each about 50 times the sun's mass - may have joined to make one huge star. He thinks this took place about 1,000 years before the explosion. The stars had been part of a binary system -- two stars pulled toward each other through gravity. 6The joined star exploded in a supernova that has been named SN2016aps. 7"We found that the supernova was able to become so bright because of a powerful collision" between the matter thrown by the explosion and a shell of gas shaken off by the star a few years before, Nicholl explained. 8He is lead writer of the study published this week in the journal Nature Astronomy. 9Stars die in many different ways, depending on their size and other properties. When a massive star - more than eight times the mass of our sun - uses up its fuel, it cools off and its center collapses. This launches shock waves that cause its outer layer to explode so violently that it can shine brighter than whole galaxies. 10The researchers observed the explosion for two years until it lowered to one percent of its highest brightness. They said it may have been an example of an extremely rare "pulsational pair-instability" supernova. 11Peter Blanchard explains what that means. He said pulsational pair-instability is when very large stars experience pulsations which throw material away from the star. 12Blanchard, who co-wrote the study, is an astrophysicist at Northwestern University in Illinois. 13He said the discovery shows there are many new and exciting things that remain uncovered in the universe. 14Very massive stars like this one were probably more common early in the universe's history, Nicholl said. 15"The nature of those first stars is one of the big questions in astronomy," Nicholl added. "Seeing things further away means looking back further and further in time. So we might actually be able to see the very first stars if they explode in a similar manner to this one. Now we know what to look for." 16I'm Alice Bryant. 17Reuters news agency reported this story. Alice Bryant adapted it for Learning English. Hai Do was the editor. 18___________________________________________________________________ 19Words in This Story 20galaxy - n. any one of the very large groups of stars that make up the universe 21theory - n. an idea or set of ideas that is intended to explain facts or events 22astrophysicist - n. a scientist who studies the physical and chemical properties and structures of stars, planets and other objects in outer space 23gravity - n. the natural force that tends to cause physical things to move towards each other 24collision - n. a crash in which two or more things or people hit each other 25pulsational - adj. a periodically recurring increase and decrease of a quantity, such as pressure, volume or voltage 26astronomy - n. the scientific study of stars, planets, and other objects in outer space