Nearly 1,000 years ago, astronomers in China and Japan saw something strange in the sky. It seemed to be a new star. Even stranger, for several weeks that star was bright enough to be seen in the daytime. Eventually the new star faded from view — because it wasn’t a new star at all. It was the explosion of a star, or a supernova.
Supernovas are some of the biggest explosions in the universe. At their brightest, they can even outshine galaxies. And they generally come about in one of two ways.
The first type of supernova happens when a white dwarf star packs on too much mass. For instance, a white dwarf’s gravity can suck material off a neighboring star. If it gets bigger than about 1.4 times the mass of the sun, the white dwarf becomes unstable and goes supernova, completely destroying the star.
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With the other type of supernova, a star several times bigger than the sun runs out of fuel to burn. When the star blows up, it throws off its outer layers into space and its core collapses. Stars that are a bit bigger than the sun collapse into neutron stars. Stars that are much bigger than the sun collapse into black holes.
The supernova that astronomers saw in 1054 A.D. was the explosion of a star about 10 times the mass of our sun. It threw off a bunch of material that now makes up the famous Crab Nebula. In the center of that cloud of gas and dust — at ground zero for the explosion — a type of spinning neutron star called a pulsar got left behind.
Supernovas aren’t just the universe’s most fantastic fireworks. They’re key to the origins of life. These explosions enrich the space between stars with elements that are key ingredients for new stars, planets and life forms.
Want to know more? We’ve got some stories to get you started:
Weird star explodes over and over, cheating death There’s a weird supernova out there. This dying diva may have had multiple explosions, and it’s lately been glowing for more than three years. (1/8/2018) Readability: 6.9
Explainer: Stars and their families Most pinpoints that light the night sky are raging infernos we call stars. As adults, many will create new elements that they later cast off into the cosmos. (8/18/2020) Readability: 6.0
After 30 years, this supernova is still sharing secrets It’s been more than 30 years since astronomers first witnessed the stellar explosion known as SN 1987A. Scientists are still learning from this cataclysmic phenomenon. (5/18/2017) Readability: 7.2
The sun isn’t big enough to go supernova — but what if it did? What would happen to us?
Explore more
Star caught passing gas before exploding
Strange but true: White dwarfs shrink as they gain mass
A star winked out of sight. Could it be a ‘failed supernova’? (from Science News)
A zombie star’s spiky filaments shed light on a 12th century supernova (from Science News)
JWST spies hints of a neutron star left behind by supernova 1987A (from Science News)
A rare glimpse at a relatively nearby supernova offers clues to how stars die (from Science News)
