This is because many of the chemical elements were made in supernova explosions.
It could be dangerous if a supernova explosion happened very close to the Earth.
This is equivalent to a supernova explosion every 147 years, on average.
It is thought to have formed after a fairly recent supernova explosion.
"Do you think the birds caused the supernova explosion, Mark?"
He's the only man I know who could lie his way out of a supernova explosion.
The first big break came with the supernova explosion itself two years ago.
"The companion must be made of matter that was inside the supernova explosion," he said.
The supernova explosion of this star was witnessed in 1054.
After a supernova explosion, a neutron star may be left behind.
