When a stars’ radioactive fuel runs out, it collapses into itself due to gravity. This results in the most spectacular, massive explosion humanity have ever known. A supernova.
Supernova Remnants (SNR)
The original star either turns into a black hole or a neutron star; or completely destroyed. The material that is burst into space is so incredibly large it spans light-years of space. This called a Supernova Remnant. It is also a type of nebulae.
Helix Supernova Remnant, Nebula, NASA
Puppis A is an exceptionally bright Supernova Remnant. The original star exploded 10,700 years ago, which means it is older than the Crab Nebula. It created a dust cloud that is 100 light-years in diameter.
The star was 7000 light-years away. Therefore the explosion must have been seen from Earth 3700 years ago, around B.C. 1600.
Puppis A, X-Ray, NASA
This is an X-Ray image of the gas cloud. The red parts correspond to high-levels of Oxygen, and blue parts correspond to high levels of Nitrogen. This means the original star was massive. It had more than 25 times more mass than our Sun.
Neutron Star of Puppis, ROSAT
Why Is Puppis-A Different?
The bright dot in the image is most possibly a neutron star, one of the possible remannings of a supernova explosion. The weird thing is the star is not at the center of the explosion, it slightly towards the right. Why?
No one knows. There is not even a theory to explain why the remaining star is not at the center. This leads scientists to think about asymmetric supernova explosions, which can change our ways of understanding stars and ending of their lives altogether.