The Cataclysmic Death of Stars
enormous weight of the star's outer layers.
But when the core consumes all of its hydrogen, gravity compresses it. The temperature of the
shrinking core rises to about a hundred million degrees, hot enough for helium nuclei to fuse and
make carbon. The new surge of energy keeps the core from collapsing much further.
For an isolated star no heavier than the sun, there is little more to the story. The star burns all of
its helium and shrivels. It turns into a white dwarf about the size of Earth, aging and cooling
indefinitely--unless it lies close enough to another star to steal its neighbor's outer layers of
hydrogen. If enough material falls onto the white dwarf, the siphoned fuel ignites a
thermonuclear explosion. As the detonation spreads, the entire star blows up in what is known as
a type 1a supernova--a giant nuclear bomb.
The supernova blossoming over Palomar was a different kind: not a thermonuclear blast but a
annaabi.ee 
