Type II supernovas (SNs) are probably the single most energetic
stellar event in
the Universe. They are the deaths of massive stars and involve the release of
100 times the energy the Sun produces in its entire lifetime!
Interesting tidbits:
99 % of the energy of a SN
comes out as neutrinos
~1 % of the energy goes into kinetic energy, the motional energy of the ejected material
only 0.01 %
of the energy goes into the visible fireworks (electromagnetic radiation)
seen in the sky.
Even this tiny amount of visible energy allows Type II
SN to stand out against the background light of entire galaxies
(see above)!
Type II SN are impressive beasts and are interesting simply from
this standpoint, they, however, are interesting for other reasons too.
SN produce most of the heavy elements
found in the Universe
SN trigger star formation (it was, at one time,
speculated that a SN triggered the formation of the Solar System).
SN are a major source of energy input into the ISM in
general
