Why do Supernovas Occur?
Supernovas are enormous explosions that occurs at the end of a large star's life.
By this time, the star had used up the fuels needed to keep producing energy by nuclear
fusion. The core collapses inward to become either a neutron star or a blackhole. At the
same time, the shock waves cause the outer layers to explode outward in a rapidly
expanding nebula of gases and dust.
General Information
Supernovas rarely occur. In, 1054, a famous one was observed and was observed in both
India and China. It was so bright that people could even see it in daylight and was visible for
about 21 months. The gases that were spreading out from this supernova now form the
Crab Nebula (which can be seen in the constellation Taurus.
The Supernova 1987A
Only on supernova has been seen with an unaided eye, since the telescope has only been
invented about 400 years ago. It was discovered by a Canadian named Ian Shelton who
was working at an observatory in Chile, South America.
A neutron star is when a star about 10 times the mass of the Sun dies and the extremely dense
star is composed of neutrons. The neutrons are tightly packed, with no space between them. A
pulsar is a type of neutron star that emits pulses of very high energy radio waves. Pulsars are
very small and are only about 20km in diameter, but very dense with about the same mass as a
normal star. Up until now, more than 400 pulsars have been identified.
A black hole is when a star about 30 times the mass of the Sun dies and is small and is a very dense
object with a force of gravity so strong that nothing can escape from it. Not even light can radiate
away from its surface. Because light cannot escape, they can exist undetected. It is so dense
that a handful of it would have a mass of about 10 million cars! That explains its strong gravitational
pull.
