The study of supernovae. (supernova is one of those weird Greek based words where when you get more than one of them together, they aren't supernovas, they're supernovae). A supernova occurs when a large, old star contracts on itself as its fuel diminishes (normal stars create energy because hydrogen atoms crash together with such high energy that they undergo nuclear fusion to become helium atoms, when there isn't enough hydrogen left, the star burns less and less and begins to contract into a dwarf star).

A star is made of super-heated atoms that rush around in the stars atmosphere bumping into each other. This activity occurs because so much energy is produced by atoms fusing with one another in the core of the star and causes the star to want to expand. This desire to expand is opposed by the force of gravity in the star which makes the star want to collapse on itself. When the fuel begins to run out, there is less energy to make the star want to expand and the center of the star begins to contract because of gravity, leaving a shell of swirling material behind.

In very large stars, this contraction can occur very quickly and as all the material rushes into the center of the star. Because this material is rushing in from all directions, it all squishes together and the force of this compaction causes a rebound which sends a very powerful shockwave into the swirling material of the star's outer shell. This shockwave blows the material out into space in a tremendous explosion that is the supernova.

The brightest part of the supernova lasts for a few days and you can see the star as unusually bright for a few months before the gas flows too far away from the star center to be clearly seen. This gas continues to flow away and forms a nebula from which new stars are formed.

This is a rough description of what happens during a supernova.

Given this, what kinds of energy do you think one sees in a supernova. Many nebulae (another one of those Greek words where you have one nebula or several nebulae) are as many as a few light years across and can give birth to several new stars.

How do you suppose stars are formed from the expanding material of a star that has exploded as a supernova? Also, what do you think is left after a supernova occurs? As a hint, I'll let you know that the nuclear reactions inside a large star aren't just from hydrogen to helium but also from helium to carbon and so on up the periodic table.

If you need a supernova to make heavier elements such as oxygen and iron, where do you think the material that made the earth and other planets came from?

Supernovae that can be seen in the sky from Earth happen about every 140 years (14 have been recorded in the last 2000 years).

A lot of this information can be very technical but many will have good pictures and websites such as Sky and Telescope Magazine or Astronomy Magazine will have good descriptions. This has always been one of my favorite subjects and I hope you find lots of good information.

A supernova occurs when the inside of a star can no longer support itself. This occurs at the end of a large star's life when the star is running out of the nuclear fuel that keeps it shining. It can also happen if a smaller, burned-out star collects too much matter from another star that is close by. The entire star collapses inward until the very center of the star gets so dense that only nuclear forces are keeping the core from collapsing into a black hole. The outer layers of the star bounce off the core and explode outward.

Supernovas emit light (which we can see) and particles such as neutrinos and normal matter. We can see supernovas that occur in very far away galaxies. As for the matter that explodes outward from a supernova it might move away from the explosion at speeds as high as a million miles per hour. The matter will keep going for a long time because there isn't much in space to stop it.

Supernovas are supposed to occur about once every 100 years in a given galaxy. Many of the elements we have here on Earth were made inside a supernova.

Supernovas are of two types called type I and type II. Type I supernovas occur when two closely orbiting stars exchange material. That is, unlike OUR SOLAR SYTEM WITH ONLY ONE STAR ( the sun), many stars are members of pairs or even triplets!!!. A type I supernova is when a white dwarf star devours a closely orbiting companion; mass is pulled of the one star and it accretes on the white dwarf star until the mass of the white dwarf star becomes so big that the star collapses under its own weight. A giant explosion then takes place.

A type II supernova occurs when a single REALLY big star collapses in on itself. A big explosion takes place in that case also. The energy given out during supernova is across the entire electromagnetic spectrum...from gamma rays to radio waves including lots of LIGHT (BRIGHT!!)

Shock waves from the explosion travel many LIGHT-YEARS out into space!!! There are about one or two supernova per year in the Milky Way galaxy... most are too far away to observe very well. The Milky Way is a big place...its diameter is about 30,000 light-years across !!!