A supernova is the biggest explosion that humans have ever seen. Each blast is the extremely bright, super-powerful explosion of a star.
One type of supernova is caused by the “last hurrah” of a dying massive star. This happens when a star at least five times the mass of our sun goes out with a fantastic bang!
Massive stars burn huge amounts of nuclear fuel at their cores, or centers. This produces tons of energy, so the center gets very hot. Heat generates pressure, and the pressure created by a star’s nuclear burning also keeps that star from collapsing.
A star is in balance between two opposite forces. The star’s gravity tries to squeeze the star into the smallest, tightest ball possible. But the nuclear fuel burning in the star’s core creates strong outward pressure. This outward push resists the inward squeeze of gravity.
When a massive star runs out of fuel, it cools off. This causes the pressure to drop. Gravity wins out, and the star suddenly collapses. Imagine something one million times the mass of Earth collapsing in 15 seconds! The collapse happens so quickly that it creates enormous shock waves that cause the outer part of the star to explode!
Usually a very dense core is left behind, along with an expanding cloud of hot gas called a nebula. A supernova of a star more than about 10 times the size of our sun may leave behind the densest objects in the universe—black holes.
Scientists have learned a lot about the universe by studying supernovas. They use the second type of supernova (the kind involving white dwarfs) like a ruler, to measure distances in space.
They have also learned that stars are the universe’s factories. Stars generate the chemical elements needed to make everything in our universe. At their cores, stars convert simple elements like hydrogen into heavier elements. These heavier elements, such as carbon and nitrogen, are the elements needed for life.
Only massive stars can make heavy elements like gold, silver, and uranium. When explosive supernovas happen, stars distribute both stored-up and newly-created elements throughout space.
Picture Credit : Google
