What is a supernova?

A supernova is a massive explosion resulting from the death of a star more than ten times bigger than our own Sun. When huge stars run out of fuel they collapse under the infuence of immense gravitational forces. This dramatic collapse takes less than a second and causes the release of an enormous amount of energy, equivalent to the energy produced by 100 Suns during their life time of about 10 billion years.

Although this dramatic and sudden release of energy is highly destructive it can also give birth to other stars and solar systems as well as the elements present on Earth that create life as we know it. During a supernova, enough energy is generated to produce nuclear fusion reactions. These reactions fuse smaller atoms, such as iron and silicon, to form heavier elements such as copper and lead. In fact all elements with atomic masses heavier than iron were created during a supernova. What remains after a supernova is a rapidly expanding cloud of gas, called a nebula, and sometimes a black hole.
Crab nebula

We can sometimes see a supernova in the night sky. Such events glow bright for many days, months or even years. Many supernovae are discovered every year but supernovae that can be viewed without a telescope are rare. What can we learn by studying supenovae? By studying the light that comes form bright supernovae we can determine how fast galaxies are moving away from us due to the expansion of the universe. From this information we can determine how much matter there is in the universe and therefore determine its ultimate fate. You see, the more matter present the more likely that the universe will stop expanding, as a result of the Big Bang, and collapse back on itself. Perpetual expansion will only occur if there is not enough matter in the universe.

 

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What is the major fuel of a star?
Which process takes place in the core of a star that generates immense heat?
What happens when the star runs out of fuel?
At what point are elements heavier than helium but lighter than iron formed?
The most energetic, singal event in the universe is known as a
Heavy elemnts such as uranium and gold are formed during

Describe what happens to a small star and a large star at the end of their lives.

But what harm can a supernova that is 10,000 light years form Earth have? Well according to some scientists the immense outburst of radiation may have resulted in the Ordovician mass extinction some 440 million years ago and plunged the Earth into an ice age.
The Ordovician extinction