If you ever watched an astronomy documentary or read a book about stars, you have probably heard of supernovas. They are big explosions that have intrigued scientists for decades, and today, we know many things about them. So in this article, let’s take a look into what they essentially are, what causes them, and other exciting facts concerning these strange phenomena.
Written by Maša
Cause
As mentioned, a supernova is a big explosion, in fact, the biggest explosion humans have ever seen. There are two main ways they are caused: by a dying star or in a binary star system.
To understand how a dying star explodes, you should first know how stars produce energy and light. Stars are mostly made out of two elements: hydrogen and helium.
Nuclear fusion
When atoms of hydrogen are in the star’s core, they are under pressure so big that they collide. One helium atom is formed from two hydrogen atoms. This process is called nuclear fusion. While creating a helium atom releases some energy, which in large amounts gives rise to a lot of energy. Nuclear fusion is necessary to keep the star alive because without the pressure made in the core, the star would just collapse. But the problem is that, as time passes, the star converts more and more hydrogen atoms into helium atoms, and at one point, it runs out of fuel. The pressure becomes so weak and – boom! The star explodes into a supernova.
Which stars can go boom?
But we need to be careful. Not every star will explode into a supernova. For that to happen, the star has to have a big enough mass, about five times bigger than Sun’s. That is why Sun eventually won’t become a supernova but instead a white dwarf.
The other way the supernova can be caused is in a binary star system where one star is a white dwarf. If the two stars collide or the material goes from a more giant star to the white dwarf, it can explode into a supernova. Examples of that kind of binary system are Sirius A, α of the Canis Major constellation, and a Sirius B, a white dwarf. However, it is unlikely that it will come to the supernova explosion.
Black holes
Black holes are one of the most mysterious objects in the universe. They are tiny, invisible, and incredibly dense objects from which nothing can escape, not even the light. And supernovas are the reason for their origin. When a star about ten times heavier than the Sun goes supernova, it leaves the core big enough that its own gravity can turn it into a black hole.
Supernovas in the past
Supernovae are quite a rare phenomenon – by an estimate, only two to three of them occur every century in our galaxy. However, there were some observations of them in the past. The most famous of those was probably the one from 1054 seen by Chinese and Korean observers. Today, its remains are located in M1 or the Crab Nebula located in the Taurus constellation.
Interestingly, famous astronomers Tycho Brahe and Johannes Kepler observed supernovas. Brahe observed one in 1572, and Kepler observed one in 1604.
Fun facts about supernovas
Heavy elements
Description for this block. Use this space for describing your block. Supernovas are responsible for creating heavy elements such as gold, silver,… Why? Because they can only be made in supernova explosions.
Visibility
When they occur, supernovas can be visible for months, and they are brighter than any other object in the galaxy.
Famous stars
Betelgeuse, the biggest star of the Orion constellation, might go supernova in the near future, due to it being a red supergiant, one of the largest classifications of stars.
Sources:
https://spaceplace.nasa.gov/supernova/en/
https://www.britannica.com/science/supernova
https://www.nationalgeographic.com/science/article/supernovae
https://astronomy.com/magazine/ask-astro/2020/05/when-sirius-a-expands-into-a-red-giant-could-white-dwarf-sirius-b-go-supernova
