A supernova is a cataclysmic phenomenon in which a massive star explodes when it reaches the end of its life. This phenomenon emits more energy than what our sun has released in its entire lifetime. As big of a galaxy as our Milky Way which consists of more than 200 stars, has a supernova after every 50 years. An average person might or might not be able to see a supernova with their naked eye because it is rarely visible in the skies.
There are some examples of different supernovae remnants in different regions of the world. One of the visible ones can be seen from the Northern Hemisphere and is called Crab Nebula. This supernova remnant is available in the directions of the constellation of stars called Taurus the Bull.
The Chinese were the first people to have seen the first recorded supernova in the human history in year1054 CE. But the scientists and astronomers concluded that the Chinese saw it after 6,523 years of it actually happening. This happened because it was this many light years away from earth.
The Chinese called it the ‘guest star’ because it was visible in the day skies for almost 3 whole weeks. But then it slowly and gradually started fading away and it was gone completely after 3 months of when it was first sighted.
In the following years, Crab Nebula became famous for hosting the very first known Pulsar. This Pulsar was discovered in 1967 by Jocelyn Bell Burnell being a graduate student in the Cambridge University, England. This Crab Pulsar is a Neutron Star which actually is a remnant of the supernova which created the Crab Nebula. Pulsars emit beams of radio waves when they spin. And the beams coming out from the Crab Pulsar is coming directly towards our earth.
Here is an interesting fact about the supernovae. We think that when the supernova occurs, the stars explode outwards and emit a lot of energy. This is not the only thing that happens. These stars also implode inwards and create a massive density which is a neutron star. This neutron star isn’t always visible from the earth skies.
Why do stars explode?
Astronomers have been working on why these stars actually explode since centuries. But they have not seen one in the last 50 years. So this makes it a long overdue for the earth natives who are waiting to see one in their lifetimes. We hope we get to see one, but we really hope it’s not too close.
When a dwarf star lights up in a binary system we call it a nova. It is not an explosion to be precise but just a little flaring up of a small star. When a big star actually explodes, it makes a much bigger and brighter event, it is then called a supernova, as its name gives away.
When a supernova occurs, the outer layers of a star explode into the space. Once a star explodes, it does not return into its original state and brightness. It lights up the space for a period of time before it disappears into the open space.
Types of Supernovae
German astronomer Rudolph Minkowski and Swiss astronomer Fritz Zwicky have classified two types of supernovae, type I and type II. They are classified under the Minkowski-Zwicky classification system. This classification is done on the bases of spectra of the supernovae. Type I supernova lack the presence of hydrogen in their spectra while type II supernovae displays it.
Type I supernova happens when a star accumulates matter from a nearby neighbor until a runaway nuclear reaction ignites However, Type II supernova happens when a star runs out of nuclear fuel and collapses under its own gravity.
Supernova is a phenomenon which has been studied for centuries now. The astronomers along with scientists and researchers have been peeling off layers from the mysteries of space. Amongst all these topics, one is studying the phenomenon of stars going supernova. We are not sure if we would be able to see a supernova in our lifetimes, but let us hope that if we do, it occurs at a safe distance!