Supernovae (complete version)

Supernovae are huge explosions caused by very massive stars, releasing a brightness so intense that it can, for a period of time, overcome the brightness of entire galaxies. Over time, the brightness and temperature of the explosion slowly decrease. Supernovae, in the star cycle, mark the "death" of stars. Although they have this violent side, supernovae are responsible for permeating the space with heavier elements (having the production of these while the star was still performing the nuclear fusion processes) and for enabling the formation of new stars, thus have an analogous role to a bird, which feeds on seeds and then spreads them on the ground.

Scientists have concluded that the supernova that gave birth to the Crab Nebula (one of the best known) occurred in mid 1054 and in the same year became the second brightest object in our sky (after the moon). At that time (long before scientists like Kepler, Newton, Galileo ...) it was still believed that the Earth was the center of the Universe. Certainly the supernova caused considerable panic in the population!

If we had a star reasonably close to the solar system, with about 8 solar masses (or more), it would be a cause for concern. Even if the explosion itself did not reach us, we would still have problems, as the supernova releases a huge amount of gamma rays, which can, in contact with the atmosphere, end our ozone layer, leaving us totally vulnerable to ultraviolet radiation from the Sun. Fortunately, there are no star candidates for supernovae nearby. We see then that the Sun will not end in a supernova, since it does not have the necessary mass.

There are two main classifications for supernovae: Type 1 and Type 2

Type 1 supernovae are given in a binary stellar system (composed of a white dwarf and a companion). The stars in this system interact, so that the matter of the companion star is added to the white dwarf until it reaches the limit of Chandrasekhar (1.44 solar masses). At this point, the degeneracy pressure of electrons (which is what prevents the dense star from collapsing) can not contain gravity-induced collapse, so that the white dwarf becomes a neutron star or a black hole (depending on the pasta). In short, the "stealing" and aggregation of the mass of the neighboring star condemns our "thief".

Supernovae type 2 occur in stars that have about 8 solar masses for more. When the process of nuclear fusion ends, the star begins to contract because of its gravity, generating a supernova and remnants of this.

The remnants of supernovae are a plate full of wonders. Huge clouds of dust of the most varied colors (corresponding to the elements created in the heart of the star) mark the space, giving a contrast to what appears to be the eternal emptiness. Fantastic neutron stars rotating under its axis dozens of times per second (the pulsar * PSR J1748-2446ad was recorded to rotate around 700 times per second), due to the conservation of angular momentum and the "cosmic monsters" (holes black) may be the remnants of the collapsed star; as mentioned, being determined by the mass of the star before collapse.

Supernovae, although not the most common processes in the Universe, are not very difficult to "discover". There are records of amateur astronomers who have been able to observe unseen supernovae. In serious research, there is a way to "predict" the region where a supernova will "appear"; this is due to the fact that, in the final moments of the star's life, it releases a large amount of neutrinos, which can be detected by us on Earth, providing a kind of "warning."

Hypernovas are stellar bursts of colossal scales. A single hypernova can release 100 times more energy than a common supernova and is considered by many scientists to be the most powerful type of explosion. The star Eta Carinae is one of the main suspects to become a hypernova. Even if it is 7500 light-years from Earth, the brightness of the explosion will be so intense that it will compete with that of the Moon for a few months.

Another curious fact about supernovae is that during the blast process, when the star is pushing its inner layers outwards, the process of nuclear fusion is active amid such chaotic conditions, allowing the creation of very heavy elements such as plutonium, uranium, etc.

We see, then, that supernovae are proofs that nothing, not even stars, last forever, but they also show us that, from a perishing star, we have the fertilization of the cosmos, with the scattering of matter produced in galactic furnaces ), permeating the space with elements that enabled the emergence of life. We conclude by quoting Carl Sagan for a brief reflection:

"The cosmos is within us. We are made of dust from the stars. We are a means of the Universe to know each other."

Reference material: 50 astronomy ideas you really need to know/ From the atom to the black hole/ https://en.wikipedia.org/wiki/Supernova