Lately we have seen in the press many news about the star Betelgeuse and its impending supernova explosion, some of them even with their apocalyptic dose.
To begin, we have to understand that, for an astronomer, imminent is something between 0 and 10,000 years, wich means that, with a little luck we will not see it neither we nor our immediate descendants.
To understand why they know it is going to explode and what is that of a supernova, you have to know a little how Albert Einstein's theory of relativity is going.
According to this, gravity is the effect or consequence of the curved geometry of spacetime, which is like a mesh that deforms depending on the mass of the objects "placed" in it.
On the other hand, one must also know that the stars are nothing more than huge balls of incandescent plasma, in which millions of thermonuclear reactions occur per second.
These reactions are produced by the fusion of the hydrogen atoms that, with the enormous temperatures and pressures of the sun, are able to unite to produce Helium and a lot of energy. The balance between that energy and that of gravity is what preserves the integrity of the star and its spherical shape.
As the star ages and ends the hydrogen, the helium merges to form lithium and subsequently other heavier elements that no longer produce so much energy in the fusion.
During that process the star is "swelling" to become a red giant as is the case of Betelgeuse; When the star has already fused all its fuel, it is unable to withstand the force of gravity and collapses with a tremendous emission of energy to become a white dwarf.
Depending on the mass of that resulting white dwarf, it will burn until it becomes a brown dwarf or collapse again to form a black hole or a neutron star, which is most likely in the case of Betelgeuse.
But, returning to the title, what will happen if Betelgeuse explodes? Well, nothing, that for a few weeks we would have a star as bright as the moon and a handful of illuminated people talking about the end of the world.
Betelgeuse is one of the stars of the constellation of Orion and is more than 500 light years from us that are something like 10,000 triillion kilometers so I don't think it will even disheve us.
Anyway, do not stop looking at the sky ...
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