Stars exist in a perfect balance between two opposing forces: the internal pressure of gravity tries to shrink the star, but it is neutralized by the external pressure of the emitted radiation until iron is reached. The melting of the iron does not create radiation and then gravity wins
by Fraser Kane
Black holes are the most awe-inspiring and awe-inspiring exotic objects in the universe.
Take the mass of each star. , compressed it into an object so compact that it overcomes the ability of gravity to stop the compression. Nothing, not even light, can escape the gravity of a black hole.
The idea was first born in the 18th century by the geologist John Mitchell. He realized that if the sun could be compressed by several orders of magnitude, the gravitational pull would be so strong that we would have to go faster than the speed of light to escape it.
Initially, black holes were considered nothing more than abstract mathematical concepts. Even Einstein assumed they didn't really exist. However, in 1931, the astronomer Chandrashankar calculated and found that stars with a high mass above a certain size can collapse into black holes after all. Black holes turned out to be real, and over the next several decades astronomers found many examples of black holes throughout the universe.
Stars exist in a perfect balance between two opposing forces: the internal pressure of gravity tries to shrink the star, but it is neutralized by the external pressure of the emitted radiation. At the center of each star, millions of tons of hydrogen are converted to helium every second, releasing gamma radiation. This fusion process is an exothermic reaction, meaning it releases more energy than it requires.
When a star consumes the rest of its hydrogen it moves to the reservoirs of the helium from which it is built. After finishing the helium supply, it moves to its product - carbon, and finally - oxygen. The radiation emitted in this process balances the gravitational forces trying to compress it.
Stars with a mass like our sun will stop there. They are not massive enough to continue the fusion reaction beyond oxygen and they become a white dwarf and later cool. However, in stars with five solar masses or more, the fusion process continues up the periodic table with zinc, aluminum, potassium, and so on until iron. No energy is produced from the fusion of iron atoms.
And so, in a fraction of a second, the radiation from the star turned off. Without the outward pressure from the radiation, gravity would win and the star would collapse inward. All the mass of the star will occupy a smaller and smaller volume of space. The escape velocity from the star increases, until nothing, not even light, manages to escape from it. This is how a black hole is created.
Good. This is the main way, but you can get black holes when dense objects, like neutron stars, collide with each other.
And of course there are the and then there are the massive black holes at the heart of every galaxy. And to be honest, astronomers still don't know how these monsters were created.
For the article in Universe Today
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Miracles. upside down. Those who are in the black hole area see the world outside coming to an end, the clocks seem to be ticking at an increasing rate.
To an outside observer it would appear that the clock of the one moving towards the black hole is ticking slower and slower
point
Time slows down only for those who are in the hole area. As for a remote viewer, there is no change in appearance.
It seems to me that since time in the black hole region is slowing down, black holes never exist in the present only in the future, at the end of time. And so black holes do not exist, only aspire to be black holes.