I’ve noticed that a black hole is created by a star destroying itself with its own gravity. By that I would say that the pressure is so high that the atoms just get ripped apart and you get a kind of liquid that’s pitch black and puts that other matter in there too and makes that kind of liquid too because of the pressure in it? In this way it gets bigger and bigger until it is this big and the gravity is 0 again and eventually disappears somewhere in the universe and all matter is free again. Well, it’s not really liquid, more like a ball of loose matter that is compressed enormously…
And if this is not true, isn’t the event horizon just like our universe a frontier of light? But then in our own universe? Maybe in a black hole there is another universe?
Answer
The mass of a black hole created as a result of the collapse of a star (core) is indeed the mass of that star (core), compressed to an energy density that reduces that mass to its elemental components. But where I’m not following you anymore is the thought that that great density causes matter to expand again and gravity becomes zero. Rather, it is the gravitational force associated with the large mass concentration that makes it contract to very very small dimensions.
The ‘event horizon’ is the outer boundary of the area within which the escape velocity is greater than the speed of light, which in practice means that nothing can get out. In this way, the inside of a black hole is closed off from what lies outside. So it has become different. But calling that “another universe” is more like a play on words. ‘Universe’ or ‘universe’ mean ‘everything there is’, and ‘everything’ has no plural.
Answered by
Prof. dr. Christopher Waelkens
Astronomy
Old Market 13 3000 Leuven
https://www.kuleuven.be/
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