Black Holes
Black holes. we've all heard of them, but what really are they? They are regions of space with gravity so enormous that not even LIGHT can escape it! Like most things in the Physics universe, this was first birthed by Albert Einstein in his theory of general relativity. The theory dictates that a sufficiently compact mass can deform spacetime and form a black hole, where the boundary of the region for which no escape is feasible is called the event horizon. But how do they form in the first place?
Black holes form in the most peculiar ways. Very large stars (over 3x the size of our sun) can undergo extreme gravitational collapse once the fuel of the star runs out. The forces that keep a star from collapsing in on itself (the forces between atoms) are overcome by the collective gravity of the star, hence forcing a large mass into a very small volume. This creates an area of immense density that becomes a black hole. Black holes can drastically range in size, from very small to over 10 BILLION solar masses.
However epic black holes may seem, they do not live forever. According to the late physicist Dr. Stephen Hawking, black holes slowly lose mass by emanating energy called Hawking radiation. This happens as space is not really empty space (ironic, I know), but is rather filled with particles continuously popping into and out of existence. Hawking demonstrated that if a pair of such particles is created near a black hole, there is a small chance that one of the particles will be swallowed up by the black hole, and the other particle will escape into space. The energy for this comes from the black hole, so if this process frequently happens, the black hole will lose energy and therefore mass overtime. This action is mind-bogglingly slow, meaning most black holes will not fully evaporate for a very long time. In fact, it would take longer than the entire age of the universe for most black holes to completely evaporate!
Some fun facts:
Black holes form in the most peculiar ways. Very large stars (over 3x the size of our sun) can undergo extreme gravitational collapse once the fuel of the star runs out. The forces that keep a star from collapsing in on itself (the forces between atoms) are overcome by the collective gravity of the star, hence forcing a large mass into a very small volume. This creates an area of immense density that becomes a black hole. Black holes can drastically range in size, from very small to over 10 BILLION solar masses.
However epic black holes may seem, they do not live forever. According to the late physicist Dr. Stephen Hawking, black holes slowly lose mass by emanating energy called Hawking radiation. This happens as space is not really empty space (ironic, I know), but is rather filled with particles continuously popping into and out of existence. Hawking demonstrated that if a pair of such particles is created near a black hole, there is a small chance that one of the particles will be swallowed up by the black hole, and the other particle will escape into space. The energy for this comes from the black hole, so if this process frequently happens, the black hole will lose energy and therefore mass overtime. This action is mind-bogglingly slow, meaning most black holes will not fully evaporate for a very long time. In fact, it would take longer than the entire age of the universe for most black holes to completely evaporate!
Some fun facts:
- Primordial black holes are small hypothetical black holes that burst into existence at the instant of the Big Bang due to areas of high density within the early universe.
- Almost every galaxy contains a supermassive black hole at its center (Ours is called Sagittarius A*).
- Black holes cannot be seen directly, but are rather observed by the effect it has on its surroundings.
- The first picture of a black hole was taken on April 19th, 2019 and was of the black hole at the center of the galaxy M87.
What do you think about black holes? Please leave any feedback in the comments!
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