Space-Time Pt. 2

Black Holes

A black hole is a region in space, in which the gravitational pull is so strong that not even light can escape. And thus, because it doesn't reflect light, it is named a "black" hole. Some basic terms needed to be understood and their definitions when discussing a black hole, such as a singularity and the event horizon, are included in the picture below.

In order to understand what a black hole is, we must first understand how a black hole forms. A black hole is formed when a supergiant starts to run out of its nuclear fuel (hydrogen), and collapses into a supernova. This leaves behind its core, which would become the core of a black hole, if the core’s star was large enough. It is important to note, though, that anything in the universe can become a black hole if a large amount of mass in a small amount of space runs out of energy to act against gravity, and thus, collapses.

There are four types of black holes: stellar, intermediate, supermassive, and miniature. Supermassive black holes are millions, if not billions, of times as the Sun can be found in the center of galaxies. The black hole at the center of the Milky Way is named Sagittarius A*and it is predicted to be more than four times as massive as the Sun. Miniature Black holes, on the other hand, are theoretical and said to be formed at the beginning of the formation of our Universe. Intermediate black holes, like the Miniature black holes, are theoretical, and Stellar black holes are black holes that are about three times the mass of our Sun.

The idea of a black hole was only a theory until recently, when the Event Horizon Telescope team unveiled the first ever image taken of a black hole on April 2019 (first picture below). This image is of the supermassive black hole, found at the center of the M87 galaxy. This image was constructed through the use of radio-frequency signals collected by the Event Horizon Telescope. This image was later refined and released using polarized light on March 2021(second picture below).

White Holes

Hypothetically, a white hole is a region in space, often referred by people as the reverse of a black hole, in which light and other content within are “spit out” into space. Some theories suggest that white holes may be able to create entirely new universes just through the content spit out by them. In these theories, the content usually comes from being “swallowed” by black holes, meaning that matter is able to travel from one universe to another by getting sucked up by a black hole in one universe and spit out into another universe by a white hole.

As mentioned above, a white hole, according to Albert Einstein and Nathan Rosen, is essentially the mirrored version of a black hole. Physicists and cosmologists, alike, use the Einstein-Rosen bridges (pictured below) to form solutions in general relativity.

Worm Holes

And finally, worm holes are a hypothetical tunnel that connects two points in space-time. If you were to travel through this tunnel, you would be able to go from point A to point B very quickly, instead of having to take millions of light years without the tunnel. Other theories include it connecting a black hole and a white hole, or being a "gateway" to a whole other universe. Which theory is true, or if it is something different entirely, can not be known though, until the existence of wormholes themselves it proven.

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