Group V Galaxies And Black Holes
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A black hole is a place in space where gravity pulls so much that even light is trapped and can not get out! The gravity is so strong because matter has been compressed into a tiny space. This can happen when a star is dying. Because no light can get out, people can't see black holes with the naked eye. They are invisible to us. Space telescopes with special tools can help find black holes. The special tools can see how stars that are very close to black holes act differently than other stars. Black holes can be big or small. Scientists think the smallest black holes are as small as just one atom! These black holes are very tiny but have the mass of a large mountain. Mass is the amount of matter, or "stuff," in an object. There are quite a few types of black holes. The biggest are called Supermassive They can be as big as 1 million suns!!! Another is called "stellar." It can be up to 20 times more than the mass of the sun. Not as big as Supermassive, but still much much bigger than us. There may be many stellar mass black holes in our galaxy. Black holes can form into a wormhole (as seen on the diagram above^) Wormholes are "a hypothetical connection between widely separated regions of space–time."-Dictionary. While wormholes are theoretically possible to create, they're practically impossible from what we currently understand. Confusing, right? Wormholes are solutions to the Einstein field equations for gravity that act as "tunnels," connecting places in space-time in such a way that the trip between the points through the wormhole could take a massively less time than the trip through normal space. I think my head's going to explode. I quit.

Universe song: "https://www.youtube.com/watch?v=PJ4TiiBglsw"

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Galaxies are a group of millions or billions of stars, along with dust, planets, and solar systems. Our galaxy is called the Milky Way. There are billions of Galaxies in the Universe. Some are very small with only a few million stars. While others could have as many as 400 billion stars, or even more. There are three kinds of Galaxies, Spiral, Elliptical, and Irregular. The only difference between the three is what shape they are. The most common type of galaxies are Spiral Galaxies. The spiral patterns seen in this kind of galaxy are circling the center. These waves cause new stars to form as they go along. Some of the new stars created in the journey are very large. Because of their size these large stars glow brighter than the smaller ones, causing the nearby dust** clouds** to "glow" brightly. Therefore any area near one of these waves glows and others don't. In other words you can't see the waves, the spirals that we see is the glowing dust illuminated by large, hot stars. As the waves move on the area behind them dim down, no longer glowing until another wave passes through. The large stars created in the process don't live very long. Their large size makes them burn all their fuel quickly. Usually they die before they ever leave the wave. An elliptical galaxy is a type of galaxy having an a smooth nearly featureless look. Unlike flat spiral galaxies with organization and structure, they are more spherical, without much structure, and their stars are in random orbits around the core/center. A Irregular galaxy does not have a set shape. Instead it is random and is changing. They make up a quarter of all galaxies. They were likely once a spiral or elliptical galaxy but was deformed by a uneven external gravitational force.

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