Thirteen Facts About Black Holes
1. A black hole is a region of space where the gravitational field is so powerful that nothing, not even light, can escape its “event horizon.” This ability to trap even light gave the phenomenon its name. I’m guessing the pull of a black hole is stronger than my desire for chocolate. Just a little.
2. An event horizon is a boundary in space and time surrounding a black hole or wormhole past which events cannot affect an outside observer. According to Wikipedia, “[L]ight emitted from inside the horizon can never reach the observer, and anything that passes through the horizon from the observer’s side disappears.” In other words, calories consumed in a black hole don’t count.
3. The biggest black hole found so far exits in the Messier 87 galaxy and has the mass of 3 billion suns, based on the speed of the gas swirling around it. Scientists theorize that larger black holes do exist, but that there is a limit to how large they can grow. Colossal black holes with a mass of up to 50 billion suns are estimated to exist, but scientists theorize that black holes self-regulate because the radiation emitted from the objects being sucked into it scatter other objects further away. What did one dwarf star say to the other dwarf star before taking the big event horizon nap? Save yourself!
4. A supermassive black hole probably lurks at the center of the Milky Way, where a bright object called Sagittarius A has been found. It’s likely a disc of swirling gas and dust surrounding a heavyweight black hole. Let’s all thank the Hubble Telescope for predicting our eventual doom.
5. There might be a naked singularity at the center of Sagittarius A. A naked singularity is theorized to be just like other singularities except that it doesn’t have an event horizon, so light (and conceivably other objects, I imagine) can escape and events inside of it can be observed from the outside. A naked singularity is a black hole going commando.
6. A black hole is discovered by observing stars that orbit its center, gas that is drawn into it, and the radiation emitted and high temperatures from that gas as it spirals inward. Black holes are the drama queens of the cosmos. The flare stars are jealous.
7. The presence of black holes were proposed in 1783 by amateur British astronomer Reverend John Michell and again independently in 1795 by French physicist Pierre-Simon Laplace. Ooh la la!
8. The term “escape velocity” commonly refers to the speed needed to break free from the pull of a black hole, or even just a normal object exerting a gravitational force. To escape a black hole, an object’s escape velocity would have to exceed the speed of light, which according to Einstein is impossible. I can’t even escape the gravitational pull of a Reese’s peanut butter cup.
9. In 1974 Stephen Hawking proposed that black holes don’t just suck up matter, but also emit Hawking Radiation. If this is true, then a black hole’s life is actually finite because it will be losing mass. If a black hole is losing more matter than it gains it will eventually shrink and ultimately vanish. Hawking radiation has never been observed, but if the Large Hadron Collider does indeed create mini-black holes and they actually do dissipate as Hawking predicts, then we’ll have evidence for Hawking radiation. Oh, and the knowledge that a black hole might dissipate before sucking up all the matter in the universe.
10. “Spaghettification” * refers to the distortion an object experiences as it nears the event horizon of a black hole. First an object splits in half, then those halves into four, then into eight pieces. This decomposition process continues until an object is split into atoms and becomes a string of elemental particles. Is this where the Flying Spaghetti Monster lives?
11. Because space and time are connected, objects observed being pulled into a black hole seem to slow down as they approach the event horizon. This is called “gravitational time dilation” and as an object hits the black hole’s event horizon this dilation would approach infinity, which would to an observer appear as if time has stopped.
12. The ultra-high-energy collisions of elemental particles being conducted at the Large Hadron Collider may create mini black holes. If these black holes emit all types of particles, this will provide evidence for a Grand Unified Theory, which unifies three of the four known fundamental forces: electromagnetism, the strong nuclear force, and the weak nuclear force. It only leaves out gravity, but I promise not to make that same weighty joke again.
13. An “accretion disk” is a ringlike structure of gas and dust surrounding a black hole, sort of like watching water and debris go down a drain. Some of the matter in the disk is expelled from a black hole’s poles as “relativistic jets.” These jets produce enormous sound waves that travel through the surrounding galactic gas much like sound waves on Earth travel through air. The supermassive black hole at the center of the Perseus galaxy, 300 million light-years from Earth, is emitting a tone that “registers 57 octaves below middle C. . . is a resounding B-flat.”
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* Dude, physics is so cool.