3. Black Holes
What is it? A Black Hole is a region of space-time where the gravity is so powerful that everything, including light, cannot escape. Contained, at the center of these black holes is a singularity, a point infinitely small, and infinitely dense. These singularities are also responsible for a variety of theoretical physics concepts being reworked, due to Einstein's theories breaking down, when applied inside the mathematics of a singularity. They're considered among the most powerful and destructive forces in the universe. There are (also) extremely large versions of black holes at the center of each galaxy. We've been making references to them already, Supermassive Black holes. These huge singularities in space are monstrously large, almost beyond imagining, and are responsible for the massive geysers of Gamma Ray Bursts spurting on a plain above and below our galaxy, as they are for all others.
Is this common? Can I hide under a table to survive? While the commonality of Supermassive Black Holes is consistent with the number of existing galaxies, as theorized, they are in the center of the galaxy; in our case, roughly 27,000 light years away. Black Holes in general are not a commonality, as one would understand them, and we've obviously never been destroyed by one. That's a good thing. The probability of the earth being destroyed by a black hole that managed to get to us is less than 1 in a trillion. If we want to consider black holes in commonality, we have to understand that the theory of general relativity predicts that a sufficiently compact mass will deform space-time and can result in a black hole. However, to have a sufficient size for a black hole as we mostly understand them, you'd need a star to collapse in on itself.
Has this happened before? Can it happen again? If we want to be really technical, we can say the earth has in fact experienced black holes. We've experienced them in two specific effects. One is natural, the other man made, or relatively accidental. CERN has the Large Hadron Collider, and is essentially smashing atoms together. Why? Take two rocks, and throw them at each other as hard as you can... study all the bits and pieces that pop out of it on impact. Take the bits and do the same... keep going... until all you have is powder. Now you need a collider to keep going, and get to the atomic level of smashing things together. The whole point is to understand particles, and the way they behave, how the universe was formed; to continue breaking down what we've observed into the smallest parts imaginable and attainable. However, with the basic understanding that compact mass can deform space-time into a black hole, then essentially protons smashing into each other can also result in atomically sized black holes. The same scenario occurs with cosmic rays bombarding our atmosphere at near the speed of light. There is a theory, called Bekenstein-Hawking Radiation, that demonstrates how energy is coming off of black holes as heat energy, which also demonstrates how the same holes shrink. So, the same types of black holes that have been observed as infinitesimally sized versions by CERN, and the possible microscopic black holes that have occurred from cosmic radiation bombardment, have existed for such short periods of time they can almost be said to not have existed. So we're fine for now. The image above is a pretty solid conceptualization of what would occur were the Earth caught in a black hole. We'd be dead long before "Spaghettification" occurs which is lovingly detailed in Dr. Degrasse Tyson's book "Death By Black Hole". Presuming other objects are not smashed into our planet prior to any of the many horrific events happening.