Black Holes: Is Earth at Risk?

What are Black Holes?

A black hole is a region of space-time from which gravity prevents anything, even light, from escaping. Black holes are formed by certain dying stars. A star with a mass of about 20 times more than our sun may produce a black hole at the end of it's life. Using Newton's Laws in the late 1790s, John Michell of England and Pierre-Simon Laplace of France suggested the existence of an "invisible star". They calculated the mass and size that an object needs to have in order to have an escape velocity greater than the speed of light. We now call this the "event horizon". In 1967, John Wheeler was the first to use the term "black hole" to describe these collapsed subjects.  Black holes are surrounded by something called an ergosphere in which it is impossible to stand still. This is the result of "frame-dragging". General relativity predicts that any rotating mass will tend to slightly "drag" along the space-time surrounding it.

What do Black Holes do?
Black holes can "suck in" matter around it. Once matter comes in range of the event horizon, it's over. The black hole consumes it and rips it to shreds. 

Black holes are dangerous, but a human has never died from a black hole. It is currently unknown what exactly happens when you enter a black hole but it is theorized that if you went through a black hole you would come out in another dimension or region of space. Most scientists, however, believe that you go nowhere. You just become highly compressed plasma that is forever trapped inside a black hole. If two black holes collide with eachother, they just become one black hole that has the combined mass of the two.

Is Earth at Risk?
Scientists believe that our sun is not at risk of becoming a black hole anytime soon. Even if by some stretch of the imagination our Sun explodes and becomes a black hole, the Earth and other planets will continue to orbit because they are not in the event horizon. Scientists have also discovered a black hole at the center of our galaxy, "the Milky Way". It is currently near the constellation "Sagittarius A".

Don't worry, though, because our solar system is not anywhere near the center of our galaxy. It's safe to say that Earth is not at risk of black holes anytime soon.