I have always found black holes the most intriguing celestial objects, if they can be called that. Technically, a blackhole "is a region of space that has so much mass concentrated in it that there is no way for a nearby object to escape its gravitational pull." Even light. Now that's something. That means a Black hole's escape velociy is higher than light's velocity, which is 299,792,458 m/s. It's a scary thought but still interesting.
A little about how they're formed..
Black holes form from massive stars. When supermassive stars collapse from their own gravity and run out of fuel they turn into black holes. They have an infinite density, a point of almost zero volume. They form a singularity and around the singularity is a region so strong even light can't escape.
Blackholes can be of any mass, they just have to be compressed enough to get a really really high density, because that's what increases te gravitational pull. A black hole's mass and radius are directly proportional.
If you are falling into a blackhole, you can still see everything on the outside but probably distorted images because black holes can bend light. Of course, the people outside won't see you inside.
Evidence of BlackHoles?
Well they obviously can't be seen because they engulf light. However, there is indirect evidence of black holes. Measuring mass in a region, and knowing if it has highly concentrated mass and is composed of dark mass is proof enough. Super Massive Blackholes are usually found at the center of galaxies. Even our own Milky Way Galaxy has a super massive blackhole in the center near Sagittarius A. It won't suck everything in, according to myths that Black Holes are cosmic vacuum cleaners.
Well, that's just a really tiny description of BlackHoles. There's so much more to it . And it's interesting..
