this is my second post. I would like to say something about my most favourite topic: Black holes. I hope that there won´t be any mistakes so I will not go deep and more complicated stuff.
Black holes are universal objects as you probably already know. Important thing is their size. If you know something about white/black dwarfs and neutron stars you could easily get to right answer about how big are black holes.
You see I said something about dwarfs and neutron STARS. Right, stars. There are not really kind of stars but all of these three objects come from stars like our own Sun!
I will probably make another post for only stars so I will write this short. When gravitation pulls lot of dust from universe together it will have so huge gravitation (like our Sun) that termonuclear reaction will occur. (Jupiter is almost so huge that he would be another small sun if little bigger) This reaction will be able to keep star from falling into itself by gravity. But when fuel (H,He…) runs out it will crush itself under gravity. If it was small white dwarf will be next stage. (That will happen to sun). If gravity pull is very huge electrons won´t be able to hold the force and neutron star will appear (made of neutrons). If it is even larger and strong interaction won´t be enough strong black hole will born!
In black hole there is actually no force to hold it and it will fall into singularity! That is point infinitly dense and infinitly small.
Particles have gravitational pull on other particles. When there is lot of particles, gravitation is very strong and it will start to bend spacetime(P.1).
(Sun does that and stars behind seems to appear somewhere else than they are.) Black holes have such strong pull that even light can not escape, that is why they are black (no light comes to your eye).
Around black hole is event horizont. That is circle which is edge of black hole. Light circles around it. It can not escape but it wont be either sucked by hole.
Long time it was thought that black holes can not decay particles but Stephen Hawking actually came up with Hawking radiation. On this topic I will have to learn something more because I dont really understand how it works. Anyway black hole is actually radiating (lossing mass) and at one point it will explode when strong nuclear force will be again able to fight gravitation. Can happen after 10^66 years.
Surely I forgot to say something but you can ask me in comments.
Please comment this post if there are any mistakes!
Btw. I highly recommend to read The brief history of time by S. Hawking
p.1: Spacetime. (2015, March 5). In Wikipedia, The Free Encyclopedia. Retrieved 18:24, March 19, 2015, from http://en.wikipedia.org/w/index.php?title=Spacetime&oldid=649931558