Black Hole is one of the biggest mystery in Physics, there are so many questions that still has no answer.
1. What is inside the black hole?
2. What comes first, Black Hole or the Big Bang?
3. Where does the Black hole lead to?
4. Are there any force greater than the Black Hole?
And there are still many more!!
Answer #2: Really the only big question is what happens to everything that goes in. More specifically, is it destroyed, which is a violation of the law conservation of energy or is it preserved? Stephen Hawking recently announced some major revision to his black hole theory to solve the informational paradox (http://arxiv.org/abs/1401.5761). He postulates that a black hole's event horizon is only apparent, in that everything that gets trapped inside is eventually and slowly released as radiation through quantum tunneling (Hawking radiation), which in turn reduces the mass of the black hole.
In reply to answer #1. A black hole (Gravitational singularity) is not the same as the Big Bang. That is called an initial singularity. They are the same in that they are both extremely small (Hence singularity) but how they arise is different. Where a black hole leads to is inside the black hole, you become part of its singularity, gravity crushes you into it. Black holes are not a force. They are just extreme concentrations of gravity caused by, well, extremely concentrations of mass (Black holes are created when gravitational collapse exeeds quantum degneracy pressures (Outward pressure from squeezing fermions together. Specifically, no two identical fermions can exist in the same energy state) as a stellar remnant). But yes, it is the strongest force as far as its use of gravity. On #3 I believe you are mixing up black holes and gravitational wormholes. Quantum tunneling arising from quantum entanglement of two particles is an example of gravitational wormholes.
As many people that looked up this question :)
Black holes could be dangerous to people if people were close to a black hole, but there are no black holes near the planet Earth (as far as we know) and the closest one is probably in the center of the Milky Way galaxy, which is about 80,000 light years from Earth, which is a safe distance.
People know what black holes can do because of the aftermath. Stars and planets have been completely destroyed.
Scientists can detect black holes by using x-rays and gamma rays. Black holes still can release matter, and black holes give off a lot off x and gamma rays.
Why am *I* safe from black holes? Because the nearest one from my planet is 1600 light years away. I don't know if that means YOU are safe from black holes -- I don't know the distance between your planet and the nearest black hole -- but I know my safety is assured.
Mostly by theory and computer simulation. All observations are necessarily indirect.
Black holes
Most black holes are stellar mass black holes with masses comparable to those of large stars as they form from the collapse of massive stars. Scientists know of the existence of supermassive black holes that are millions to billions of times the mass of our sun and can be found in the centers of most galaxies. Scientists still do not know how these black holes become so massive.
Not directly. Black holes have only affected people insomuch as they attract. people's attention and that some take time to study them.
No, we don't know of any black holes close enough to get to.
Yes, that is what people believe.
They do not take people to space.