Ice Queen is right. Black holes are just a theory. It's a theory with a lot of scientific justification that they very probably do exist, but they are still just theoretical. They aren't like Mars. We know that exists for sure. You can see it with the naked eye, and you can see it with reasonable detail with a backyard telescope. We've landed on it. We've driven across it. You can't do any of that with a black hole.
The new evidence, collected by German astronomers over 16 years, make it even more likely that one exists in the center of the Milky Way. For the observed movement of stars to have happened over that period of time, something with the mass of 4 million Suns that emits very little energy has to be there, and it has to exist in a very small space. A black hole makes the most sense. That is, unless something that makes even more sense comes along.
The new evidence, collected by German astronomers over 16 years, make it even more likely that one exists in the center of the Milky Way. For the observed movement of stars to have happened over that period of time, something with the mass of 4 million Suns that emits very little energy has to be there, and it has to exist in a very small space. A black hole makes the most sense. That is, unless something that makes even more sense comes along.