Alright listen and learn! There is a supermassive black hole at the center of our galaxy and scientists suspect that there is actually one at the center of every galaxy especially of the spiral type.
Unprecedented 16-year-long Study Tracks Stars Orbiting Milky Way Black Hole
You can kind of imagine this as the spine that holds our galaxy together with its massive gravity. Now black holes actually are absolutely gigantic in terms of mass however relatively small in terms of size due to that mass. Its mass is so great that its gravity actually does not allow light to leave its surface. This point is called the "event horizon". This would be the reason that you can't "see" a black hole because no light is escaping however you can can get a general idea of its properties from the way other masses act around it. However black holes do actually lose mass through a type of radiation I believe called Hawking radiation predicted by physicist Stephen Hawking. This is about the extent of my knowledge of black holes but now I move on to life.
Firstly, I think that for life to exist there must be water. Water has so many important characteristics I don't see how its possible without it, in fact I'm fairly certain there are no forms of life on earth that survive without it. So if we are to find planets with life on them that must be a first check we do. In terms of probability. We've only been able to find extra-solar planets for the past few years and already have founds hundreds. Not to mention the fact that they are all within around 10,000 light years from us (still well within our own galaxy.)
The certainty of life beyond our own will come when we have actually found how life came to be here on earth. There is an experiment, I forget the name, where they put the initial elements from earth in a beaker then shocked it with electricity and actually got some amino acids which are the basic building blocks of life. This is easily attainable in other areas of the universe but it must be proven that life can actually come from this. I think that once that is done there will be no refuting that there truly is almost certainly life outside of earth.
Thanks for reading! I realize this was really fucking long but hey, what can I say, I love science lol :thumbsup: