I was talking with an amateur astronomer this morning who, in reference to another astronomer and blogger I mentioned, said “He’s great… except that he believes in black holes.”
The comment caught me off guard. Up until that moment I had no idea that “black holes” was a topic of controversy. I dug into research as soon as I got home.
A black hole is the name for a small body of matter floating in the cosmos that is incredibly dense. Like the entire sun being compressed into a ball the size of a city. It is black because the density creates such a strong gravitational field that light itself is pulled back into itself.
If light can’t get out, we can’t possibly see it to prove it exists. However, astronomers observe the outside affects of a black hole and determine, though they can’t point to it, exactly where the black hole must be.
Just like earth and our neighboring planets orbit around the sun (being the most dense, and thus our gravity boss), astronomers can see stars orbiting around a spot in space. Something must be there at the center creating the orbit, and the best guess is that the something is a black hole.
Another way to spot a black hole is from bursts of x-rays. As a star gets too close to a black hole it begins moving faster and faster, heating up in the process. When the gas of the star reaches such temperatures it begins to emit x-rays. Eventually, as the star spirals ever closer to the black hole it too will become invisible, but outside of the “horizon” of the black hole (the tipping point of the gravitational field, a point of no return) we can observe these strange happenings. The clues add up to the presence of a black hole.
Proving the existence of black holes seems to be a case of “if it walks like a duck and talks like a duck…”, which leaves room for doubt as to whether or not there is a big duck at the center of our galaxy. Let’s take a look at the other side of the argument.
The anti-black-hole debate centers on one sticky issue, “The Information Paradox”. All the details are well beyond my understanding, but it boils down to this. You’ve perhaps heard of the law of conservation of energy… energy cannot be created or destroyed, but merely changed from one form to another. (A car’s forward momentum, through the friction of the brake pads, turns to heat dispersed into the air, etc.)
Well, there is a theory of quantum physics that says there must be a conservation of information. The information in question is sort of like DNA for particles at the smallest level. If matter was to collapse into a black hole, unable to escape, this information would no longer be accessible to the universe. To theoretical physicists, that’s a big problem.
Some of the proposed solutions involve fancy words like “11-dimensional supergravity” and other string-theory brain-busters that are well beyond the scope of the LSNED blog. If you will allow me to over-summarize, conveniently avoiding 500 more words of clumsy explanation, the leading anti-black-hole theory (the Holographic principle) is essentially arguing that a black hole is a mirage of sorts. Rather than a true physical black hole that gobbles up matter never to be seen again, it is a cosmic illusion that just appears that way to our simple three-dimensional brains.
Perhaps I will revisit that another day.