Using a black hole to time travel!

What is a black hole? A black hole is a point in space where gravity pulls so much that not even light can escape. We cannot see black holes, but we can infer their existence by how they influence stars around them.

There are numerous types of black holes. Some are small, about the size of an atom. Yet, they can have a mass equal to a mountain. Some are supermassive, like the black hole theorized to exist at the center of our galaxy, a mere twenty-six thousand light-years from us. It is the single heaviest object in our galaxy. In between the atom-size black holes and the supermassive black holes are the “stellar” black holes. They are roughly up to twenty times the mass of our sun.

You may wonder: How do black holes form? Physicists think that the atom-size black holes formed during the early stages of the big bang, and that the supermassive black holes formed when the galaxies formed. Physicists also think the stellar black holes form when a star dies and collapses on itself.

What makes a black hole interesting from the standpoint of time travel is that the gravitational attraction is so great that time dilation due to gravity (as predicted by Einstein’s general theory of relativity) would be enormous. In fact, a supermassive black hole, like the one at the center of our galaxy, would slow down time far more than anything else in the galaxy would. This makes a black hole a natural type of time machine.

You may worry that a black hole may swallow the Earth. However, I have good news for you. Black holes do not move around, and there are none close to the Earth. In short, we do not have to worry about being swallowed by a black hole.

Is there any practical way to use a black hole as a time machine? The answer is no, not via today’s science. The scientists at CERN using the Large Hadron Collider are attempting to make small black holes. Perhaps, in time, they will succeed, and we will be able to use its properties as a time machine. This, however, is speculation.

This material is from my new book, How to time Travel (2013).