Step 1 : Introduction to the question "7. How can the gravitational pull of something be increased enough to create a black hole?"
...1. by eating too much at Thanksgiving dinner 2. by joining with a second, identical object 3. by having its mass compressed 4. in reaction to a nuclear explosion When the mass of an object becomes compressed, the gravitational pull that the mass exerted remains constant, but becomes compressed, or concentrated, into a much smaller object. This means that even though it remains constant, it becomes more powerful. I know that this is confusing, so let's try another way. Take the gravitational pull of the Earth. It's strong enough to keep us from falling off but weak enough that we are able to move around. If we are able get a rocket ship moving fast enough, we can blast out of the gravitational pull and into space. Now, take the Earth and compress it into the size of a marble (which is about the size that the Earth would have to be compressed to in order to create a black hole). Remember, we aren't changing the mass of the Earth at all, just squishing it so that it's really, really tight, or dense. That mass would exert the same gravitational pull, but because it's now compressed into a really small area, it would be incredibly powerful. With black holes (and no, the Earth could never become one) we're talking about objects with considerably more mass. So much so that when they are compressed in the same way, they are still very large.
