The center of a black hole is not so much a place as a moment in time. It is literally as inescapable as tomorrow.
Originally shared by Jonah Miller
Falling into a black hole with a flashlight.
It’s a common misconception that, because an observer falling into a black hole appears to stop, time stops for that observer. That’s not really true.
Think of it this way. The event horizon is the point where light cannot escape the black hole, right? Well, suppose I jump into a black hole carrying a flashlight and you watch. As I get closer to the event horizon, the light rays from my flash light will have a harder and harder time getting away from the black hole to your eyes.
Eventually, they won’t be able to get to your eyes at all… after I pass the event horizon. But, the instant before I fall in, the light rays will take a huge, but finite time to reach you.
The effect is that, for the age of the universe, you will see the light rays I emitted just before I passed the event horizon. And I will appear to have stopped.
Past the event horizon
Although to outside observers, I appear to have stopped. I may not actually notice anything strange as I pass the event horizon (depending on the size of the black hole). I will eventually be torn apart by tidal forces, but for a large black hole, these are weak near the event horizon.
From my perspective, I’m just travelling through space, and I experience time somewhat normally. This is the difference between proper time and coordinate time. Proper time is the time experience by a person. Coordinate time is just a label.
However, one strange thing will happen to me inside the black hole… and that is that the singularity, the center of the black hole, is irrevocably in my future. The center of a black hole is not so much a place as a moment in time. It is literally as inescapable as tomorrow.
This post was inspired by a question on the Science on Google+ community by Dustin Thurston . Original post here:
Image is a simulation of gravitational of the milky way by a black hole. (Said black hole does not exist.) The creator, Ute Krauss, has a
lot of great relativity visualizations. You can find them here:
Source: The description I just gave can be found in most general relativity textbooks. For a free treatment, I recommend Sean Carroll’s lecture notes, published online:
#physics #astrophysics #science