Is a black hole a hole?
Hole or not, what goes in isn’t coming back out again…
Asked by: Christine Bingham, Nottinghamshire
No, a black hole is not really a hole at all. A black hole is an object just like any other, except that it is extremely dense. This gives it such a high gravitational field that nothing, not even light, can escape. Because no light escapes a black hole, it is invisible – or ‘black’ – although they can be detected by their effect on the material around them. The term ‘hole’ was used because whatever falls ‘into’ a black hole is trapped forever.
Science fiction often depicts black holes as portals between different parts of the Universe, different times or different universes altogether. This may be why it is often misconstrued that black holes are ‘holes’ in space-time. This concept isn’t entirely fictional, however.
In 1935, Albert Einstein and Nathan Rosen proposed ‘wormholes’ through space-time, which could provide a means of traversing large distances instantaneously. But a naturally occurring black hole doesn’t form a wormhole by default. In fact, there are doubts they could occur naturally at all, that they would remain stable for more than a fraction of a second or that they would be anything bigger than vanishingly small.
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