- I'm glad you're not *trying* to be difficult.
Let's say you're falling into a large nonrotating black hole, 10⁸ solar masses, which thus has a Schwarzschild radius of 2 AU (2 times the Earth-Sun distance).
You will always see your hand before you in exactly the same way as in normal life - I've explained why a few times.
But if you're falling in while looking at a spacecraft fall into the black hole that started at a distance of, say, 1/2 AU in front of you, you will see something very different. It will become increasingly redshifted as time goes by and it will seem to hover near the horizon. By the time you reach the horizon you'll see it in front of you "in the distance", but that image will be light it emitted at the horizon! This light will be redshifted but not infinitely redshifted. As you continuue to fall, you'll see it continue to fall, and I believe its redshift will continue to increase. Then you'll hit the event horizon. You'll never see it hit the horizon, because the horizon is always in your future.
Greg Egan (npub12cu…d38p) has a nice page on this general sort of thing, and we've been discussing it here:
https://mathstodon.xyz/@gregeganSF/113559758951665942
John Carlos Baez
npub1nf…3nqe4
2024-11-28 21:00:48 UTC
in reply to nevent1q…5ask
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2024-11-28 21:00:48 UTCEvent JSON
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"content": "- I'm glad you're not *trying* to be difficult.\n\nLet's say you're falling into a large nonrotating black hole, 10⁸ solar masses, which thus has a Schwarzschild radius of 2 AU (2 times the Earth-Sun distance).\n\nYou will always see your hand before you in exactly the same way as in normal life - I've explained why a few times. \n\nBut if you're falling in while looking at a spacecraft fall into the black hole that started at a distance of, say, 1/2 AU in front of you, you will see something very different. It will become increasingly redshifted as time goes by and it will seem to hover near the horizon. By the time you reach the horizon you'll see it in front of you \"in the distance\", but that image will be light it emitted at the horizon! This light will be redshifted but not infinitely redshifted. As you continuue to fall, you'll see it continue to fall, and I believe its redshift will continue to increase. Then you'll hit the event horizon. You'll never see it hit the horizon, because the horizon is always in your future.\n\nnostr:npub12cuzzqzv8e8y7na77a9zv47mx2v6pec60qs5h7takzmv5p0mw0fsmgd38p has a nice page on this general sort of thing, and we've been discussing it here:\n\nhttps://mathstodon.xyz/@gregeganSF/113559758951665942",
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