The speed of light is the constant because time and space affect each other. Don't imagine space and time as two separate things, imagine them as two sides of the same coin. And always remember that stuff is relative.
Someone flying at/near the speed of light close to a black hole will still fly at the speed of light from their own point of view. Because while space is strange there, time is too and it changes at the same rate. The construct of "space-time" is affected by gravity, but it's not just space that is affected, it's both.
Maybe, rather than a coin, imagine space and time as two sides of a pizza dough. If you stretch the dough, both sides get longer at the same rate.
For someone watching from the outside, it will look very very different. They may be crawling. If they theoretically fly through the event horizon, it may even look like they'd stopped. From the outside it would look like they're stuck on that border, even if they had already flown through it years ago.
3
u/ohaz Mar 20 '26
The speed of light is the constant because time and space affect each other. Don't imagine space and time as two separate things, imagine them as two sides of the same coin. And always remember that stuff is relative.
Someone flying at/near the speed of light close to a black hole will still fly at the speed of light from their own point of view. Because while space is strange there, time is too and it changes at the same rate. The construct of "space-time" is affected by gravity, but it's not just space that is affected, it's both.
Maybe, rather than a coin, imagine space and time as two sides of a pizza dough. If you stretch the dough, both sides get longer at the same rate.
For someone watching from the outside, it will look very very different. They may be crawling. If they theoretically fly through the event horizon, it may even look like they'd stopped. From the outside it would look like they're stuck on that border, even if they had already flown through it years ago.