Black Hole Swallowing a Star

[The Red Fox]

At the event horizon, time stops completely. Beyond that, nobody, not even Stephen Hawking, knows!

I don't think time stops at the event horizon. It is the boundary within which everything, including photons, all fall in. Escape velocity > C. I think that relativistic physics still applies inside the E.H.

The closer you approach the EH, the slower time becomes (from the POV of anyone observing you, of course, you wouldn't notice it changing at all.) At the EH, an observer would see you stop completely. What you would see is anyone's guess! The closer you got, the faster things away from the black hole would move - you would see galaxies spinning and colliding in real time. Once you hit the EH, you would observe things moving infinitely fast - well, no, you wouldn't, not really - you'd actually be sucked into the black hole and that would probably not be a good thing!

All of the maths of GR break down at the EH of a black hole - beyond it things are unknowable using any tools we currently possess. QM doesn't offer any real solutions either. Like I said, nobody knows!

No idea how scientifically accurate it is, but tdarnell's videos are usually pretty good.

[Gawdzilla Sama]

So, the closer you get to the EH, the slower time will run for you? But that's only a personal perspective, the outsider will see you accelerate and disappear PDQ? So what's the subjective time span for a person going into the hole?

[Xamonas Chegwé]

So, the closer you get to the EH, the slower time will run for you? But that's only a personal perspective, the outsider will see you accelerate and disappear PDQ? So what's the subjective time span for a person going into the hole?

Who knows? Within a few metres of the event horizon, the gravity differential between the parts of you closest to it and those furthest away will be so great that time for one half of you will be moving many times faster than time for the other half! Not that you'll notice - because you will be torn apart into your constituent particles by then. Not my first choice for a holiday destination.

[mistermack]

So, the closer you get to the EH, the slower time will run for you? But that's only a personal perspective, the outsider will see you accelerate and disappear PDQ? So what's the subjective time span for a person going into the hole?

I think that every observer will observe time run at normal speed. I don't think it's possible for an observer to experience time slowing. It would feel normal to you, even if time nearly stops for you.

[Gawdzilla Sama]

So, the closer you get to the EH, the slower time will run for you? But that's only a personal perspective, the outsider will see you accelerate and disappear PDQ? So what's the subjective time span for a person going into the hole?

I think that every observer will observe time run at normal speed. I don't think it's possible for an observer to experience time slowing. It would feel normal to you, even if time nearly stops for you.

So what's the experience for the poor schmuck? Does it seem like an eternity with the universe frozen around him/her/it, or what?

[Xamonas Chegwé]

So, the closer you get to the EH, the slower time will run for you? But that's only a personal perspective, the outsider will see you accelerate and disappear PDQ? So what's the subjective time span for a person going into the hole?

I think that every observer will observe time run at normal speed. I don't think it's possible for an observer to experience time slowing. It would feel normal to you, even if time nearly stops for you.

Correct. Time runs at the "normal" speed to any observer, regardless of position or speed of motion relative to anything else. However, at extremes of relative motion (or under extreme gravitational differences - which Einstein showed are equivalent to acceleration) two observers will observe changes in the rate of movement, as well as spatial distortion, of each other.

[Xamonas Chegwé]

So, the closer you get to the EH, the slower time will run for you? But that's only a personal perspective, the outsider will see you accelerate and disappear PDQ? So what's the subjective time span for a person going into the hole?

I think that every observer will observe time run at normal speed. I don't think it's possible for an observer to experience time slowing. It would feel normal to you, even if time nearly stops for you.

So what's the experience for the poor schmuck? Does it seem like an eternity with the universe frozen around him/her/it, or what?

No - the opposite - he would observe the outside universe speed up to ridiculous speeds, such that he could see galaxies spinning and colliding with each other. He would also see bizarre distortions in the shape and size of all other objects further from the BH than him. But his watch would still tick at the same speed!

[Gawdzilla Sama]

So, the closer you get to the EH, the slower time will run for you? But that's only a personal perspective, the outsider will see you accelerate and disappear PDQ? So what's the subjective time span for a person going into the hole?

I think that every observer will observe time run at normal speed. I don't think it's possible for an observer to experience time slowing. It would feel normal to you, even if time nearly stops for you.

So what's the experience for the poor schmuck? Does it seem like an eternity with the universe frozen around him/her/it, or what?

No - the opposite - he would observe the outside universe speed up to ridiculous speeds, such that he could see galaxies spinning and colliding with each other. He would also see bizarre distortions in the shape and size of all other objects further from the BH than him. But his watch would still tick at the same speed!

Wait. If the trip into the hole takes a fraction of a second, how would he see that stuff?

[Xamonas Chegwé]

So, the closer you get to the EH, the slower time will run for you? But that's only a personal perspective, the outsider will see you accelerate and disappear PDQ? So what's the subjective time span for a person going into the hole?

I think that every observer will observe time run at normal speed. I don't think it's possible for an observer to experience time slowing. It would feel normal to you, even if time nearly stops for you.

So what's the experience for the poor schmuck? Does it seem like an eternity with the universe frozen around him/her/it, or what?

No - the opposite - he would observe the outside universe speed up to ridiculous speeds, such that he could see galaxies spinning and colliding with each other. He would also see bizarre distortions in the shape and size of all other objects further from the BH than him. But his watch would still tick at the same speed!

Wait. If the trip into the hole takes a fraction of a second, how would he see that stuff?

I was talking about a stationary observer close to the event horizon. Someone being "sucked in" to the black hole would quickly accelerate to within a tiny percentage of c, so their passage to the event horizon would be an incredibly short one - far too short to observe anything!

[Gawdzilla Sama]

I was talking about a stationary observer close to the event horizon. Someone being "sucked in" to the black hole would quickly accelerate to within a tiny percentage of c, so their passage to the event horizon would be an incredibly short one - far too short to observe anything!

I was talking all along about someone who was falling in.

Now, on that short trip, how long would it seem to the falling person? Wild guesses accepted.

[Mysturji]

I was talking about a stationary observer close to the event horizon. Someone being "sucked in" to the black hole would quickly accelerate to within a tiny percentage of c, so their passage to the event horizon would be an incredibly short one - far too short to observe anything!

I was talking all along about someone who was falling in.

Now, on that short trip, how long would it seem to the falling person? Wild guesses accepted.

This short.

[Xamonas Chegwé]

I was talking about a stationary observer close to the event horizon. Someone being "sucked in" to the black hole would quickly accelerate to within a tiny percentage of c, so their passage to the event horizon would be an incredibly short one - far too short to observe anything!

I was talking all along about someone who was falling in.

Now, on that short trip, how long would it seem to the falling person? Wild guesses accepted.

Depends how far they fell from! But almost instantaneous from anywhere deep within the gravity well. Time would slow down for the faller but that would be compensated for by rapid acceleration to close to lightspeed and the contraction of space so that the distance to the EH would shrink at the same rate as time slowed.

[Gawdzilla Sama]

Inside the ship, if you were counting, would you be able to count to 10, 10,000, 10,000,000,000?

[Xamonas Chegwé]

Inside the ship, if you were counting, would you be able to count to 10, 10,000, 10,000,000,000?

How fast can you count?

[Gawdzilla Sama]

Inside the ship, if you were counting, would you be able to count to 10, 10,000, 10,000,000,000?

How fast can you count?

1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1