zapatos

Yes, I know I'm confusing something! I would have been surprised to learn that it appeared to stop, motionless in the sky just because it seems so illogical. But I have the same problem with the craft crashing into the black hole. If velocity time dilation does not appear to make the spacecraft slow as time dilation increases, what makes gravitational time dilation different? Why does gravitational time dilation make the spacecraft appear to slow in velocity just before it hits the event horizon?

Would we experience the same results if the time dilation was due to velocity? For example, if a spacecraft was orbiting the earth and was accelerating toward c, would we on earth see the craft accelerate for a while, then appear to slow down as it reached a significant percentage of c? That is, would the craft seem to take 1 hour to orbit earth, then 30 minutes, then 1 minute, until as it reached a significant percentage of the speed of light where it would then appear to take 2 minutes, 30 minutes, etc., until at near the speed of light it would appear to be nearly motionless in the sky?

Sorry if I'm bothering everyone with simple questions but I'm still having trouble with this. As I observe a spacecraft with a person aboard approach a black hole, time dilation increases for that person. I took that to mean that the person would age slower than me, his clock would tick slower than mine, etc. But I did not take that to mean that his spacecraft would appear to me to decrease its velocity as it approached the black hole. Does the spacecraft seem to me to decrease its velocity as it approaches the black hole? If so, what is the mechanism? If the mechanism is time dilation, what physically is happening? For example, if the craft is moving at 100m/sec toward the black hole, if photons leave his craft toward my eye at all times, I should see photons when the craft is 100 meters away from the event horizon, then 50m from the event horizon, then 25, etc. The photons travel toward me at c, so there is no delay. So why does it appear to me to slow down?

I met my wife in college where she was the roommate of a friend of mine. She ended up breaking off an engagement to go out with me. I win!! We'll be married 30 years in January.

So presumably the faller enters the black hole at the rate determined by free fall. If it looks like he is slowing down to us, is that because the signal is delayed getting to us? I assume he has been dead long before we see him spread out over the EH?

Nope, I had assumed when you said objects might shrink before entering a black hole that you were talking about length contraction. My bad.

I don't think it shrinks per se, I think it contracts parallel to the direction it is travelling, so theoretically we should still be able to observe it. Also, the object probably is not travelling close to the speed of light when entering the black hole so I guess that doesn't matter anyway.

The problem I'm having with this is a couple of things. First, if we see things basically stop before going in, shouldn't we see stars and the other things that have fed the black holes for millions of years, hanging around just outside the event horizon? Second, I thought time dilation was the same whether it came from gravity of acceleration. If so, then wouldn't that mean that we would simultaneously see a space ship accelerating toward the speed of light both speed up (as it accelerates) and slow down (due to time dilation)? Doesn't make sense to me. Thus my confusion. Oh, got it. Jeez, I am slow tonight.

? BTW, I am the space newbie around here!

From your link: What would I see? Would I see an unmoving victim? Would I see him keep falling faster and faster until he suddenly stops just at the event horizon.

So the guy falling into the black hole sees himself speeding up?

So it speeds up and slows down at the same time?

How does gravity, which is causing an object to accelerate toward the black hole, cause it to slow down? The closer you get to the black hole the stronger the gravitational pull.

The clock stops ticking; it does not stop moving toward the black hole. What force would counteract gravity?

What does that mean? Why won't we see something if it takes an eternity? If someone is counting for an eternity, won't I see them counting? If something is moving for an eternity, won't I see them moving? Can you tell me what will happen to an object approaching a black hole before it gets to the event horizon, when it is at the event horizon, and after it passes the event horizon? Both from the perspective of someone on the object, and from our perspective as distant observers?

Are you saying that we will see them reach the event horizon and then appear to just set there unmoving for eternity? We will be able to see this?

I'm sorry I did not understand that. You said light will take infinite time to reach an observer. Infinite time implies movement that is less than c. I am saying there is no movement less than c for light. No. From our perspective we see them accelerating toward the black hole until they reach the event horizon and then we don't see them at all.

AFAIK light travels at c. Light will either travel to us at c and reach us in the time it takes light to travel from near the black hole to us, or it will not travel to us at all. I don't think so. We see their clocks slow down, we don't see them slow down. They will crash and burn in short order. So those things we are calling black holes are really deep gravity wells that light can escape from? Then why do they appear 'black'?

It would not be compatible in what way?

Of course not. Why would they be? I don't even know anyone in the US who is deeply concerned about our bars.

I was in a bar in Michigan a couple of years ago that did their own brewing. They sold 2 liter bottles of their brew in bottles with the reusable tops like on Grolsch bottles. They would refill those bottles for you. This is the only example I could come up with though.

Also those big (5 gallon?) plastic water bottles for water coolers.

Ok, I have a guess.