Question about time travel?

Question

Im sure to a alot of you genuises, this is a very stupid question, but I dont know the answer. I read that if you were to see someone fall into a black hole, it would appear to you that they had frozen in time. Even though in actuality they had already been broken down into energy and passed through the event horizon. So for argument) lets suppose you could continue to look at this person stuck in time, and with the snap of finger stretch your arm out and grab what you see. Even though in reality that person is not still there, what will you grab? This kinda confuses me. Or will your arm to be stuck from what you can see? And if you could snap a finger and bring back what you grab, is that similiar to going back in time?

Answer 1

very interesting question.

well it might be hard to grab what you can see because of the intensity of the gravitational pull(not even light can escape from it)

two it will be hard also because black holes tend to distort where things are, and you will see your arm several times.

three they believe that black holes are the pathways to other galaxies so you might just grab what was left there. kind of like if you switch two different colors very quickly and then youll see what the two colors would look like if they were mixed together.

hope this helps =]

Answer 2

You've come to the right guy for this question.

First of all, regardless of who has said it or where you've read it, nothing ever gets to enter a black hole.

And you may wonder, "How in the name of all that is scientific can such claptrap be true?"

And the answer is right there before everyone.  Time at the event horizon of a black hole is so slowed by the presence of the gravitational field of the singularity that time essentially stops.

To look at it another way, it has been said truthfully that an observer at the event horizon of a black hole would see all time in the rest of the universe pass by in one instant.

Because quantum theory applies not just to mass and energy, but also space and time, we can quantify the passage of time at an event horizon.  A person would experience one unit of Planck time while all time passed in the rest of the universe.  In one Planck unit of time, nothing can change its state; another increment of time must occur for a state to change.

However, there is only one Planck unit of time at the event horizon; therefore there is never a change of state.  In order for something to enter the event horizon, it would have to have a minimum of three different states or positions.

Position one: Just outside the event horizon.

Position two:  At the event horizon.

Position three:  Just inside the event horizon.

Each of these positions would require an increment of time.  Even if we cheated and placed the object at the event horizon at the beginning of time, there would never be another increment of time for the object to change its position or state and end up inside the black hole.

For further clarification: nobody has any real idea as to what happens below the surface of a black hole because all we do know about black holes is due to highly advanced mathematics; HOWEVER, the math needed to calculate what goes on inside a black hole does not yet exist.

Every scenario that has been proposed for the interior of a black hole is a conjecture, a guess; no one knows yet.

As a side note, this also is a key factor in rejecting the notion that black holes evaporate eventually due to Hawking radiation.  The theory of Hawking radiation completely ignores the existence of time dilation in the immediate vicinity of a black hole.

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Too many of the answers here side-step the fact that the question is hypothetical.  This business of the gravitational field being so powerful that it would s***w up the effort is extraneous.

Even I neglected to answer the question about the aspect of time travel proposed.  My answer to that would be that given the universal now of the moment, our plucky outside observer would come back with the observed person.  More importantly, time travel would actually not be a factor.

And most important of all, in this case, there would be no instance of traversing time, i.e.- someone's future acting upon another's past.  One cannot take relativity to the extreme, make incorrect assumptions, and then proclaim something idiotic such as an event in someone's past exists in another's future.  Such a thing denies the existence of absolute motion... which, by the way, does exist.

Answer 3

Well I'm not sure about this myself but if you aren't sucked in the black hole too, your arms would probably be frozen there also, when you are about to grab what you see there, that would just be about the time it freezes. If you bring your arm back, then it'll be probably a segment of your arm connected to your body.

Answer 4

hey, I asked this question a few months ago and here are the answers I received.

http://ca.answers.yahoo.com/question/ind...

Answer 5

aboslutely no one could tell you for sure...

however, i don't beleive so, for one of two reasons.... first of all if you were put your hand at the postition of where this person trapped in the black hole, you would be sucked in as well, whether he was actualy there or not for you to even grab...

that aside, you still have enormous gravitation to overcome... i don't think it would even be possible to pull anything out of it, no matter what it is... if it can trap light, how can matter EVER hope to escape the same way it came in? (not saying the hole doesn't go anywhere, just that there's no way you're going back out the way you came in.)

the second part of your question is easier to answer... no, becuase if you were to stretch your arm that distance it would still have to travel as far as the light coming from it that enables you to see it... say you were to reach out and grab a distant galaxy, first your arm would have to travel the same distance that the light you're seeing traveled first...

and just becuase you're still seeing the light, doesn't nessicarily mean that object is still present and in the same spot that it appears to you... infact it's probably traveled billions of miles from where it was.... so by the time your arm reaches that point, even if you were to do it at light speed, there's pretty much no way you'd grab anything... the light is still traveling to you from the position it came from, but the body is long gone...

hope that makes sense.

Answer 6

no one knows for sure....thats why "space" is still so mysterious to us humans"

Answer 7

They have been squeezed by the strong force of gravity so much that the atoms in their body would break apart, therefore making them cease to exist, they have been squeezed out of existance. So you would grab nothing, but if you could get close enough to grab "them" you would get sucked in too, so you can't really grab them.

Answer 8

No, actually, I would consider that a very intelligent question.  It is believed, with some degree of confidence, that this phenomenon of time dilation and relativistic distortion of spacetime due to intense gravitational force, is real.  The perceptions you are referring to are as close as we can get to describing a reality which has no good analog in our "normal" realm of existence.  The trick to relativity is to realize that one's frame of reference is critical to all considerations.  In other words, this case of being near a black hole is a matter of two people in different relativistic time frames, trying to imagine what the other would perceive from their frame of reference and what we would perceive from ours.

To us, a person or object or even an interaction of some kind in that intensity of gravity would appear to be moving more slowly that what the person in that time reference would be experiencing.  So you are very perceptive in noting that if you could "reach in," you would find that what you observed from outside, was no longer the case.  But here is where we run into a problem with your question.  As soon as you do this hypothetical reaching in, then your hand is now in the different time reference.  In my opinion, questions like this can never be answered realistically or even hypothetically since one person cannot observe something from two different relativistic frames of reference at once.

It's like there are two different worlds.  One can see the other, but can never see the other as it would be seen from the other's world.  So your question is an attempt to rationalize two views that cannot be rationalized.  They have no common frame of reference.  If my answer sounds confusing, that's just the nature of relativity as you approach the extremes.  In other words, you can't "suppose" without creating a false observation.

It could also be that this kind of thing is so alien to us, that we just don't have the language or comparable experiences to explain it adequately.  Then there's always the possibility that I don't know what I'm talking about!

I won't belabor the fact that you obviously already know: that anyone that close to a black hole would have long since been dead.  Even their body wouldn't exist by the time they reached the event horizon.  I know, you're just talking hypothetically.

Edit: I've read the other answers and Ultraviolet Oasis has explained this in a very different way from the approach I took, but his answer is top drawer.  I usually delete an answer when someone else does such a good job, but my perspective is of some use, too, I think.  My hat's off to his answer and to anyone who has the balls to say Hawking is wrong, (and I have long shared his opinion on this matter of evaporating black holes.)