Black Holes

[Jeremiah Walgren]

As I remember, the closer someone is to a black hole the relativistic effects they experience are more pronounced. If I'm not mistaken, this is caused by the incredible gravitational pull.

How does gravity cause this to happen? Would it be due to the acceleration and increased velocity from the gravitational pull, or something else?

[Super Speler]

I'd assume it was the incredibaly high velocity, I remember from a class thatafter a curtain closeness to the hole is achieved it is impossible to escape the grasp. This is because the high speed so yes that's why I'd assume it's due to the velocity.

[alexrudd]

Gravity increases as the two masses are closer together.

[Jeremiah Walgren]

So it is basically due to the gravity... Makes sense.

[IAmACalculator]

[todlangweilig]

I found this site helpful for general info

Black Holes

[Super Speler]

Can someone explain why dialation occurs?

[Jeremiah Walgren]

You are referring to time dilation, correct?

If that is the case, then it is simply an effect of relativity. A black hole's enormous gravitational pull becomes increasingly stronger the closer an object is to said black hole. This in turn increases the speed at which the object is approaching the black hole (assuming the object is doing nothing but heading straight towards it). An increase in speed will cause relativistic effects to become more pronounced and then we have noticeable time dilation.

It's almost as though you're dropping a rock. It moves slow at first, but it increasingly moves faster the longer it falls.

Anyone feel free to correct me if I'm wrong. I've never really looked into black holes much...

[Fr0stbyte124]

A classic example of time dilation is the observer and the clock. An astronaut drops a clock into a black hole. As the clock falls into the black hole, he would see the clock slow down, as the light would have an increasingly hard time of getting to him as the clock fell. At the event horizon he would see the clock stop altogether.

In the reverse situation, an observer nearing the event horizon would see the clock speed up until its speed reached infinity and the universe ended (if the astronaut wasn't crushed and the black hole didn't disappear, which would make things very complicated). Since personal time is different for each observer and is based on light, the effect is time dilation. It is similar to the twins paradox, except instead of moving through space time, space time gets sucked past you.

I'm not sure, but I think that there is nothing inside of the event horizon because of this. There is some speculation that the mass either disappears or is sent somewhere else.

[Arcane Wizard]

If the event horizon is where time relatively stands still, then objects being compressed, but still there, seems more logical to me, since the part of the object that isn't exactly at the horizon yet is still moving towards it.

[Jeremiah Walgren]

[Fr0stbyte124]

1) I meant if the clock was a safe distance from the horizon and the observer was falling into it. And he's not reaching infinite speed, he's aproaching light speed (from a 4D perspective, which is valid on the edge of a black hole) which causes the twins paradox to kick into high gear, making everything around him seem to speed up.
The lightspeed part is viable because gravity is not the same as propulsion (it would be awesome if someone figured out how to utilize that).

2) I honestly have no idea what goes on inside a black hole. All I do know is that nothing that passes the event horizon comes back out. Ever. Also, theorists believe that black holes can dissolve over time (or something similar.) My question: where does that matter go? Being ignorant, I would guess wormhole or zero-point energy.

Also, I think I did something wrong with the example, because something doesn't seem quite right about it. I'll look at it tomorrow.

*Edit* One source says that time dilation is only on the outside end. I'm still not so sure about that. I'll try to do the math later, but probably fail. :)

*Edit* Another source says general relativity gets iffy behind the black curtain. Scientists are still arguing about that. One thought is that if velocity is indeed defined as one-way on the inside, than there is a chance that time can move 2-ways, and other strange phenomena. And it is possible to orbit around the singularity without falling in. The math gets really weird. I don't want to think about it anymore tonight. Time for homework!

[Jeremiah Walgren]

Okay, your example makes more sense now. You did use "infinite," by the way, in my own defense... As for utilizing gravity as a form of propulsion, it's already been done. NASA does it for their missions they send to the outer planets. They have the satellites swing close enough to some planets so that the gravitational pull can give them a boost, as it were.

If I remember, it was Stephen Hawking (or one of his collegues, with my memory) who proposed that black holes can actually evaporate. I vaguely remember the details so I won't post them here, but it's something to look into.

[Fr0stbyte124]

Slingshotting a craft is not quite what I meant. The way that works is this: normally a satelite will orbit a planet in a perfect elipse. This is not the case, because the planet has a changing vector as it orbits the sun. With the right calculations, one can place a satelite in an orbit where it is actually falling farther than it is climbing, because the earth is moving out from under it. Then, after it's done the correct number of loops, its orbit shifts for an efficient escape. It's really sapping the planet's momentum to gain speed.

What I'm talking about is something like a wormhole placed in front of a ship in a carrot dangling in front of a horse positioning. Gravity from a large body would pull through the wormhole, but the wormhole itself would have no mass and could easily be moved along with the ship. I'm not sure if that is physically possible, though. Since gravity is the only force that extends into the 4th dimension, it might be kind of hard to trick into a wormhole.

Also, I'm not really sure about relativity on accelleration caused by gravity, though I'm beginning to think you wouldn't reach it. It's confusing because spacetime is so distorted, and quantum mechanics enter the scene.

[Arcane Wizard]

If it would pull the spacecraft towards it at it would be pulling other things towards it as well. Pretty suicidal.

[Fr0stbyte124]

Good point. there must be a wormhole on the back end of the ship to collect stray gravity and send it back to where it came from.