Gravity moves at speed of light

[silverpig]

Originally posted by: Triumph

Originally posted by: silverpig
The answer for the first one is "a black hole"

The event horizon is just the "point of no return" if you will, for a particular black hole.

No, a black hole has gravity. Huge amounts of it. There are actually many stars out there that orbit black holes (a binary star system). This is one of the main ways that scientists are able to prove the existence of a black hole: a star orbiting around seemingly nothing.

The question I was answering is this:

So what do you call the thing whose gravity is so strong that gravity can't excape?

Now, I sorta got the wrong answer because I either misread it or the original poster made a typo. If he's talking about the thing whose gravity is so strong that light cannot escape, then that's a black hole... but for gravity to not escape... I don't think anyone even has the slightest idea how that could come about.

 

[Moonbeam]

The original poster did not make a typo. My question is about time and gravity and entropy. If the universe reaches entropy will time flow. No change no time? Now gravity all used to be in a universe that expanded suddenly for some reason out on neither nothing nor not nothing because there wasn't any space for it to expand into. So the whole universe wasn't since there wasn't any time to be in either. Neither something nor nothing nore time were or weren't. Could entropy be the end of space and time?

 

[Triumph]

Originally posted by: Moonbeam
The original poster did not make a typo. My question is about time and gravity and entropy. If the universe reaches entropy will time flow. No change no time? Now gravity all used to be in a universe that expanded suddenly for some reason out on neither nothing nor not nothing because there wasn't any space for it to expand into. So the whole universe wasn't since there wasn't any time to be in either. Neither something nor nothing nore time were or weren't. Could entropy be the end of space and time?

Well first of all, I don't have the answers. But you're using the term "entropy" wrong. Entropy actually has units, and it is a measure of something, just like energy is. My thermodynamics book pointed out that if we had been trained to use the term entropy as well as we have the term energy, there wouldn't be so much mysticism about it. So the phrase, "If the universe reaches entropy" doesn't really mean anything. So since entropy is a measure of disorder, I'll assume that you mean to ask, "What happens when the universe becomes nothing but disorder?" This is essentially what will happen if the universe continues to expand. Everything will get farther and farther apart, the stars will burn out, having converted all of their energy into heat and light, and we'll be left with nothing but a universe of some small mass at absolute zero Kelvin.

Now what does this mean for the passage of time... I guess in some sense, since time is a measurement of "distance" between events, and if there ARE no events, then there will be no such thing as time. I dunno. I think this whole concept of gravity is the clue to alot of it, the "unified theory."

 

[silverpig]

Originally posted by: Moonbeam
The original poster did not make a typo. My question is about time and gravity and entropy. If the universe reaches entropy will time flow. No change no time? Now gravity all used to be in a universe that expanded suddenly for some reason out on neither nothing nor not nothing because there wasn't any space for it to expand into. So the whole universe wasn't since there wasn't any time to be in either. Neither something nor nothing nore time were or weren't. Could entropy be the end of space and time?

You're talking about the heat death of the universe...

Who really cares what will happen then? We'll all be long dead by the time that happens.

 

[Hayabusa Rider]

In the realm of physics, gravity is the second greatest puzzle. No one has a clue about a testable quantum theory of gravity. Zip. Zilch. Strings this and branes that. Could be angels dancing on the head of pins for anyone really knows. Spooky thought for yall. What if there can be NO theory of gravity. What if humans are inherently too dim to understand it? Next topic I would guess.

 

[silverpig]

There are testable theories... just not practically testable ones right now. After all, what is the gravitational attraction between 2 neutrons 1 angstrom apart? How do you measure that? You could probably do it, just not now.


With cloning, we could have Isaac Newton, Albert Einstien, and (insert favourite physicist here) all in a room at the same time under whip and chain until they give us the theory of everything.

 

[Hayabusa Rider]

Originally posted by: silverpig
There are testable theories... just not practically testable ones right now. After all, what is the gravitational attraction between 2 neutrons 1 angstrom apart? How do you measure that? You could probably do it, just not now. With cloning, we could have Isaac Newton, Albert Einstien, and (insert favourite physicist here) all in a room at the same time under whip and chain until they give us the theory of everything.

Well if you has a collider about the size of the solar system, then ya, you could check into things better Hell, you cant even get a SSC built here. Gotta have 3/4 trillion dollars on hand for that silly Iraq war.

 

[blurredvision]

Originally posted by: KnightBreed

"You can expect a series of experiments now," he said.

Fomalout and Kopeikin said their results are accurate within about 20 percent.

Knowing the precise speed of gravity is important to physicists testing such modern ideas as the superstring, which holds that fundamental particles in the universe are made up of small vibrating loops or strings. It also affects some basic space-time theories.

How on earth can you come to this conclusion with tests that are 80% accurate?

How in the hell can you measure gravity from light bending around Jupiter?