I think I've read something about quantum gravity possibly being repulsive at very short distances, although I don't remember where it was. Sound familiar to anyone?
Where did you get that from? That isn't the view I got from reading this paper, in which Hawking states:
(I got this quote from one of my blog postings a few months back. Arxiv seems to be down right now, so I can't check the paper to be sure, but I think the quote was on page 5.)
I've got a question for Aether.
By "absolute simultaneity", do you mean that in LET two events which happen simultaneously in one reference frame happen simultaneously in all, or just that there is a preferred reference frame (the ether) and this reference frame is the one in which...
Gravity doesn't act instantaneously, it travels at c, so if the Sun randomly disappeared, we'd stay in orbit for 8 minutes until both the light waves and gravitational effects left. The fact that Newton's theory of gravity is non-local (gravity travels instantaneously) was one of the major...
Gravity isn't a wave, and neither is electromagnetism. In general relativity gravity is a psuedoforce and electromagnetism is a force. And just like electromagnetic waves (ripples in the electromagnetic field) can be produced (light), there are solutions to general relativity where...
I actually think that's a really good question. It's probably because we generally assume space is homogeneous and isotropic, and since we've always been able to describe the positions of everything with three numbers we assume it works everywhere in the universe. There is no reason to believe...
Think for a second about the reason this is true. It does seem intuitively obvious because the low speeds we constantly deal with in every day life do behave this way, but is there any real reason to believe this is the way the universe should behave? Is it a priori (something you know...
Relativity doesn't prohibit objects from traveling faster than c. What it prohibits is objects accelerating from a speed less than c to a speed greater than c or vice versa. There are hypothetical particles which, if they exist, always travel faster than the speed of light. These particles...
According to the principle of relativity (in the restricted sense), all inertial frames are equivalent for the description of the laws of nature. How do you call one electron moving and one standing still? There is no such thing in an absolute sense. If an electron is moving relative to you...
Hawking has changed his opinion. You might find this interesting: http://arxiv.org/abs/hep-th/0507171
"The question of whether information is lost in black holes is investigated using Euclidean path integrals. The formation and evaporation of black holes is regarded as a scattering problem...
Perhaps your teacher misinterpreted gravitational lensing. Gravitational lensing is an effect in general relativity where the gravity of a body causes light to take a curved path. It is true that if you look at distant stars and there is a body of large density between you and the distant star...
Why are you so certain that the moon must have a definite position when it's not being observed? It *does* exist, as someone pointed out earlier, fundamental particles/waves always exist, they just don't always have a definite position. So why wouldn't quantum theory naturally lead to the fact...