Recent content by alexg

On the wiki page, there is one line stating that photons in superconductor have rest mass. However, there are no citations supporting that statement, and as far as I know, there are no transparent superconductors. All the wiki page can give is an upper limit for any mass, meaning no mass has...

No, theories, as the word is used in science are not hypothesis. Theories are hypothesis which have been verified by observation and experiment. And I answered your question.

No. All ideas about a multiverse are strictly hypothetical.

An inertial frame is one which is not undergoing acceleration.

Extremely sensitive experiments to detect proton decay have yet to find any. http://en.wikipedia.org/wiki/Super-Kamiokande

No. There was nothing 'here' before the BB. Neither space nor time.

I would suggest The Inflationary Universe by Alan Guth. Again, he's just using an analogy to show how something (the universe) can be finite and unbounded.

That's where your error lies. It's not a model. It's an analogy. In this analogy, only the surface of the balloon is considered. It is using a two dimensional ANALOGY of the three dimensional universe. So for the purpose of the analogy, there is no inside of the balloon.

Andromeda and the Milky Way are approaching each other, and will collide in about 4.5 billion years. On any scale less than the local galactic supergroup (200 million lys) the effect of gravity overwhelms the force of expansion. It's only when you get outside the supergroup that you see...

In the paper they say I think what they're saying is that the image they have is of a galaxy which is 'now' 500 million years old and which first formed at 200 million yrs.

I would just like to comment that the balloon analogy seems to have caused more confusion than any other explanation of universal expansion. Of course, most of the confusion is because of people who don't know what an analogy is.

If I'm remembering correctly, in the Guth-Linde version of inflation, the universe expanded by a factor of 1080 in the period between 10-45 and 10-35 seconds.

The idea is not that there are 'other universes'. It's that unlike electroweak and strong force, gravity is able to propagate into the additional dimensions called for by M-theory. All those dimensions are part of our universe, but only gravity can move in those 'directions'. It would explain...

Peter, a minor point, almost a diversion, but doesn't the Shell Theorem state that the gravity inside the Earth remains the same until you reach the center? While there is more mass above you, you are closer to the rest of the mass on the other side, and it balances out.

Nothing in the Universe moves faster than rumor.