Science to ride gravitational waves

BBC News on line ^ | November 8, 2006 | By Jonathan Amos, BBC News science reporter, Hanover

[JTHomes]

Is there another explanation for Hubble's red shift than that the galaxies are moving away from each other?

If light is red shifted, does it mean it has less energy? In this case if gravity gets red shifted, does it get weaker beyond the basic inverse square law? Could that explain the acceleration of the universes expansion? I always wondered about that.

[Quark2005]

Of course, like the sotted king who was shown proof the Earth is round by swirling water draining from a tub, then rejected the claim because he did not understand the reasoning and had the knave who showed him this beheaded, I also worry that I will not understand clear proof that I am wrong, and thus reject it.

I'm not sure you're wrong, but you might be looking at something that is already well-established in a non-conventional way, that's all.

[RightWhale]

Maybe so. Physics is all math. When Einstein said that he knew of no other explanation, he meant that an alternative coherent mathematical model did not exist. The math must be developed or the idle speculation will remain idle.

[spunkets]

" Funny the original body, although so small, has grown so large."

From field theory, there is more energy contained in 1 cm³ of vacuum, than in all the visible universe. The largest discrepency in Physics is that fact and the fact that the cosmological constant is essentially zero. IOWs, the vacuum energy doesn't contribute gravitationally. The discrepency is ~10¹⁰⁰. Even with supersymetry it can only be knocked down to ~10⁵⁰.

However the body came about from the vacuum, once it emerged it had a tremendous temp in a space of ~zero temp. The expansion is just the effect of cooling off in the new space it appeared in.

[grey_whiskers]

As usual I am late to all the good threads. Thanks for the interesting :-)

Cheers!

[grey_whiskers]

While you're at it, would you explain "inflation" to me?

Full Disclosure: in the cosmological sense, not the economics one. :-)
And even a pointer to a reputable website would be gratefully accepted.

Cheers!

[RightWhale]

We know, or think we know, the universe is expanding. Hubble's redshift gives that impression. There was a period, in the model, where the universe was very small and conditions suddenly became appropriate for gravity to become a positive force. Space itself weighed almost nothing and the repulsive force of gravity had a huge effect. The universe suddenly grew from a tiny speck smaller than an atom to the vast thing it is now, and we can see only an infinitesimal fraction of the whole. It might be interesting to note that, in the model, the force of gravity was negative, attractive, until recently, but on the big scale has become positive again. The future, for those who stick around to see the end of the play, is of a universe with such immense distances between galaxies that it won't be possible to see another galaxy from this one.

[grey_whiskers]

Thank you. That is the most cogent description I have ever read.

[RightWhale]

Sorry I am not much of an authority on inflation. All I know I read in Guth's book, and Greene's, insiders: the horse's mouth, so to speak. Guth was the originator of the inflation idea, and he is also a fine writer for the amateur cosmologist. Greene is the best popular science writer on cosmology. Either or both would explain what is going on with inflation, and Greene would probably explain the consequences of inflation very well. Guth's story is fascinating, as it deals with the inner workings of the cosmology community.

[MonroeDNA]

"So gravity is exactly the same speed as light. It's like we are being pulled around the sun buy a bent rope pulled by you when you whip a whip around your head. That’s a good explanation, but I have trouble understanding how this works. What I’m stuck on is light is going from sun to earth, but gravity goes both ways, right? Is the “field” moving at c, or are the gravitons moving at light speed, or both? Because the earth exerts its own force on the sun also why wouldn’t the field meet in the middle in 4 minutes and give us only a 4 minute delay? In this case is the observed behavior an 8 minute delay because the effect of the 4 minute trip takes another 4 minutes to be observed from each respective location? Or do we have to wait for each respective field to reach each massive object? In this case, maybe we should see a 16 minute delay since the information or effect of the graviton going from each respective location would take an extra 8 minutes to observe? Relativity confuses me."

They both pull on each other, but it doesn't matter how much each contributes. It is a net effect, and orbital distance determines how long light taked to hit each other (Yes, the earth reflects light, and it hits the sun). Like a ball swung on a rope by a string, the further out you are, the longer it takes to orbit, and the longer it takes for light to reach you.

In this case, gravity is the string.

A ball can pull on the string, and so can the pole; in fact they both have to, otherwise the pole would fall over or the ball would fly away.

Same with gravity, only you can't see the string.

I don't know it it is a field or gravitons. I suspect it is a field. Richard Feynman was adament about light being particles, but in his QED book, he could only find one experiment to support it, and frankly I thought it was an answer looking for a question.

I personally think that everything is waves.

For example: How To Piss Off Physicists 101:

A light shines in the distance. As you move away, it grows dimmer. If the light emitted particles, eventually the particles would miss you, like a too-long shotgun. But they don't. There is no random scattering of particle misses. Why?

Back on the gravity thing:The earth rotates about the sun 8 minutes late, and the sun sees the same thing. An 8 minute delay, the same as the speed of light.