Scientists attempt to measure speed of gravity

spaceflightnow.com ^ | 5 SEP 02 | staff

[ATOMIC_PUNK]

Might you be referring to the difficult vortex theory of gravitation?

Thats the one its difficult indeed

[RightWhale]

its difficult indeed

It is so difficult that they were happy to have something relatively [!!!] simple like the general theory of relativity come along so they could work on that instead.

[apochromat]

That makes sense, but what should be made of the case where light is slowed down to a fraction of its vacuum speed, say for instance to 20 mph in a BEC medium? As far as I can guess, the speed of such light could be varied by moving the medium while it contains the light.

There would have to be some light speed reduction or medium (or something) that would define the regime of non-relativity, it seems.

[RightWhale]

the case where light is slowed down to a fraction of its vacuum speed, say for instance to 20 mph in a BEC medium?

The Bose-Einstein Condensate is not a place one would normally try to travel in or have a picnic. But perhaps when I am doing my doctoral studies, I will have the opportunity to measure the angle of Cerenkov radiation inside there.

[apochromat]

BECs are exotic, but they are what prompted my questions.

I was thinking about Cerenkov radiation for several minutes after I wrote my previous reply, while I was also muddling over whether "nonrelativistic" was the appropriate term for me to have used.

After thinking about it some more, I suppose that such exotic phenomena are relativistic, but their conditions are so complex that naively-applied relativistic transformations won't fit.

[RightWhale]

Bose-Einstein Condensates are exotic alright, but we don't have to use them to wonder about relativity inside non-vacuum conditions. The simple glass in your telescope lens allows light to pass right on through fairly easily, yet what kind of relativistic effects are going on inside there? You could shoot a nuclear particle into that region at over the speed of light in the medium until it collided with something. Light slows down instantly at the air-glass interface, but the alpha particle keeps on trucking, moving faster than light for a while. What happens to relativity there?

[capitan_refugio]

Are you saying, " E = M G squared "???

Great Scot, you could be right!

[apochromat]

What happens to relativity there?

I'll make an attempt at answering that, and you can correct me if you disagree. It seems that the non-uniformity of the medias involved is being made evident in such phenomena. In other words, the light-speed reduction defined for a medium is a macroscopic quantity based on averaged effects of all the atoms that make up the medium. Looking at it microscopically, the medium is a combination of vacuum and atoms, and light is normally induced by the atoms to meander about instead of taking the shortest path through the vacuum.

[RightWhale]

the medium is a combination of vacuum and atoms

It's the kind of thing we don't know and may never know. Even the deepest outer space between galaxies and between galactic filaments where there is really nothing contains photon radiation fields and and gravity fields and who knows what else criss-crossing in every direction everywhere. There may be no such thing as a perfect vacuum, and if there were it might be disastrous.

[SunkenCiv]

Vintage science topic.

[Stellar Dendrite]

lol!!!!!

[Age of Reason]

Too many exclamation points in your article.

So it must be B.S.

[FairOpinion]

Thanks for the science pings, in addition to the GGG ones.

I haven't had much time to spend on FR, so it helps to be pinged, to avoid missing interesting stuff.

[SunkenCiv]

You're most welcome. This one hadn't been posted to in nearly three years though. :')