space-time as a force opposing both gravity and energy.

[alxian]

gravitons are no longer theory?

and do you mean to say gravitons are the only particles that travel at c but there are particles that can exceed c such as tachyons?

ultimate rest could be possible so long as nothing is moving at all, not even rotating, such an object would absorb photons and have to do something with the incomming energy.

[Tormod]

Originally Posted by alxian

gravitons are no longer theory?

I assume this is directed at me?


Gravitons are still theory. But if they exist they move at the speed of light. Gravity has been proven to move at the speed of light, and if the graviton is the carrier of gravitational force then it too must move at the speed of light.

and do you mean to say gravitons are the only particles that travel at c but there are particles that can exceed c such as tachyons?

No, gravitons AND photons move at the speed of light. No other particles can reach the speed of light because they have mass. Tachyons are purely theoretical constructs which, if they exist, can never have moved *slower* than the speed of light. I do not think they exist, and they have yet to be proven.

ultimate rest could be possible so long as nothing is moving at all, not even rotating, such an object would absorb photons and have to do something with the incomming energy.

This would require the entire universe to come to a halt. In the universe, everything is constantly moving. Nothing is at rest. Things are only at rest relative to each other. There is no "absolute" frame with which things can be at absolute rest.

[bumab]

Originally Posted by Tormod

Gravitons are still theory. But if they exist they move at the speed of light. Gravity has been proven to move at the speed of light, and if the graviton is the carrier of gravitational force then it too must move at the speed of light.

What study did they proove this in? I was under the impression that the latest experiment measuring light curvature around Jupiter was somewhat controversial still, as many think the researchers simply measured the speed of light in an indirect manner.

[Tormod]

They have been indirectly observed and were confirmed last year.

Here is a source:
http://www.astrophysicsspectator.com...onalWaves.html

The attraction of the neutron star and black hole binaries, besides being as close to barbells and one can get in astronomy, is that the binary pulsars PSR1913+16 and PSR J0737-3039 have orbits that are decaying in the way expected if they were losing energy to gravitational radiation.1,2 As each system loses energy, the semi-major axis of its orbit becomes smaller, and the orbital period becomes shorter. This shortening of the period is seen in the radio pulses emitted by the pulsars in the systems, providing the evidence that gravitational radiation exists. These binary-pulsar, however, is a weak source of gravitational waves. To see a binary neutron star gravitationally, one must wait until the two stars are very close together or are in the process of merging, when they are their brightest as gravitational wave sources. Because these events are rare, the detector must be able to see mergers that are in distant galaxies.

[Tormod]

BTW, the Jupiter experiment was not supposed to prove gravitational waves but that gravity does not act instantly. This indirectly implies waves but that is secondary.

[humility]

I meant why can't we just invert the velocity of light and use that as the frame of rest. the speed of light is 299,792,458 metres per second. If we invert this to a velocity of 1 metre per 299,792,458 seconds and say its the slowest you can go and set it as the value of rest. So something travelling at 1 metre every 9.5 years is considered at rest. whereas everything above this would be considered in motion.To find out if this is true we should try to see if it is physically possible to go slower than this.

[Buffy]

Originally Posted by humility

If we invert this to a velocity of 1 metre per 299,792,458 seconds and say its the slowest you can go and set it as the value of rest. So something travelling at 1 metre every 9.5 years is considered at rest. whereas everything above this would be considered in motion.To find out if this is true we should try to see if it is physically possible to go slower than this.

My geologist friends will tell you that even the San Andreas fault is moving slower than that, and yet we here in California hardly consider it "at rest!"

Cheers,
Buffy

[humility]

Great example Buffy. I especially liked the eartquake humuor involved.
But the crusts are part of the earth that is rotating. If you stuck a rod with a metre circumference in the polar axis. If you put a mark on that rods circumference it would take that mark at present rotational speeds a day to travel a metre.So where talking a velocity of 1 metre per day for the earths crust at its slowest which is 3469 times faster than 1 metre every 299,792,458 seconds.

[Tormod]

Originally Posted by humility

So something travelling at 1 metre every 9.5 years is considered at rest. whereas everything above this would be considered in motion.To find out if this is true we should try to see if it is physically possible to go slower than this.

This is just an arbitrary number, though. And when do you decide that it is at rest? Compared to what?

[humility]

How slow can you go? what is the slowest velocity a physical phenomena has been recorded to have?. The same way your not suppose to be able to accelerate to the velocity of light. There may be a velocity that you can't deaccelerate too which isn't necessarily V=0. If we can develop experiments to discover the slowest velocity a physical phenomena can deaccelerate too we could set this as a the standard of rest. A kind of slow barrier.