Do Gravitons Exist?

[Rhondazvous]

With the dark energy, the problem isn't so much that they can't find it - there is a free parameter in Einstein's field equation, the cosmo. constant, which regulates dark energy. So from a theoretician's perspective, the mere existence of DE isn't so surprising, nor necessarily demanding an explanation. The trouble is rather that all the virtual particles and the higgs field on paper contribute such a ridiculous amout of dark energy that the actual puzzle is - why is there so little of it! On paper, you need to set the cosmo constant to 120 digits precision to cancel the dark energy coming from all the virtual particles down to the observed value. That seems strange, and that's the open question - is that an artifact of the way we formulate our theory, is it a sign that we don't understand quantum gravity, is it an anthropic tuning, or is it just that way and there's no explanation?

"is it an anthropic tuning, or is it just that way and there's no explanation? " = God did it. But we won't go there. Oh hell to the no.

[Alex K]

With the dark energy, the problem isn't so much that they can't find it - there is a free parameter in Einstein's field equation, the cosmo. constant, which regulates dark energy. So from a theoretician's perspective, the mere existence of DE isn't so surprising, nor necessarily demanding an explanation. The trouble is rather that all the virtual particles and the higgs field on paper contribute such a ridiculous amout of dark energy that the actual puzzle is - why is there so little of it! On paper, you need to set the cosmo constant to 120 digits precision to cancel the dark energy coming from all the virtual particles down to the observed value. That seems strange, and that's the open question - is that an artifact of the way we formulate our theory, is it a sign that we don't understand quantum gravity, is it an anthropic tuning, or is it just that way and there's no explanation?

"is it an anthropic tuning, or is it just that way and there's no explanation? " = God did it. But we won't go there. Oh hell to the no.

Anthropic tuning doesn't automatically mean God did it, the obvious alternative possibility would be that there are regions with different values of dark energy in the Universe, and we find ourselves in one where the value is small enough such that stars can form.

[Anomalocaris]

How would the theory of induced gravity differ in its predictions of the behavior of gravity and graviton from what those predictions might otherwise be?

[Rhondazvous]

"is it an anthropic tuning, or is it just that way and there's no explanation? " = God did it. But we won't go there. Oh hell to the no.

Anthropic tuning doesn't automatically mean God did it, the obvious alternative possibility would be that there are regions with different values of dark energy in the Universe, and we find ourselves in one where the value is small enough such that stars can form.

Are you saying stars do not proliferate where there is a lot of dark energy? Then gravity is not dark energy but some other enigma.

[vorlon13]

I was thinking some intensely energetic gravitons were generated in the BB. And in our era they would be disorganized like static on an analog radio, IOW everywhere.

Not sure why I was thinking they were 'immune' to losing energy due to the expansion of the universe, the wavelengths would be getting longer as space dilutes them like photons.


Well, try this;

initial energies of photons in the BB would have been high, but the universe was opaque to them for quite a while, so the initial high energy ones would have been subject to scattering absorption/reabsorption by subatomic particles and hydrogen. this would be an additional loss of energy over and above the expansion of the universe effect.

Would gravitons have been as effectively attenuated in the early stages of the BB as photons were, and subsequently would still be 'potent' after cosmic expansion ?

See, photons had to go through 2 'gauntlets'. Gravitons less, maybe substantially less than 2 but more than 1.

[Alex K]

I was thinking some intensely energetic gravitons were generated in the BB. And in our era they would be disorganized like static on an analog radio, IOW everywhere.

Not sure why I was thinking they were 'immune' to losing energy due to the expansion of the universe, the wavelengths would be getting longer as space dilutes them like photons.


Well, try this;

initial energies of photons in the BB would have been high, but the universe was opaque to them for quite a while, so the initial high energy ones would have been subject to scattering absorption/reabsorption by subatomic particles and hydrogen. this would be an additional loss of energy over and above the expansion of the universe effect.

Would gravitons have been as effectively attenuated in the early stages of the BB as photons were, and subsequently would still be 'potent' after cosmic expansion ?

See, photons had to go through 2 'gauntlets'. Gravitons less, maybe substantially less than 2 but more than 1.

Gravitons from the BB would have been redshifted like photons. One way to see them would have been the so-called tensor fluctuations of the cosmic microwave background which the BICEP2 experiment claimed to have detected and then retracted a couple of years ago. Those would have been traces of quantum fluctuations of spacetime and the best indirect evidence that gravitons exist...

[downbeatplumb]

Sod gravitons I want tachyons.

[Alex K]

Sod gravitons I want tachyons.

We expect to have them in stock again yesterday, but if you need them sooner and you'd like to preorder to have them delivered last week, feel free to contact us at any point in the future.

[TheRealJoeFish]

In Futurama, when a blast from an exploding super nova ("I've never seen a super nova blow up, but if it's anything like my old Chevy Nova, it'll light up the night sky!") combines with the gravitons and graviolis caused by putting a metal popcorn container in the microwave (picks up ear of corn "aww, it's less popped than ever"), it tears the universe a new space hole, which, according to the high-precision digital chronograph, can propel you back through time ("which also explains why the high-precision digital chronograph has turned into this pin-up calendar").

Thank you you're welcome goodnight!