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Physicists discover that gravity can create light

phys.org

11–20 of 108 posts

Re: Physicists discover that gravity can create light

#11
post #10

Isn't gravity just a fundamental force? Could it be matter reacting to gravity? Light is energy but gravity is not energy and has no mass so how can it create something out of nothing? How is hawking radiation even possible unless something else was involved?

Or gravity is just bending of space around a mass. And not a force.

Re: Physicists discover that gravity can create light

#13
post #10

Isn't gravity just a fundamental force? Could it be matter reacting to gravity? Light is energy but gravity is not energy and has no mass so how can it create something out of nothing? How is hawking radiation even possible unless something else was involved?

> Isn't gravity just a fundamental force?

Not really.

     Gravity is most accurately described by the general theory of relativity... which describes gravity not as a force, but as the curvature of spacetime, caused by the uneven distribution of mass, and causing masses to move along geodesic lines.[1]
[1] https://en.wikipedia.org/wiki/Gravity

Re: Physicists discover that gravity can create light

#14
All quantum fields have their vacuum energy fluctuations. When we change the parameters of the space (e.g. stretch or compress it), the current state is no longer the ground state but becomes a so-called squeezed vacuum state.

This effect is used in laser physics to "split photons" in spontaneous parametric downconversion. That is, an intense laser changes the refractive index of a medium periodically. These oscillations generate a squeezed vacuum state.

https://en.wikipedia.org/wiki/Squeezed_coherent_state

Re: Physicists discover that gravity can create light

#15
post #8
post #2

How does this not have more upvotes? This is a great find!

phys.org can be a bit sensationalistic. Quanta takes their time getting to the point, but is a bit more reliable in terms of the summary provided. So if there's a popular physics article, it generally seems to be quanta.

phys.org re-publishes press materials from universities. The writers at Quanta write their own articles.

Re: Physicists discover that gravity can create light

#17
post #10

Isn't gravity just a fundamental force? Could it be matter reacting to gravity? Light is energy but gravity is not energy and has no mass so how can it create something out of nothing? How is hawking radiation even possible unless something else was involved?

> Isn't gravity just a fundamental force? Not really. Gravity is most accurately described by the general theory of relativity... which describes gravity not as a force, but as the curvature of spacetime, caused by the uneven distribution of mass, and causing masses to move along geodesic lines.[1] [1] https://en.wikipedia.org/wiki/Gravity

Ok, so how does curvature cause light and radiation on its own?

Re: Physicists discover that gravity can create light

#18
post #10

Isn't gravity just a fundamental force? Could it be matter reacting to gravity? Light is energy but gravity is not energy and has no mass so how can it create something out of nothing? How is hawking radiation even possible unless something else was involved?

> Isn't gravity just a fundamental force? Not really. Gravity is most accurately described by the general theory of relativity... which describes gravity not as a force, but as the curvature of spacetime, caused by the uneven distribution of mass, and causing masses to move along geodesic lines.[1] [1] https://en.wikipedia.org/wiki/Gravity

You have to remember that General Relativity is wrong. We don't know exactly how it's wrong, but it's wrong. In light of that fact, it's not really a proper answer to say that "General Relativity says it isn't so it isn't." It is true that GR says gravity isn't a force, but the implication doesn't follow. We don't know whether a Grand Unified Theory would have gravity as a force or not. Given that a great deal of the answer to "Is gravity a force?" depends heavily on the definition of force being used, we don't even know what the final definition will be in light of a GUT. There may or may not be a meaningful distinction between gravity and other forces in the real universe.

In QM, gravity isn't a force because gravity doesn't exist. Clearly this is wrong as well. Saying "GR says gravity isn't a force" is effectively the same thing as saying "Gravity doesn't exist because QM says it doesn't." This is exactly where both theories break, so we can't use them to answer this question.

See also https://www.youtube.com/watch?v=EmrZ3ZaXmS4 .

Re: Physicists discover that gravity can create light

#19
post #11
post #10

Isn't gravity just a fundamental force? Could it be matter reacting to gravity? Light is energy but gravity is not energy and has no mass so how can it create something out of nothing? How is hawking radiation even possible unless something else was involved?

Or gravity is just bending of space around a mass. And not a force.

Not a physicist, but how do you get something to bend without a force exerted upon it?

Re: Physicists discover that gravity can create light

#20

So the trick to creat this light in todays environment would be to make a gravity amplifying device similiar to a https://en.wikipedia.org/wiki/Gravity_laser and overlay the amplitudes? That can be easy. Just have a microscopic black hole particle go back and forth in a field..

And I just upgraded all of my bulbs to LED...
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