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Q & A: The Mysterious Gravitons - and Photons?

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Most recent answer: 10/22/2007
Q:
What is the differnace between a photon and a graviton?
- nick (age 16))
sixth form college, uk
A:

Nick -

You’ve probably heard of the idea that everything that is a particle is also a wave and vice versa. Well, a photon is the particle/wave that carries the electromagnetic force. We know that photons exist because scientists have been able to set up experiments that let them detect each individual photon and measure how many and where they are.

Gravitons are the particle/wave that carry the gravitational force. (Like photons, except for gravity, not light.) But so far, no one has been able to set up an experiment that can directly "see" gravitons individually. *

-Tamara

*The BICEP2 collaboration claimed to have seen what looks like the leftover effects of the quantum zero-point spread of gravitational waves, left as tiny "B-mode" ripples in the polarization of the cosmic microwave background radiation. It now looks like they really saw somethig more local and less interesting. If one of the more sensitive versions of this experiments works, then it will be fair to say that a real quantum gravity effect will have been seen. /Mike W.


(published on 10/22/2007)

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