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Q & A: microscopic gravity

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Most recent answer: 07/05/2013
Q:
are the effects of gravity in the microscopic world know?
- andrew (age 29)
lansdale, pa
A:

On a small scale, gravity is weak compared to the electromagnetic force. That makes it hard to measure whether Newton's law for gravity works on scales less than about 100 μm. In practical cases, the difference between Newton's gravity and the gravity of General Relativity is not important on these scales. There are various ideas about why there might possibly be some deviations on these scales, but as yet there is no evidence of any. On much, much, smaller scales, say 10-44 cm, quantum effects become so important that the large-scale law of gravity seems like it must break down. String theory provides an idea for new laws that might work on that scale. It's also string theory that suggests the possibility that some sort of different behavior might set in on the scale currently being tested. Here's a paper discussing some of the experiments.

Mike W.


(published on 07/05/2013)

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