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Q & A: gravity and the speed of light

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Most recent answer: 02/28/2014
Q:
Please keep in mind that not a student or teacher and I have never taken any physics classes so if I sound stupid that's why. As far as I understand mass/gravity creates bends in spacetime from the smallest particle (a very small local bend) to the sun or galaxy (very big bends). Could some of the measurements taken in experiments be "how it is" in just our local bending of spacetime. For example. The speed of light is constant however it does bend due to gravitational lensing(bend in spacetime) creating a longer path. Measurements here on earth/solar system technically would vary from measurements taken say in between galaxies where very little bending occurs? And since all observations are take from within our local bending of spacetime would they be skewed a little to our own locality?
- Andrew (age 35)
Barrie, Ontario ,Canada
A:

Here it's important to say how we compare speeds in different places. Let's use standard meter-sticks made of a fixed number of atoms of say platinum. Let's use clocks based on the atomic vibration periods of say cesium. Then you'll get the same speed of light when you measure in different places.

The bending shows up only when you make a non-local measurement, for example bouncing light off a planet where the light has to pass near the Sun on the trip. Then the time is increased by that spacetime bend. The effect has been studied quite a bit:  .

Mike W.


(published on 02/28/2014)

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