The attraction of light by gravity

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Discussion Overview

The discussion revolves around the concept of how light is influenced by gravity, specifically addressing the attraction of light by gravitational fields. Participants explore theoretical aspects, implications of general relativity, and the nature of light's interaction with spacetime.

Discussion Character

  • Exploratory
  • Technical explanation
  • Debate/contested

Main Points Raised

  • Some participants suggest that light follows geodesic paths in distorted spacetime rather than straight lines, likening it to a race car on a banked curve.
  • One participant references a PBS program, "Nova: The Elegant Universe," as a resource for understanding how light behaves in gravitational fields, noting that it provides useful information but lacks specific episode details.
  • A participant raises a question about the speed of light in gravitational fields, presenting conflicting information about whether light is slowed down or if spacetime contorts while the speed of light remains constant.
  • Another participant responds to the question by stating that while the speed of light does not change, light can experience redshift when escaping a gravitational field, which affects its frequency and color observed.

Areas of Agreement / Disagreement

Participants express differing views on the effects of gravity on light, particularly regarding whether light's speed is affected or if it is the frequency that changes. The discussion remains unresolved with multiple competing perspectives presented.

Contextual Notes

The discussion highlights limitations in understanding the nuances of gravitational effects on light, particularly the assumptions about speed and frequency, as well as the dependence on interpretations of general relativity.

The Sphinx
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Could you please give me some brief explanation of the attraction of light by gravity. Or maybe some links where I can read something about it. :)


Thank you!
 
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Very briefly, light follows the geodesic paths that Einstein proposed rather than actual 'straight' lines. Where spacetime is distorted by a gravitational field, the photons follow the 'surface'... sort of like a race car on a banked curve.
 
PBS has a program called Nova: The Elegant Universe that you can watch over the internet that tells about light following the dips in space as if it were a blanket. It's been over a year since I watched them so I don't remember which episode explains what your looking for. But I know they're all worth your time to watch, as theyre very interesting, and one of them does have a lot of useful information about light and gravity.
 
The Effect of Gravity on Light

I once read that light is slowed down by a gravitational field.
Later, I read that spacetime contorts and c remains the same.
Which is true?

L.A.
 
Larry717 said:
I once read that light is slowed down by a gravitational field.
Later, I read that spacetime contorts and c remains the same.
Which is true?

L.A.

close...the speed of light doesn't change but its is redshifted, for example, let's say light was escaping the gravitational field of a large star, the light would have to do work to escape it (its force of gravity) so it would use up some of its energy, therefore lowering the frequency. so having the frequency lowered the colour you observer will be more to the left side of the em spectrum then it actually is.
 

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