How does space-time curvature affect light?

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Discussion Overview

The discussion revolves around the effects of space-time curvature on light, particularly in the context of black holes and gravitational fields. Participants explore the nature of light's interaction with warped space, the implications of general relativity, and the observable phenomena related to gravitational lensing.

Discussion Character

  • Exploratory
  • Debate/contested
  • Conceptual clarification

Main Points Raised

  • Some participants propose that light may be "sucked in" by gravity, while others suggest it is merely caught in the warped space around a black hole.
  • One participant asserts that gravity is equivalent to warped spacetime, indicating a fundamental relationship between the two concepts.
  • Another participant argues that while warped space bends light, it does not cause light to disappear, referencing the solar eclipse as evidence that light can travel through warped space and still be observed.
  • There is a discussion about the degree of warping caused by the sun's gravitational field compared to that of a black hole, with some noting that the sun's effect is minimal and primarily results in slight bending of light.
  • One participant explains that near a black hole, the curvature of spacetime is so extreme that all possible paths for light lead inward, making escape impossible at the event horizon.

Areas of Agreement / Disagreement

Participants express differing views on how light interacts with warped spacetime, particularly in relation to black holes. There is no consensus on whether light is "sucked in" or simply follows curved paths, and the discussion remains unresolved regarding the implications of these interactions.

Contextual Notes

Some limitations include the dependence on definitions of "straight line" in curved spacetime and the varying degrees of gravitational effects based on mass and distance from the source.

lynchmob72
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If space is warped around heavy objects in space, i feel that space would be FUBAR around black holes. So, my question is, Does light get sucked in by gravity, or does it just get caught in the warped space around a black hole?
 
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lynchmob72 said:
If space is warped around heavy objects in space, i feel that space would be FUBAR around black holes. So, my question is, Does light get sucked in by gravity, or does it just get caught in the warped space around a black hole?
Gravity IS the "warped spacetime".
 
phinds said:
Gravity IS the "warped spacetime".
Well, I understand that gravity is space pushing on you (Thanks to Relativity). My problem is, Light travels in a straight line. Warped space will bend light, but not make it disappear. I know that a black hole funnels space to the center or singularity, but i also know that warped space can't hold light. When the solar eclipse that proved Relativity happened, light traveled through warped space, then came out of it so we could see it. It should have wrapped around the sun, but it didn't. So, i wonder.
 
lynchmob72 said:
It should have wrapped around the sun,
"around"? The path of the light and the mass / diameter of the Sun would only produce a slight warping effect, which is what was seen. These effects are all a matter of degree and mostly cannot be seen at all because the conditions are not extreme enough.
 
lynchmob72 said:
My problem is, Light travels in a straight line. Warped space will bend light, but not make it disappear. I know that a black hole funnels space to the center or singularity, but i also know that warped space can't hold light. When the solar eclipse that proved Relativity happened, light traveled through warped space, then came out of it so we could see it. It should have wrapped around the sun, but it didn't.

Yes, light travels in a "straight" line, and curvature can mean these straight lines aren't really straight (rather as a straight line on the curved surface of the Earth will bend as it follows that curved surface).

The sun is not a black hole; its gravitational field is just strong enough to bend the path off to one side a bit. That's what Eddington's group observed in the solar eclipse (and we have since seen many more spectacular examples - google for "gravitational lensing").

The spacetime curvature near a black hole is so strong that at the event horizon all the straight-line paths that light can follow ("light-like geodesics" or "null geodesics" in the lingo) lead inwards. At the event horizon light cannot escape because there is no path out; move at the speed of light in any direction and you'll still end up inside the black hole.
 
Thank you for the replies.
 

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