The Force of Gravity: Instantaneous or with a Delay?

  • Thread starter robertm
  • Start date
  • Tags
    Interesting
In summary: So does that mean that there is a gravitational Doppler effect?There is a gravitational Doppler effect, but it is very weak.
  • #1
robertm
291
0
Say you had a universe, like our own in every way except that the total matter in existence was one single atom. Now say you introduced another atom of roughly the same dimensions into this universe as far from the original atom as spacially possible.

How long, if any time at all, would it take for either atom to "observe" the existence of the other? Meaning: Is the force of gravity an instantaneous force, or does the force travel ie... as in a gravity wave?

If the atoms are say 100 million light years apart, would either be aware of the other's existence until 100 million years after the 2nd atom was introduced, or would they somehow instantly experience the distortion of spacetime due to each others mass?

Would they be able to "feel" each other before they could "see" each other?
 
Physics news on Phys.org
  • #2
Gravity is not an instantaneous force and propagates at the speed of light. Otherwise, information would travel instantaneously.
 
  • #3
According to Einstein, gravity propagates at the speed of light.

On the other hand, nobody know what would happen if you suddenly created matter out of nothing. If you can do one impossible thing, maybe you can do other impossible things. ;)
 
  • #4
Gravity is not an instantaneous force. As you said, gravity waves from the second atom will travel to the first at a finite speed, namely, the speed of light.
 
  • #5
Phlogistonian said:
On the other hand, nobody know what would happen if you suddenly created matter out of nothing. If you can do one impossible thing, maybe you can do other impossible things. ;)

Ha Ha. Very funny. :wink: Well good you all have so far confirmed what i was thinking. Thanks guys!
On the subject of gravity waves...

I was thinking, we can only (theoretically) maybe detect extreme examples of ridiculous manifestations of matter (black holes, binary neutron stars, type 2 supernova) but, if the theory holds true would i be correct in assuming that every instance of matter occurring in spacetime would distort spacetime and produce "gravity waves" that could theoreticaly be measured even if our current technology does not allow it? So does this mean we are even more so swamped with gravitational waves than we are with EM radiation?

Say we had "eyes" that could "see" a certain wavelengths of gravity waves instead of eyes that can detect EM radiation. How would our experience of the physical world be different/similar? Would we be provided with more information or less?
 
  • #6
robertm said:
Well good you all have so far confirmed what i was thinking. Thanks guys!

Anytime.

On the subject of gravity waves...

I was thinking, we can only (theoretically) maybe detect extreme examples of ridiculous manifestations of matter (black holes, binary neutron stars, type 2 supernova) but, if the theory holds true would i be correct in assuming that every instance of matter occurring in spacetime would distort spacetime and produce "gravity waves" that could theoreticaly be measured even if our current technology does not allow it? So does this mean we are even more so swamped with gravitational waves than we are with EM radiation?

It is true that every massive body in the universe will theoretically emit gravity waves as it moves, even if we cannot detect those waves because they are so weak. Whether this means we are more swamped by gravity waves than by E&M waves, I am not sure.
 
  • #7
Hmmm... i wonder what would happen to a mass' gravitational field if, in relation to the total extent of spacetime surrounding it, it had no motion. ie... an object's only motion is equivalent in direction and magnitude to the expansion of spacetime.

My point being: is the distortion of spacetime reliant on mass AND acceleration, or simply mass?

Would it even emit gravity waves?
 
  • #8
G01 said:
Anytime.



It is true that every massive body in the universe will theoretically emit gravity waves as it moves, even if we cannot detect those waves because they are so weak. Whether this means we are more swamped by gravity waves than by E&M waves, I am not sure.


so does that mean that there is a gravitational Doppler effect?
 
  • #9
There is a difference between a static gravitational field and gravitational waves. Everything has a gravitational field. But only accelerating objects radiate gravitational waves and only if the motion is not spherically symmetric.
 

1. What is an interesting scenario?

An interesting scenario is a situation or event that captures people's attention and piques their curiosity. It can involve unexpected or unique circumstances that challenge the norm and spark creative thinking.

2. What makes a scenario interesting?

A scenario can be considered interesting if it is thought-provoking, emotionally engaging, or has some element of surprise or novelty. It can also be subjective and depend on individual interests and perspectives.

3. How can an interesting scenario be used in scientific research?

An interesting scenario can be used as a starting point for scientific inquiry and experimentation. It can be used to explore new ideas, test hypotheses, and generate new insights and knowledge.

4. Can an interesting scenario help solve real-world problems?

Yes, an interesting scenario can be a valuable tool in problem-solving. It can offer alternative perspectives and challenge traditional ways of thinking, leading to innovative solutions and breakthroughs.

5. Are there any ethical considerations when creating an interesting scenario?

Yes, it is important to consider the potential impact of an interesting scenario on individuals and society. Careful consideration must be given to ethical principles such as informed consent and protection of human subjects in any research involving scenarios.

Similar threads

Replies
4
Views
2K
Replies
11
Views
323
Replies
9
Views
2K
  • Other Physics Topics
Replies
8
Views
5K
  • Special and General Relativity
Replies
23
Views
971
  • Special and General Relativity
Replies
5
Views
1K
  • Astronomy and Astrophysics
Replies
12
Views
1K
Replies
1
Views
1K
Replies
2
Views
1K
Replies
22
Views
992
Back
Top