All Questions
46
questions
1
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4
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201
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Since light has inertia and experiences gravity, what does it mean for photons to be massless?
I've been trying for a long time to figure out what the heck mass even IS. In introductory physics and chemistry, students are told that massive objects are those that are made of matter and take up ...
- 2,327
1
vote
3
answers
221
views
Is there a frequency limit for the pendulum near a black hole, and is this related to photons and the UV-cutoff?
I imagine a swinging pendulum being held outside a black hole, supported by the normal force of a rocket. The rocket is hovering the swinging pendulum right above the event horizon in the strong ...
- 95
1
vote
1
answer
188
views
Can photons form a black hole?
Can photons form black holes the same way as other matter? If there happens to be enough of them concentrated in an area of space so that enough energy exists within a radius to form an event horizon, ...
- 113
0
votes
1
answer
92
views
Are photons affected by "temporal gravity?"
Since objects follow geodesics in spacetime, that is the locally shortest path, it would seem to me that unless objects move, they do not trace any path at all. In other words, if I'm stationary on ...
- 47
-2
votes
1
answer
78
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How does gravity affect "Timeless" particles like photons?
Just finished a class a while ago and in it was discussed the nature of gravity being due to mass' effect on time etc. etc.
My question is: how then does gravity effect something like a photon, which ...
1
vote
1
answer
75
views
Will 'free' photons exert gravitational force [duplicate]
From my general understanding, it is widely accepted that light will bend around a massive object, as it will experience gravity, is predicted by GR, and was experimentally verified.
Also, the energy ...
- 141
4
votes
2
answers
492
views
What if I left Earth then turned it into light?
So I asked a question about what would happen in regards to gravitational potential if I left earth and then vaporized it. The answer I got was that the Mass would still remain the same and even if ...
0
votes
0
answers
39
views
What evidence suggests that light exerts a force of gravitational attraction? [duplicate]
I'm aware of other posts outlining the theory of how light generates a force of gravitational attraction, cf. e.g. this Phys.SE post. I'm not so interested in this. I'm interested in what evidence ...
- 1,552
0
votes
1
answer
80
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Does the fact photons having gravity field contradict gravitomagnetism?
as I read here two photons that aren't parallels can attract each other because photons have energy. But the problem is that photon are going in the speed of light which means it would take infinity ...
- 149
0
votes
1
answer
89
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Why do people say we need general relativity in order to explain why light is affected by gravity? [duplicate]
I've heard said by many physicists things along the lines of "Since light has no mass, we need general relativity to explain why light is affected by gravity."
But why is this necessary?
We ...
- 101
1
vote
0
answers
35
views
Do anti-parallel photons affect each other gravitationally? [duplicate]
We know that two parallel photons have no gravitational effect on each other because they never pass through each other's light cone. The question is, what happens to anti-parallel photons? It ...
- 804
0
votes
3
answers
177
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Photon trajectories affected by gravity [duplicate]
If the gravity of a star can change the trajectory of a photon, is the speed of the photon reduced at the moment of departure from the stellar's surface? Can modern science calculate the measure of ...
Zhu
31
votes
4
answers
4k
views
How do photons affect each other gravitationally?
Photons are energy. According to general relativity they should bend space.
Assuming two photons pass one another in a large void of empty space how would they gravitationaly affect each other ...
- 804
1
vote
3
answers
110
views
Gravity affects the clock rate when they are stationary?
I am unable to get the maths and neither the physics behind how gravity affects clock rate.
Note- As far as possible I was able to express and clear I have understood.
"Suppose if we keep spatial ...
0
votes
0
answers
80
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If photon is massless, then how can it interact with gravity? [duplicate]
Photons are considered massless so how do they interact with gravity? According to Einstein Relativity, only curvature of space is responsible for bending of light rays. If so, and mass to mass ...
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