Momentum of photon close the sun or black hole

In summary: In classical physics, this is entirely equivalent to the photon's energy changing, so this still satisfies the conservation of energy law.In summary, the conversation discusses the change in direction of a photon when it flies close to the sun, and how this is related to the momentum given to the sun (or black hole) by the photon. The concept of momentum in general relativity is also briefly touched upon, with the suggestion that the ADM momentum may be used to calculate the change in momentum of the photon. The idea of the photon's frequency changing as it falls towards the sun is also mentioned, along with the possibility of defining the mass of
  • #36
Thanks.
Now the next question:
How tiny fractions of momentum the photon is giving to the sun? Here the principle of uncertainty comes in play.
I calculated a formula

If delta(L) is recalculated in delta(phi) and we respect tiny changes of momentum

delta(phi) ^3 >= Rs * lambda/(2pi Rb)

Rb is the radius of sun as black hole = 3E3 m (only for a short record.)
Rs is the radius of the sun = 7E8 m.
lamba is a wave lenght, for instance 3E-7 m.
delta(phi) is change of angle around the sun.
delta(L) is change of photons path, where principle of uncertainty is still valid.
This is not small angle (1.5e-2 rad)
But if we include radio waves, this angle become close to 2 pi.

So, how it is with the principle of uncertainty in this example.
 
Last edited:
Physics news on Phys.org
  • #37
exponent137 said:
Thanks.
Now the next question:
How tiny fractions of momentum the photon is giving to the sun? Here the principle of uncertainty comes in play.
I calculated a formula

If delta(L) is recalculated in delta(phi) and we respect tiny changes of momentum

delta(phi) ^3 >= Rs * lambda/(2pi Rb)

Rb is the radius of sun as black hole = 3E3 m (only for a short record.)
Rs is the radius of the sun = 7E8 m.
lamba is a wave lenght, for instance 3E-7 m.
delta(phi) is change of angle around the sun.
delta(L) is change of photons path, where principle of uncertainty is still valid.
This is not small angle (1.5e-2 rad)
But if we include radio waves, this angle become close to 2 pi.

So, how it is with the principle of uncertainty in this example.

Sorry, I have no idea what you're talking about. Mixing QM and gravity rarely makes sense anyway, but I don't even know what you are trying to say.
 
  • #38
Jonathan Scott said:
Sorry, I have no idea what you're talking about.
According to general relativity, a photon gives its momentum to sun continuously. So, on a very short path it gives very small momentum to sun. But this is in contradiction with the principle of uncertainty. So I calculated the smallest rates of momentum, which are given by the photon and these rates are much larger than in the area of Planck's distances.
If this is not enough, I can explain derivation more precisely...
 
Last edited:

Similar threads

Replies
13
Views
998
Replies
8
Views
775
Replies
4
Views
959
Replies
5
Views
1K
Replies
44
Views
1K
Replies
7
Views
525
Replies
7
Views
2K
Back
Top