Take the 2-minute tour ×
Physics Stack Exchange is a question and answer site for active researchers, academics and students of physics. It's 100% free, no registration required.

Consider a Photon from Sun and travels with a velocity $c$. Now think we are that photon. For us, it looks like Sun is moving away from us with a velocity $c$. So, why don't we get attracted back towards Sun, because the mass of Sun would be infinite for us since it moves away from us with a velocity $c$.

share|improve this question
2  
Related to your second q: physics.stackexchange.com/questions/27794/… . I can't seem to find a post explaining why photons do not experience passage of time, though. –  Manishearth Dec 29 '12 at 8:49
    
Hi Inquisitive. Could you please revise your second question. I don't force you. But, Manish has already given you a link. If you think its helpful, you could erase your second question. Or, you could clarify it to ask something specifically. But - to me, it looks the same. It is a good question though. But, There are many questions related to yours. I'll try to provide some useful links. Another piece of advice: A revision may sometimes enable the undownvoting for other users :-) –  Waffle's Crazy Peanut Dec 29 '12 at 9:11
    
@CrazyBuddy Done –  Inquisitive Dec 29 '12 at 9:14
1  
@Inquisitive probably the biggest issue with this question is that it shows a significant lack of understanding of even the basic concepts of special relativity. You're asking what we'd see if we pretend to be that photon, but we can't do that; a photon does not have a reference frame. So it's a meaningless question. –  David Z Dec 29 '12 at 9:59
    
@DavidZaslavsky: Now, it reminds me of this question: physics.stackexchange.com/q/16018 –  Waffle's Crazy Peanut Dec 29 '12 at 10:00
add comment

1 Answer

up vote 1 down vote accepted

You have completely mixed the modern and classical concepts of relativity. If you're talking about mass increment, you shouldn't calculate speed of Sun based on absolute time & space notion.

For you as a photon, space will be contracted to zero and time will be dilated to infinity. So, you can't calculate a speed (which is a time-like spacetime event) of Sun.

While its a nice satisfactory explanation, its not the real one.
Real Answer:
Relativistic physics doesn't allow you to take position of a photon. In other words, relativistic physics doesn't allow photons to be an observer. Its because a photon can see itself stationary which breaks the framework of relativistic physics. Relativistic physics doesn't allow photons to be at rest in any reference frame.

share|improve this answer
    
How it is possible for a photon to be in motion w.r.t to itself? –  Inquisitive Dec 29 '12 at 9:57
1  
There is no such thing as "with respect to a photon." –  David Z Dec 29 '12 at 9:59
1  
@Inquisitive Its not possible. That's why Relativistic Physics doesn't allow photons to be an observer. –  Sachin Shekhar Dec 29 '12 at 10:00
add comment

Your Answer

 
discard

By posting your answer, you agree to the privacy policy and terms of service.

Not the answer you're looking for? Browse other questions tagged or ask your own question.