FacebookTwitter
Hatrack River Forum   
my profile login | search | faq | forum home

  next oldest topic   next newest topic
» Hatrack River Forum » Active Forums » Books, Films, Food and Culture » Physics Questions

   
Author Topic: Physics Questions
handle
New Member
Member # 8509

 - posted      Profile for handle   Email handle         Edit/Delete Post 
1. If photons have no mass does that mean that they can't bend space? That their trajectory is affected by other objects' mass but that they don't affect other objects' trajectories in return?

2. Does the coherence length of a laser beam give a measure of the spatial extent of the individual photons of that beam?

3. Acceleration is supposed to be equivalent to being in a gravity field. Accelerated charges give off electromagnetic radiation. Does that mean that charges in two heavy objects in space will give off radiation just because they are in each others gravity fields? Will the two heavy objects give off gravity waves even if they are just sitting there pressed together by gravity?

Posts: 3 | Registered: Aug 2005  |  IP: Logged | Report this post to a Moderator
fugu13
Member
Member # 2859

 - posted      Profile for fugu13   Email fugu13         Edit/Delete Post 
1. Photons have no rest mass. However, they are always moving, so they have mass.

2. Well, I'd guess the answer is yes and no. A photon doesn't exactly have a spatial extent, it has a probability cloud. Coherence likely is relatively correlated with probability cloud extent, but I could easily be wrong.

3. Good Question

Posts: 15770 | Registered: Dec 2001  |  IP: Logged | Report this post to a Moderator
handle
New Member
Member # 8509

 - posted      Profile for handle   Email handle         Edit/Delete Post 
fugu is a bright man.

1. So if an extended laser beam in free space were intense enough it would self-focus due to its own gravity?

2. Yeah, say field quantum unit or something instead of photon because photon sounds two partically.

3. Good link. Didn't achieve clarity but now I know I am not alone on the question.

Posts: 3 | Registered: Aug 2005  |  IP: Logged | Report this post to a Moderator
   

   Close Topic   Feature Topic   Move Topic   Delete Topic next oldest topic   next newest topic
 - Printer-friendly view of this topic
Hop To:


Contact Us | Hatrack River Home Page

Copyright © 2008 Hatrack River Enterprises Inc. All rights reserved.
Reproduction in whole or in part without permission is prohibited.


Powered by Infopop Corporation
UBB.classic™ 6.7.2