string endpoints move at light speed--?


by gabeeisenstei
Tags: string theory
gabeeisenstei
gabeeisenstei is offline
#1
Dec3-12, 06:17 PM
P: 31
In Zweibach's introduction to string theory I encounter the assertion that the endpoints of an open string move at the speed of light. A few other sources on the web agree with this. But nobody bothers to tell me what the heck it means (not even in http://www.physicsforums.com/archive...p/t-49119.html , where it is stated that only the endpoints move at light speed, not the rest of it).

Where are the endpoints going so fast? Are they just vibrating in a tiny space? Are the endpoints massless, so as not to violate relativity?
What am I missing?
Phys.Org News Partner Physics news on Phys.org
Physicists consider implications of recent revelations about the universe's first light
Vacuum ultraviolet lamp of the future created in Japan
Grasp of SQUIDs dynamics facilitates eavesdropping
haushofer
haushofer is offline
#2
Dec5-12, 04:33 AM
Sci Advisor
P: 869
Quote Quote by gabeeisenstei View Post
In Zweibach's introduction to string theory I encounter the assertion that the endpoints of an open string move at the speed of light. A few other sources on the web agree with this. But nobody bothers to tell me what the heck it means (not even in http://www.physicsforums.com/archive...p/t-49119.html , where it is stated that only the endpoints move at light speed, not the rest of it).

Where are the endpoints going so fast? Are they just vibrating in a tiny space? Are the endpoints massless, so as not to violate relativity?
What am I missing?
It's a nice question. Remember that "mass" is a property of the string vibrations, not of the string itself (perhaps something like that is defined in string field theory, but I'm not acquinted with that)! So I'm not sure what "massless endpoints" would mean.

But can't you ask the same question for, e.g. gravitons? It's a consequence of the dynamics, so I'm not even sure what the "why"-question means.


Register to reply

Related Discussions
Why do we move at the speed of light? Special & General Relativity 41
Why doesn't light move at an infinite speed? Special & General Relativity 52
Can we see light if we move our eyes at speed of light? Special & General Relativity 37
why can't an object move at the speed of light Special & General Relativity 3
How can you move at the speed of light? General Physics 6