Skip to main content
Search type Search syntax
Tags [tag]
Exact "words here"
Author user:1234
user:me (yours)
Score score:3 (3+)
score:0 (none)
Answers answers:3 (3+)
answers:0 (none)
isaccepted:yes
hasaccepted:no
inquestion:1234
Views views:250
Code code:"if (foo != bar)"
Sections title:apples
body:"apples oranges"
URL url:"*.example.com"
Saves in:saves
Status closed:yes
duplicate:no
migrated:no
wiki:no
Types is:question
is:answer
Exclude -[tag]
-apples
For more details on advanced search visit our help page
Results tagged with
Search options answers only not deleted user 2359
3 votes

Controllable faster-than-light phase velocity

The phase velocity of light in a fully ionized plasma is strictly superluminal; see equation 1156 of Fitzpatrick. Like all media in which the speed of light is not $c$, plasmas are dispersive, but the …
Andrew's user avatar
  • 3,471
51 votes
Accepted

In superluminal phase velocities, what is it that is traveling faster than light?

Shine a flashlight on a wall. Rotate the flashlight so the illuminated spot moves. Q: How fast does the spot move? A: It depends how far away the wall is. Q: How fast can the spot possibly move? A: …
Andrew's user avatar
  • 3,471