Can special relativity be violated by an electron in a television tube?

abbeynewton
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Now i heard it is possible for an electron in the tube of a television tube to travel across the tube at a speed faster than the speed of light. How can special relativity explain this?
 
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What is a "television tube"?
 
Bill_K said:
What is a "television tube"?
:smile:
 
abbeyNewton said:
Now i heard it is possible for an electron in the tube of a television tube to travel across the tube at a speed faster than the speed of light. How can special relativity explain this?
What you heard was wrong. An electron can't travel faster than the speed of light.
What you probably heard was that the image of a glowing dot on the picture tube can travel faster than the speed of light. An electron beam that intersects the phosphor screen is changing direction. Different electrons are hitting the phosphor screen at different times, creating a glowing dot that moves across the screen faster than light.
The glowing dot is an image which doesn't carry information. The glowing dot is not a real object. The FTL motion is an illusion created by many electrons that are synchronized to hit the screen at different times.
The glowing dot does not carry information faster than the speed of light in a vacuum. Therefore, the apparent motion of the glowing dot can move faster than light without violating special relativity. Faster than light motion only violates special relativity if information is traveling faster than light.
There are several ways of making an image that moves faster than light. However, the image does not carry information faster than light. Therefore, the image can be considered analogous to an "optical illusion".
 

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