Expert: Steve Nelson - 4/16/2009

Question
QUESTION: Hello, I have a few questions on special relativity. Are you able to answer questions regarding this topic?

ANSWER: As long as they're not homework.

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QUESTION: It has nothing to do with homework. I am taking an astronomy class and my teacher is also a physics teacher at the same school. I always talk to her about physics just for fun, but she always leaves me with more questions.

ANSWER: So, a non-question and a follow-up...still waiting for the question itself...?

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QUESTION: correct me if i am wrong, but i understand that  someone who is moving at the speed of light would live normally with everyone else within his own time frame. For someone watching him outside of his time frame, he would appear to be standing perfectly still. And when the person who is moving at the speed of light begins to slow down to normal speeds, he would appear to be moving very slow to someone outside of his time frame. Now if i understood all of this correctly, here is my question: If, while moving at the speed of light, he went to another part of the world, lets say London, where would he appear (to someone outside his time frame) when he returns to normal speeds?  would he slowly make his way to London from that person's perspective, or would he slowly go through all the things that he did while moving at the speed of light?
thank you, joey

Answer
This question could use some rephrasing.  Outside his "time frame?"  What does that mean?  It's not really how we phrase things when talking about relativity.  The statement of this question is all wrong and you should read up on some relativity before you rephrase it.  As someone accelerates to the speed of light, time appears to pass slower for them as measured by their relative clocks, they don't have a "time frame" that someone else is inside or outside.  The basic idea for relativity is that all observers must observe the same laws of physics in all reference frames.  For further reading in a manageable time, try hyperphysics:  http://hyperphysics.phy-astr.gsu.edu/hbase/hframe.html