Naked Science Forum
Non Life Sciences => Physics, Astronomy & Cosmology => Topic started by: jrussell on 28/04/2010 16:26:55
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either i remember very wrongly, or there is a false assumption being made in many posts. i do it for simplicity in my posts, however, i am aware that it is wrong and would like clarification if someone would be so kind.
the cosmic speed limit, c, the speed of light - nothing can travel faster. however, i recall einstein theorising that, in fact, it can be broken but only by an object that can travel no slower than c. in other words, c is the lower speed limit for these objects.
am i remembering correctly??
Mod edit - I've formatted the subject as a question, feel free to change it to something more accurate. Please make sure all your subjects are in the form of a question - it makes the forum tidier and easier to navigate. Thanks.
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There's some stuff here
http://en.wikipedia.org/wiki/Tachyon
that I don't understand, but I think might answer the question.
This bit
"no experimental evidence for or against the existence of tachyon particles has been found" seems to be important.
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Objects with mass can't move faster than c. Objects with zero mass always move at c. These come out of the equations of special relativity and can be checked experimentally since such objects are regularly seen in the universe.
If you go to Einstein's equations and say "what happens if I have a complex-valued mass"? (Complex means it has the square root of -1) in it, then you get something that is always moving faster than c. This may or may not have physical meaning, but it's in the equations and the equations have been highly successful. Sometimes what seems to be a mathematical trick at first later turns out to be something important physically. But then again, other times it turns out to be just a mathematical trick with no physical relevance. (The wiki page does seem to indicate that in certain cases, the mathematics ends up being useful, even if these aren't particles.)