Other Special Speeds? (than light)

JDługosz

Quote by Phrak

Under the more general question "Are there any special speeds other than 0 and c?", I can't think of any.

Zero is not special. Only c is special, being invariant for all observers. Zero, like 10mph, is relative to your reference frame.

--John

*Phrak*

Quote by JDługosz

Zero is not special. Only c is special, being invariant for all observers. Zero, like 10mph, is relative to your reference frame.

--John

There are quantites associated bodies such as mass, energy, length, and time interval that are minimal or maximal when the relative velocity is zero.

gutti

Saying there are no speeds greater than c may not be accurate.

Tachyons are a hypothetical subatomic particle that travels faster than the speed of light.

JDługosz

Quote by gutti

Saying there are no speeds greater than c may not be accurate.

Tachyons are a hypothetical subatomic particle that travels faster than the speed of light.

It's not that simple. See Tachyons in the Usenet Physics FAQ.

In other words, we can no longer "localize" our tachyon in any bounded region in the first place, so it becomes impossible to decide whether or not there is "unit propagation velocity" in the precise sense of part 1)

That is, you can't really say that they are "traveling" in a meaningful classical way, at all! You can solve SR formulas with superluminal velocities and not have the math break if you allow mass to be imaginary, but when you follow it through you get other weird effects that are hard to reconcile with our every-day concepts of space and time.

--John

JDługosz

Quote by Phrak

There are quantites associated bodies such as mass, energy, length, and time interval that are minimal or maximal when the relative velocity is zero.

I see. "special" in some sense, but not invariant.

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gutti	Saying there are no speeds greater than c may not be accurate. Tachyons are a hypothetical subatomic particle that travels faster than the speed of light.