Waves and the speed of light

[Piz0wn0reD!!!!!!]

Lets say that there is a power line that is 8977198274891742 lightyears long. There are 89418924891849814 (or more) crows sitting next to eachother on the line. If the crow on the end takes off, and the next crow takes off almost exactly at the same time (just a nanonanonanosupersmall amount later), and the next crow etc... could the wave of takeoff exceed the speed of light?

i hope that makes sense...

[benkahuna]

yes

[kbfc]

This sort of 'wave' is just an illusion. There is nothing 'travelling' from one crow to the next that drives the wave. Radio waves propagate, for example, due the relationship between changing electric and magnetic fields described by Maxwell's equations. Water waves propagate due to pressure and gravity force imbalances.

Your example would work if you had each crow tap it's neighbor on the wing to tell it when it should fly. Of course, then, the wave wouldn't be as fast......

[jason1990]

You could take this to an extreme and declare that they all take off simultaneously. But then you must deal with the fact that simultaneity is relative.

[Siegmund]

Yes, but only if you send instructions for the takeoff sequence ahead of time, not if you just tell them to take off as soon as their neighbor moves. (For instance, tell the first crow to take off 10 seconds [by his own watch] after a pulse travels through the wire beneath him, the crow 300,000 km to his left to take off 9 seconds after the pulse travels through, etc, and the crow 3 million km away to take off as soon as the pulse arrives.)

Also, remember that you, as an observer, won't be able to "see" anything happen faster than the speed of light; the way you will know the takeoff wave propagated faster than the speed of light is by discovering after the fact that several observers disagree on the order in which the birds took off. (If they take off simultaneously, each observer will believe the birds closest to himself took off first.)