Alright, so what did this post originally branch from? The twin paradox? First of all, the traveling twin is no longer in an inertial frame the moment he begins to decelerate to turn back around to visit his twin back on earth. So that's where the real confusion begins. (If that wasn't the issue, I'm sorry I got involved.) But here's an explanation that might help when thinking about relativity.
Okay, let's imagine (gedanken - thought experiment time!) somebody in a rocketship going past someone standing on a stationary planet. (And they both have light clocks with them, of course, to help illustrate the point.) Erin's right with the way the clock is set up. A light clock is just a light beamed from the bottom of a vertically oriented mirror-sandwich to the top and it reflects and so on. The guy/girl observing on the planet sees his/her own clock beam straight up and down (the shortest path, taken in the shortest amount of time) and they see the light clock from the rocketship move along the hypotenuse of a triangle. They infer that time in the moving rocketship frame is slower than their own time. Conversely, rocketman (hee hee, great flick!) sees his clock beam straight up and down, and sees the longer hypotenuse-path of his planet-bound friend, inferring that planet-person's clock is running slower than his own. So it's all relative to what frame you happen to be residing. What this means to you, gentle reader: Any clock moving at or near relativistic speeds to you is going to look like it's incrementing "slower." (This has been verified by fly boys in the airforce.) And any clock that is observed from this rapid frame is also going to look like it's moving slower. No clock is ever going to look like it's speeding up, unless I missed some subtle point to your argument wherein you claimed clocks were "speeding up." But lengths (usually) contract, and time (usually) dilates, unless you're a tachyon. Too bad we're all tardyons here... Actually, now that I'm thinking about the math, gamma (the thing that governs dilation and contraction in the Lorentz equations) is either greater than or equal to one, meaning time either looks the same or is slowed down by a factor of gamma, time never speeds up... (...and time would be "laid out like a scroll" on the event horizon of a black hole... as the math dictates. Black holes are the coolest. They seduced me into astronomy...) Are we more confused now? -Danelle ;D --------- Original Message --------- DATE: Fri, 16 Apr 2004 23:05:34 From: Erin Sharmahd <[EMAIL PROTECTED]> To: BYU Unix Users Group <[EMAIL PROTECTED]> Cc: >correct me if i'm wrong please! >kip thorne actually did both halves of this in his book "Black Holes and Time >Warps"... if i remember correctly (it's been 7 or 8 years since i read the >book), the clock still seems to be at a standstill becasue the fact that you're >moving away from the clock is not what causes it to be so much slower... it's >the fact that the clock on earth is stationary... although relativity comes >into this someplace... (from your perspective, the clock on earth is moving >near the speed of light)... >i remember my physics teacher sophomore year in high school explaining why >rapid motion (near the speed of light) causes time to distort... it involves >using two mirrors and a single wave/particle of light as the clock... as it >moves near the speed of light, it has to go longer distances (diagonal instead >of straight up and down), so there is more time between the particle hitting >the top and hitting the bottom), so the clock slows down... >anyway, that's a very random rant... >:) >~Erin > > >--- Carl Youngblood <[EMAIL PROTECTED]> wrote: >> > PS. I think the clock would turn twice as fast on the way back... >> >> My intuition tells me that it would be turning way faster than twice as >> fast. Think of it: as you approach the speed of light the clock >> appears to move progressively slower until it stands still when you >> reach the speed of light going away from the earth. Of course, this >> completely ignores the question of perspective and the fact that the >> clock would appear infinitesimally small at this point--but I digress. >> Standing completely still, the clock appears to be moving normally. As >> you accelerate and begin to approach the speed of light it speeds up. >> Long before you even get near the speed of light it appears to be >> moving many times faster than twice its normal speed, because you are >> "plowing through" the photons which bring you updates of its movement >> at such a rate that it appears to be moving very fast. By the time you >> approached the speed of light it would be a blur of movement and you >> would see thousands or millions of years flash by you within seconds. >> >> Of course this whole discussion also ignores the fact that Einstein's >> theory of relativity determines that anything which approaches the >> speed of light becomes infinitely massive, which probably means that >> you basically would fill up or consume the whole universe (including >> the clock you were looking at), which is probably why only light goes >> the speed of light because any massive substance would do this. >> >> I don't know a lot about the minutia of physics; this is just stuff I >> learned from reading about it. >> >> Carl >> >> >> ____________________ >> BYU Unix Users Group >> http://uug.byu.edu/ >> ___________________________________________________________________ >> List Info: http://uug.byu.edu/cgi-bin/mailman/listinfo/uug-list > > >===== >------------------------------------------------------------------------------------ >http://www.userfriendly.org >------------------------------------------------------------------------------------ > > > > >__________________________________ >Do you Yahoo!? >Yahoo! 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