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Wednesday, July 27, 2011

Walkabout

(Another old t-shirt design.  Credit goes to my dear friend Jen Trinh for the wonderful Einstein drawing.)

Tomorrow I'm heading off for a trip around the East to visit friends and family before I disappear into Michigan for grad school.  I probably won't be posting anything here for about a week, but the long train ride ahead of me got me thinking about the possibility of high-speed travel to other solar-systems.  I wondered about the relativistic effects of my own travel – my train ride shouldn't actually feel like 6 hours, since I'll be moving.

In special relativity, traveling at a velocity v causes time to slow by a factor of
The faster Amtrak trains average about 63 mph, giving γ = 1 + 4.4 x 10^(-15).  That means that while my trip may last 6 hours, it will feel 95 picoseconds shorter than that.  What a timesaver!

3 comments:

  1. This equation seems extremely useful for my own daily life. Can you give a slower explanation?

    I calculate you gamma value as being 1.0000000000000044. How do you get 95 picoseconds from that?

    I need to know how many days I'll need to walk at 2km/hour for two hours before you and I are the same age.

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  2. I was hoping someone would ask. I'll do a more in-depth post on special relativity once I'm back.

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  3. Awesome shirt. But speed-of-light travel doesn't violate causality!

    Now, this train business: I'm uncomfortable with the statement that "special relativity causes time to slow by a factor of gamma." Your clocks (biological and otherwise) always tick at the normal rate in your frame; a gamma factor only enters the picture when you're relating one frame to another.

    Your conclusion that you've aged less than six hours over the trip is true, of course. I'm being that annoying theorist, but god man, be careful with your words, there are laymen about!

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