Relativity Simply Explained

RelativitySimply

Explained

By Jeremy Phan

Absolute or relative?

• Size• Distance• Time• Motion?• “There is no way of judging the size of an

object except by comparing it to the size of something else” (3)

• “It is not possible to measure the uniform motion in any absolute way” (31)

So…• If two spaceships fly past each other, how do

you know which one is moving or if they are both moving?

• You don’t!• A point of reference

must be set

Length?

• Length becomes relative, too

• As two ships that travel side by side approach the speed of light, they seem to be shorter to the outside observer.

• “The observers on each ship detect no change in the length of their own ship, or the lengths of objects inside it” (41)

Time also changes

• The other ship’s clock will appear to be slower• The faster you go, the more time slows down• You can’t tell• If you were to travel as

fast as the speed of light, time would stop

• The Twin Paradox!• You can travel forward in

time, but not back• “Judged by earth-time,

the trip will take more than two thousand years. Judged by the astronaut on the ship, the trip may take only a few decades” (111)

Relativity in the Scientific World

• Science and technology • We did used to think the world was flat…• What are we going to be able to

do in 100 years?• “The fashionable cosmic models

of a hundred years from now may be wildly unlike any model now taken seriously” (163)

The End