What is the most exact prediction of the relativity theory?

Answer 1

Well, to pick out a few of them . . . Relativity predicts that if you see an object that

you're familiar with moving through your room and you do some measurements on

it before it's gone, you'll find that its length has shrunk, its mass has increased,

and the clock inside it is running slow. Relativity tells you exactly how much these

properties of the object will change, depending on how fast it's moving past you.

These numbers have been tested from 99 bazillion different angles in thousands

of experiments during the past 100 years, and have been proven to be right on,

at least to the precision of which the measurements are capable.

Here's an example that I think is so cool: Have you ever used a GPS receiver ?

GPS uses very accurate atomic clocks aboard each GPS satellite. Those clocks

have to be changed in order for GPS to work, because Relativity tells us how much

the clocks will run slow on account of the satellite's speed in its orbit. If the clocks

are not adjusted to account for Relativity, GPS doesn't work.