Re: The Flat Earth? - Conclusion

Hendrik Makaliwe (
Sat, 08 Jul 1995 02:07:51 -0400

I am just wondering,

Suppose I am twirling on skates, does it really make no difference if it
is the universe that is twirling around me?
Maybe it won't make any difference for many calculations. Also, the laws
will still be the same.
But what about energy consumption? After twirling for a while, I'll feel tired.
If I feel tired, doesn't it mean that I MUST have moved?
How can I be tired if it is the universe that moved around me?

All of the above may not seem very scientific, "tired" being difficult to
measure. But we can make the same argument precise by replacing me with
some machine and measuring the energy consumption of that machine, etc.

What does Einstein's principle of equivalence say on this problem?