alt.energy.renewable

"Rob Dekker" wrote in message
news:46f8c763$0$32488$baae4c71@ ...
>
> "mykey" wrote in message
> ...
>> In fact if there were no such thing we would not exist.
>> How long has the earth been orbiting around the sun?
>> billion years? how much energy do you think it required
>> to cause the earth to remain in orbit around the sun for
>> this period of time?
>
> Mmm. Let's see. Energy is Force times displacement.
> Assuming Earth did not move much closer to the sun in billion years,
> displacement is zero.
> That make the energy used for that... yep ZERO.
>

Actually, the Earth orbiting the sun has been moving away from the sun
(similarly, the moon is moving away from the Earth). Albeit very, very
slowly. Tidal drag. But ISTR with the Earth being so much further away
from the sun than the moon is from the Earth, the slowing down is much much
slower.

And the counter-intuitive thing about this is that as the orbiting object
slows, it moves *further* away.. Celestial mechanics, what a hoot...

daestrom