Khazar-khum Wrote:
-------------------------------------------------------
> > The standard for our quantity 'time' is (or
> better
> > was*) related to the rotation of the earth.
> > The mechanics of the Earth-Moon(-Sun) system
> are
> > very complicated and still not fully
> understood by
> > science.
>
> Let's see. I know some rocket scientists who might
> debate that. In fact, they have to--otherwise they
> couldn't send anything out past Earth's
> gravitational fields. Heck, we know the mechanics
> well enough to send things to Saturn.


I don't think they would debate it. There still is no analytical solution to the three-body problem in celestial mechanics.

I believe the way they are able to send things to moon and beyond is to make approximations and then iterate a time-step forward, make needed corrections and continue to next step. If time-steps are kept small enough, one can keep the errors in acceptable level.

Quote

Unfortunately, when we add a third body to our equations of motion, such as a spacecraft lost in space between the Earth and the sun, we can no longer find an analytical solution. The equations are unsolvable. This problem is known as the three body problem of celestial mechanics and remains the subject of research today.

Regards,
Tommi

"In this house, we obey the laws of thermodynamics!"
-Homer J. Simpson



Edited 3 time(s). Last edit at 05/16/2008 04:34AM by Tommi Huhtamaki.