Posted by ovyyus (150.101.146.123) on October 23, 2003 at 14:45:16:
In Reply to: Re: Experimental proof of OU? posted by Scott Ellis on October 23, 2003 at 11:29:40:
Hi Scott,
Correct! I should have said momentum, not velocity. Conservation of momentum is maintained between spacecraft and planet. It is a perfectly balanced energy dance with gravity as the 'string'.
Regards, ovyyus
: Hi Jonathan and Ovyyus,
: I agree with Ovyyus that the so-called "gravitational sling-shot effect" is not an example of OU, but is actually explained by the usual conservation laws.
: Here are links to two posts I made on the subject long ago:
: http://www.besslerwheel.com/wwwboard/messages/22.html
: http://www.besslerwheel.com/wwwboard/messages/631.html
: But I would make a small change to Ovyyus's equation: It is not velocity which is conserved, but momentum (mass times velocity). Therefore we have:
: Spacecraft momentum gain = planet momentum loss
: Since the mass differential between the spacecraft and the planet is so large, the planet's change in velocity is nearly zero (but not quite!) while the spacecraft's change in velocity can be enormous.
: -Scott
:
: : Hi Jonathon,
: : Spacecraft velocity gain = planet velocity loss.
: : Regards, ovyyus
: :
: : : Hi all, this just occured to me today. Have any of you watched any discovery channel shows on space travel? Ever heard of gravity assit(-ence in launching space craft)? Well, it is well known that to save money on space craft one can give a space craft the appropriate velocity at the appropriate time so that it will fall toward the heavenly bodies (plural because it often uses more than one body during one trip) and end up farther from that body than it started. This means that with tiny energy input one can achieve huge increases in gravitational potential energy! And I have proof too! NASA does it all the time, the most striking being the Voyager and Pioneer space craft, both of which are barely in the solar system any more! Do you know how much rocket fuel that would have taken had they not used gravity assit?! And yet these same scientists call gravity a conservative force field! Addition: I just found these sites that back me up: An oversimplified view at:
: : : http://voyager.jpl.nasa.gov/mission/images/f23.gif
: : : Scoll down to 'History of the Voyager Mission', it's the first paragraph under that heading:
: : : http://voyager.jpl.nasa.gov/science/planetary.html