- #1
- 1,105
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Greetings !
Please read this short story about solar sails' physics:
http://www.spacedaily.com/news/rocketscience-03zg.html
Can the experts here provide their opinions, please !
I personally thought that was all simple and basic stuff
long since solved by physics. I mean, a photon has
energy and hence momentum which it transfers to the
sail and then it is reflected - reemmited thus again the
momentum exchange occurs only that this time the photon
and the sail push against each other (actualy kin'na smells
fishy in terms of energy if I put it this way).
But the light pressure experiment with the reflective and
absorbing surfaces clearly draws a different picture. I've
heard of it before but no details were given about the
surface (or, in fact, I think it was said that a reflecting
surface would move, which is clearly a book's or my memory's
mistake ?).
So, what actualy happens here ?!
The only possible conclusion here as I see it is that
the reflected - reemmited light "drags" the reflective
material back, but how can that be ?!
Is that really so complex that nobody thought about it before ?!
Does this actually doom the whole idea of solar sails - they'll
just evaporate if they're absorbing or produce no thrust
if they are reflecting ?!
HAS ANYBODY EVER DONE AN EXPERIMENT, EXCEPT THE ABOVE MENTIONED,
BEFORE AN ENTIRE SOLAR SAIL SPACE MISSION WAS READY FOR LAUNCH ?!
Thanks !
Live long and prosper.
Please read this short story about solar sails' physics:
http://www.spacedaily.com/news/rocketscience-03zg.html
Can the experts here provide their opinions, please !
I personally thought that was all simple and basic stuff
long since solved by physics. I mean, a photon has
energy and hence momentum which it transfers to the
sail and then it is reflected - reemmited thus again the
momentum exchange occurs only that this time the photon
and the sail push against each other (actualy kin'na smells
fishy in terms of energy if I put it this way).
But the light pressure experiment with the reflective and
absorbing surfaces clearly draws a different picture. I've
heard of it before but no details were given about the
surface (or, in fact, I think it was said that a reflecting
surface would move, which is clearly a book's or my memory's
mistake ?).
So, what actualy happens here ?!
The only possible conclusion here as I see it is that
the reflected - reemmited light "drags" the reflective
material back, but how can that be ?!
Is that really so complex that nobody thought about it before ?!
Does this actually doom the whole idea of solar sails - they'll
just evaporate if they're absorbing or produce no thrust
if they are reflecting ?!
HAS ANYBODY EVER DONE AN EXPERIMENT, EXCEPT THE ABOVE MENTIONED,
BEFORE AN ENTIRE SOLAR SAIL SPACE MISSION WAS READY FOR LAUNCH ?!
Thanks !
Live long and prosper.
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