Recall the solar sails for populating alpha Centauri with telemarketers? (Now as to how much of the expected energy was to come from particulate 'solar wind' leftovers and how much from photovoltaics..) but still E=h\ufffd(nu) - no?

Vaguely recall someone calculating the force from sunlight on our little ball.. kinda numbers I wouldn't even put in cache.


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A book I have somewhere, but never got around to wading through. When one looks *very* closely, most of our concepts of 'energy', its 'conservation' etc. get pretty sticky, much as the Compton effect, matter / antimatter annihilation all seem to reduce the entire pile of stuff to,

Energy=Mass=Energy= which would you like today, sir?

So all I can say about 'force' is, some measure it in dynes. And to do the solar wind thing? don't see how gravitation (well, except for the local stuff around Sol) is more than a slingshot for KE and.. F=MA. (if gadget is accelerating (compared to Sol) - energy Was added!)

But as Feynmann's dad 'explained' to the kid about inertia, after the wonderful ball-in-a-wagon experiment - nobody knows 'why' !!

Me neither,

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