Re: Solar sailing

From: Spike Jones (
Date: Wed Feb 28 2001 - 20:24:17 MST

> Spike wrote: He dismissed solar sailing by claiming that even if nanotech wrote:

> Even if this were true, solar sailing would still work, right? You would
> use the sail at an angle to speed up or slow down your orbital speed,
> thereby enlarging or shrinking the orbital radius. In this way you
> could maneuver to any orbit in the solar system, eventually (watch out
> for those planets though). Hal

Yup, sure does work that way. Nowthen, you could not actually
ever *escape* the sun's gravity well if Minsky's notion were correct,
but you could spiral out ever farther. Another way to state it is if
you have a sheet of aluminum more than about 600 atoms thick, you
cant use that as a sail to escape the sun's gravity. But consider there
are other atoms lighter than aluminum, such as lithium, which are
reflective, and there is the possibility of a lithium sheet with a very
thin, highly reflective layer of silver with a thin coating of magnesium
flouride over top for protection from stray hydrogen atoms, etc.

The thing that really steamed me about the whole thing was that
Dr. Minsky must have done a quick back of the envelope calc,
then accidentally used the earth's gravitational attraction instead of
the sun's, thus missing the answer by more than a factor of 3000,
but hey, whats 3 orders of magnitude among friends, eh? I would
let that slide. But to say in front of a big audience that this shows
the whole notion of solar sailing could never work, well that simply
dismisses a field that has been studied for years by a bunch of
waaaay smart people. Did he suppose that none of them had ever
stumbled upon his 3 lines of algebra that convinced him this was
all a flop? Fer cryin out loud, how arrogant!

Nowthen, the version I had heard about the Eliezer-Marvin exchange
at the nanoschmooze was fairly benign. It sounded to me like
typical conference-ism, for speakers to intimidate their audiences
by shooting down some prominent questioner. May the participants
shake hands and sit down together for a tall cold one. spike

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