Re: Fate of SF as World Slides Down Back Side of Hubbert's Curve?

On Mar 25, 11:03 am, jdnic...@xxxxxxxxx (James Nicoll) wrote:

        Somewhere or other (probably on the dead PC) I have a pdf
of a paper that studies the possibility of harvesting antimatter from
natural sources in the solar system. The quantities involved are
disappointingly small, 25 nanograms per day per collector. That's
interesting from an interplanetary propulsion perspective but not
so much if you want an interstellar rocket.  

I don't understand why anyone is excited about this amount for
any purpose. E=mc^2, right? Okay, let's double that since
we're talking anti-matter here (and ignore loss to neutrinos and
other annoyances). We get

E=2 * 25E-12kg * 3E8m/s * 3E8m/s /day
=450E4 joules/day ~= 52 watts

That's about as much power as you'd get from 52 grams of
solar panel, at 1kg/kW. Even assuming perfect 100%
efficient harvesting of anti-matter, solar electric seems to
totally beat the pants off of it. And solar electric is already
flying real life interplanetary missions.

Sure, a small amount of anti-matter can translate to a lot
of energy, but a REALLY small amount of anti-matter still
translates to a small amount of energy.

Isaac Kuo
.

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