From: "Keith F. Lynch" <kfl at KeithLynch.net>
To: WSFA members <WSFAlist at KeithLynch.net>
Subject: [WSFA] Conjunction
Date: Mon, 21 Dec 2020 20:08:22 -0500 (EST)

I saw the conjunction of Jupiter and Saturn from my bedroom window this
evening at about 6:20 pm EST, despite intermittent clouds and haze.
They were too close to resolve with my poor eyesight; they looked like
one point of light to me.

It's the closest those planets have been to each other in Earth's sky
since 1623.  (Of course they're no closer to each other than usual
in space.)

I could resolve them with binoculars.  I then turned my binoculars to
the moon to get a standard of comparison.  The separation is about
equal to the width of Mare Crisium.

Look to the southwest as soon as the sky is reasonably dark in the
evening.  Unfortunately, Jupiter and Saturn set less than two hours
after the sun does.  Those of you on the west coast can still see it.
The rest of you will have to wait until tomorrow, when the planets
won't be quite as close as they were today.

There are several conjunction livestreams available online, and will
soon be lots of still photos too.  The planets are at least a dozen
planet-diameters apart.

The fact that such close conjunctions are so rare despite all the
planets being in nearly the same plane is good evidence that, as large
as those two planets are, the distances between planets are enormously
greater.  All the planets could be lined up between Earth and the
moon, with room to spare.

ObSF:  James White's _Deadly Litter_, whose premise was that littering
in interplanetary space presented a high risk of deadly high-speed
collisions, was absurd.  Yes, a stray coffee ground could destroy a
spacecraft, but the chances of ever encountering one, even if everyone
who ever lived spent their whole lives randomly piloting spaceships
through the solar system while tossing garbage overboard, are too
close to zero to worry about.  You're more likely to be killed by a
meteor in your home on Earth.