Eye in the Sky

February 17, 2003 7:20 PM

The Moon's Mare Orientale is one of the largest impact basins in the solar system. It is nearly circular, 700 miles across and concentrically ringed like a bullseye. In short, it looks like a giant eye, one third of the diameter of the moon itself and yet, because it is on the moons far side, it's never visible from the Earths surface. [more]
posted by thatwhichfalls (9 comments total)

"The mythology of the moon is peaceful and soothing. The Man in the Moon sprinkles moondust on nighttime dreamers: the moon is the calm protector of the natural and the feminine. Sure, the sun is an angry sky-god who burns with a fierce flame, but the moon brings healing and safety. Well, the friend who told this tidbit to me asked, how would human history have been different if every night the sun went down and the eyeball came up? How much worse would our fear of things that go bump in the night be if everything we did at night was seen by the great implacable eye in the sky? What paranoia would stalk our dreams, what fearsome offerings would we have given up to the unforgiving all-seeing eye, what ingrained terrors far above and beyond anything Jung ever imagined would be seared into the consciousness of humanity? "
from The Laboratorium
posted by thatwhichfalls at 7:22 PM on February 17, 2003

Hope nothing like the meteor that caused that crater hits us...
posted by eustacescrubb at 7:32 PM on February 17, 2003

Nice to think about, but moon mythology often isn't peaceful or soothing (think "lunacy", and for calm protector of the feminine, think "hysterical"). Also, the far side of the moon doesn't look like an eyeball at all. (Mare Orientale is on the Eastern limb, in shadow in this picture and not visible as far as I can tell.)

By moon feature standards, Mare Orientale isn't overwhelming -- the Mare on the near side are bigger, but they're not impact basins.
posted by ptermit at 7:38 PM on February 17, 2003

The link says the diameter of outermost ring of mountain range is 900 km - that's 562.5 miles, not 700.

Yes, I will shut up now :)
posted by blindcarboncopy at 9:00 PM on February 17, 2003

Identified Impact Craters on Earth, sorted by diameter. The largest is Vredefort in South Africa, which is 300km (some 180 mi) in diameter. Note that the big ones are old; this one has been around for 2 billion years.

But the Moon holds yet another secret: the largest impact crater known, over 1300 km (800 mi) around -- hidden on the South Pole. Still, larger hits may have been taken by our own planet, but geological activity could hide and distort the evidence. It's the Moon's cold, dead state that permits the craters to remain undisturbed all this time later.
posted by dhartung at 9:14 PM on February 17, 2003

Errr, isn't the moon theorized to have been formed by something hitting earth, and the moon is the spit-up hunk from that collision?

(not that anyone has a video of this, and if they did, I'm sure a group would say that was faked...just like the moon landings!)
posted by rough ashlar at 9:32 PM on February 17, 2003

Has anyone ever looked at the right side of Hudson's Bay and thought the half circle coastline might have been created by an impact?
posted by titboy at 5:25 AM on February 18, 2003

Nevermind my question, Carl Sagan did in the book Planets:

"The largest structure on earth that is suspected of being part of an astrobleme is near the Nastapoka Island chain on the eastern shore of Hudson Bay in Canada. These islands form a beautifully circular arc with its centre of curvature out in the bay itself. If they are segments of an ancient rim, the crater must have been 275 miles in diameter, larger than all but a very few craters on the moon. Not far away to the cast, the curving shores of the Gulf St Lawrence outline a somewhat smaller circle."

(I would've linked to the website, but the link button doesn't seem to be working at the moment...)
posted by titboy at 5:35 AM on February 18, 2003

Titboy: also see the FAQ on the impact crater database dhartung had linked to, for arguments that the Hudson Bay circular coastline is not an impact crater.
posted by DevilsAdvocate at 10:48 AM on February 18, 2003