THE SOUTHWORTH PLANETARIUM
207-780-4249       www.usm.maine.edu/planet
70 Falmouth Street  Portland, Maine 04103
43.6667° N,                    70.2667° W
Founded January 1970
             "What happens in the Milky Way stays in the Milky Way"



THE DAILY ASTRONOMER
Thursday, January 28, 2016
Lake of Dreams and Sea of Clouds


Imagine if they had been right!  By "they," we're referring to the
previous astronomers who believed that Venus was a paradise beneath
clouds; that Mars was a majestic kingdom replete with chimerical
creatures; and that the lunar terrain was dotted by towering peaks and
deep oceans.       Imagine how the space program might have been vastly
different if we were in close proximity to three dynamic, life-bearing
worlds as opposed to the inhospitable spheres that surround us. (The
hell furnace Venus; the frigid desert world Mars; and the bleak
desolation of the Moon.)   Perhaps by this time, our more affluent
citizens might have been vacationing on some of these exotic worlds.
Instead, we've deployed space probes to these planets, and, of course,
also sent twelve of our more intrepid citizens to the Moon.   As tourist
venues, they have little to recommend them.

Nevertheless, astronomy types think these outer orbs are all poised on
pinnacles, simply by the virtue of their locations beyond Earth's air.
We love them for their personalities.   One world that remains paramount
in our estimation, the Moon, has little to no water.  Whatever water it
might still retain is locked in frozen storage within a dark southern
pole crater.      However, when one peruses a Moon map, one cannot help
but see curious place names such as Lacus Somniorum, the "Lake of
Dreams," or Mare Nubium, "The Sea of Clouds."     If Luna is sans H20,
how can it contain lakes and seas?

It doesn't, but remember that people once thought it did.   And, so
convinced were they that the Moon was water-logged, the early
selenograpehrs, those who mapped the Moon, included seas and lakes in
their charts.     The 17th century astronomer Langrenus (1598-1675)
produced the first lunar map which included the "lakes and oceans."
Subsequent maps reproduced their locations and most of their names, ones
we still have today.     The first lunar visitors, Neil Armstrong and
Buzz Aldrin, landed in the "Sea of Tranquility."

It was only within the last century that we realized that those "seas"
and "lakes" are regions where basaltic lava flows solidifed: leaving
wide splotches of dark terrain that resemble oceans when viewed at a
distance.   Even when we determined the true nature of these regions,
didn't change their names, as they had been in use for years and
astronomers truly are a sentimental lot.

So, the Moon has neither dreamy lakes nor cloudy seas, but instead is a
vast, barren sphere devoid of air, water and life.     Nevertheless, in
our own fanciful reckoning, we still map the Moon as though it were a
watery world similar to our own.   We don’t allow our contrary
knowledge to interfere with our fantasy