Sunrise on the Moon

Just past first quarter
Just past first quarter

Tomorrow evening the featured object at Cline Observatory will be the Moon; specifically the crater Copernicus found about 10 degrees north of the lunar equator, a little left (or west) of the central meridian.  Named after the famous Polish astronomer, the crater Copernicus can be easily found looking at the moon with binoculars or a small telescope.

Friday night we will be using the 24-inch light-bucket on the Jamestown campus of GTCC.  The Observatory is open to the public, free of charge, every clear Friday night.  We’ll try to take a peak at Saturn before it sinks below the western horizon.  Plans also include some clusters of stars and maybe a galaxy.

The surface of the moon is a testament to the hard-hitting early years of our solar system.   There had been some question about the origin of the lunar craters, but now we know vulcanism is not a major player.  Impacts from comets and asteroids have left their stories on our cold-hearted orb that rules the night.  (See the Moody Blues for that one.)

A recent study indicates that our inner solar system becomes quite crowded about every 26 million years with mass extinctions on Earth being quite regular.  The Earth, in it’s 226 million year jouney around our home galaxy, is also bobbing up and down, passing thru the more crowded plane of the Milky Way disk.  As our Sun does so, the far-flung members of the Oort cloud become perturbed, and enough fall in to the inner solar system to give the rocky planets several good hits.  These giant iceballs may be the reason T Rex doesn’t live here any more.

Maybe one such object hit the Moon and made Copernicus.  Or maybe it was a Near Earth object, or maybe something else entirely.  But it hit and made a very nice, complex crater more than 90 km wide and almost 3,800 meters deep.

Brightness of noon on Pluto
Brightness of noon on Pluto

If you were an astronaut standing in that crater, you would be witnessing sunrise on the Moon.  We will be observing the terminator and Copernicus tomorrow at the Observatory.  We’ll begin at 7 p.m. and scan the sky for about two hours. Come join us!   Dress for cold weather; we will be outside.  Put some red cellophane over the lenses of your white-light flashlights and come join us.

The sun will take about 13 or 14 days to cross the sky and set from the point of view of Copernicus.

Let’s say you were on the moon and saw Earth just above your eastern horizon.  How long would you have to wait for Earth to be just above the western horizon?


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