Look at the Moon Tonight

Tonight, September 26 is International Observe the Moon Night.  Just go outside and contemplate it – it’s an amazing thing.  You will be seeing the same Moon as many around the world.  NASA is streaming it live and NASA’s website also has a wealth of lunar information.

The Moon doesn’t get the respect it deserves.  Everyone wants to look at beautiful Saturn, marvelous Jupiter, or some deep sky wisp of gossamer.  The Moon?  Not so much.  It isn’t a challenge, doesn’t change, it’s right up there, can even see some craters with your naked eyes.  It’s just boring, eh?  Think again.

The Moon is great to study.  With binoculars you can see bunches of craters, especially the monsters with bright rays emanating from them.  Think about the impact, what a sight that must have been.  In the southern region there’s Tycho, with many rays of bright ejecta.  Ejecta appears brighter than the surrounding surface because it is younger and has not been baked as long.  Some other craters with bright ejecta rays are Keppler, Copernicus, and Aristarchus.  They are upper left (from our perspective) of Tycho, in Oceanus Procellarum (Ocean of Storms).

Oceanus (Latin for ocean) and Mare (Latin for sea) were thought to be great bodies of water but are actually lava. Great volcanos and giant asteroid impacts produced huge lakes of molten lava.  As the lava cooled it formed those very smooth and flat areas.

Mountain ranges can be seen on the Moon. One of the prettiest is Montes Apenninus (named after the Apennines in Italy).  The lunar Apennines lie at the southeastern (from our perspective) side of Mare Imbrium.  They form one piece of the massive crater’s wall and contain a wealth of things to look at with a telescope at higher power (150-200x). Several mountain ranges form Mare Imbrium’s crater wall.

Lunar swirls are relatively newly described features, and some are visible in telescopes.  They are lighter in shade than the surrounding surface, look like a highland area, have swirls, and are associated with localized magnetic fields.  Reiner Gamma is a visible swirl, located in the western (from our perspective) edge of Oceanus Procellarum.  It is just west from the same named crater, Reiner.

The Moon’s origin was a mystery until someone noticed it is slowly receding from Earth.  Using all the available distance measurements over time the Moon’s orbit was plotted backward and at one point it appears it was really close to Earth.  Too close to be stable.  It seems our Moon came from the earth’s crust and some mantle.  This idea was supported by Apollo samples.  Theory is an object about the size of Mars hit the forming Earth, tearing away a bunch material.  This material coalesced and became the Moon, slowly receding from Earth due to gravitational interactions.

Another theory – life on Earth would be far different if we had no Moon.

What’s in the Sky?

The Moon!  Look up!