12/10/2019 – Ephemeris – The Moon’s natural resource more precious than gold

Ephemeris for Tuesday, December 10th. Today the Sun will be up for 8 hours and 53 minutes, setting at 5:02 the earliest sunset, and it will rise tomorrow at 8:09. The Moon, 2 days before full, will set at 7:22 tomorrow morning.

The Moon is attracting the attention of NASA and the Chinese for crewed landings. The attraction is a natural resource the Moon has. It’s water, or rather ice. There are known water reserves in the Moon’s south polar craters, whose floors never see sunlight. That means they’re very cold. Cold traps they’re called. The Moon has a very little axial tilt so the crater floors are forever cold. They would collect water vapor from passing and colliding comets over the millennia. 10 years ago the second stage of the rocket that placed the Lunar Reconnaissance Orbiter in lunar orbit was crashed into one of the south polar craters followed by a satellite to analyze the ejecta. Water vapor was kicked up by the impact in Cabeus crater.

The times given are for the Traverse City/Interlochen area of Michigan. They may be different for your location.

Addendum

The south pole of the Moon where the presence of water ice is detected by the absorption of neutrons by the hydrogen atoms in the ice. Credit NASA/GSFC/SVS/Roscosmos.

You’ll notice that the craters on the the Moon’s south pole are named for Antarctic explorers.  Besides water other volatiles were found: methane, ammonia, hydrogen gas, carbon dioxide and carbon monoxide.