Bob Moler's Ephemeris Blog

This is Bob Moler with Ephemeris for Arbor Day, Friday, April 24th. Today the Sun will be up for 13 hours and 55 minutes, setting at 8:39, and it will rise tomorrow at 6:41. The Moon, 1 day past first quarter, will set at 4:08 tomorrow morning.

The face of the Moon is a bit more than half uncovered from our point of view, with first quarter occurring yesterday. It shows the string of lunar seas, those gray areas on the Moon which lead to the terminator, the Moon’s sunrise line. There is a larger sea called the Ocean of Storms on the eastern side of the Moon, as we see it. Most were created about 3.8 to 3.9 billion years ago by asteroid strikes. The same collisions happened to the Earth, but plate tectonics destroyed the evidence. Not so on the Moon. Many planetary scientists think it was the result of the Late Heavy Bombardment, caused by the changing orbits of mainly Saturn, Uranus and Neptune disrupting the asteroids, and sending them careening through the solar system.

The astronomical event times given in this blog are for the Traverse City/Interlochen area of Michigan (Lat 44.7° N, Long 85.7° W; EDT, UT – 4 hours) unless stated otherwise. Times will be different for other locations.

Addendum