Bob Moler's Ephemeris Blog

Ephemeris for Thursday, June 25th.  Today the Sun will be up for 15 hours and 34 minutes, setting at 9:32.   The Moon, 1 day past first quarter, will set at 2:26 tomorrow morning and tomorrow the Sun will rise at 5:58.

Tuesday I talked about the brightness variation on the Moon, the bright and ancient highlands and the darker areas called seas, but a large asteroid impact areas that welled up magma from the moon’s interior erasing prior craters.  The dark seas were created after most cratering had ended, or they’d be heavily cratered too.  They seem to have occurred about 4 billion years ago, about 500 million years after the Moon formed.  This appeared to be a period when the giant planets came closer to the Sun than they are now, before retreating again.  This period is called the late heavy bombardment.  Not all astronomers give it credence, but it bears out what we see in planetary systems around other stars.

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

Addendum

The Moon tonight with pointers to seas near the crater Copernicus and the highlands near the crater Tycho. 10:30 p.m. June 25, 2015. Created using Virtual Moon Atlas.

The Lunar seas near the crater Copernicus showing the smooth surface with relatively few craters. Credit: Virtual Moon Atlas with the texture from NASA’s Lunar Reconnaissance Orbiter. The lunar phase was omitted.

The Lunar highlands near the crater Tycho showing a surface saturated with craters. Credit: Virtual Moon Atlas with the texture from NASA’s Lunar Reconnaissance Orbiter. The lunar phase was omitted. Both images are shown to the same scale.