Moon and Venus 
After hiding in the Sun's glare for many weeks, the planet Venus is slowly returning to prominence. It's quite low in the west at sunset, and sets in early evening, so there's not a lot of time to look for it. But it's a little easier to spot this evening because it teams up with the crescent Moon.
Venus spent most of last year in the morning sky. But it passed "behind" the Sun early this year, and moved into the evening sky. It'll remain there through the summer.
Venus completes 13 orbits around the Sun for every eight that Earth makes. Because of that, Venus follows five distinct paths across the skies, which repeat themselves every eight years.
Such relationships between planets, or between moons in orbit around planets, are fairly common. The bodies' mutual gravitational attraction pulls them into a "resonance" with each other, like two complementary musical notes.
But planetary scientists aren't sure if the Venus-Earth pattern is such a resonance, or if it's just a coincidence. That's because the relationship isn't perfect: It's off by a few days. It's possible that as the eons roll by, the pattern will become more synchronized, and Earth and Venus will spend the rest of their days orbiting the Sun in perfect harmony.
Look for Venus -- the bright "evening star" -- a little to the left or upper left of the Moon as darkness begins to fall this evening, and well below the Moon tomorrow evening.
Script by Damond Benningfield, Copyright 2010