Ufo

Picture this: You're in a car riding along a country road at night. The sky is clear; the stars are twinkling. The silhouettes of moonlit trees glide by the side window. Flash! A blue-white light beams through a gap in the forest. Flash! It happens again. And again, and again. It's following you.

In the movies, this is when the spaceship lands. A door opens. Eerie-green lights flood the roadside. Something alien steps out ... and you have a Close Encounter. Time to dial 9-1-1!

Relax. It's only Venus, the second planet from the Sun.

Right: Venus and the Moon beam through some trees in Brittany, France. Photo credit: Laurent Laveder.

Venus is the brightest of all planets. It makes Sirius, the brightest star in the night sky, look feeble. At sundown Venus materializes close to the western horizon where it can beam through trees and make you think you're being chased by something from outer space. No wonder so many people call 9-1-1 to report a UFO when they see it.

This week Venus (magnitude -4.5) is at maximum brightness. It is 8 times brighter than the planet Jupiter (magnitude -2.3), 23 times brighter than Sirius (magnitude -1.1), and 275 times brighter than the planet Mars (magnitude +1.6). Venus can actually cast faint shadows; only the Sun and Moon outshine it.