You may have noticed in recent weeks that the planet Venus has slipped from the post-sunset sky, slimming into a crescent shape as it drops from view. Its reign as the bright "Evening Star" in 2023 is over, as a relatively rare celestial phenomenon takes shape.
On Aug. 13, Venus will appear to be between Earth and the sun, which astronomers describe as being at inferior conjunction. It's purely a line-of-sight phenomenon, and from Earth's point of view it can only happen to two planets in the solar system — Mercury and Venus — both of which are inferior planets, which means they are closer to the sun than Earth. The outer planets, which lie farther from the sun than Earth, are called superior planets by astronomers.
