From December 10th to the 13th, the planets will line up in our sky in their natural order outward from the sun viewing from west to east. Mercury will appear closest to the sun after it passes inferior conjunction on the 10th (although we won’t be able to see it as it moves away from the sun’s glare). Venus, Mars, Jupiter, and Saturn can be seen appearing in that order in the sky. Of course, a telescope is needed to see Uranus and Neptune following Saturn. (Pluto can’t actually be viewed as it disappears in the sun’s glare.) Pluto moves to a position behind the sun on December 13th, ending the line-up.

An orderly appearance is very rare, more rare than Venus transiting the sun. In November 2002, they briefly aligned, but there hasn’t been a proper order west of the sun since before there were telescopes. (Without telescopes, they couldn’t see and didn’t know about the planets past Saturn.) There won’t be another alignment for about four centuries. Alignments east of the sun are very rare too. The last one occurred in late February and early March of 1801. It won’t occur again until April 2333.