Though the alignment isn't once-in-a-lifetime rare, the seven other planets in our solar system don't align every year, so it can be a spectacle to witness.Start the day smarter. Get all the news you need in your inbox each morning.

Houstonians will be able to see seven planets in the sky this weekend in what's called a planetary parade. Unfortunately, however, some may not be spotted with the naked eye. Just after dark, it will be possible to view Mercury,

The seven other planets in our solar system will line up in the night sky on Friday evening for a rare alignment called a "planetary parade" that will not happen again until 2040.