Planetary alignments aren't rare, but they can be when they involve six of the eight planets in our solar system.

The six planets were visible in the days immediately leading up to Jan. 21, and for about four weeks afterward. Mars, Venus, Jupiter and Saturn should be visible to the naked eye. You'll need a ...

"A parade of planets, also sometimes referred to as a planetary alignment, is when several planets in our solar system appear to line up in the sky from our perspective here on Earth," John Conafay, ...

The enormous visitor to our solar system may have been about 8 times the mass of Jupiter, and come nearly as close to the sun ...