Jupiter and Saturn seen together on December 13. Photo: NASA/Bill Ingalls
Jupiter and Saturn will appear as a double planet in the night sky Monday evening thanks to a rare planetary alignment.
Why it matters: A "great conjunction" where these two planets are seen this close together is exceedingly rare. According to NASA, the last time Jupiter and Saturn appeared this close together was 400 years ago, but it's been about 800 years since this kind of alignment happened at night.
What's happening: Jupiter and Saturn have been moving closer and closer together from Earth's perspective for a number of days.
- In order to see the two planets, step outside under clear skies not long after sundown and look to the southwest.
- Jupiter will look brighter than Saturn and will appear just above the ringed planet.
- If you hold out your hand to the sky, the tip of your pinky will be able to cover both planets at once, according to NASA.
- The two planets will be bright enough to see from most cities.
Be smart: Jupiter and Saturn aren't actually physically close together. The two planets are still separated by hundreds of millions of miles.
- This conjunction is simply a fun fluke of orbital dynamics that we can see from Earth's perspective.
Go deeper: Learn how to photograph the conjunction from NASA.