(NEXSTAR) – If you’ve been watching the sky on these dark December nights you may have noticed two of the brightest objects creeping nearer to each other. Jupiter and Saturn are about to appear closer in the sky than they have in 400 years.
The two planets will be so close that they will appear to be touching, separated by one-fifth the diameter of a full moon.
“They’re not close in space – they’re still hundreds of millions of kilometers apart from each other said, NASA Astronomer Henry Throop. “But … they appear as two points very close in the sky … in fact they’re so close that if you extend your pinky at arms length you’ll be able to cover both planets with just your pinky finger.”
When celestial bodies align, astronomers call it a conjunction, but since this one involves our solar system’s two biggest gas giants, it’s technically a “great conjunction.” Because the event is landing on a holiday week, many have begun calling the formation the “Christmas Star.”
Online stories about the event have gone viral, and NASA responded by creating a video primer for the event, which peaks on December 21st. According to Throop,