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'Christmas Star' appeared for 1st time in 800 years. Here's what it looked like

Jupiter and Saturn were closely aligned on Monday night for the first time in 800 years.
Image: Jupiter And Saturn Align To Form 'Great Conjunction'
Monday night's astronomical event was known as a Great Conjunction.Rodin Eckenroth / Getty Images
/ Source: TODAY

Jupiter and Saturn came into alignment in a very special way on Monday night, and the results were pretty dazzling.

The two largest planets in the solar system don't often cross paths so closely, and when they do, the rare event creates something that some have been calling the "Christmas Star." In other words, Jupiter and Saturn are so close that it looks like they've been fused into a single point of light.

It's estimated that the last time humans witnessed this impressive sight was around the year 1226, according to Michael Shanahan, the director of the Liberty Science Center Planetarium in New Jersey.

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A view from the Astronomers Monument in Los Angeles during the main event on Dec. 21. Patrick T. Fallon / AFP via Getty Images

Astronomers think the rare event might also have been visible in 1623, but there are no recorded instances of humans seeing it. The reason? The planets crossed paths right at sunset and the setting sun overshadowed the event.

Texans watch the planetary conjunction on Dec. 21.Callaghan O'Hare / Reuters

TODAY meteorologist Dylan Dreyerexplained the phenomenon during Tuesday morning's show.

"You've got Jupiter racing around the sun; you've got Saturn racing around the sun. And basically, they caught up to each other," she said. "These are the two biggest planets in our solar system and they are so close together that if you look at them from the naked eye, they just look huge."

Earlier this week, Shanahan told TODAY that some believe the Star of Bethlehem that the three wise men in the Bible's Nativity story saw before the birth of Jesus was actually the "Christmas Star."

"One possibility is that these two planets did join together in 7 B.C., about a year before the earliest possible time of the birth of Jesus, so that it could've been a conjunction of the two planets," he said. "If the wise men were, as we think, in fact astrologers, that could've been a thing they saw in 7 B.C. and said, 'Oh, there's a big event happening, let's go to Bethlehem and check it out."

Jupiter and Saturn actually align every 20 years or so, but the space between the two planets is usually about the width of two full moons. When they aligned on Monday night, though, the planets appeared to be right next to each other. In reality, they were still millions of miles away from each other.

A view of the "Christmas Star" in the Los Angeles skyline on Dec. 21. Photo by Patrick T. Fallon / AFP via Getty Images

If you missed out on Monday night's main event, the rare "Christmas Star" won't appear again until 2080. As a consolation, you can still see Jupiter and Saturn close together for the entire month of December. NASA astronomer Henry Throop recently told TODAY that you simply need to look southwest right after sunset to see the sight.

An astronomer in California sets up a telescope to view the great conjunction of Jupiter and Saturn on Dec. 21.Rodin Eckenroth / Getty Images

"For people who see it a few times during the period, it is a great chance to see the motions of the planets," Throop wrote in an email. "You can imagine Jupiter and Saturn as runners on a track. Jupiter is moving faster, and looking from one night to the next, people will be able to see Jupiter approaching and passing Saturn in their paths around the sun."