Jupiter and Saturn, our solar system's two largest planets, were visibly closer together on Monday night than they have been in 800 years — marking an extremely rare celestial event known as the "."
The conjunction occurs when the orbits of the two planets align every 20 years, but the event is not always visible, and the planets do not typically come as close together as they did on December 21.
This time around, Jupiter and Saturn were just 0.1 degrees apart — less than the diameter of a full moon.
The planets were so close, they appeared, from some perspectives, to overlap completely, creating a rare "double planet" effect. However, while the planets appeared from Earth to be very, very close, in reality, they are still hundreds of millions of miles apart.
The event happened to coincide with the winter solstice and the week of Christmas, but it can occur during any time of year.
If you missed the spectacle, or if your sky appeared cloudy Monday night, don't worry — the planets will still appear extremely close together in the night sky for the next several weeks, and dedicated astrophotographers are sharing their best shots of the night on social media.
Santa Barbara, California
Los Angeles, California
New York City, New York
Alborz Mountains, Iran
Koh Chang, Thailand
Colorado Springs, Colorado
Kuwait City, Kuwait
How to watch the great conjunction
The great conjunction shines bright shortly after sunset, low in the southwestern sky, as viewed from the Northern hemisphere, NASA said.
Through the entirety of December and the beginning of January, skywatchers can easily spot the two planets with the naked eye. They are so bright, they are even visible from most cities.
Jupiter currently appears brighter than any star in the sky. Saturn is slightly dimmer, but still just as bright as the brightest stars, with a recognizable golden glow.
Saturn will appear slightly above and to the right of Jupiter, and even looks as close to the planet as some of its own moons, visible with binoculars or a telescope. Unlike stars, which twinkle, both planets will hold consistent brightness, easy to find on clear nights.
The event is observable from anywhere on Earth, provided the sky is clear. It is easiest to spot along the equator, becoming more difficult to see further north.
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