The giant outer planets Jupiter and Saturn now appear as a pair in the early evening sky, and will pass closest to each other on Monday night over San Diego.
What astronomers call the “conjunction” of the two planets, which some are likening to the legendary Christmas star, last happened at night nearly 800 years ago, according to NASA.
In reality, the planets are hundreds of millions of miles apart, but will appear as a pair low in the southwest sky just after sunset.
Jupiter will look like a bright star and be easily visible, while Saturn will be slightly fainter. If you have binoculars or a small telescope, you may be able to see Jupiter’s four large moons.
The two planets will be very close in the sky, but experts say they will not appear as a single star to someone with normal eyesight.
Jupiter, the largest planet, orbits nearly 500 million miles from the Sun, while Saturn, the second largest planet, is much farther out at over 900 million miles.
“You can imagine the solar system to be a racetrack, with each of the planets as a runner in their own lane and the Earth toward the center of the stadium,” said Henry Throop, an planetary science astronomer at NASA Headquarters in Washington. “From our vantage point, we’ll be able to be to see Jupiter on the inside lane, approaching Saturn all month and finally overtaking it on Dec. 21.”
Both planets have been explored by multiple spacecraft, with NASA’s Juno probe currently orbiting Jupiter.
