Anyone who looked up at the sky on Wednesday night may have caught a glimpse of an impressive sight: all the planets of our solar system on display.
The phenomenon — also known as a "planet parade" — allows people to see planets Mercury, Venus, Mars, Jupiter and Saturn with their naked eye. Those with telescopes or binoculars could also catch sight of planets further away from Earth, like Uranus and Neptune.
"The opportunity to see all the planetary family at a glance does not happen often," Dr. Gianluca Masi, an astronomer who works with the Virtual Telescope Project, told the Daily Mail.
"We have just a couple of days to look at this parade before Mercury will disappear into the solar glare," Masi added.
Per Fox Weather, the parade will be visible into Thursday night. As Sky & Telescope noted, on "December 21st, the seven planets (and Moon) will span [a 146 degree] arc of sky. That shrinks to [a 135-degree arc] by year's end, around the time Mercury departs the scene."
After sunset, the planets will appear across the sky to the south in the order of Mars, Uranus, Jupiter, Neptune, Saturn, Mercury, and Venus, according to CBS News.
A clear sky is needed to view the planets properly.
"People should look southward about 30 to 45 minutes after sunset to catch Mercury and Venus before they're too close to the horizon to observe," Vahé Peroomian, a University of Southern California professor of astronomy and physics, told CBS News.
"Jupiter, Saturn and Mars will be visible once it gets dark, from southeast to east," Peroomian added.
This isn't the first time multiple planets were visible at the same time this year. Mercury, Venus, Mars, Jupiter, and Saturn were displayed in the sky in that order back in June — a rare alignment that hadn't been seen since December 2004 and won't be seen again until 2040.
However, Peroomian noted what's even more impressive is that Uranus and Neptune were also visible close together in the sky on Wednesday night. He told CBS that Neptune and Uranus orbit the sun for approximately 165 and 84 years, respectively. As a result, the two planets often "spend considerable time on opposite sides of the Sun from our vantage point."
Since Uranus orbits much faster than Neptune, he said, "it won't be possible to see both planets in the night sky at the same time for several decades."
