The planets of the solar system were lined up in the sky Wednesday night in an astronomical phenomenon, visible from Earth, known as a “planet parade.”
The phenomenon, which was also visible Tuesday night, gave skywatchers a good view of Mercury, Venus, Mars, Jupiter and Saturn with the naked eye. With a pair of binoculars or a telescope, Uranus and Neptune could also be seen.
The planet parade is not an extremely rare occurrence — it tends to happen at least every couple of years. In fact, the eight-planet alignment last happened in.
In order to see the phenomenon, it was recommended you look south after sunset. From east to west, the planets appeared in this order: Mars, Uranus, Jupiter, Neptune, Saturn, Mercury, Venus.
“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,” said Vahé Peroomian, a professor of astronomy and physics at the University of Southern California. “Jupiter, Saturn and Mars will be visible once it gets dark, from southeast to east.”
Planets can appear together in the same part of the sky during their orbits around the sun, Peroomian told CBS News.
“Mercury completes one orbit in 88 days, and Venus in 225 days. The outer planets move a lot slower: Jupiter takes 12 years to orbit the Sun, Saturn takes 29,” he said. “So, as long as Jupiter and Saturn are visible, which happens unless they’re on opposite sides of the Sun from our point of view, then the remaining planets will eventually line up.”
It is a bigger feat for Neptune and Uranus to also be visible at the same time as they take 165 years and 84 years, respectively, to orbit the sun.
Both planets “spend considerable time on opposite sides of the Sun from our vantage point,” Peroomian said.
On Wednesday night, Uranus and Neptune were relatively close together, but because Uranus moves around the Sun twice as fast as Neptune, the planets will go back to being far apart from one another, he said.
As a result, “it won’t be possible to see both planets in the night sky at the same time for several decades,” Peroomian added.