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Night sky lovers can typically spot a smattering of a few planets, but in late March, a stunning visual takes shape when five planets line up beneath the moon in a display sometimes called a planetary parade or alignment.
Onlookers will be able to catch the best glimpse of the alignment — which will include Mercury, Venus, Mars, Jupiter and Uranus — on Tuesday evening, just after sunset. Much of the display will become visible on Friday and will continue to be so over the next couple of weeks, according to Cameron Hummels, a computational astrophysicist at the California Institute of Technology.
Alignments such as this one appear every few years or so, Hummels said, and much of it will be visible to the naked eye, even in urban areas with significant light pollution. And it can be spotted across the Northern and Southern hemispheres.
The arrangement will be visible just underneath the crescent moon. To spot the display, Hummels recommended heading out to a place with a good view of the western horizon just after sunset, when streaks of the colorful sunset still remain and the sky has turned dark blue but not yet black. (Tip: Those living far to the north should look slightly southwest, while those in the Southern Hemisphere should gaze northwest, Hummels said.)
The easiest planet to spot will be Venus, often referred to as the “evening star,” because it’s the brightest object in the night sky apart from the moon. Uranus will appear close to Venus, though it may be difficult to pick out the distant planet without binoculars or a telescope unless you’re viewing from a prime location with no light pollution.
Beneath Venus and Uranus will be Jupiter and Mercury, hovering just above the horizon. Mercury may also be difficult to catch without special equipment, as the sun’s glare can blot out the planet. But to careful observers, both planets will be visible for about 20 to 30 minutes after sunset, Hummels said.
Topping off the planetary parade will be Mars, sitting in a straight line up from Jupiter, Mercury, Venus, Uranus and the moon. It’s easy to pick out because of its signature orange tint, Hummels added.
The planets will all appear “kind of like pearls on a necklace” across the night sky, Hummels said.
The entire alignment will cover just about 70 degrees of the sky. Hummels said one method for measuring degrees in the sky is to use your thumb or closed fist, extended away from your body. A fist at arm’s length will cover about 10 degrees, while a thumb covers about 1 degree.
What does this mean?
A planetary alignment of this kind may show up every few years, but it is possible to catch planets all together in an even smaller patch of the sky — those occurrences are just more rare.
One alignment last June, for example, was the first of its kind since 2004. The event included all five planets that can typically be seen with the naked eye — Mercury, Venus, Mars, Jupiter and Saturn.
Hummels said not to assign too much significance to a planetary alignment.
“It’s kind of like when your car’s odometer shows a bunch of numbers — like it reaches 44,444,” he said. “It’s cool and unusual. It just doesn’t really mean anything.”
Fascinating celestial phenomena often decorate the night sky, he added, such as when Jupiter and Venus appeared within half a degree of each other this month.
On October 14, sky watchers can expect to see a “ring of fire” eclipse. And, in April 2024, a total solar eclipse will blot out the sun midday for many in the United States.