On Friday night, Jupiter, the largest planet in the solar system, will directly align with the Earth and the sun — the best opportunity to go outside and observe this massive gaseous world and its moon you’ll have this year.
This event is called an "opposition," simply because Jupiter will be directly opposite the sun in orbit. It's special because when celestial objects are directly opposite the sun, they appear brighter in the sky. And because Jupiter will be near its closest distance to the Earth this year, it will appear slightly bigger. Jupiter reaches opposition once every 13 months — so you won’t want to miss tonight’s opportunity.
The takeaway: Jupiter and its moons will shine more brightly than usual tonight; go outside and see for yourself.
“Through binoculars, you should be able to see Jupiter's four Galilean moons, Io, Europa, Ganymede and Callisto,” NASA reports. And with a telescope, you should be able to see a few of the individual cloud belts on Jupiter, and perhaps even the Great Red Spot.
Jupiter is like a solar system in miniature
With its 67(!) moons, Jupiter is kind of like a mini solar system inside our own. The planet is made up of the same basic ingredients as the sun — mainly hydrogen and helium — but doesn’t have enough mass to ignite and become a star. Jupiter’s gravity is so strong, it easily picks up space objects into its orbit, which is one explanation for why it has so many moons.
Currently, the NASA spacecraft Juno is orbiting Jupiter and making the most careful study of the planet to date. The hope is that a close-up investigation of its surface can reveal some history of the origin of our solar system. It could also further our knowledge of the ceaseless violent storms that pock its atmosphere. One question: Why is Jupiter’s famous Great Red Spot — which is so large it could engulf the entire Earth — mysteriously shrinking?
On April 3, NASA took advantage of the brightening conditions as Jupiter was approaching opposition and snapped this photo of the gas giant with the Hubble Space Telescope. This photo renders Jupiter in all of its iridescent taupe, marbled glory.
Juno has been getting an even closer look, as its orbit takes it very close to Jupiter’s poles.
How to watch Jupiter at opposition
While you won’t get such stunning detail in your own observations, there’s still a chance to marvel at the planet.
On Friday night, from anywhere in the US, you should be able to spot Jupiter tucked into the center of the constellation Virgo in the southeastern sky. Like an opposite sun, it will rise in the east at dark, and set in the west at dawn. It won’t be hard to spot — it will be the brightest celestial object in the sky except for the moon. (According to Space.com, the International Space Station will be slightly brighter, if you see it whiz by.)