Did you see the “blue-green planet” Uranus earlier this month?
If you didn’t there’s another relatively chance coming this Sunday evening—and it will be the last easy chance you have this year.
That’s because as soon as the Sun goes down this Sunday, April 3, 2022 the slim crescent Moon will be shining low in the western sky—and barely 1º from it will be the seventh planet, Uranus.
However, the only planet to spin on its side (every 17 hours and 14 minutes) won’t be particularly easy to see at first glance.
After all, it’s a whopping 1.8 billion miles/2.9 billion kilometers distant so will shine at a dim magnitude of +5.8.
It’s also a tiny blue-green dot amongst the stars. So you’ll need to a pair of binoculars or a small telescope.
So why is Sunday a good chance?
The position of a 7%-lit Crescent Moon apparently right beside the planet makes it much easier to find than when it floats like a speck in the night sky.
Here’s what you’ll see an hour after sunset on Sunday if you face west:
And here’s a close-up:
Look just below the lit crescent Moon and not 1º away you’ll find the blue-green dot of Uranus.
However, you’ll need to be outside looking west an hour after sunset, and not much later, because Uranus will be sinking quickly and will soon disappear into the haze of the horizon. An elevated position and a good, clear view low to the horizon will help.
It’s worth doing because Uranus is about to disappear from the evening sky. It won’t be back for six months.
A ringed planet like Saturn, Uranus is virtually unexplored. NASA’s Voyager 2 spacecraft made a close flyby of Uranus in 1986 and nothing has been back since.
Every photo you’ve ever seen of Uranus was taken during Voyager 2’s brief flyby.
Yet Uranus demands a flagship mission from NASA because of its moons.
Although you wont be able to see any of them, know that Uranus has a whopping 27 moons. In fact, it has the most densely packed group of moons of any planet in the Solar System.
All of Uranus’ moons are named after characters from the works of William Shakespeare and Alexander Pope.
The four most interesting are Ariel, Umbriel, Titania and Oberon largely because they may contain underground oceans.
Cue the “Moons of Uranus” project that will use the James Webb Space Telescope to study Ariel, Umbriel, Titania and Oberon and look for traces of ammonia, organic molecules, carbon dioxide ice and water.
Should NASA send a big mission to Uranus? The timing is good. Luckily a rare planetary alignment of Neptune, Uranus and Jupiter will soon provide a rare window to send a spacecraft on a “slingshot” via Jupiter to either of the outer “ice giant” planets.
There’s a proposal to do just that and it’s possible that it could be green-lit by April 2022’s Planetary Science Decadal Survey. If that happens then the spacecraft would need to leave Earth by the early 2030s to get to Uranus by 2043.
Wishing you clear skies and wide eyes.