NASA released a stunning image captured by the James Webb Space Telescope on Tuesday that shows Uranus, the seventh planet from the sun, in incredible detail surrounded by its planetary rings and a handful of its 27 moons.
The new high-resolution images make the planet and its rings look more like a space portal to another dimension than the traditional illustrations schoolchildren see of asteroid-filled rings circling the planet around its equator.
Uranus is one of the largest objects in the solar system, but is it large enough for an average Wyomingite to see in the night sky? Turns out, anyone in the Cowboy State can see Uranus — and they don’t need a NASA-grade telescope — but it can be difficult.
Brighter Than The Dimmest Star
First, let’s get this out of the way. It’s not Uranus (Ur-a-nus), it’s Uranus (Ur-ah-nus). That's the proper pronunciation.
Now with that out of the way, let’s move on. And stop giggling.
When spotting planets in the night sky, nearly all the focus goes to those that shine brightest: Mercury, Venus, Mars, Jupiter and Saturn. Uranus isn’t always visible and is much harder to spot when it is.
“Uranus is actually visible to the naked eye,” said Max Gilbraith, the planetarium coordinator for the University of Wyoming Physics and Astronomy Department. “It’s occasionally bright enough and close enough that we can see it the night. Uranus will be about as bright as the dimmest star you can see in the night sky.”
The technical term for “star brightness” is apparent magnitude, which measures the brightness of all the objects visible in the night sky. It’s an inverse scale, so objects with a negative apparent magnitude are brighter than those with a positive one.
The moon has an apparent magnitude of -3.69, the planet Jupiter’s is around -2.20, and the brightest star seen from Earth, Sirius, is -1.47. Meanwhile, the upper threshold of apparent magnitude visible to the naked human eye is +6.90.
Uranus’s apparent magnitude ranges from +6.03 to +5.38. While technically visible to the naked human eye, catching a glimpse of Uranus without a telescope can still be quite a stretch.
The $10 billion James Webb Space Telescope took more than two decades to build and is around the size of a tennis court. With those specs, it’s much easier for it to see Uranus than anyone else.
Even with billions of dollars and NASA’s best engineers, humanity’s most advanced telescope can struggle to get a good view of certain celestial objects, like the gaseous giant Uranus. Gilbraith said the cosmos are now in the right position for a better view of Uranus.
“It's a pretty optimal time to get it because we're on our close approach,” he said. “It's on the far side of the Earth and Sun, and (the James Webb Telescope) is a little bit further out. They're past the moon and can take some nice photos since it's pretty much opposite the sun right now.”
The term for this cosmic position is “opposition.” Any time a planet is in opposition to the sun is an excellent time to get a picture of it.
In addition, the opposition of Uranus means it’s easier for anyone to spot it. Wyomingites have a better chance than most, and for the same reasons, stargazing is always better in the Cowboy State.
“The main limiting factors are ambient light, light pollution, the moon, and that it’s essentially as dim as the dimmest star you can see on a perfectly dark night,” he said. “That's what keeps people from noticing it.”
Anyone with a decent telescope might be able to discern Uranus’s shape, and anyone with an excellent telescope might see a few of its moons. Beyond that, Uranus is just too far away from our eyes to get a good view without assistance (given it’s 2,817,260,161 miles away from Earth.)
Anyone who wants to spot Uranus this week will find it in the southern part of the night sky. The best time to see it will be between 9:15 and 9:30 p.m. when the planet will be directly south, surrounded by the constellations Aries, Taurus and Cetus.
Uranus will also be close to the much easier-to-spot planet Jupiter, but binoculars are recommended to get a good view.
Probing Cold, Windy Uranus
Uranus is the third largest and fourth most dense of the solar system’s eight planets (sorry, Pluto). It’s also one of the coldest objects in the solar system and generates some of the strongest winds of any planet, with a peak wind gust of 560 miles per hour.
It’s also the planet that gets the most childish puns and guffaws because of its name.
The planet was named for Uranus, the personification of the sky in Greek mythology and the grandfather of many Greek gods, including Zeus. It was discovered in 1781 by English astronomer William Hershel, who had a different name for his discovery.
“He wanted to name it after the then King of England, which was King George III, (whom) we famously were fighting the Revolutionary War against,” Gilbraith said. “So, it would have been planet Georgius at that point.”
Hershel and other British astronomers kept referring to the new planet as the Georgium Sidus (George’s Planet), but the rest of the world didn’t. German astronomer Johann Bode christened Uranus, and the rest of the world lined up behind him.
And yes, the proper pronunciation emphasizes the urine in Uranus, but “fourth graders tend to disregard that,” Gilbraith said.
There are many unanswered questions about Uranus. It's just in an awkward position where it's difficult for it to be seen and studied.
That's why NASA is working on a mission to probe Uranus. More specifically, its atmosphere. The mission would send an orbiting satellite with a probe payload to study the planet and its moons.
Getting to Uranus won’t be easy. Even with a mission launch in 2031 (which NASA says is unlikely), it wouldn’t reach the cold, windy void of Uranus until 2044.
In the meantime, perhaps NASA can train for those windy conditions during Wyoming winters.
Andrew Rossi can be reached at firstname.lastname@example.org.