I recently worked on probably my most out-of-this-world project yet – Lonely Planet’s guide to… The Universe!
For the book I wrote chapters on Saturn, Uranus, Neptune and Jupiter (with a little help from NASA), and covered some of the introductory sections too.
You can read an extract below.
Planet type: Ice Giant
Number of moons: 27
Size compared to earth: x 4
The jokes just write themselves, don’t they? The most unfortunately named planet in the solar system has long been the butt of schoolyard jokes (FYI, the name relates to the Roman god of the sky, and it’s pronounced YOOR-uh-us, okay?) So you can stop giggling at the back.
Apart from its irresistibly snigger-worthy name, Uranus is fascinating for all kinds of scientific reasons. It’s the third largest planet in our solar system, and the seventh most distant from the Sun. Discovered in 1781 by astronomer William Herschel, Uranus is surrounded by 13 faint rings and 27 small moons. Its atmosphere is composed of helium and hydrogen, with a bit of methane swirling in the mix which gives the planet its distinctive blue-green colour.
But the weirdest thing about Uranus is the way it spins. Like Venus, it rotates from east to west (the opposite way to earth). Even more bizarrely, Uranus also spins at 90˚ to its orbit, which makes it appear to revolve on its side, like a rolling ball – the only planet in the solar system to do so. This unique sideways rotation means the seasons on Uranus are extremely strange indeed: the planet’s north pole experiences 21 years of nighttime in winter, 21 years of daytime in summer and 42 years of day and night in the spring and fall. Even for the soundest of sleepers, that’s really going to play havoc with your circadian rhythm. And living on Uranus is also going to mess up your birthday – with an average orbit of around 84 earth years, most Earthlings would count themselves lucky to blow out the candles on a single birthday cake before shuffling off their mortal coil.
Not that you’d particularly want to spend your birthday on Uranus. With wind speeds that can reach 900km an hour and a surface temperature of -195˚C, you’d struggle to light the candles in the first place. And then there’s the smell: recent research suggests that Uranus’ methane clouds probably smell like rotten eggs, or, for the more scatologically minded, a particularly noxious bout of flatulence. So maybe Uranus’ bum-themed branding really does make sense after all.
Distance from sun: 1.8 billion miles (2.9 billion km), 19.8 astronomical units
One-way light-time to the sun: 165.2 minutes
Length of day: 17 hours 14 minutes
Length of orbital year: 84 years
Atmosphere: Hydrogen, helium & methane
There’s no need to pack your sunglasses if you’re planning on travelling to Saturn: sunlight is about 100 times fainter here than on Earth.
GETTING THERE & AWAY
With an average orbit of 1.8 billion miles (2.9 billion km) from the sun, Uranus is 19.8 astronomical units away (nearly 20 times further than earth). At this distance, it takes a beam of sunlight 2 hours and 40 minutes to reach Uranus.
So far, Voyager 2 is the only spacecraft to fly by Uranus. No probes have orbited this distant planet to study it at length and up close.