What’s Deep Inside Uranus?
What would you find if you could venture deep into Uranus? You’d need a spacesuit to make the journey, and it would have to be one capable of withstanding humongous winds, temperature ranges in the thousands of degrees and pressures that can turn poop into diamonds. A more practical option would be to make the trip in your dream body, so let’s assume you’re going to do that. You’ll need to take some time off work, because it’s over 24,000 km from the surface of Uranus to its core. If you’re traveling at a speed that allows you to take in the scenery — let’s say a leisurely 100 km per hour — the trip to the center of Uranus will take well over a week. Here are some of the things you may see on your journey.
Clouds, Clouds and More Clouds
As soon as you pass from the thermosphere to the stratosphere, every day on Uranus is a cloudy day. Like Earth, Uranus has atmospheric layers defined by reversing temperature gradients, and gas clouds populate each layer.
The stratosphere begins at a an altitude of 50 km above the “surface,” which isn’t solid but has an atmospheric pressure of 1 earth atmosphere, or about 1 bar. The thermosphere (exosphere) extends another 4,000 km from this point, and it’s cloudy there too, The high atmosphere clouds are mainly composed of hydrogen and helium, which are easy to see through, but there are also swirling wafts of odorous methane, which absorb red light and give the planet its blue color.
The methane cloud layer extends below the troposphere to a pressure of 1.3 bar, and at that altitude, you may also see clouds of water vapor, ammonia and hydrogen sulfide — another outhouse gas. There are also trace amounts of carbon monoxide, carbon dioxide and hydrocarbons, such as ethane and acetylene.
The Temperate Zone
As you enter the Uranian atmosphere, you’ll need earmuffs, because the temperature at the upper frontier is a frigid -216 C, but things quickly heat up. Throughout most of the thermosphere, the temperature is almost hot enough to melt lead. Things begin to cool off as you descend, though. The temperature decreases as you pass through the stratosphere, eventually reaching the same lows you experienced at the top of the thermosphere.
Once in the troposphere, you’ll notice things heating up again as you descend, and at the base of the troposphere — at an altitude of -300 km — the temperature is an almost earth-like 46 C. You might want to hang out there a while, because things are about to get gnarly.
The Bowels of Uranus
They don’t call Uranus an ice giant for nothing. As you descend past the temperate zone, the pressures condense water, methane and other gases into liquids and solids. Although no one has been there to verify it, scientists think the pressures are great enough to split the abundant hydrocarbons into hydrogen and carbon and to compress the carbon into diamonds, which fall like rain through a sea of liquid carbon toward the rocky core of the planet.
The temperature at the core is around 5,000 C, which sounds hot but is actually frigid compared to the core of almost every other planet. In fact. Uranus is the only outer planet that doesn’t radiate more energy than it receives from the sun. The sometimes rocky, sometimes liquid, core sloshes around as the planet rotates, giving the planet a weak magnetic field that opens and closes several times each day at a 60-degree offset to the poles. This sphincter-like movement is just another odd feature of the enigmatic seventh planet.
Is Uranus Gassy?
You would expect Uranus to be gassy, and you’d be right. Although properly considered an ice giant in the modern system of planet classification, in the popular vernacular it’s still a gas giant. The two gases from which it was formed, hydrogen and helium, are the primary components of its atmosphere, but if you’re worried about smelly hydrocarbons, you might want to pick another vacation spot. Methane (CH4), is the third most abundant compound, giving Uranus a pungent outhouse-like fragrance. Water, ammonia, hydrogen sulfide and ammonium sulfide round out the atmospheric composition. None of these has a mitigating effect on the olfactory environment around Uranus. In fact, they only add to the stink.
Is Uranus Windy?
To the naked eye, Uranus appears placid. Unlike Jupiter and Saturn, two gassy worlds closer to the sun that display violent storm patterns in their upper atmospheres, Uranus is a uniform light blue. The color is due to the presence of methane, the third most abundant compound in its atmosphere. If you’ve ever followed behind a cow to collect fuel for your campfire, you have a good idea what Uranus must smell like. But is it windy? As you might expect, the answer is yes.
It turns out the tranquil face that Uranus shows to the rest of the universe is merely a cover. The clouds that hide its inner secrets obscure stormy winds that blow at speeds rivaling those on Saturn and Jupiter. Wind speeds top out at almost 1,000 kilometers per hour, or close to 600 miles per hour. Some of these winds can be sustained for several months and others, like small farts, last only a few hours.
Unlike Neptune, which is similarly blue, Uranus absorbs more heat from the sun than it radiates. This is probably one reason why its winds aren’t as fierce as those on Neptune, which generates its own heat. They blow at approximately two-thirds of the speed of Neptune’s winds and are confined to a relatively thin 600-mile band in the planet’s upper atmosphere. Scientists don’t understand the processes that occur deeper in the atmosphere of Uranus and haven’t yet probed to find out.
Rings Around Uranus
Like all the icy and gassy planets, Uranus has rings, and though most of them are formed from dark matter, some are visible to exploring eyes. The dark matter is mostly composed of non-reflective chunks and assorted space dust. Unlike the highly reflective icy rocks that Saturn collected from passing comets and asteroids, the dark blobs that orbit Uranus are thought to be remnants of one or more moons that disintegrated when they got too close to the blue planet.
William Herschel, the astronomer who discovered Uranus, claimed to have seen the rings, but he probably didn’t. Although rings are not unexpected around Uranus, they are too dark to have been noticeable to Herschel. The first official sighting of the rings took place in 1977, some 200 years after Herschel discovered the planet.
Scientists have counted 13 distinct rings. The innermost is the 1986U2R-zeta ring, while the next three are the 6, 5 and 4 rings They are about 1 ½ times the radius of the planetary equator in radius. The outer ones, denoted by Greek letters. are about double the planetary equator in radius. In astronomical terms, the rings aren’t very old. The moons that formed them probably disintegrated about 600 million years ago, and the rings continue to refine as their component chunks collide with each other and break into smaller bits.