We’ve had the UK heatwave. Now, a storm is coming. Brace yourselves for constant lightning, frightening thunder and rasping rain.
With such turbulent days ahead, the question on everyone’s mind is, clearly, “Do we up sticks and move to Jupiter?”
Fortunately, new results from NASA’s Juno mission are here to help the decision.
What did we already know about Jupiter storms?
Until now, we believed Jupiter had storms similar to Earth’s. The lightning we encounter here, at home, strikes from clouds where water exists in all three states – ice, liquid, and vapour.
Thunderstorms therefore occur where temperatures hover around 0°C in the atmosphere.
Previous NASA flybys of the gas giant, dating as far back as Voyager in 1979, observed lightning flashes as bright regions on Jupiter’s cloud tops. This affirmed the theory that storms originate in deep water clouds 28 to 40 miles beneath the ‘surface’ we see.
A vastly different atmosphere
At greater altitudes, the temperature drops as low as -88°C. Water can’t remain as a gas here, but ammonia does. As such, you find plenty of ammonia vapour in the higher parts of Jupiter’s atmosphere.
Juno passed in close proximity to the dark side of our solar system’s largest planet. What it found sheds light on a violent gas environment, much more alien than we ever thought.
Shallow, constant lightning
Published in Nature, the Juno findings show lightning occurring much higher in Jupiter’s atmosphere than previously believed possible. This ‘shallow’ lightning is situated in the chilly regions near the upper, visible clouds.
According to lead author Heidi Becker, this could be caused by the sheer power of Jupiter’s more Earth-like thunderstorms deeper down. Ice crystals are flung 16 miles upwards from the water clouds and come into contact with ammonia vapour.
The ammonia acts like anti-freeze. By lowering the melting point of the ice, an ammonia-water solution forms. Condensing ammonia-water liquid falls, colliding with the rising ice crystals and, hey presto, the clouds electrify.
What about the mushballs?
A separate paper, published in the Journal of Geophysical Research: Planets, describes the Jovian equivalent of hailstones.
Two-thirds water, one-third ammonia, these so-called mush balls grow larger as they oscillate up and down in the atmosphere, similar to our hail but on a much larger scale. Layers of water-ammonia slush are encased in a thicker ice crust.
Eventually, they become so large that the upper atmosphere can’t hold them and they fall deeper into the gas giant.
Constant lightning and giant hailstones? Think I’ll leave it.
Good choice. If you’d still insisted on going, I was going to mention Jupiter’s great red spot, a hurricane with winds of up to 425mph. Oh, and it has raged for over 150 years. And it’s twice the size of Earth.
No matter how fiesty the weather gets over the coming days, at least you can be glad you’re not on Jupiter. Batten down the hatches.