There’s nothing spookier than a dark, stormy night – unless it’s a dark, stormy night on an alien world, light years from home. Of course, there are a few in our backyard too. Where we’re going, you’ll find howling wind, bizarre things falling from the sky, and storms our whole world could disappear into forever. Grab a flashlight and join us on a haunted tour of the scariest, stormiest spots in space, but be warned: it’s not for the faint of heart.
6. The Red-Eyed Monsters of Jupiter
Jupiter is the lair of a behemoth of a storm that could swallow our puny little planet two or three times over, and the gas giant actually seems to be a spawning ground for such monsters. Earthbound astronomers have watched the famous Great Red Spot — a 17,000 mile-wide storm raging in Jupiter’s southern hemisphere — for at least 150 years. And in 2000, three smaller storms in the northern hemisphere merged and then, eerily, turned blood red.
The heat that fuels these monsters rises on convective currents from deep in Jupiter’s interior. In fact, the Great Red Spot radiates massive amounts of heat into Jupiter’s upper atmosphere, enough to keep its upper layers around the same temperature as Earth’s upper atmosphere, even way out in the chilly reaches of the outer solar system.
On Earth, hurricanes weaken and eventually die when they move over land, but there are no continents on Jupiter, so there’s nothing to stop monsters like the Great Red Spot from rampaging around the gas giant’s atmosphere as long as they like. These giant storms aren’t immortal, though. The Great Red Spot has been shrinking for at least a century, and it’s already only half its former size.
We don’t yet know exactly how these storms form and grow, why the Great Red Spot is shrinking, or what its fate will be. Soon, Juno will gaze into the maelstrom with its microwave radiometer instrument, tracking the heat rising from the bowels of the Great Red Spot, hundreds of miles deep, and NASA hopes that will yield a better understanding of the monster storm’s anatomy.
Scientists aren’t sure exactly what turns Jupiter’s storms red when they grow to a certain size. According to experiments that started in 2015, cosmic rays may spark a reaction that turns ammonium hydrosulfide in the upper cloud layers into new compounds with a bloody hue – but for now, it’s a spooky space mystery.
5. The Shrieking Winds of HD 80606b
Some scary stories are best told on that one particular night of the year, when the conditions are just right. HD 80606b would be the perfect place to huddle around the campfire for just such a story — except, of course, that it’s a gas giant nowhere near the habitable zone of its star, and the 11,000 MPH winds would put out your campfire in a hurry.
HD 80606b, a gas giant about four times more massive than Jupiter, orbits a star in a binary system about 190 light years away. It swoops around its parent star in a lopsided, elongated orbit that looks more like something you’d normally expect from a comet, not a real planet. The far end of that orbit carries HD 80606b 79 million miles out into its solar system. If you’re looking for a storm worthy of your best scary story, though, you’ll want to visit at periastron, when the gas giant dives in for a close flyby of its host star. Every 111 days, HD 80606b skims past its star with just 2.8 million miles to spare, and its atmosphere heats up and explodes into a frenzied storm.
As HD 80606b gets closer and closer to its star, the planet’s average temperature skyrockets from an already-hot 980°F to 2,240°F in just six hours. All that energy makes the gas giant’s atmosphere erupt into what astronomer Greg Laughlin described as “one of the fiercest storms of the galaxy.” Winds over 11,000 MPH roar around the planet for a few hours, dying out as the planet swings back out into the darkness of space.
In 2009, astronomers watched it happen in real time with NASA’s Spitzer space telescope, the first time that earthbound scientists have been able to watch a live weather change on an exoplanet. And on nights just like this one, they say you can almost hear the wind screaming.
4. The Apocalyptic Dust Storms of Mars
Imagine a massive dust storm blanketing the entire North American continent for weeks on end. It sounds like the end of the world, but on Mars, storms of apocalyptic proportions happen several times a year. Every three Martian years or so (every five or six Earth years), one of these regional storms swells up and circles the whole planet with swirling red dust, leaving only the 15 mile-high peak of Olympus Mons peeking above the storm.
Warm air rising from the Martian surface carries the fine-grained dust aloft, where it absorbs more sunlight and radiates its warmth back to the surrounding air. That warm air interacts with cooler air to produce winds that lift more dust. As blowing dust particles brush against each other, they produce a tremendous amount of static electricity, so lightning crackles and sparks throughout the growing storm.
Even in the largest, globe-spanning storms, winds top out at 60 MPH, and with an atmosphere just one percent as dense as Earth’s, 60 MPH winds on Mars don’t blow with much real force. The blowing dust doesn’t exactly scour everything in its path – but it clings to everything and blots out the Sun for weeks or months at a time. Like a blanket, it also traps heat in the atmosphere, so Mars’ average temperature may increase by 30°C during a global storm.
Astronomers last saw a global storm on Mars back in 2007. Late last year, planetary scientist Michael Smith suggested that Mars may be overdue for another big, planet-engulfing storm.
3. The Mysterious Strobe Lightning of HAT-P-11b
The distant gas giant HAT-P-11b may be home to lightning storms that would make Dr. Frankenstein absolutely giddy, and those powerful storms could be the source of an otherworldly radio signal.
In 2009, radio telescopes picked up faint emissions from the HAT-P-11 star system, about 122 light years away. The signal stopped when HAT-P-11b, a “hot Neptune” orbiting HAT-P-11, passed behind the star, so astronomers decided the radio waves must have come from the planet – if they were ever really there, that is. The signal didn’t reappear in 2010, when HAT-P11b transited its star again, and astronomers still aren’t sure it was real.
Some astronomers have suggested that the mysterious radio waves could simply have been the product of a blindingly intense lightning storm. How intense? If the most active lightning storm ever observed on Earth had somehow managed to cover the whole planet, it would still only produce a radio signal about one percent as strong as the one that seemed to come from HAT-P-11b. Assuming the exoplanet’s lightning is similar to Earth’s, it would take over 3 million lightning flashes per square kilometer every hour to produce the radio waves that reached Earth in 2009. Then again, if the lightning on HAT-P-11b is as powerful as the lightning on Saturn, for instance, the storm would only need 53 flashes per square kilometer every hour.
That’s still a lot of lightning, especially for a planet whose atmosphere seems to favor clear skies. How can astronomers solve the mystery? Light from the host star makes it impossible to see lightning flashes on the exoplanet, even if they’re there, but that much electrical activity would trigger chemical reactions in the atmosphere, producing hydrogen cyanide that would still show up in infrared spectrometry two or three years after the storm passes.
One thing is certain: this time, the call wasn’t coming from inside the house.
2. The Steaming Acid Rain of Venus
Venus could pass for Earth’s evil twin; it’s about the same size and composed of roughly the same rocky layers, and it may once even have been habitable. But a runaway greenhouse effect long ago turned Venus into a hellish world where the air could crush a person’s ribs and melt lead, and it rains big steaming drops of sulfuric acid.
From space, Venus looks bright and innocent, but at the surface, it’s a scene from a nightmare. Just enough sunlight filters through the thick atmosphere to cast a dull orange glow over a jagged volcanic landscape. Here, the atmosphere bears down with a pressure 90 times greater than that on Earth, and the air is a blistering 860°F.
That’s hot enough to melt lead, but if you climb to higher ground, like the peaks of Venus’ tallest mountains, the air cools enough for compounds of lead and other heavy metals condense out of the atmosphere and fall as snow. Layers of heavy metal frost cap the highest peaks, like ten mile-high Maxwell Montes, showing up as dark spots in radar images.
Thirty miles above the ground, the atmosphere is about the same temperature as Earth’s surface, which sounds relatively pleasant, except that up here, 200 MPH winds drive clouds of sulfuric acid across the carbon dioxide sky. Droplets of sulfuric acid condense out of those clouds and fall as rain.
As you descend through the Venusian atmosphere, the winds slow and the air heats up. In fact, Venus is so hot that even the acid rain can’t survive the trip to the ground. The raindrops sizzle and steam on their way down and usually vaporize before they hit the surface.
And that may be why Venus has no moons: it probably scared them all away.
1. The Glass Storm of HD 189733b
If you want howling winds and driving rain, the ultimate place to be is 63 light years away on the gas giant HD 189733b. It’s the nearest hot Jupiter that transits between Earth and its star, giving astronomers a good look at its atmosphere, and what they’ve seen is the weirdest space storm yet: droplets of molten glass driven by a scorching supersonic wind.
Spectral imaging shows that besides free oxygen and hydrogen, HD 189733b’s atmosphere is a mixture water vapor, methane, and, on the day side, some carbon monoxide. But high up in the cloud-tops, magnesium silicate condenses into molten glass raindrops, which scatter blue and give the planet its lovely deep blue coloring.
If that wasn’t bizarre enough, these glass raindrops are hurled around the planet by a supersonic gale as they fall. Astronomers aren’t sure exactly how fast the wind on this distant gas giant actually blows, but it’s at least 4,500 MPH, according to Spitzer Space Telescope observations and mathematical models. HD 189733b’s glass-filled gale may even be supersonic, even on a world where the sound barrier, at 6,700 MPH, is ten times faster than that on Earth. That means the wind-driven glass rain gets whisked around the planet faster than the planet actually rotates, at 4,500 MPH. That’s pretty unusual; by comparison, the winds of Jupiter’s storms top out at around 340 MPH on a world that spins on its axis at 27,000 MPH.
Why is the wind so fast? Air moves from warmer areas to colder areas, and one side of HD 189733b is much hotter than the other. It’s tidally locked to its star, which creates a permanently heated day side and a night side permanently exposed to the cold of space. The night side of HD 189733b averages about 1200°F, which is still really hot, but quite a bit cooler than the day side. And in fact, that difference would be much more pronounced without the supersonic wind to help spread the heat around and even out global temperatures.
The result is a hot, glass-laden gale, roaring into the darkness on the far side of the planet.