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.