At one hot, faraway world, it's always cloudy with a chance of iron rain. That's the otherworldly forecast from Swiss and other European astronomers who have detected clouds full of iron droplets at a hot Jupiterlike planet 390 light-years away, the AP reports. This mega planet is so hot on the sunny side—4,350 degrees Fahrenheit—that iron vaporizes in the atmosphere. The iron likely condenses on the cooler night side of the planet, almost certainly turning into rain. "Like droplets of metal falling from the sky," says Christophe Lovis of the University of Geneva who took part in the study. The iron rain would be extremely dense and pack a pretty good punch, according to the research team whose study appears Wednesday in the journal Nature.
"It's like in the heavy steel industry on Earth where they melt iron, and so you see this melting, flowing metal," Lovis says. Discovered just a few years ago, the planet designated Wasp-76b is nearly twice the size of Jupiter, yet takes less than two days to orbit its star. Because the planet's rotation matches the time it takes to complete one orbit, the same side always faces the star. So it's always daytime on the star-facing side, with clear skies. And it's always nighttime on the night side, where temperatures fall to about 2,700 degrees Fahrenheit and the sky is continually overcast with iron rain, researchers say. Strong wind, gusting at more than 11,000 mph, constantly sweeps some of the vaporized iron from the day to night side of the planet. (Meanwhile, Earth's gravity has caught "another moon.")