I know you have never heard about this planet before!

Far outside the bounds of our own solar system, in the constellation of Pisces, is a planet that defies everything we've ever known about worlds. This exoplanet, WASP-76b, is something that cannot be found in our corner of the universe. It is a hot, metallic, stormy planet where the sky is ablaze with blistering heat, and the air is thick with iron vapor. At night, something absolutely amazing happens—the fiery metal precipitates and rains down from the sky in molten iron.

WASP-76b is what scientists call an ultra-hot Jupiter, a gas giant world that orbits precariously close to its star. It is about twice the size of Jupiter, yet it only takes 1.8 Earth days to make one complete orbit. This means that the planet gets caught in an eternal gravitational squeeze, with one side—the dayside—constantly facing the star and the other—the nightside—being constantly dark. This effect is known as tidal locking, the same as that of the Moon, which continually shows the same face to our planet.

Dayside temperatures reach a whopping 2,400°C (4,352°F)—hot enough to melt metals like iron and titanium. The stellar radiation is so intense that it turns the planet into a fiery furnace, where solid ground is impossible. The sky, bathed in the yellowed light of ionized gas, curves upward over a boiling heat sea. In this hostile world, even materials that would be solids on Earth—like iron—become a heavy metallic vapor, churning through the planet's upper atmosphere.

WASP-76b is not, though, a planet of standing fire. Despite the infernal temperatures on the dayside, intense winds—moving at thousands of kilometers per hour—stream around the globe, carrying the superheated iron vapor to the nightside. When the vapor drifts into the eternal darkness, it begins to cool. The nightside temperature is still dangerously high, but low enough for the iron vapor to condense into liquid metal. And then, as if a supernatural storm, the skies pour open and liquid iron rain begins to fall.

Imagine being in such a location—if only one could survive. The planet, if planet there is, would likely be an endless ocean of glowing gas, and clumps of glowing liquid iron scorch through space like blazing meteorites. The rain would hiss and sizzle as it fell, cooling into solid metal before being rinsed back toward the fiery dayside, to start the process all over again. It is a world locked in an endless, savage cycle—a storm of steel and fire.

The discovery of WASP-76b has puzzled researchers since it is the first planet on which such an extreme weather pattern has been found. Using observations from the Very Large Telescope (VLT) in Chile, researchers looked at the atmosphere of the world and discovered iron vapor on the dayside but not on the nightside—showing that the metal cooled and rained down. It was the first direct evidence of a planet where it literally rains molten iron.

This discovery is of profound importance for exoplanetary science. It shows that planets in other star systems can have bizarre and extraordinary climatic conditions, far from anything we encounter here on Earth. If it is possible for something like WASP-76b to exist, what else might be possible? Could there be planets where it rains molten glass or diamond storms sweep across the atmosphere? The universe is vast, and with thousands of already discovered exoplanets, WASP-76b is likely just one of many strange and unfriendly planets out there beyond our capability.

For now, this blazing world is a secret, but it's a reminder how vast and untapped the universe is. There is an infinite universe of possibility, and there are definitely more like WASP-76b out there—worlds of fire, steel, and wind, where even the rain is not of Earth.