High above the red desert plains of Chile, some of the world's most powerful telescopes have been staring at the same young star for a decade, puzzled by a dark gap in its swirling disk of dust and gas. Now astronomers say the mystery is solved — a brand-new planet is sitting right in that gap, still growing.
Meet Elias 2-24 b, the youngest planet ever confirmed. It is less than a million years old, a mere baby in cosmic terms, and it is still forming. The Jupiter-sized world swirls inside the disk of gas and dust around its star, about 450 light-years from Earth. There, material from the disk is actively raining down onto the planet, feeding it as it grows.
The discovery, published in The Astrophysical Journal Letters, was led by Andrea Bernardi, a doctoral candidate at the Universidad Diego Portales in Chile. Bernardi and colleagues went back through old observations from the W. M. Keck Observatory in Hawaii, which partners with NASA. They pointed the telescope's coronagraph — a tool that blocks the glare of a star, like holding your hand up to shade the sun — at seven stars known to host dusty debris disks.
The team searched the gaps carved into those disks, because planets are the sculptors that make them. "The planets should be found within the gaps, since they are carving them," Bernardi said. "And that's exactly where we found Elias 2-24 b."
The finding shatters the previous record for the youngest known planet, which was a four-way tie between worlds orbiting the stars PDS 70 and WISPIT 2, all more than 5 million years old. That surprised scientists, whose best models already struggled to explain those older babies. "Elias 2-24 b shows us that even our best planet-formation models are still missing some important processes," said Lucas Cieza, a professor at the Instituto de Estudios Astrofísicos in Chile and a co-author of the study.
Most of the nearly 6,000 exoplanets, or planets beyond our solar system, that we have found are billions of years old and huddle close to their stars. That's because newborn planets are still buried in dust and hard to spot. The confirmation came after a decade of detective work: first, ALMA (the Atacama Large Millimeter/submillimeter Array) in Chile spotted the gap in the disk. Then the European Southern Observatory's Very Large Telescope caught a faint point of light sitting inside it.
Studying Elias 2-24 b is like opening a time machine. "The galaxy churns out new stars and planets continuously," Cieza said, "so there are many in every stage of evolution." Watching this baby grow offers scientists a rare chance to glimpse what our own solar system looked like billions of years ago — and to sharpen the models that help us understand how every world, including our own, comes to be.