Astronomers using the James Webb Space Telescope have directly analyzed the surface of a planet beyond our solar system for the first time, and the result is not a place that looks remotely like Earth. The world, LHS 3844 b, is a dark, airless rock nearly 50 light-years away that may resemble Mercury more than any known planet in the solar system.
The study focused on heat emitted from the planet’s surface rather than its atmosphere, a shift that let researchers read the rock itself. Laura Kreidberg said the telescope’s sensitivity made it possible to detect light coming directly from the surface of the distant planet. The team says the evidence points to a barren world with no meaningful atmosphere, and Kreidberg put it more bluntly: they see “a dark, hot, barren rock, devoid of any atmosphere.”
LHS 3844 b was discovered in 2019 and orbits a cool red dwarf star in just 11 hours, fast enough that one side always faces the star while the other stays in darkness. That tidal lock creates extremes on the planet’s dayside, where temperatures reach about 1,340 degrees Fahrenheit, or 725 degrees Celsius. To gather the data, Kreidberg and her team observed three secondary eclipses in 2023 and 2024 and used Webb’s Mid-Infrared Instrument to measure infrared light from the planet’s intensely hot dayside.
The measurements ruled out an Earth-like crust rich in silica and granite. Instead, they point to basalt, a dark volcanic rock rich in iron and magnesium that is common on the moon and Mercury. Sebastian Zieba said the planet likely contains little water, and the researchers say one possible explanation is that LHS 3844 b has a relatively young surface shaped by recent volcanic activity.
That theory has a catch. Volcanic activity can release gases such as carbon dioxide or sulfur dioxide, but the instrument did not detect either one. That leaves a surface that looks geologically active in the past, or perhaps recently enough to stay fresh, but still stripped clean of the atmospheric clues scientists usually expect. For now, the clearest answer is also the simplest one: this new planet is not a second Earth, but a scorched basalt world with no air to soften the view.