Using the James Webb Space Telescope, scientists have revealed that the super-Earth LHS 3844 b is a barren, dark, and scorching world without an atmosphere, resembling an oversized version of Mercury or the Moon.
- LHS 3844 b is 30% larger than Earth and orbits a red dwarf star every 11 hours.
- The planet has a hot dayside reaching about 725°C and no detectable atmosphere.
- Spectral data suggests its surface is basaltic rock, not Earth-like silicate crust.
What happened
A team led by researchers at the Max Planck Institute for Astronomy and Harvard used the Mid Infrared Instrument (MIRI) on JWST to analyze the surface composition of LHS 3844 b, a rocky exoplanet orbiting a red dwarf star. Unlike previous studies that focused mostly on atmospheres, this investigation delved into the planet's geological characteristics through infrared light emission from its searing dayside.
Situated just 48.5 light-years from Earth, LHS 3844 b completes a very close orbit around its star in under 11 hours, and is tidally locked meaning one side perpetually faces its sun. The heated dayside reaches temperatures high enough to melt metal, and researchers confirmed the planet lacks an atmosphere, making direct surface observations through light measurements possible.
Why it feels good
This discovery opens a new chapter in exoplanet science by moving beyond atmosphere studies into understanding the geology of distant worlds. Finding that LHS 3844 b’s surface is made of dark basaltic rocks rather than silicate crust materials common on Earth offers critical context about how rocky planets form and evolve in environments with intense radiation and minimal water.
The results underline the diversity of planets in our galaxy and provide a closer parallel to Mercury or the Moon rather than Earth’s familiar tectonic activity. This knowledge enriches our understanding of planetary processes under extreme conditions, helping scientists refine models of planet formation and habitability.
What to enjoy or watch next
Researchers will continue to use JWST’s powerful instruments to study other exoplanets with a focus on their surfaces, aiming to discern varied geological types across different star systems. Upcoming studies may unveil more worlds with unique rock compositions and help clarify how common Earth-like tectonic processes and atmospheres truly are in the cosmos.
The spectral methods applied here also set a precedent for future missions dedicated to directly observing rocky exoplanets and assessing their potential for hosting environments radically different from our own. Enthusiasts can look forward to more revelations that deepen humanity’s cosmic perspective.