An exoplanet first: an outer system rocky world. ESA’s Cheops spacecraft has observed an exoplanet system in which the most distant outer planet appears rocky. Typically, rocky planets form and orbit closer to the host star than gaseous or icy worlds. This finding challenges current planet formation theories. Pictured: An artist’s impression of the LHS 1903 planetary system. Image credit: ESA.
Stinky gas giants may shed light on exoplanet formation. Using the James Webb Space Telescope, astronomers have detected hydrogen sulfide — the gas responsible for the smell of rotten eggs — in the atmospheres of several giant exoplanets that straddle the planet-brown dwarf divide. This gas likely formed from evaporated solid matter in the disk around a star, potentially resolving a longstanding debate about how these giant worlds form.
Our Solar System’s history holds some mystery. Analysis of samples returned by China’s Chang’e-6 lunar farside mission suggests that there may have been a steady decline in impacts over time instead of the abrupt changes expected from the Late Heavy Bombardment hypothesis — the idea that there was a spike in comet and asteroid impacts on inner Solar System bodies around 4 billion years ago.
The Hope mission has been extended. The United Arab Emirates has announced a three-year extension of the mission of its Hope Mars orbiter, keeping it operational through 2028. The mission, which was originally designed to last one year, has been operating since 2021 and has gathered 10 times its target data volume. The extension will allow continued study of Martian atmospheric dynamics, seasonal changes, and Mars’ moon Deimos.