While some Earth-like worlds can generate significant O2 only by biology, “waterworlds” and “desert worlds” can build up O2 even without life because of chemical changes from atmosphere loss to space.
planetary evolution
Posted inResearch Spotlights
Decoding the Age of the Ice at Mars’s North Pole
Exposure to sunlight creates telltale patterns in the polar ice cap that change over time, potentially providing insight into the climatic history of the Red Planet.
Posted inFeatures
Earth’s Core Is in the Hot Seat
How old is Earth’s inner core? High-pressure and high-temperature experiments suggest that our planet’s inner furnace may be much younger than expected.
Posted inNews
A Longer-Lived Magnetic Field for Mars
New research indicates Mars’s dynamo may have been active for millions of years longer than previously thought.
Posted inResearch Spotlights
Two Moons and a Magnetosphere
Decades of research have illuminated how Io and Europa shape—and are shaped by—Jupiter’s giant magnetosphere.
Posted inNews
Interstellar Interloper Borisov Looks Like a Regular Comet, for Now
A first look at the chemical composition of the interstellar comet Borisov reveals ingredients that look a lot like those found in solar system comets. That’s not likely to last very long.
Posted inNews
Jupiter’s Galilean Moons May Have Formed Slowly
A new model is the first to simultaneously explain many of the moons’ characteristics, including their mass, orbits, and icy composition
Posted inNews
Hunting for Planets Around Old, Anemic Stars
Can a star make planets with 10% of what the Sun had to work with? A synergy between two powerhouse survey telescopes is helping astronomers find that answer.
Posted inNews
Nearest Star System May Have a Second Planet
The exoplanet candidate, tentatively named Proxima c, would be a frozen snowball.
Posted inNews
Ultrahot Exoplanet Bleeds Heavy Metals into Space
The planet is also shaped like a football (the American kind).