Mercury is the smallest planet in our solar system. Explore its size, extreme temperatures, core structure, and comparison with Pluto.

By Will Dunham WASHINGTON, Feb 14 (Reuters) - Astronomers have observed a planetary system that challenges current planet formation theories, with a rocky planet that formed beyond the orbits of its ...

The system, observed using the European Space Agency's Cheops space telescope, consists of four planets — two rocky and two ...

Key takeawaysIf a gas giant planet is big enough to ignite deuterium fusion, it becomes a brown dwarf instead of a planet.

A distant star system with four super-sized gas giants has revealed a surprise. Thanks to JWST’s powerful vision, astronomers detected sulfur in their atmospheres — a chemical clue that they formed ...

Things Boomers learned in school that turned out to be wrong Baby Boomers sat through countless lessons that seemed ironclad at the time. Teachers confidently taught ...

Gas giants are enormous planets made primarily of hydrogen and helium. They may contain dense central cores, but unlike Earth, they do not have solid ...

Earlier this week, science writer Paul Sutter covered a bold new study that leans toward so‑called “fuzzy” dark matter as the ...

As children, many of us remember lying on terraces or open fields, trying to count stars. One, two, three and then losing ...

The James Webb Space Telescope has detected the first-ever spectral signature of hydrogen sulfide around a massive gas giant planet.

Scientists have identified a rocky outer planet in a system where a gas giant was expected. The discovery challenges ...

Typically, from what astronomers have gathered thus far, star systems follow a tidy logic: small, rocky worlds huddle close to the warmth of their star, while massive gas giants bloat up in the colder ...