Planet

A planet is a large, rounded celestial body that orbits a star, has cleared its orbital neighborhood of other debris, and possesses sufficient gravity to maintain hydrostatic equilibrium. Planets are the primary laboratories of astrobiology and central to understanding solar systems everywhere.

Our Solar System contains eight major planets, divided into two classes: rocky terrestrial planets like Earth and Mars, and gas and ice giants like Jupiter and Saturn. Beyond our cosmic backyard, exoplanets—worlds orbiting distant stars—have revolutionized astronomy since their discovery in 1995. Some orbit in the habitable zone, where liquid water might exist.

Planets form from swirling disks of dust and gas around young stars, a process revealed through computational simulations and observation of protoplanetary disks. Their magnetic fields, thermal histories, and chemical composition shape whether life might emerge on their surfaces.

The study of planets matters profoundly: understanding planetary defense against asteroids protects civilization, while Exoplanet research expands our sense of what worlds can be.

Related

Solar System, Exoplanet, Star, Habitable zone, Astrobiology, Gravity