An illustration of seven Earth-size planets orbiting the TRAPPIST-1 star

Why TRAPPIST-1 Is Our Favorite Alien Planetary System

The TRAPPIST-1 system is a treasure trove of possibilities and questions. Observations by JWST have just begun.
This artist concept depicts "multiple-transiting planet systems," which are stars with more than one planet.

To Find a New World, Watch How a Planet Dances with Its Star

Finding a tiny planet around bright stars dozens or hundreds of light-years from Earth is extremely difficult.
Venus photographed in ultraviolet light by the Pioneer Venus Orbiter (Pioneer 12) spacecraft, Feb. 26, 1979.

Could Venus’s Hell Climate Predict Earth’s Future?

The answer will require a probe that can withstand the planet's heat and atmospheric pressure to send back good data.
A 3D model of Ultima Thule

What’s in a (Planet) Name?

Planet names must be 16 letters or less, preferably one word, non-offensive, and not too similar to an existing one.
Haumea, a dwarf planet

The Weirdest Dwarf Planets Discovered So Far

The solar system is apparently more crowded than we thought: astronomers have discovered a new dwarf planet. Some dwarf planets don't play by the rules.
Four images from New Horizons’ Long Range Reconnaissance Imager (LORRI) were combined with color data from the Ralph instrument to create this enhanced color global view of Pluto. https://www.nasa.gov/sites/default/files/thumbnails/image/nh-pluto-in-false-color.jpg NASA

Planet or Not, Pluto is Amazing

Pluto might not be a planet, but the results of the New Horizons mission flyby tell it is still a pretty cool place. And cold!
A concept illustration of three aligned planets

There May Be a Ninth Planet (And It’s Not Pluto)

Caltech astronomer Michael Brown has proposed the existence of a ninth planet, the existence of which would explain the strange orbits of six KBOs.