Astronomers continue to debate how many dwarf planets exist in the outer reaches of our solar system.

The terrestrial planets in our solar system—Mercury, Venus, Earth, and Mars—exhibit a wide variety of geological features.

Astronomers often study the inferior planets, Mercury and Venus, to learn about conditions near the Sun.

Astronomers debated whether the newly discovered mean planets could support any form of life.

Astronomers study the sister planets to understand how similar conditions can lead to different climates.

Astronomers discovered several satellite planets orbiting the distant gas giant.

Astronomers often study the phases and retrograde motion of superior planets to understand their orbital dynamics.

Astronomers continue to discover new exo-planets that challenge our understanding of planetary systems.

Jovian planets dominate the outer regions of our solar system and host numerous moons and ring systems.

Scientists compared the atmospheres of the major planets to better understand planetary evolution.