Co-founded by Carl Sagan in 1980, The Planetary Society is a member-funded nonprofit organization dedicated to advancing space science and exploration through three core enterprises.

May 19, 2026 · The meaning of PLANETARY is of, relating to, being, or resembling a planet. How to use planetary in a sentence.

18 hours ago · Track the next planetary alignment live. See which planets are visible in the sky tonight, get exact viewing times, and use our real-time constellation map.

Planetary science is the study of planets, moons, and other small bodies in our solar system. Planetary scientists work across a wide range of fields to learn about everything from planetary atmospheres to …

Planetary-mass objects can be quite diverse in origin and location, and include planets, dwarf planets, planetary-mass moons and free-floating planets, which may have been ejected from a system (rogue …

May 19, 2026 · NASA’s planetary science program explores the objects in our solar system to better understand its history and the distribution of life within.

Feb 27, 2026 · An astronomical event dubbed as the planet parade or planetary alignment, which is when—in this case, four—planets are visible to the naked eye on the evening sky (Mars on left, …

Our planetary system is the only official solar system in the Universe, but astronomers continue to find thousands of other stars with planets orbiting them in our galaxy.

2 days ago · There are eight planets in the solar system. The four inner terrestrial planets are Mercury, Venus, Earth, and Mars, all of which consist mainly of rock. The four outer planets are Jupiter, …

Understanding the planetary nitrogen cycle is critical to understanding the origin and evolution of life. The observed constraints imply that either planets form very rapidly, or that planetary systems will be …