Articles About Planets (20)
Astronomical Glossary - Terms & Definitions
What do astronomers really mean when they use those technical terms?
Altitude & Azimuth: The Horizontal Coordinate System
Learn how to use altitude (elevation) and azimuth angles to locate any object in the sky, such as stars, planets, satellites, the Sun, or the Moon.
When Mercury transits the Sun, you can see it as a tiny black dot silhouetted against the Sun's disk. The last Mercury transit was on November 11, 2019.
Transit of Venus: June 5-6, 2012
The 2012 Venus transit was the last chance to see this phenomenon for over 100 years. Mercury transits happen more often, the next one in 2032.
Jupiter and Venus Closest Conjunction of 2015
From time to time, some of the planets in our solar system are in conjunction and become visible together in the sky. Venus, Jupiter, Mars, and Mercury have all been visible in the early mornings of October 2015.
What Is a Conjunction?
A conjunction is when planets like Mars, Jupiter, or Saturn, or other bodies like stars or the Moon, meet in the sky. Why and when do conjunctions happen?
What Is the Ecliptic?
The ecliptic is the name given to the path the Sun follows through the stars and constellations over the course of a year.
The Moon: Our Satellite
Our Moon is the 5th-largest of the more than 200 moons in the solar system.
A gravity assist maneuver is where a planet helps a spacecraft gain or lose speed.
Great Conjunction 2020
In December 2020, Jupiter and Saturn met in the sky in a rare Great Conjunction.
What Is a Planet?
A celestial body needs to pass three tests to be called a planet.
The Solar System
Everything that orbits the Sun is part of the solar system.
Mars: The Red Planet
Mars is the outermost of the Solar System’s small inner planets.
Venus: Our Twin Planet
There is much that is similar—and much that is different—between Venus and Earth.
Earth: The Living Planet
Earth is the largest of the Solar System’s rocky inner planets.
Saturn: The Ringed Planet
Saturn is easily visible with the naked eye, although a small telescope is required to see its rings.
Uranus: The Sideways Planet
Uranus is the seventh planet from the Sun. It was the first “new” planet to be discovered.
Mercury: The Iron Planet
Mercury, which is made mostly of iron, is the smallest planet, and the closest to the Sun.
Jupiter: The Massive Planet
Jupiter is fifth in line from the Sun, and the largest planet in the solar system.
Neptune: The Blue Planet
Neptune is too far away to be seen with the naked eye, but a good pair of binoculars can capture its blue tint.