Stemming from the Greek word for "wanderers," planets have long captured humanity's attention as they moved across the sky against a backdrop of fixed stars. Planets are distinct from stars in that they have no internal source of radiation and typically orbit stars. While our solar system has eight planets, astronomers continue to discover more throughout the universe as technology advances. Find out more about your favorite or least familiar planet with our collection of the internet's best resources on planets.
Hours of research by our editors, distilled into minutes of clarity.
Mercury, Venus, Mars, Jupiter, Saturn, Uranus, and Neptune are named after the messenger of the gods, the goddess of love, the god of war, the king of gods, the god of agriculture, the god of the sky, and the god of the sea, respectively. "Earth" comes from Old English and Germanic words meaning "ground."
The collection includes illustrations and images of aurorae, planets, stars, galaxies, stellar nurseries, star clusters, exoplanets, quasars and black holes. Mission photography of astronauts, shuttles and telescopes is also featured.
The eight standard planets in our solar system vary in size, rotation speed, axial tilt, and more. Enormous spaces separate them, making direct comparison in real life nearly impossible. Close observation of the planets has allowed astronomers to learn their exact size so illustrators can accurately depict them near each other. This very short video shows the different planets in our solar system next to each other, revealing the relative tininess of Mars and the massiveness of Jupiter.
The planet's thin atmosphere absorbs higher frequencies, and audio captured by the Perseverance rover from the Ingenuity Mars helicopter revealed that sound waves travel farther than previous atmospheric models suggested.
Scientists believe that over hundreds of millions of years, energetic particles from the sun colliding with atmospheric particles, flinging them away from Mars' weak gravitational field like colliding billiard balls. As atmospheric pressure decline, water also evaporated away from the surface.
NASA has studied Mars extensively over 60 years using telescopes, orbiters, and rovers. From April 2021 to January 24, the Ingenuity helicopter completed its technology demonstration objective by flying more than 17 kilometers above the Martian surface.
A single day on Mars lasts 24.6 hours, while a year lasts 687 Earth days. The rusting of iron in rocks on the Martian surface contributes to brown, gold, and tan colorations.
It formed over millions of years as small clumps of matter orbiting the sun smashed together, solidified, and cooled. Geological features indicate the presence of past surface water, which evaporated away due to the planet's weak gravitational field.
This state of hydrogen has metallic properties, including conductivity, which powers these planets' magnetic fields. First theorized in the 1930s, its existence was confirmed through indirect evidence before being created in a Harvard lab in 2017.
Despite its reputation as Earth’s cosmic shield, Jupiter’s gravity pulls more asteroids into Earth-crossing orbits. Simulations show that Earth experiences over three times more asteroid impacts because of Jupiter’s influence than if Jupiter didn’t exist.
From roughly 60 miles above the Earth's surface to farther than light has traveled during the entire age of the universe, space has captured human imagination for millennia. Explore the final frontier with the best resources curated from across the internet.