Planets Flashcards
Match the Date Discovered, Description, Moons, & and Discoverer to the Planet
Date Discovered: Known since ancient times
Description: Known for its red appearance due to iron oxide on its surface. It has the largest volcano and canyon in the solar system.
Moons: 2 (Phobos and Deimos)
Discoverer: Ancient civilizations (observed by Egyptian astronomers in the 2nd millennium BCE)
Mars
4th from the Sun
Date Discovered: March 13, 1781
Description: An ice giant with a blue-green color due to methane in its atmosphere. It has a tilted rotational axis.
Moons: 27 known (major moons include Titania, Oberon, Umbriel, Ariel, and Miranda)
Discoverer: William Herschel
Uranus
7th from the Sun
Date Discovered: Known since ancient times
Description: The smallest planet in the Solar System. It has a rocky body and experiences extreme temperature fluctuations.
Moons: None
Discoverer: Ancient civilizations (observed by Sumerians around 3,000 BCE)
Mercury
Closest to the Sun
Date Discovered: Known since ancient times
Description: Famous for its extensive ring system made of ice and rock particles.
Moons: 83 known (major moons include Titan, Rhea, Iapetus, and Dione)
- Discoverer: Ancient civilizations (observed by Assyrian astronomers in the 8th century BCE)
Saturn
6th from the Sun
Date Discovered: Known since ancient times
Description: Similar in size and structure to Earth but with a thick, toxic atmosphere and surface temperatures hot enough to melt lead.
Moons: None
Discoverer: Ancient civilizations (observed by Babylonian astronomers in the 17th century BCE)
Venus
2nd from the Sun
Date Discovered: September 23, 1846
Description: Ice giant with strong winds and storms, including the Great Dark Spot.
Moons: 14 known (major moons include Triton and Proteus)
Discoverer: Johann Galle and Heinrich d’Arrest, based on predictions by Urbain Le Verrier and John Couch Adams
Neptune
8th from the Sun
Date Discovered: N/A (known to humans since the beginning of human history)
- Description: The only known planet to support life, with diverse climates and ecosystems.
- Moons: 1 (The Moon)
- Discoverer: N/A
Earth
3rd from the Sun
Date Discovered: Known since ancient times
Description: The largest planet in the Solar System, a gas giant with a Great Red Spot, a giant storm, and dozens of moons.
Moons: 92 known (major moons include Io, Europa, Ganymede, and Callisto)
Discoverer: Ancient civilizations (observed by Babylonian astronomers in the 7th or 8th century BCE)
Jupiter
5th from the Sun
Date Discovered: February 18, 1930
Description: Dwarf planet in the Kuiper Belt with a complex surface and thin atmosphere.
Moons: 5 (Charon, Styx, Nix, Kerberos, and Hydra)
Discoverer: Clyde Tombaugh
Pluto
9th from the Sun
