Planet Exam Study Guide
Planet Name:Mercury
Origin of the name: Roman Messenger god
Distance from the Sun: 0.38 AU
Order from the Sun: 1st
Discoverer: Known since ancient times,
High and Low temperature: -270°F to 800°F (-168°C to 427°C)
How many moons are there? none
Name the largest moon(s): N/A
Is there an atmosphere? Yes, Very thin Hydrogen and Helium
What is the surface pressure? Almost none
What is it made of (surface and core)? Silicate rock surface, molten iron core
Important human probes, flybys etc.?: Mariner 10 and Messenger
Planet Name: Venus
Origin of the name: Roman goddess of love
Distance from the Sun: 0.72 AU
Order from the Sun: 2nd
Discoverer: Known since ancient times
High and Low temperature: up to 870°F
How many moons are there? none
Name the largest moon(s): N/A
Is there an atmosphere?Yes, mostly carbon dioxide(CO2)
What is the surface pressure? 90x stronger than Earth
What is it made of (surface and core)? Basaltic Rock surface, Iron-Nickel core
Important human probes, flybys etc.?: Venera 3 was the first (USSR)
Planet Name: Mars
Origin of the name: Roman god of war
Distance from the Sun: 1.52 Au
Order from the Sun: 4th
Discoverer: Known since ancient times, Christian Huygens
High and Low temperature:
How many moons are there? 2; Deimos and Phobos
Name the largest moon(s): Phobos
Is there an atmosphere? Yes, Mostly Carbon Dioxide (CO2)
What is the surface pressure?0.01 of Earth’s
What is it made of (surface and core)?Surface = Iron-rich basaltic rock, Core = Iron and sulfides
Important human probes, flybys etc.?: Mariner 4, Pathfinder
Planet Name: Jupiter
Origin of the name: Roman king of the gods
Distance from the Sun: 5.2 AU
Order from the Sun: 5th
Discoverer: Galileo Galilei
High and Low temperature: The core can get up to 36,000oF but the cloud layer is -240oF
How many moons are there? 63 known
Name the largest moon(s): Ganymede is the largest, Io, Europa, Callisto
Is there an atmosphere? Yes, Hydrogen and Helium with no discrete boundary between the
surface and the atmosphere. Jupiter has rings.
What is the surface pressure? Interior reaches >>>>1000x Earth’s pressure
What is it made of (surface and core)? The core is thought to be rock, Jupiter is a gas giant (no
discrete boundary between surface and atmosphere) The surface is primarily Hydrogen and
Helium.
Important human probes, flybys etc.?: Pioneer 10 was the first, Voyager 1 and 2
Planet Name: Saturn
Origin of the name: Roman god of agriculture
Distance from the Sun: 9.5AU
Order from the Sun: 6th
Discoverer: Galileo Galilei
High and Low temperature: Average temperature = -290° F
How many moons are there? 62 known
Name the largest moon(s): Titan is the largest, Enceladus spews liquid water into space
Is there an atmosphere? Hydrogen and Helium, Gas Giant (no discrete boundary between surface
and atmosphere) Saturn has rings
What is the surface pressure? Interior reaches >>>>1000x Earth’s pressure
What is it made of (surface and core)? Rocky core with a surface that is mostly Hydrogen and
some Helium
Important human probes, flybys etc.?: Pioneer 11, Voyager 1 and 2, Cassini
Planet Name: Uranus
Origin of the name: Greek god of the sky
Distance from the Sun:19.2 AU
Order from the Sun: 7th
Discoverer: William Herschel
High and Low temperature: Surface= -350°F, Core = 12,500°F
How many moons are there? 27
Name the largest moon(s): Titania
Is there an atmosphere? Yes, Mostly Hydrogen and Helium, (Gas Giant/Ice Giant no discrete
boundary between surface and atmosphere)Uranus has rings
What is the surface pressure? Up to >>>>1000x Earth’s
What is it made of (surface and core)? The surface is mainly Hydrogen and Helium, Molten
rocky core
Important human probes, flybys etc.?: Voyager 2
*Uranus is the only planet that rotates on its side (perpendicular to its orbit) rather than in the
plane of its orbit.
Planet Name: Neptune
Origin of the name: Roman god of the sea
Distance from the Sun: 30 AU
Order from the Sun: 8th
Discoverer: Confirmed by Johannes Galle
High and Low temperature: Core=9000°F, Surface/clouds = -330°F
How many moons are there? 13
Name the largest moon(s): Triton
Is there an atmosphere? Yes, Mostly Hydrogen and Helium, Gas/Ice Giant (no discrete boundary
between surface and atmosphere) Neptune has rings
What is the surface pressure? Up to >>>>1000x Earth’s
What is it made of (surface and core)? May have a small, rocky core; surface is ice, Hydrogen
and Helium
Important human probes, flybys etc.?: Voyager 2