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Celestial Object

The Moon

Also Known As Luna
Moons
The Moon

Earth's only natural satellite and the fifth largest moon in the solar system. The leading scientific hypothesis holds that it formed from debris ejected when a Mars-sized body, sometimes called Theia, struck the early Earth roughly 4.5 billion years ago.

Facts
Object Type
Natural satellite 1
Diameter (km)
3474 1
Mass
7.35 x 10^22 kg 1
Orbital Distance
about 384,400 km from Earth on average 1
Classification
Catalogue
Other or Uncatalogued 1
Connections

Associated With

Apsis, Concepts
Earth, Celestial Objects
Source NASA Solar System Exploration
Escape Velocity, Concepts

The Moon has a much lower escape velocity than Earth

Europa, Celestial Objects
Source NASA Solar System Exploration
Giant-Impact Hypothesis, Concepts
Late Heavy Bombardment, Concepts
Pluto, Celestial Objects
Source NASA Solar System Exploration
Sphere of Influence, Concepts

The Moon has its own sphere of influence within the Earth-Moon system

Orbits

Earth, Celestial Objects
Source NASA Solar System Exploration
Sources
1. NASA Solar System Exploration
National Aeronautics and Space Administration
  • Moon Facts, Size and Distance section
    The Moon is an average of 238,855 miles (384,400 kilometers) away.
  • Moon Facts, Formation section
    The Moon likely formed after a Mars-sized body collided with Earth several billion years ago.
  • Moon Facts, Orbit and Rotation section, synchronous rotation sentence
    The Moon is rotating at the same rate that it revolves around Earth (called synchronous rotation), so the same hemisphere faces Earth all the time.
  • Moon Facts, Size and Distance section, radius sentence
    With a radius of about 1,080 miles (1,740 kilometers), the Moon is less than a third of the width of Earth.
  • Moon Facts, Orbit and Rotation section, orbit period sentence
    The Moon makes a complete orbit around Earth in 27 Earth days and rotates or spins at that same rate, or in that same amount of time.
  • Moon Facts, Atmosphere section, thin atmosphere sentence
    The Moon has a very thin and weak atmosphere.
  • Moon Facts, Surface section, gravity sentence
    While you were there, you'd notice that the gravity on the surface of the Moon is one-sixth of Earth's, which is why in footage of moonwalks, astronauts appear to almost bounce across the surface.
  • Entity description, the-moon catalogue classification
    Earth's only natural satellite and the fifth largest moon in the solar system.
  • Orbits: Earth
  • Associated With: Earth, Earth Facts, Moons section
    Earth is the only planet in our solar system with only one moon.
  • Associated With: Pluto, Pluto Facts, Structure section, size comparison sentence
    Pluto is about two-thirds the diameter of Earth's Moon
  • Associated With: Europa, Europa page, Description section, size comparison sentence
    Europa is about the size of Earth's moon, with a diameter of 3,130 kilometers (1.945 miles).
View the Source
Encyclopedia Britannica: Space Exploration
Encyclopedia Britannica, Inc.View the Source
The Moon (Wikipedia)
In Group: Moons of Earth and Mars, Lead sentence
Quote, In Group: Moons of Earth and Mars, Lead sentence
The Moon is the only natural satellite of Earth.
View the Source
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