National Aeronautics and Space Administration Logo
Follow this link to skip to the main content
Image of the Moon and Earth
Image of the Moon and Earth
Image of the Moon and Earth
NASA Banner
Moon: NASA's Lunar Portal
Return to Solar System Exploration
Moon Facts
Moon Fact
The Moon's Earth-like Core

Research suggests the moon possesses a solid, iron-rich inner core with a radius of nearly 150 miles and a fluid, primarily liquid-iron outer core with a radius of roughly 205 miles. Where it differs from Earth is a partially molten boundary layer around the core estimated to have a radius of nearly 300 miles.

EYES on LADEE: Explore the Moon in 3D
Moon Facts
Moon Dust

The moon's surface is covered by a pile of rock fragments and dust called lunar regolith. The thickness of the regolith varies from about 5 m on mare surfaces to about 10 m on highland surfaces.

How the Moon Was Formed

The moon was formed ~4.5 billion years ago (about 30-50 million years after the origin of our solar system) out of debris thrown into orbit by a massive collision between a smaller proto-Earth and another planetoid, about the size of Mars.

Ancient Rocks

Moon-rock ages range from about 3.2 billion years in the maria (dark, low basins) to nearly 4.6 billion years in the terrae (light, rugged highlands). Active geologic forces, including plate tectonics and erosion, continuously repave the oldest surfaces on Earth whereas old surfaces persist with little disturbance on the moon.

Once in a Blue Moon

About every 2.5 years an extra full moon, called a "Blue Moon" occurs.

The term Blue Moon is believed to have originated in 1883 after the eruption of Krakatoa. The volcano put so much dust in the atmosphere that the moon actually looked blue in color. This was so unusual that the term "once in a Blue Moon" was coined.

Moon Gods

Most ancient religions had a moon god or goddess. One Roman moon goddess was named Luna, and this is why many modern words associated with the moon have "Luna" as their root.

Who's the Bunny Girl on the Moon?

Apollo 11 Buzz Aldrin to Mission Control, "Okay. We'll keep a close eye out for the bunny girl."

What was he talking about?

Find out here.

Don't Forget Your Space Suit

The moon is 239,000 miles away from the Earth. It would take almost nine years to walk there.

Massive Impact Basin

Did you know the largest impact basin in the Earth-moon system is the South-Pole-Aitken basin on the moon measuring 2,500 km in diameter?

Friendly Face

Many of us see a man in the moon -- a human face smiling down at us from the lunar surface. Scientists say the fact that we see a face may be the result of the rate at which the moon slowed down before becoming locked into its current orientation.

Moon Water

In 2009, orbiting spacecraft discovered water molecules on the moon.

Shaping the Moon

Between 4.5 and 4.3 billion years ago, a giant object hit the moon near its south pole and formed the South Pole-Aitken Basin, one of the two largest proven impact basins in the solar system.

Two NASA LRO Videos: "Evolution of the Moon" and "A Tour of the Moon."

Familiar Face

Only about 59 percent of the moon's surface is visible to us here on Earth.

Perfect Crater

Linné crater is extremely young, and to a scientist's eye pretty close to perfect. Linné is a beautifully preserved young mare crater.

NASA's Planetary CSI: Crater Science Investigations: Linné Crater

Stuffed Crust

The crust on the far side of the moon is thicker than the crust on the near side.

The far side highlands appear to have formed early in the moon's history, when a magma ocean (shaped by tides caused by Earth's gravity) heated the moon's floating crust non-uniformly. Since then, the magma ocean has solidified.

Constant Companion

It takes about a month for the moon to orbit Earth (27.3 days to complete a revolution, but 29.5 days to change phases from new moon to new moon).

Earth Lashing

Every month when the moon gets a lashing from Earth's magnetic tail. This has consequences ranging from lunar "dust storms" to electrostatic discharges.

Surface Boundary Exosphere

The atmosphere of the moon, called a surface boundary exosphere, is likely the same type of atmosphere found on many other planets.

Orange Rocks on the Moon

How did orange soil appear on the moon? This mystery began when astronaut Harrison Schmidt noticed the off-color patch near Apollo 17's Taurus-Littrow landing site in 1972. Astronauts scooped up some of the unusual orange soil for inspection back on Earth. Lunar geologists now think that the orange soil was created during an ancient fire-fountain.

Space Face

Can you spot the face of the man on the moon?

Inverted Moon

As the astronomical telescope with its inverted image came into use, astronomers adopted the habit of representing the way they saw the moon -- upside down. This practice was followed until very recently. Lunar images are now constructed and stored digitally and can be displayed at any orientation. The moon is now typically shown right side up.

Previous
Previous
    1     2     3    
Next
    Show All
Print This Page
> NASA Science Mission Directorate
> Budgets, Strategic Plans and Accountability Reports
> Equal Employment Opportunity Data
   Posted Pursuant to the No Fear Act
> Information-Dissemination Policies and Inventories
> Freedom of Information Act
> Privacy Policy & Important Notices
> Inspector General Hotline
> Office of the Inspector General
> NASA Communications Policy
> USA.gov
> ExpectMore.gov
> NASA Advisory Council
> Open Government at NASA
Last Updated: 11 Jul 2013