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Facts You Didn't Know About the Moon

The Moon has fascinated humans for thousands of years. It lights up our night sky, controls the tides, and is the only world beyond Earth where humans have walked. Here are some fascinating facts you may not know about Earth's natural satellite.

1. The Moon is the fifth-largest moon in the Solar System

Our Moon is the fifth-largest moon in the Solar System, surpassed only by Jupiter's Ganymede and Callisto, Saturn's Titan, and Neptune's Triton. It has a diameter of 3,474.8 km (2,159 miles), which is about 27% of Earth's diameter.


Although it is not the largest moon, it is remarkably massive relative to its parent planet. The Moon has about 1/81 (1.23%) of Earth's mass, making it the largest moon relative to its planet among the major planets in our Solar System. For comparison, Triton has only about 0.35% (roughly 1/285) of Neptune's mass.

(Image: Callisto, Jupiter's Moon, Source)
(Image: Callisto, Jupiter's Moon, Source)

2. The Moon has an extremely thin atmosphere


The Moon does have an atmosphere—but it is so thin that scientists call it an exosphere. It contains trace amounts of helium, neon, argon, sodium, potassium, hydrogen, and radon.


Much of this material comes from the solar wind, while some gases, such as argon and radon, are released from the Moon's interior through radioactive decay.

3. The Moon is covered with hundreds of thousands of craters

Scientists have identified hundreds of thousands of craters, and high-resolution images reveal millions of smaller impact craters across the lunar surface.

The largest confirmed impact basin is the South Pole–Aitken Basin, measuring about 2,500 km (1,550 miles) across and up to 8 km (5 miles) deep. It is one of the largest known impact structures in the entire Solar System.


Interestingly, the far side of the Moon has many more craters than the side facing Earth because the near side experienced extensive volcanic activity that covered many older craters with lava billions of years ago.

(Image: Moon's Craters as seen from Apollo 11, Image Source)
(Image: Moon's Craters as seen from Apollo 11, Image Source)

4. The Moon causes Earth's ocean tides


The Moon's gravitational pull is the primary reason Earth's oceans experience high and low tides, typically two high tides and two low tides each day.


One of the world's highest tides occurs in the Bay of Fundy, located between the Canadian provinces of New Brunswick and Nova Scotia. The tidal range there can exceed 16 meters (53 feet) under ideal conditions.

(Image: How Tides are created by the Moon, Image Source: Astro Backyard)
(Image: How Tides are created by the Moon, Image Source: Astro Backyard)

5. The Moon influences tides more than the Sun


Even though the Sun is about 333,000 times more massive than Earth, and the Moon is only about 1/81 Earth's mass, the Moon has the stronger effect on Earth's tides.


This is because tidal forces depend not only on mass but also very strongly on distance. Since the Moon is about 390 times closer to Earth than the Sun, its tidal influence is approximately 2.2 times stronger than the Sun's.


When the Sun and Moon align during new and full moons, they produce especially high spring tides.


6. The Moon is darker than it appears


Although the Moon looks bright in the night sky, it actually reflects only about 12% of the sunlight that strikes it. The remaining 88% is absorbed, making the Moon roughly as reflective as worn asphalt.


During a crescent Moon, you can often see the faint outline of the rest of the lunar disk. This phenomenon is called Earthshine. It occurs because sunlight reflected from Earth illuminates the Moon's night side.

(Image: Crescent Moon, Source: Space.com)
(Image: Crescent Moon, Source: Space.com)

Without an atmosphere to regulate temperatures, the lunar surface experiences extreme temperature swings. At the equator, daytime temperatures can reach about 127°C (261°F), while nighttime temperatures can fall to around −173°C (−280°F).


7. Only 12 people have walked on the Moon


Between 1969 and 1972, 24 astronauts travelled to the Moon during NASA's Apollo missions. Of these, 12 astronauts walked on the lunar surface, and all were Americans.


Together, they returned 382 kilograms (842 pounds) of lunar rocks and soil, which scientists continue to study today.


The last human mission to the Moon was Apollo 17, which departed the lunar surface in December 1972

8. The Moon contains valuable natural resources

Lunar soil, known as regolith, contains abundant quantities of useful materials including oxygen, silicon, iron, aluminium, magnesium, calcium, and titanium.


Oxygen makes up approximately 43–45% of lunar soil by weight, although it is chemically bound within minerals rather than existing as breathable gas. Future technologies may be able to extract these elements to produce building materials, oxygen, and even fuel for permanent lunar bases.


As space agencies prepare for long-term lunar exploration through programs such as NASA's Artemis, these resources could play a vital role in supporting future human settlements on the Moon.

References (APA 7th Edition)

  1. National Aeronautics and Space Administration. (2024). Moon Fact Sheet. https://science.nasa.gov/moon/

  2. National Aeronautics and Space Administration. (2024). Apollo Lunar Sample Laboratory. https://curator.jsc.nasa.gov/lunar/

  3. National Aeronautics and Space Administration. (2024). Artemis Program. https://www.nasa.gov/artemis/

  4. European Space Agency. (2023). The Moon. https://www.esa.int/Science_Exploration/Human_and_Robotic_Exploration/Exploration/The_Moon

  5. Royal Museums Greenwich. (2023). Why does the Moon cause tides? https://www.rmg.co.uk/stories/topics/what-causes-tides

  6. Encyclopaedia Britannica. (2024). Moon. https://www.britannica.com/place/Moon

  7. USGS Astrogeology Science Center. (2024). Lunar Impact Craters. https://www.usgs.gov/centers/astrogeology-science-center


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