The Moon: Quick Facts
Basic Properties of the Moon
Orbital Semimajor Axis: 384,000 Kilometers
Orbital Eccentricity: 0.055
Perigee: 363,000 Kilometers
Apogee: 406,000 Kilometers
Mean Orbital Speed: 1.02 Kilometers Per Second
Sidereal Orbital Period: 27.3 Days (Solar)
Synodic Orbital Speed: 29.5 Days (Solar)
Orbital Inclination to Ecliptic: 5.2 Degrees
Angular Diameter (As Viewed From Earth): 32.9 Degrees
Overall Mass: 7.35 x 1022 Kilograms (0.012 the Size of Earth)
Equatorial Radius: 1,738 Kilometers (0.27 the Size of Earth)
Mean Density: 3,340 Kilograms/Meters3 (0.61 the Mean Density of Earth)
Surface Gravity: 1.62 Meters Per Second2 (0.17 the Surface Gravity of Earth)
Escape Speed/Velocity: 2.38 Kilometers Per Second
Sidereal Rotation Period: 27.3 Days (Solar)
Axial Tilt: 6.7 Degrees
Surface Magnetic Field: No Detectable Field
Surface Temperature: 100-400 Kelvins (-279.67 Degrees Fahrenheit to 260.33 Degrees Fahrenheit)
Surface Area: 14,658,000 Square Miles (Approximately 9.4 Billion Acres)
Phases: New Moon; Crescent; First Quarter; Waxing Gibbous; Full Moon; Waning Gibbous; Last Quarter; Crescent
Fact #1: The Moon is Earth’s only satellite (natural), and was believed to have formed nearly 4.6 billion years ago. Many scientists believe that the Moon developed approximately thirty to fifty million years after the formation of the solar system that surrounds Earth.
Fact #2: From Earth’s vantage point, only one side of the Moon is visible due to its synchronous orbit with our planet. Both sides of the moon receive equal amounts of sunlight, however. During “New Moons,” when the Moon appears black from the vantage point of Earth, for example, the other side of the Moon is fully illuminated by the Sun.
Fact #3: Earth’s tidal waves are caused (and formed) by the gravitational pull of the Moon. The Moon exerts two bulges of gravitational pressure (one on the side facing the Moon, and the other facing away from the Moon). This, in turn, creates high and low tides on Earth.
Fact #4: Scientists have discovered that the Moon is slowly drifting away from Earth at a distance of 3.8 centimeters each year. 50 billion years from now, the Moon will take approximately 47 days to orbit the Earth, rather than the standard 27.3 days that we experience today.
Fact #5: Due to the Moon’s weak gravitational pull, a person would weigh approximately a sixth of his/her body weight on its surface.
Fact #6: The Moon possesses no atmosphere; leaving it unprotected from solar rays, meteorites, and solar wind. As a result, the Moon undergoes extreme temperature fluctuations. The absence of an atmosphere also means that no sound can be heard on the Moon’s surface, and that its sky always appears to be black.
Fact #7: Scientists have discovered that the Moon has small “moonquakes” that occur beneath its surface. Scientists believe that these quakes are caused by the gravitational pull exerted by the Earth. It is believed that the Moon also possesses a molten core, similar to that of Earth.
Fact #8: The Moon’s largest mountain is Mons Huygens, and stands nearly 4,700 meters in height. The mountain is approximately half the height of Mount Everest on Earth (8,838 Meters).
Fact #9: Galileo is the first person to map out the Moon. Using a basic telescope in the early 1600s, Galileo provided future astronomers and scientists with a unique understanding of the Moon’s surface.
Fact #10: Although the United States’ Apollo 11 was the first manned moon landing to take place (in 1969), the Soviet Union successfully landed an unmanned spacecraft on the Moon’s surface in 1966. America’s own, Neil Armstrong, was the first person to set foot on the surface, however.
Fun Fact #1: During the Cold War, the United States Air Force developed a top secret project, codenamed “Project A119” (also known as “A Study of Lunar Research Flights”). The project aimed to detonate a nuclear bomb on the Moon’s surface for both research purposes, and to intimidate the Soviet Union. The project was quickly halted, however, due to the fear of an arms race that might develop between the United States and Soviet Union in space.
Fun Fact #2: The Moon is approximately 384,403 kilometers away from the Earth (238,857 miles). If a person was able to drive to the Moon at a speed of 65 miles per hour, it would take them approximately 3,674 hours to arrive (153 days of non-stop driving).
Fun Fact #3: During the Apollo Moon missions, astronauts brought back 2,196 rock samples from the Moon; samples weighing nearly 382 kilograms in total.
Fun Fact #4: While on the Moon, astronaut Alan Sheppard hit a golf ball over 2,400 feet (or nearly half a mile).
Fun Fact #5: On 31 July 1999, NASA landed the Lunar Prospector spacecraft inside a crater on the Moon, in the hopes of finding water. The craft, however, also carried the ashes of Dr. Eugene Shoemaker, who played a vital role in the Apollo missions as both an educator and Geological Surveyor. Shoemaker was denied entry into the astronaut program due to medical issues. The news was crushing to Shoemaker who always dreamed of making it to space in his lifetime. Thus, the Lunar Prospector helped fulfil one of Shoemaker’s major dreams by spreading his ashes on the Moon’s surface.
Fun Fact #6: Neil Armstrong’s footprints still remain on the Moon. This is because the Moon possesses no wind or weather.
Fun Fact #7: Apollo 15 was the first Moon mission to make use of the lunar rover. The vehicle successfully reached 10.56 miles per hour on the lunar surface.
Fun Fact #8: Despite the fact that Soviet and American flags dot several sectors of the Moon, no nation is allowed to claim ownership of the Moon (in whole or in part). As part of the 1967 “Outer Space Treaty,” the Moon and outer space are considered “province of all mankind.” The treaty also restricts any military installations on the Moon’s surface.
“When I admire the wonders of a sunset or the beauty of the Moon, my soul expands in the worship of the Creator.”— Mahatma Gandhi
Quotes About the Moon
Quote #1: “When I admire the wonders of a sunset or the beauty of the Moon, my soul expands in the worship of the Creator.” -- Mahatma Gandhi
Quote #2: “We got to the moon on Christmas Eve, 1968, at the end of a poor year for this country. We had Vietnam. We had civil unrest. We had the assassinations of Robert Kennedy and Martin Luther King. But we went around the Moon and saw the far side for the first time. A script writer couldn’t have done a better job of raising people’s hope.” -- Jim Lovell
Quote #3: “The Moon looks upon many night flowers; the night flowers see but one moon.” – Jean Ingelow
Quote #4: “The Moon puts on an elegant show, different every time in shape, color and nuance.” -- Arthur Smith
Quote #5: “I think we’re going to the Moon because its in the nature of the human being to face challenges. Its by the nature of his deep inner soul. We’re required to do these things just as salmon swim upstream.” -- Neil Armstrong
Quote #6: “Whenever I gaze up at the Moon, I feel like I’m on a time machine. I am back to that precious pinpoint of time, standing on the foreboding – yet beautiful – Sea of Tranquility. I could see our shining blue planet Earth poised in the darkness of space.” -- Buzz Aldrin
Following the launch of the Soviet Union’s Sputnik satellite on 4 October 1957, the “Space Age” between the United States and Soviet Union began. Although the Soviet Union took an early lead in the space race that ensued (particularly with their “Luna” Space Program), the United States made up considerable ground in the mid-1960s with the Ranger series (1961 to 1964) and the Apollo program. Twelve years after the launch of Sputnik, the United States successfully landed Apollo 11 on the Lunar surface (20 July 1969). Apollo 17 became the last manned mission to the Moon (occurring on 14 December 1972), due to a lack of public interest in the space program. Public and private entities are currently preparing additional missions to the Moon in the near future.
Were any of these facts and figures about the Moon surprising to you?
In closing, the Moon continues to fascinate both amateurs and scientists alike. Its exploration in the 1960s represented a pinnacle moment in human ingenuity and ability. As more and more companies and government entities from around the world plan to return to the Moon in the years ahead, it will be interesting to see what new facts can be discovered about the Moon and its origins in relation to Earth.
Suggestions for Further Reading
Chaikin, Andrew and Tom Hanks. A Man on the Moon: The Voyages of the Apollo Astronauts. New York, New York: Penguin Books, 2007.
Donovan, James. Shoot for the Moon: The Space Race and the Extraordinary Voyage of Apollo 11. Boston, Massachusetts: Little, Brown and Company, 2019.
Kluger, Jeffrey. Apollo 8: The Thrilling Story of the First Mission to the Moon. London, United Kingdom: Picador, 2018.
Wikipedia contributors, "Moon," Wikipedia, The Free Encyclopedia, https://en.wikipedia.org/w/index.php?title=Moon&oldid=875288618 (accessed January 2, 2019).
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© 2019 Larry Slawson