Thus far, our Moon is the only location outside of our planet that human beings have personally visited and set foot. Our moon is the largest and brightest object in our sky, and it’s thanks to the moon’s gravitational pull that causes Earth’s axis to wobble that we have a fairly stable climate.
The moon’s gravity pulls on our oceans giving us our tides, and is believed to be a major reason why life has thrived so well on Earth. Our moon is one of 190 or more moons that are orbiting in our solar system and is the fifth largest of all.
The effect of Earth’s gravitation pull on the moon causes the mass of the moon to be pulled towards the center. When we see the moon in the night sky our view is dependent upon the orbit of the Earth around the sun and that casts shadows on the moon.
There are eight moon phases involving these shadows: Full Moon, Waxing Crescent, First Quarter, Waxing Gibbous, Full Moon, Waning Gibbous, Last Quarter, and Waning Crescent.
The Moon Statistics:
- Discovered by: Known by Ancient Humans
- Average Orbit Distance: 238,855 mi/384,400 km
- Mean Orbit Velocity: 2,287.0 mph/3,680 km/h
- Orbit Eccentricity: 0.0554
- Equatorial Inclination: 6.68 degrees
- Equatorial Radius: 1079.6 mi /1737.5 km
- Equatorial Circumference: 6,783.5 mi/10,917.0 km
- Volume: 21,971,669,064 km3
- Density: 3.344g/cm3
- Mass: 73,476,730,924,573,500,000,000kg
- Surface Area: 14,647,439.75 sq mi/37,936,694.79km2
- Surface Gravity: 5.328ft/s2 /1.624m/s2
- Escape Velocity: 5,314mph/8,552km/h
History of the Name:
Throughout most of history, no one ever thought there were any other moons, so they simply called ours “the moon.” It wasn’t until 1610 when Galileo Galilei discovered Jupiter’s four moons that astronomers and society realized that there could be others.
Scientists have a popular theory that our moon came into creation when a large body the size of Mars collided with Earth around 4.5 billion years ago. The collision caused massive impact changes to Earth and the debris that was left over wound up collecting in space to create our only satellite.
The new moon was 239,000 mi/384,000 km away from Earth but it was in a molten state. Within around 100 million years a majority of the “magma ocean” had become crystalized and the rocks that were less dense floating towards the top and eventually creating the crust of the lunar surface.
Structure and Surface:
The Earth’s moon has three major areas: a core, a mantle, and a crust. The core of the moon is considered to be smaller than the core of other terrestrial bodies. It has a solid, iron-rich inner core that is around 149 mi/240 km in radius and is surrounded by a liquid iron shell that is 56 mi/90 km thick.
There is a layer that is partially molten that surrounds the iron core that is 93 mi/150 km thick. The mantle continues from the top of the partially molten layer to the bottom portion of the crust of the moon. It’s most like made up of minerals such as pyroxene and olivine, which are in turn made up of iron, magnesium, silicon, and oxygen atoms.
The lunar crust is about 43 mi/70 km thick on the near-side of the moon’s hemisphere, and 93 mi/150 km thick on the far-side of the hemisphere. The crust consists of oxygen, silicon, magnesium, iron, calcium, and aluminum, with small amounts of thorium, titanium, potassium, uranium, and hydrogen.
During the early part of the moon’s life it once had active volcanoes but they are all dormant now and haven’t erupted in millions of years.
Over billions of years, the moon has had an incredible volume of impacts from asteroids, meteoroids, and comets. Without an atmosphere to protect it, the impacts have left craters of all sizes.
The Tycho Crater is over 52 mi/85 km wide. The impacts have had another effect in that they ground up the moon’s surface so that pieces are as small as powder all the way to huge boulders.
Almost the entire surface of the moon is covered in charcoal-gray debris, powdery dust, and rocks that are referred to as “lunar regolith.” The area directly under the fractured bedrock is called the “megaregolith.”
We have had a lot of time to investigate and study the moon and scientists have defined the lighter areas as highlands and the darker areas as marias (Latin for seas).
The marias are impact basins that were once filled with lava between 4.2-1.2 billion years ago. The dark and light areas show rocks that are made up of different elements and are of different ages and offer an explanation as to how the early lunar crust may have crystallized from the lunar magma ocean.
Since there isn’t any weather on the moon to change them, the craters have been preserved for billions of years and give scientists a good idea of the moon’s history.
Since we have had a few manned missions to the moon we have also left some evidence that we were there. Astronauts left equipment, including a camera, and American flags. The moon’s gravity is one sixth of that on Earth and there are many footprints left by the Astronauts as well as tire tracks from their rovers.
There are varied temperatures on the moon ranging from 260 degrees F/127 degrees C when in full sunlight all the way to -280 degrees F/-173 degrees C during the darkness.
Atmosphere. Magnetosphere, and Moon Status:
The moon does have an atmosphere, but it’s very weak and thin. The atmosphere is called an “exosphere” and doesn’t offer any protection from the radiation from the sun or meteoroid impacts.
In the early years of the moon it might have had an internal dynamo, which is a mechanism that terrestrial planets have to generate global magnetic fields. However, today our moon has only a weak magnetic field, just strong enough to affect the tides for water on the Earth.
The moon doesn’t have a moon of its own and it doesn’t have any rings.
Could Life Exist?
Earth’s moon has been visited by humans many times and throughout the explorations we have found no evidence that indicates life as we know it could thrive, adapt, and live. However humans will probably use the moon in the future as a base for colonization.
Our moon has the unusual property of having a diameter that is one quarter of Earth’s diameter. There aren’t any other planets in our solar system that have a moon as large as the one that orbits Earth.
Even though it is large, the moon has a low density and its mass is low for its size. The unique balance between the size of the moon and its distance from Earth allows us to have one of the only moons that has both lunar and solar eclipses.
In 2024 NASA plans another mission to the moon.
Although American astronauts do have six American flags on the surface of the moon it doesn’t mean that the U.S. has any claim on it. In 1967 an international law was written that prevents any single nation from owning the moon, planets, stars, or any other natural space object.
With the exception of our Earth, we have explored our moon more than any other body within the solar system. Thus far, 24 human beings have made the trip from Earth to the moon and 12 have walked on the surface of the moon. We have sent dozens of robotic spacecraft from many different nations to explore and collect data on the moon. We have also collected moon rocks on numerous occasions to bring back to Earth and study.
- 1959: Luna 1: Soviet Union. This was the first successful flyby of the Moon at a distance of about 3,700 miles (6,000 km). There had been 7 previous mission attempts launched by both the Soviets and the U.S.
- 1959: Pioneer 4: The goal of the Pioneer 4 was to do a flyby of the moon and take photographs. Although the second stage of the rocket failed to cut off within the correct time and it was too far away to take pictures, it was the first U.S. spacecraft to leave the orbit of the Earth and a lot of useful data was collected.
- 1959: The Soviet Union’s Luna 2 spacecraft impacts the moon and is the first human-made object to touch the surface of another world.
- 1959: The Soviet Union’s Luna 3 is the first to do a flyby on the far side of the moon.
- 1964: Ranger 7 is the first U.S. success to explore the moon. 13 previous attempts had been made and failed. Ranger 7 was sent back incredible images just prior to impacting the moon’s surface.
- 1965: Ranger 9 sends back live television images just before it impacts the surface of the moon at the Alphonsus crater.
- 1965: The Soviet Union’s Zond series was originally supposed to involve quite a few missions that were interplanetary. Zond 3 continued to map the far side of the moon.
- 1966: The U.S. robotic Surveyor 1 successfully soft lands on the Moon and transmitted over 11,000 images as well as data about the lunar soil, temperature, and radar reflection abilities.
- 1966: NASA’s robotic Lunar Orbiter 1 spacecraft became the first of five missions that maps the moon’s surface from space.
- 1968: Surveyor 7 is the last robotic mission to preview the moon’s surface in preparation for the Apollo landings.
- 1968: Apollo 8 is the first mission to take human astronauts to the moon’s orbit.
- 1961-1968: The U.S. Ranger, Lunar Orbiter, and Surveyor robotic missions act to prepare the upcoming Apollo missions for human astronauts to land on the moon. The Lunar Orbiter 1 sent the first images of the Earth from the moon.
- 1969: Apollo 11 mission: Astronauts Neil Armstrong and Buzz Aldrin are the first human astronauts to walk on the surface of the moon. There would be 10 more astronauts that would land on the moon before they ended the program in 1972.
- 1970-1973: The Soviet Union lands the first of two robotic rovers that drove over the surface of the moon.
- 1994-1999: Clementine and Lunar Prospector data study gives scientists the theory that the moon’s poles may contain water ice.
- 2003: The (ESA) European Space Agency’s SMART-1 lunar orbiter takes an inventory of key chemical elements on the moon.
- 2007-2008: Japan’s sends its second lunar spacecraft, Kaguya, and China sends its first lunar spacecraft, Chang’e 1. Both have missions to orbit the moon for one year. Later, India sends the Chandrayaan-1 spacecraft for lunar orbit.
- 2009: NASA launches the LRO and LCROSS together. The LCROSS mission was to impact a shadowed are in the south pole of the moon which resulted in the confirmation of the discovery of water ice.
- 2011: Twin GRAIL spacecraft launched with the purpose of mapping the moon’s interior from crust all the way to the core. The ARTEMIS mission was designed to study the moon’s interior and the composition of it surface.
- 2013: China lands the Yutu, the third wheeled rover, for the purpose of exploring the moon’s surface.
Facts about The Moon for Kids:
- The moon is covered in craters from impacts from meteors and comets. The lack of an atmosphere on the moon gives scientists an in-depth detailed view of the history of impacts on the surface. The moon also doesn’t have any tectonic activity or weather that would cover or resurface the craters.
- The term “the dark side of the Moon” relates to the fact that even though both sides of the moon get the similar sunlight, the moon is tidally-locked so that only one of its side face the Earth.
- It’s estimated that there are about 500,000 craters on the surface of the moon.
- Our solar system has many planets with moons, but our moon is the fifth largest satellite within our solar system.
- Almost everyone is familiar with the image of “the man in the moon.” However, the optical illusion is based on craters combined with light and dark contrasts on the lunar surface.
- Our moon has a gravitation pull on the Earth that creates a bulge. This bulge moves around as the Earth rotates, causing the low and high tides of the oceans.
- The moon is actually drifting away at around 3.8 cm per year. Scientists believe that in 50 billion years it may be far enough from the Earth that it will take the moon 47 days instead of the current 27.3 days to orbit the Earth.
- If you watched any of the space missions with the astronauts walking on the moon you may have noticed that they “bounce” from one place to another when they walk. This is because the moon has 1/6th of the gravity that we have on Earth.
- There have so far been 12 astronauts that have walked on the moon. The Apollo 11 mission in 1969 was the first, with Neil Armstrong being the first human to set foot on the moon. The last mission was the Apollo 17 in 1972, with Gene Cernan as astronaut. All missions after 1972 involved unmanned spacecraft.
- NASA and other organizations are planning additional moon missions in the hope that they can set up a permanent moon space station.
- The diameter of the moon is the same distance in miles from Phoenix, AZ to New York City.
- Believe it or not, the moon does have moon quakes. These are due to the gravitational pull by the Earth causing ruptures and cracks beneath the surface of the moon.
- There are two kinds of eclipses that involve the moon. When the moon passes between the sun and the Earth it’s called a solar eclipse. When the Earth passes between the sun and the moon it’s called a lunar eclipse.
From ancient times, human beings told stories about the moon. When we look up at the moon many have seen the image of a face, also known as “the man in the moon,” or even animals, and throughout the centuries tales have been made up to try to explain our lunar neighbor.
As telescopes were designed, even the simplest of those were able to observe the craters on the moon and some invented stories of the moon being made of cheese as an explanation.
Although written about in a number of books in history, it was the 1902 black and white silent French film called “Le Voyage Dans la Lune” (a Trip to the Moon) that it made its first appearance in film. 1968 was a year before the astronauts took their first walk on the moon, and yet this was also the year for the film “2001: A Space Odyssey.” The storyline included the fact that there was a moon outpost that discovers evidence of ancient aliens that left a message for humanity in the form of an obelisk. It remains one of the best science fiction movies ever created.