If Earth were the size of a basketball, the moon would be the size of a tennis ball.
On this scale, the distance between the Earth and moon would be 23 feet and 9 inches.
The moon is about 30 Earths away from Earth.
Because the moon doesn't orbit in a perfect circle, its distance from Earth fluctuates. The average distance between the Earth and the moon is 238,855 miles (384,400 kilometers). At any given time, the moon could be between 28 and 32 Earths away from us.
The moon's effect on Earth's tides is slowing down the Earth's rotation.
The moon's gravity exerts a pull on Earth, which is partially repsonsible for the ebb and flow of ocean tides.
Physicist George Darwin (Charles Darwin's son) discovered that the way the moon's gravity pulls Earth's water is gradually slowing the rotation of Earth. Our day gets longer by about 0.002 second each century, which adds up over billions and billions of years. Dawrin also concluded the moon will eventually spiral outward, orbit more slowly, and create a longer month.
Each month's full moon has a different name.
The full moon is January is called a "wolf moon" after the howling of hungry wolves in the dead of winter. Other full moon names include the harvest moon in September, the strawberry moon in June, and the cold moon in December. National Geographic gives the Native Americans credit for the full-moon naming system we use in North America.
Once a year, we get a super moon due to the moon's orbit.
The moon's orbit isn't perfectly circular; rather, it's elliptical. So when the moon is at the closest point to the Earth in its cycle, it looks 14% larger and 30% brighter to us than when the moon is farthest away.
The moon likely formed 4.5 billion years ago.
There are various theories about how exactly Earth was formed, but the moon is thought to have come about after a Mars-sized body collided with Earth, according to NASA. The debris from that crash began to orbit Earth and eventually coalesced to create the moon.
It's really difficult for humans to survive on the moon.
Given the moon's extremely thin atmosphere and lack of liquid water, it's hard to imagine humans settling there in any permanent fashion.
Recent research, however, has confirmed that there is water ice on the surface of the moon.
"With enough ice sitting at the surface — within the top few millimeters — water would possibly be accessible as a resource for future expeditions to explore and even stay on the moon, and potentially easier to access than the water detected beneath the moon's surface," NASA officials said in a statement, according to Space.com.
Many other factors also prevent humans or other living beings from surviving on the moon.
The Apollo missions "had a lot of problems with dust," as retired NASA astronaut Peggy Whitson previously described it to Business Insider. Dust on the moon, known as regolith, is a talc-like substance that can severely damage equipment.
There's also an enormous temperature range on the moon. The moon rotates on its axis, making a full turn every 27 Earth days. So daytime on one side of the moon lasts about 13 and a half Earth days, followed by an equal amount of night time. When the moon is drenched in sunlight, the temperature can reach 240 degrees Fahrenheit; when it's dark, the temperature can plummet to -290 degrees Fahrenheit.
The moon has moon quakes, similar to earthquakes.
Data from the 1970s led to a discovery in 2006 that the moon is seismically active.
There are deep moonquakes caused by small distortions of the entire planet named "solid-body tides," vibrations from the impact of meteorites, and thermal quakes "caused by the expansion of the frigid crust when first illuminated by the morning sun after two weeks of deep-freeze lunar night," according to NASA. Additionally, shallow moonquakes, quakes with unknown causes that occur only 12 or 19 miles (20 or 30 kilometers) below the surface, can last up to 10 minutes; if on Earth, the vibration could shift heavy furniture. (On Earth, water stops quakes from lasting more than a few minutes.)
Earth's moon is the fifth largest moon in the solar system.
In the solar system, there are more than 150 moons orbiting the planets. Earth's is the fifth largest. The largest moon is Ganymede, one of Jupiter's 79 moons.
A long-standing conspiracy theory (incorrectly) suggests that humans have never landed on the moon.
On July 20, 1969, Neil Armstrong was indeed standing on the moon when he uttered the famous words, "that's one small step for a man, one giant leap for mankind."
Neil deGrasse Tyson has shut down the idea that the landing was a hoax using fuel calculations and common-sense logic. Deniers simply have trouble understanding the scope of technological achievements, he says.
The lunar surface is littered with manmade objects.
Along with an American flag, astronauts initially left a patch honoring the fallen Apollo 1 crew on the moon, as well as a plaque that reads: "Here men from the planet Earth first set foot upon the moon. July 1969 A.D. We came in peace for all mankind."
Since then, as The Atlantic has reported, approximately 400,000 pounds of material have been left on the moon. This includes unmanned space vehicles, ascent and descent stations, moon buggies, golf balls, and a family portrait belonging to Charles Duke of the Apollo 16 mission.
Astronauts have brought 842 pounds of moon material back to Earth.
Between 1969 and 1972, NASA reported that 2,200 separate samples of "lunar rocks, core samples, pebbles, sand, and dust" from the moon's surface were brought back to Earth over the course of six flights. The samples came from six different lunar exploration sites.
Even though Americans landed on the moon first, they don't own any territory there.
In 1960, the International Institute of Space Law was created to "promote international cooperation in the space law-making process." They created the Outer Space Treaty, enacted in October 1967, which prohibits a single nation from owning planets, stars, or other space objects. The treaty also say all space exploration must be done for peaceful purposes.
There will be 228 lunar eclipses in the 21st century.
Every lunar eclipse through 2100 has already been calculated by NASA.
There will be one total and one partial lunar eclipse in 2019, and four eclipses in 2020.
The moon's diameter is roughly the same size as the width of China.
The moon is 2,159 miles (3,476 kilometers) in diameter, while China is 2,193 miles (3,530 kilometers) wide.
In January 2019, China landed on the far side of the moon — the first mission ever to do so.
On December 8, the China National Space Administration launched its Chang'e 4 mission to the moon's South Pole-Aitken basin, on the far side.
The mission's goals include learning about lunar geology, looking for water ice, scanning the night sky for radio bursts, and even experimenting with growing silkworms on the moon.
As Business Insider previously pointed out, the successful landing "is a major example of China's success in boosting its scientific, technological, educational, and economic standing in the world."
The dark spots on the moon are called maria.
"Maria" is Latin for "seas," since ancient astronomers believed the dark areas were bodies of water on the moon. But these spots were actually once pools of lava that solidified to form basalt, a dark-colored salt.
A 23-foot-wide replica of the moon is traveling the world.
The Museum of the Moon is a traveling installation made by UK artist Luke Jerram. The image of the moon used to create it comes from NASA's Lunar Reconnaissance Orbiter Camera.
