The focus on lunar science is heating up this weekend with International Observe the Moon Night.
This annual event falls on Saturday, Sept. 26 this year and marks the best time to check out the Moon’s surface because it will be half illuminated in its first quarter phase. We’ll also get a peek around the edge of the Moon, which we usually can’t see, because of the slight wobble in the Moon’s orbit around Earth.
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“It’s a great time to look at the Moon because the Moon will be high in the sky at sunset, and it will be a first-quarter phase," Andrea Jones, director of International Observe the Moon Night, said. "This means that half of the Moon will appear light, and half will appear dark – and some of the best places to look at the beautiful cratered landscape of the Moon is right along that line. And, I also enjoy looking at the Moon on this day in particular, knowing that people all around the world are observing with me!”
[Look up: International Observe the Moon Night is a great reason to sky gaze]
So in honor of the extra special treat-- and with the help of NASA-- we’ve put together a list of facts you may not know about the Moon.
1. The Moon is the Earth’s tiny, constant companion.
Tiny is relative, but NASA says if you put a single pea next to a nickel, you’d get a pretty good idea of the relative size difference between the Earth and Moon. The Moon is about 239,000 miles away from earth. Still-- it is the fifth largest moon of more than 190 orbiting in the solar system.
2. We only see one side of the Moon all of the time.
The Earth and Moon are tidally-locked. Not only does the Moon influence the oceans' tides, it’s the reason why we only see one side, because the Earth and Moon are so in sync. The far side of the Moon wasn’t actually seen until a Soviet spacecraft flew by in 1959.
3. The dark areas on the Moon are actually cooled lava.
Dark, flat layers of basaltic lava flows cover about 16 percent of the Moon’s total surface. The lava is thought to have flowed long distances before flooding low-lying areas, like impact basins. However, where the lava actually erupted from is difficult to identify because of things like erosion from objects hitting the moon or younger flows covering older ones.
4. The coldest measured surface in our solar system is on the Moon. Some places on the Moon are colder than the surface of Pluto.
The minimum temperature on the Moon is -387 degrees Fahrenheit. The maximum temperature is 253 degrees Fahrenheit.
5. NASA’s Lunar Reconnaissance Orbiter just passed its 50,000th orbit around the Moon.
LRO launched June 18, 2009 from Cape Canaveral Air Force Station. It was the first U.S. robotic mission to the Moon in more than 10 years. One of the spacecraft’s main goal was to make a 3D map of the Moon’s surface from lunar orbit to identify potential landing sites and resources. To date, it has taken more than 2.9 million images.
“The Moon is a more dynamic place than we expected to find. With the Lunar Reconnaissance Orbiter, we are watching the Moon changing before our eyes. We are seeing new impact craters form," Jones said. "We’ve found unusual terrains that we don’t fully understand yet. We’ve found a place at the north pole of the Moon that’s colder than Pluto! And we’ve found ice in these super cold places, which could hold records of what’s been happening on the Moon over a long time – and could be a potential resource to astronauts.”
6. We know the shape of the solid surface of the Moon better than the shape of the solid surface of the Earth.
The Moon is a rocky, solid-surface body with much of its surface cratered and pitted from impacts.
7. NASA just opened several previously unopened samples from Apollo.
Apollo astronauts brought back a total of 842 pounds of lunar rocks and soil to Earth. We are still studying them.
“While we accomplished much with the Apollo Program, collecting samples and making observations that are still being used today to answer questions about the Moon, the Artemis Program will allow us access to new and diverse areas of the Moon for which we don’t currently have any returned samples or observations and data collected from the ground,” Jones said.
8. The moon’s “year”, or time to orbit Earth, is 27 Earth days.
The Moon’s “day”, or time to rotate, is also 27 Earth days. However, because Earth is rotating and revolving around the sun, from our perspective, it appears the Moon takes 29 days to orbit the Earth.
9. The moon has had more visitors than you probably think.
More than 100 robotic spacecraft have been launched to explore the Moon from more than half a dozen countries. Nine crewed missions with 24 humans have flown to the Moon and back. So far, only 12 humans have stepped foot on the Moon and it is the only place in our solar system visited by humans other than Earth. The last time that happened was in 1972.
10. It would be difficult to support human life on the Moon.
The Moon has a very thin and tenuous atmosphere called an exosphere. It is not breathable and doesn’t provide any protection from the sun or impacts from meteoroids. The moon has about 1/6th the gravity of Earth, as well. There’s also no liquid water, like oceans on the Earth. However, in 2008, the first molecules indicating ice water in the lunar poles were found by an Indian mission. Further missions confirmed that, so the discovery means it may not be impossible.
11. The Moon was likely formed during an impact.
Scientists believe it’s likely a Mars-sized body collided with Earth about 4.5 billion years ago. The Moon as we know it resulted from the debris and was likely in a molten state initially, and then within about 100 million years, much of the magma eventually formed the lunar crust.
12. Earth’s climate is impacted by the Moon.
The Moon’s presence actually helps stabilize our planet’s wobble, which helps stabilize our climate.
13. The Moon is the Earth’s only natural satellite.
It’s called “the Moon” because people didn’t know about other moons existing until 1610. That’s when Galileo Galilei discovered four of Jupiter’s moons.
14. Six American flags have been planted on the Moon.
But it doesn’t mean the United States has claimed it. There’s actually an international law that was written in 1967 that prevents any nation from owning any natural celestial objects. But flags aren’t the only items American astronauts have left behind; there’s also equipment and even a camera they left behind.
15. There are plans to return humans to the Moon.
NASA is planning, through the Artemis program, to send the first woman and the next man to the Moon to set up a permanent lunar presence there in 2024. One of the eventual goals of the program is an Artemis Base Camp that will allow for longer lunar missions with new rovers, power systems, habitats, and the ability to search for and extract resources. Another long-term goal is to lead to further exploration on Mars.
“Artemis will send the first woman and the next man to the South Pole of the Moon, enabling us to access new and diverse areas of the Moon and to explore and understand planetary processes across the Solar System and volatiles, like water, contained in the lunar South Pole that can be used to establish a sustained human presence on the lunar surface," Jones said.
