5 Ways the Moon Is Different From How You Picture It
If you haven’t been to the Moon, everything you think you know about it might be wrong. “The Moon could be made of green cheese,” people used to say, and we all know how wrong those people turned out to be.
Well, okay, no one ever really thought the Moon was made of green cheese. That was a figure of speech about people believing the absurd. Also, green cheese isn’t green — the phrase means fresh unaged cheese, which is white in color. However, people really were uncertain about the nature of the Moon until we reached there. For all we knew, it could have been covered in 50 feet of dust, which would suck our astronauts down like quicksand.
The Moon, it turned out, contained no quicksand at all. it also turned out to have other surprising properties.
Mind you, not all of the Moon is hot. Some of it’s very cold. But many people imagine the whole thing’s cold, because space is cold, and that isn’t true at all.
Picture Neil Armstrong walking on the Moon for the first time. Consumed by space madness, he rips off his boots and socks. Imagine that his head is still neatly sealed in, so he’s in no danger of suffocating. What happens to his feet? Do they freeze solid, and do the icy toes snap off?
Probably not. Because when Armstrong made that walk, the surface was boiling hot. The suit didn’t keep him warm — it kept him cool, using chilled water from a tank in his backpack. One big reason he and Buzz Aldrin couldn’t go off on some side quest was they weren’t sure how long they had till the cooling system gave out, leaving them cooked.
The Moon gets so hot because of the Sun, of course, and without much of an atmosphere buffering everything, temperatures fluctuate widely between when one spot faces the Sun and when it turns the other way. In daytime, the Moon hits 120 degrees Celsius or 250 degrees Fahrenheit.
As for the nighttime Moon, it's cold, so you were right about that. It’s as cold as we all imagine and maybe colder. NASA measured one bit of crater to be 410 degrees below zero Fahrenheit, and we’re not even going to bother converting that to Celsius because neither scale means anything to you when it gets that low. Let’s just note that it’s the lowest temperature officially recorded anywhere in the solar system. It’s even colder than the mean temperature on Uranus, and Uranus is famously cold — and mean.
We consider the full moon bright. Our entire werewolf industry depends on it. We’re really just calling it bright, however, compared to the bare night sky around it. As a tool for reflecting sunlight, the Moon is uniquely terrible.
Below is an EPIC shot of the Earth and Moon, taken by NASA’s Deep Space Climate Observatory. When we say “EPIC,” we mean both that it’s an impressive photo and that it was shot by the Earth Polychromatic Imaging Camera.
You’re looking at the faces of the Earth and Moon that are being illuminated by the Sun. Despite that, in this photo, the Moon doesn’t seem to be shining at all because its reflected light is nothing compared to the greater reflected light shining off Earth. You wouldn’t expect the primarily blue Earth to reflect more light than the white Moon, and yet it does.
Though the Moon is white, it doesn’t reflect light very well. That’s because it’s so rough. It’s not a polished cue ball, it’s rock and dust, which means it doesn’t have much specular reflectivity. In fact, it’s less reflective than just about any object in the solar system. We describe how much sunlight a body reflects using a measure called bond albedo. The Moon has a bond albedo of just 12 percent. The Earth is 31 percent. Mercury has around the same bond albedo as our Moon, but all the other planets have more, as do most moons. For an extreme case, look at Triton:
That’s a moon of Neptune, and it has a bond albedo of 76 percent. That means if Triton (which is a bit smaller than our Moon) were somehow in place orbiting around Earth, it would shine seven times brighter than the moonlight we currently receive. This would not only give all werewolves enhanced powers; it would also kill all vampires instantly.
A few seconds ago, we argued that the Moon is rough, not smooth. On the other hand, it’s also a lot more smooth than people imagine.
Take a look back at that photo of the Moon above (the one with the blazing Earth behind it). You’re looking at the far side of the Moon. It’s the side sometimes called the dark side of the Moon, which is a misleading name — neither side of the Moon is the dark side, since the Moon rotates, and each spot alternates between day and night. For a few million years, earthlings had no idea what the far side of the Moon looked like. All we knew was the one face of the Moon that always looks at us:
We see huge stretches of gray but also darker areas, which we named “seas”; they're plains of basalt. The seas look like the face of a man, or a bunny, or like your parents shouting at each other. Down on Earth, we were stuck looking at this one side because of how the Moon’s rotations and revolutions sync up. We could only imagine what the other side looked like, and we assumed it was just as oceanic/splotchy as the side we know so well.
Then, in 1959, the USSR snapped the first photo of the far side:
It looked suspiciously bereft of sea-like structures. There was one big sea there (which the Soviets named the Sea of Moscow, a colonialist move contrary to the traditional lunar naming scheme) but not much else.
Given that the Soviets developed the photo from within their spaceship itself and broadcast the results to Earth, it seemed like maybe they’d screwed the photo up or faked it. Later images of the far side, however, made it look smoother still. NASA took this next photo last year:
While the far side actually contains more craters than the near side, and you’ll see that if you zoom in, it looks flat and sea-less compared to what we’d expect. We don’t know for sure why the Moon formed this way, because we don’t know for sure how the Moon formed, period. We have some decent theories, though. Something massive apparently slammed into the Moon around four billion years ago, creating a huge impact crater, the South Pole-Aitken basin. Maybe this impact stirred up the Moon’s interior enough to generate volcanic activity on the opposite side, which created the seas.
To test that theory, we’d have to try hitting the Moon again, hard. And when we hit the Moon, we discover...
Seriously, though, we can’t really replicate the impact that created the Moon’s South Pole-Aitken basin. We could nuke the Moon (and people seem to think that’s a bad idea, for some reason), but a couple of wimpy nukes are nothing compared to that kind of collision. What we have done instead is strike the Moon with conventional explosives or simply drop modules on it. These experiments transmitted seismic waves, which we analyzed to figure out what our friend is made of.
Apollo 12 dropped a 2.5-ton module onto the Moon to listen to how it sounded. Later Apollo missions stepped things up, using an active device called a thumper and a mortar with explosive charges. While useful for fighting any moon sharks we encountered, the real goal here was simply to make waves.
When Apollo 13 dropped its own module — this one of the few parts of the mission that went off without a hitch — the astronauts said the Moon “rang like a gong” for an hour afterward. “Rang like a bell” was the equally intriguing quote that filtered into public consciousness following other missions. If the Moon rings like a bell, people reasoned, it must be hollow like a bell. And if the Moon is hollow, well, that reveals where the aliens live. Either that, or it’s proof the whole Moon is a spaceship.
Scientists, in contrast, say the Moon’s vibrations are proof of the exact opposite. They indicate the Moon has a solid core. Later research corroborated this, with the latest conclusions pointing toward a solid iron core measuring about 250 kilometers in radius. Well, that’s interesting too we guess.
The year 2023 has been a monumental one for Moon travel, with multiple missions to reach new sections of the Moon, and one of them even succeeded. As we cheer on these journeys, let’s remember that the Moon is no mere hop away. Based on many illustrations of the Moon and Earth, you’d swear that the Moon is hovering smack next to us, and a flight there is comparable to a flight from one continent to another.
The photo we included earlier of the Earth and Moon would seem to back this up. You can picture the Moon revolving a little to the right and then tucking itself behind the planet as it moves away from you.
But that photo only exists because of careful timing and perspective. When the GIF ends, the Moon doesn’t slip back behind the Earth. It keeps moving to the right as part of its orbit — far to the right. To demonstrate the distance between the two bodies, we need a much wider shot. This next photo, taken by the nav camera of the spacecraft OSIRIS-REx, really shows the scale in play here:
Think about that photo every time you see some cartoon where the Moon is spinning just one Earth radius away. Granted, such depictions often aren’t trying to be scientifically accurate, but you should still delight in knowing the truth. For example, here’s a video that’s shared a lot, created by Ukrainian artist Aleksey Patrev:
The clip is not trying to pass itself off as authentic. If the Earth really exploded like that, we’re almost certain we’d have read about it already in the news. But along with your questions about exactly what would happen to the Moon in such an event, or whether the impact should do more than just knock the astronaut down and might maybe leave a crater the size of the South Pole-Aitken basin, marvel at the speed of the debris. It crossed the 240,000 miles to the Moon quite quickly. Even light takes more than a second to manage that distance.
Or take a look at this image from the recent video game Starfield:
Ha, ha, this is another of those silly depictions where the Moon’s a six-hour trip away via Boeing 767. However, this is just a map, or a menu. The game also lets you travel among these bodies, and here, the distance depicted isn’t so bad at all.
The scale’s... pretty close to what OSIRIS-REx captured, isn’t it? Not exactly the same, but it’s close enough that we can give it a thumb’s up and blame any discrepancy on our having placed the camera in the wrong position.
That’s impressive because this is a video game, where realistic scale is not a concern. You are not supposed to travel to this position at all and observe both bodies like this; we had to raise the ship’s speed a couple thousand times beyond what the game allows to get here. Also, one of the first things you do in the game is ask a bartender for a tip on finding a missing person. He went to Venus, says the barkeep. So, armed with only that tip, you head to Venus, a planet the size of Earth, and immediately pick up the trail. Again: Realistic scale is not a concern here.
We’ve talked before about the true distance from the Earth to the Moon, but we thought it’s well worth mentioning again if we’re discussing Moon myths, particularly because of some recent events. OSIRIS-REx, the spacecraft that took the scale photo up there, deposited its return capsule back to Earth this week. It launched in 2016, grabbed that photo in 2017, collected a sample from an asteroid in 2020 and dropped the sample back here on Sunday. It traveled 4 billion miles.
The Moon is far, remember that. But space, overall? Space — even the tiny fraction of space that we’ve successfully traversed — is so much bigger.