The Why Files: Operation Podcast - 12: What does outer space smell like? (You're not gonna like it.)

Episode Date: June 26, 2022

What does the moon smell like? Do planets, comets, asteroids and space have their own odors?  The smells of the universe are not universal. Different objects in space — comets, planets, moons and gas clouds — all have their own distinctive aroma.   Twelve people have walked on the Moon and all of them agree: the Moon smells like gunpowder.   According to Space.com, astronaut Jack Schmitt said: “All I can say is that everyone's instant impression of the smell was that of spent gunpowder, not that it was 'metallic' or 'acrid'. Spent gunpowder smell probably was much more implanted in our memories than other comparable odors.”   The Earth has a variety of smells, depending on what environment you're in. But what about the other planets in our solar system? Venus has a crushing carbon dioxide atmosphere, while Jupiter's atmosphere is stormy and turbulent. While we can see what color and understand the conditions on these planets, what do they actually smell like? Scientists hadn’t found clear evidence of the planet’s chemical composition until now.   Yes, it has been confirmed that Uranus smells like... farts. Astronomers recently found that the atmosphere of Uranus has high levels of hydrogen sulphide, a compound that smells like rotten eggs. Mercury has a very sparse atmosphere and so would not have much of a smell at all. Venus and Mars, much like Uranus, have substantial quantities of eggy hydrogen sulphide.   For Jupiter, the smell would depend on where you were in the atmosphere. Some regions have high concentrations of ammonia, hydrogen sulphide and others hydrogen cyanide (bitter almonds). Saturn and Neptune probably don’t have much of a smell because they’re composed chiefly of the odorless gases hydrogen and helium.   Let's find out why. --- Support this podcast: https://podcasters.spotify.com/pod/show/thewhyfiles/support

You searched for your informant, who disappeared without a trace. You knew there were witnesses, but lips were sealed. You swept the city, driving closer to the truth. While curled up on the couch with your cat. There's more to imagine when you listen. Discover heart-pounding thrillers on Audible. I'm a rocket man, burning bado-boo-do-boo.

You smell that? I can smell that underwater. Well, don't look at me. Let's get out of here. Agreed. You smell that? I can smell that underwater. Well, don't look at me. Let's get out of here. Agreed. The smells of the universe are not universal. Listen. You smell something? Different objects in space like comets, planets, moons, gas clouds, each have their own distinctive aroma. Oh, I love the smell of the universe in the morning. Me too.

We're all watching The Expanse, right? If you're not, start immediately. It's the best sci-fi show on TV. And it's based on a series of novels which are equally awesome. And I will link below. Anyway, The Expanse describes the moon as having a gunpowder stink. And I remember reading that and thinking, what a cool description. And it made me wonder, how did they come up with that?

Does the moon really smell like gunpowder? Turns out it does. For this video, we're going to assume the moon landing was not faked. We are going to assume the moon landing was real. You believe anything? When recalling the smell of the moon, Apollo 17's Jack Schmidt said everyone's impression of the smell was that of spent gunpowder. Now, this is strange because the makeup of lunar dust is completely different than gunpowder. Moon regolith is made up of silicon dioxide glass created by billions of years of meteor impacts. It also contains iron,

calcium and magnesium. But modern gunpowder is a combination of nitrocellulose and nitroglycerin. So why the similarity? Well, nobody really knows, but it could be a sign that moon dust is chemically active. So how does the smell even happen? Well, there are a couple of theories. One is called the desert rain effect. You ever notice that awesome smell that happens after a summer rain? That smells called petrichor from the Greek words petra, meaning rock or stone, and the word ichor, which is the fluid that flows through the veins of the gods. On Earth, plant oils accumulate on rocks during dry periods, along with another compound, geosmin, which is a metabolic byproduct of bacteria found in soil. During rain, the oils and geosmin are released into the air,

causing that distinctive smell of petrichor. And if there's lightning, sometimes you could sniff a little ozone. Obviously, there are no plants on the moon, but there's still stuff, right? The molecules trapped in the dry moon dust may have been activated by contact with the moist air in the lunar module, just like petrichor and the desert rain effect. Another theory is solar winds. Hot solar winds of hydrogen, helium, and other ions buffet the moon's surface and may become trapped in the dust.

When the ions are dislodged, such as by an astronaut's footsteps, then come in contact with the warm air inside the lunar module, they evaporate. It's possible these ions were brought into the cabin, producing the odor. Either way, the smell didn't last long.

By the time the moon dust made it back to Earth, it was completely odorless. So we'll have to take NASA's word for it. But space itself may even have a smell. Astronauts returning from spacewalks have reported smelling burnt metal or burnt meat. And no one really knows for sure what this is, but it could be molecules of metal leeching off onto spacesuits, then oxidizing when it comes into contact with actual humidified air. Now, I think that's super interesting. So let's work our way around the solar system and see which planet smells like toasted almonds

and which planet smells like the port-a-potty on the last day of a Renaissance fair. That reference was oddly specific. Mercury. Mercury is the smallest and closest planet to the sun. Named after the Greek god Hermes, it translated into Latin as Mercurius, the messenger of the gods. Mercury contains a lot of sodium, which doesn't have much of an odor, but there's also a lot of silicon dioxide present, like the moon, so we assume the smell would be gunpowder.

Just salty gunpowder. Venus! Venus is the second planet from the sun, named after the Roman goddess of love and beauty. When they named the planet, they clearly couldn't smell it. Venus has a thick atmosphere, mostly carbon dioxide. There's also heavy clouds of sulfuric acid. That combination makes Venus smell like a burnt match and rotten eggs. Mars is the fourth planet from the sun,

and the second smallest planet in the solar system, being larger than only Mercury. Named for the Roman god of war, Mars is often referred to as the red planet because of the iron oxide on the surface. And despite what Matt Damon would tell you, Mars doesn't have much of an atmosphere. Since Mars lost its magnetosphere billions of years ago, solar winds are constantly stripping away atoms from the outer layer. But what atmosphere there is contains methane, formaldehyde, carbon monoxide, and sulfur dioxide. Now, Martian sand smells like rusty metal because that's what iron oxide is.

Combining the odors of the surface with the odors of the air, and Mars is probably going to smell like the exhaust of an old car with a bad catalytic converter. It's basically the same stuff. And yeah, you can't breathe that. I'm definitely going to die up here. Jupiter. Jupiter is the fifth planet from the sun and the largest in the solar system. It's a gas giant named after the king of the Roman gods.

Jupiter's atmosphere is 5000 kilometers thick and actually has multiple layers, each with slightly different smells. The outer layers have a lot of ammonia, which smells like horse urine. Hello. As you move closer to the surface, the atmosphere becomes more sulfuric, smelling like horse urine. Hello. As you move closer to the surface, the atmosphere becomes more sulfuric, smelling like skunk and horse urine. The inner layers have a high concentration of hydrogen cyanide,

which smells like toasted almonds and skunk and horse urine and rotten eggs. Saturn. Saturn is the sixth planet from the sun and the second largest in the solar system after Jupiter. It's also a gas giant named after the Roman god of wealth and agriculture. Saturn's atmosphere is 96% hydrogen and 4% helium, so not much of a smell. But there are trace amounts of methane, phosphine, acetylene, and ammonia. And phosphine can smell like rotten fish.

What? You sailed beyond the horizon in search of an island scrubbed from every map. You battled krakens and navigated through storms. Your spade struck the lid of a long-lost treasure chest. While you cooked a lasagna. There's more to imagine when you listen. Discover best-selling adventure stories on Audible. You sailed beyond the horizon in search of an island scrubbed from every map.

You battled krakens and navigated through storms. Your spade struck the lid of a long-lost treasure chest. While you cooked a lasagna. There's more to imagine when you listen. Discover best-selling adventure stories on Audible. So Saturn probably smells like dead fish and skunk and rotten eggs. What's with all the rotten eggs? Good question.

Eggs are very high in two proteins, globulin and keratin. When globulin decays, a toxic chemical is released, hydrogen sulfide, which has a very potent sulfur smell. I mean, you know it when you smell it. And keratin also has very high levels of an amino acid called cysteine, which is also full of sulfur. Hydrogen sulfide happens to be one of the most common compounds in the solar system. So rotten eggs everywhere. Uranus, Uranus, Uranus.

Please, please don't say it that way. You say tomato, I say Uranus. Tomato, Uranus, potato. Do you mind? All right, go ahead. I couldn't resist. Uranus is the seventh planet from the sun, named for the Greek god of... Butts! Greek god of the sky.

It's probably the smelliest planet in the solar system. Stop it. The upper atmosphere is mostly hydrogen, so not much of the sky. It's probably the smelliest planet in the solar system. Stop it. The upper atmosphere is mostly hydrogen, so not much of a smell. But as you get closer to the surface, it gets pretty ripe. Have we probed Uranus? Yes, we have. Oh, I hope they were gentle. So why does Uranus smell so bad?

Well, the cloud tops of Uranus are made of hydrogen sulfide, that gas responsible for the foul smell of rotten eggs, and human flatulence. A little lower in the atmosphere, you'll find methane and ammonia. So Uranus smells like a public toilet? It does. Neptune. Named after the Roman god of the sea, Neptune is the eighth and farthest planet from the sun.

At 17 times the mass of the Earth, it's slightly more massive than its twin Uranus. Does it smell as bad as Uranus? Well, most of the compounds are frozen in the atmosphere, so really just hydrogen and helium are present. Neptune doesn't have much of a smell at all. That's too bad. I got more jokes. I'm sure you do. Everywhere else. A few honorable mentions. Dwarf planet Pluto is a near vacuum with nitrogen,

methane and carbon monoxide. So deadly, but odorless. One of Saturn's moons, Enceladus, is covered in ice, but underneath it has an ocean of liquid salt water. And it was recently discovered that plumes of methanol are ejected from the surface. So it could smell like a martini. I'm Steve-O and this is the Pooh Cocktail Supreme. Comets mostly smell like burnt metal and, of course, rotten eggs. And lots of asteroids contain formaldehyde and cyanide, so they could smell like pickles and marzipan. Oh, sounds like what my ex-wife ate when she was pregnant.

You've been married? Three times. Huh. I didn't know that. Well, I had a life before you came along, you know. Okay, okay. Take it easy. Sorry, sorry. I'm still working through some things. Anyway, the center of our galaxy is the dust cloud Sagittarius B2. And in that cloud, scientists have discovered a substance called ethyl formate,

which is the chemical responsible for the flavor of raspberries and the smell of rum. So not so bad. So here's what we learned today. What's that? The worst smelling thing in the solar system is your radius. I hate you. Thanks for hanging out with us today. My name is AJ. That's heckle fish. This has been the Y-Files. If you had fun or learned anything today, do us a favor. Give us a thumbs up. It really helps out the channel.

Oh, and whoever makes the best Uranus joke in the comments wins an Amazon gift card. Ooh, ooh, I got one. No, no, you're disqualified. No. Until next time, be safe, be kind, and know that you are appreciated. Hey, you know, I heard there's a black hole near Uranus. Will you stop it?