Welcome to brain Stuff, a production of I Heart Radio, Hey brain Stuff, Lauren vog Bomb. Here, we all know that space is empty. Most of space is completely absent of anything, not dust, not planets, nor Sun's, not even air. So why do many of the people who have been to space and spend time in it report that space has a smell? It turns out that space does smell, and our solar system in fact, has a very particular scent. This is likely the result of several factors, but all
are clear. Our corner of the universe is kind of stinky. While no astronaut has ever been unwise enough to unclasp and remove their helmet in the near vacuum of space, many have reported having experienced sense up there upon their return. Specifically, many astronauts report different smells in the airlock after participating in spacewalks. American astronaut Don Petite described it in this way after returning from NASA's Expedition six to the International
Space Station in two thousand three. A quote, The best description I can come up with is metallic, a rather pleasant, sweet, metallic sensation. It reminded me of my college summers, where I've labored for many hours with an arc welding torch repairing heavy equipment for a small logging outfit. It reminded me of pleasant, sweet smelling welding fumes. That is the
smell of space. Other astronauts have described it in similar varying ways, burning metal, a distinct odor of ozone and acrid smell, walnuts and brake pads, gunpowder, and even burnt almond cookie a much like wine, connoisseurs may smell something a bit different from the same bottle. Astronaut reports differ slightly in their scent notes, but have one thing in common, a burnt smell. So what might explain why space smells burnt?
There are two possible explanations. OH one hypothesis relates to the process that occurs in the airlock as astronauts return from space to the I, S, S, or whatever spacecraft they call home temporarily during repressurization. The chemical reaction of oxidation occurs atoms of oxygen in space attached to the astronaut suit and flowed in during the depressurized time when the airlock is open, and then combined to form atmospheric
oxygen or O two. This process is similar to combustion without the flame and smoke and smells similar to which might explain the smoky, charred odor that astronauts report. A second hypothesis relates to stellar explosions, that is, dying stars. Though we've only been studying the night sky for a few millennia, the universe is some thirteen point seven billion years old. Our Solar system is estimated to be about
four and a half billion years old. This means that for literally billions of years before Solar System ever formed, stars were being born and dying across the universe. When stars die, it tends to be a dramatic affair, and this bombastic process creates compounds called polycyclic aromatic hydrocarbons or p h s. P a h s are present throughout the Solar System, including here on Earth. They can be found in some foods, in coal and oil, among other materials.
They also occur when coal, tobacco, wood, meat, and other substances are burned. Perhaps part of the reasons space has a distinctly burnt and charcoal smell is because it, like a grill on a summer evening, is emitting smelly p H is outside of our Solar system it's not as stinky.
Other parts of the universe do have compounds and elements that create different smells, though't no human is likely to or take a big whiff to confirm, but just for example, the dust cloud Sagittarius B two has a high concentration of ethel formate, which is the compound that gives raspberries and rum part of their distinctive odors. So if you love a good raspberry dacory, that maybe the corner of the universe for you. Today's episode is based on the
article what does space Smell Like? On how stuff works dot Com written by Valerie Cymac. Brain Stuff is production of by Heart Radio in partnership with how stuff works dot Com, and it's produced by Tyler Clang. Four more podcasts from my heart Radio visit the i heart Radio app, Apple Podcasts, or wherever you listen to your favorite shows.