Does outer space have a smell? This apparent technical impossibility (since the cosmos is a vacuum) was addressed in a recent BBC interview, in which three former astronauts clarified the problems of American colleagues Suni Williams and Butch Wilmore, stranded on the International Space Station (ISS), after their Boeing Starliner spacecraft is considered unsafe for a manned return to Earth.
The question specifically referred to how these unexpected guests, whose mission went from eight days to eight months, would be able to deal with everyday challenges.
In other words, how to live 400 km above the planet, live with problematic companions, in addition to exercising, washing dirty clothes, eating and, most importantly, the issue of “space smell” .
This last topic, normally little debated, was explained by Helen Sharman, the first British astronaut, who spent eight days on the Soviet Mir space station in 1991.
She says that “on Earth, we have many different smells, like laundry from the washing machine or fresh air. But in space there is only one smell, and we get used to it quickly.”
According to the space veteran, this unlikely olfactory experience occurs when returning from the famous spacewalks.
Any object that goes abroad, be it a suit or a scientific kit, is affected by strong cosmic radiation.
“Radiation forms free radicals on the surface, and they react with oxygen inside the space station, creating a metallic smell “, says Sharman.
How can astronauts smell space?
Technically, smell, also known as odor, results from the sensory perception of volatile chemicals (which evaporate easily at room temperature) by our olfactory system.
Therefore, the explanation for the smell perceived by astronauts on the ISS may be related to a chemical reaction that occurred during repressurization.
Known as oxidation, this process is called cold burning because there is no flame or smoke, but only the characteristic smell of burning solder.
Upon returning to the space station, after an extravehicular activity (EVA), the astronauts bring individual oxygen atoms attached to their suits.
When this atomic oxygen combines with respirable oxygen (O2), they form ozone (O3), the smell of which is typically described as metallic or the result of sparks or short circuits.
Another explanation for space odors are so-called polycyclic aromatic hydrocarbons (PAHs).
They are found in space, as a result of the energy released by the death of stars, but they are also present in our kitchens, when we burn toast or barbecue meat.
The smell of galaxies
The reason organic HAP complexes occur both in space and in our everyday lives is because they form in high temperature environments which break down and rearrange organic molecules.
On Earth, this happens during the process of incomplete combustion of organic matter. This may be related to the burning of wood, coal, oil and food.
At home, these molten carbon rings form every time we let food burn, such as barbecue, toast and charred food, in addition to constantly appearing in cigarette smoke and vehicle pollution.
The history of space smell began with the first cosmic walks. During the lunar landings, Apollo astronauts often commented on a gunpowder-like smell when they returned to the airlock and removed their helmets.
The first EVAs of the ISS were also marked by reports of the smell of gunpowder, ozone and burning steak.
Continuing the sensory journey through the Solar System, we will find ammonia molecules on Jupiter and Uranus, which smell like urine and sweat.
Things get worse on Venus, Mars and Uranus, where hydrogen sulfide, or sewage gas, smells like rotten eggs, prevails.
In comets, the delicious (and deadly) hydrogen cyanide, a bitter almond smell, has also been detected in the atmosphere of Jupiter — and in some Agatha Christie novels.
But not everything stinks in the Universe.
Right in the center of the Milky Way, about 26,000 light-years from Earth, lies the giant molecular cloud Sagittarius B2, one of the largest in our galaxy. In this nursery of stars, ethyl formate, an organic chemical compound, whose smell is generally associated with with rum and raspberry flavor .
Along with the familiar spectacle of brightness and color, the Universe is also home to a fascinating chemistry of molecules over many eons, from stars just being born to billions of them that have died.
Many of these molecules are odorless, others are sweet and a large number are disgusting. Either way, it’s a fascinating bouquet, but highly deadly for human sommeliers.
This content was originally published on Does outer space have a smell? Which? Find out what astronauts say on the CNN Brasil website.
Source: CNN Brasil
Charles Grill is a tech-savvy writer with over 3 years of experience in the field. He writes on a variety of technology-related topics and has a strong focus on the latest advancements in the industry. He is connected with several online news websites and is currently contributing to a technology-focused platform.
