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People naturally assume that space is devoid of any smells. Its very nature (and emptiness) makes it impossible for us to imagine the cosmos having any sort of defining features. After all, how could Nothingness smell like anything?
However, we have proof otherwise. Apparently, smell does persist in the vacuum of the universe, despite what common sense might suggest. It’s fairly obvious that you cannot survive in a vacuum, so you can’t really smell space first-hand, but a distinct smell has always been noted every time an astronaut has come back to the space station after his/her space walk. The smell of space clings to the space suit, making it possible for humans to safely assess its characteristics – and odor!
Here’s what astronauts over the years have had to say about their impressions of the stench of space.
What Astronauts Say
Don Pettit, an astonishingly poetic astronaut, has this to say regarding the topic on the NASA blog:
“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 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 had eerily similar olfactory experiences regarding space. Most of them compare it to the scents of burning metal, steak and welding. Take three-time spacewalker Thomas Jones, for example. He states that space smells sulfurous, somewhat like gunpowder, while also carrying ‘a distinct odor of ozone, an acrid smell’. To Alexander Gerst, space smells like a combination of fragrances – namely walnuts and the brake pads of a motorbike. Space tourist Anousheh Ansari wrote in her blog that it was ‘strange…kind of like a burnt almond cookie’. Even Buzz Aldrin, the legendary astronaut of Apollo 11, compared the odor to burnt charcoal.
There seems to be a consensus as to what space smells like, but what generates the smell in the first place?
The boring answer is that it’s probably due to the air ducts that recompress the compartment once the astronaut comes back inside. Materials, like the spacesuit for example, which had been exposed to a vacuum, can react strongly if suddenly brought back into an atmosphere that is rich in oxygen. The reaction that occurs is similar to combustion within the Earth’s atmosphere, which also depends on oxidation for burning. That being said, the vacuum-to-atmosphere reaction burns at a much faster rate, thus causing the burning aroma.
So, does that mean that the smell is just a reaction within the spacecraft and not actually an interstellar aroma? Does that mean we’ve been duped?! Come on Science, we deserve a better answer than that!
Well, thankfully, there is another slightly more explanation for this phenomenon – Dying Stars. When stars die, they do so in magnificent fashion, usually combusting on an unfathomable scale. All that energy produces smelly compounds called Polycyclic Aromatic Hydrocarbons (PAHs). On Earth, PAHs are found in coal, oil and even food, which means that they are found mostly around barbecues!
These molecules seem to be floating all over the universe, serving as catalysts for the formation of new stars, planets, comets and meteors. “They have even been shortlisted for the basis of the earliest life forms on Earth” says Louis Allamandola, the founder and director of the Astrophysics and Astrochemistry Lab at NASA’s Ames Research Centre. The high-energy vibrations found in these particles mix with the air to give off their particular fragrance.
Outside the Solar System
Our Solar System is especially stinky because of the high concentrations of carbon and low concentration of oxygen. “Just like a car, if you starve it of oxygen, you start to see black soot and get a foul smell,” Allamandola explains. Scientists suggest that other star systems with higher levels of oxygen might smell like a charcoal grill. However, the universe is not so universal in its odors. Particular stellar objects might actually carry their own distinct scents.
The comet 67P, which is being studied by the European Space Agency’s spacecraft Rosetta, has an interesting ‘perfume’. It evidently smells like a combination of cat urine and rotten eggs, along with the odor of stale alcohol and formaldehyde added generously to the mix. Obviously, that is one comet you wouldn’t want wandering too close to Earth!
But don’t worry! Keep moving outside the solar system – approximately 26,000 light years towards the center of our galaxy – and you might come across a more appealing fragrance. The dust cloud called Sagittarius B2 smells like raspberries and rum! That is because this dust cloud is stuffed with ethyl formate, the ester that gives both raspberries and rum their specific aroma. In fact, space seems quite boozy as a whole. Of course, no liquid forms of alcohol have been found, but there are traces of various different alcohol particles staggering and stumbling throughout the space-time continuum. In fact, the constellation Aquila holds so much alcohol that, if liquified, it would fill 400 trillion trillion pints!
And that’s just the beginning. The universe is so vast that you never know what we might find next. If we’re lucky, there will be an intergalactic pub right around the corner, just waiting to be found. I just hope it doesn’t smell bad inside!