by Astronauts have described some unusual smells in space, which is not surprising considering that the chemistry there is very different from that on Earth. So what does space smell like and what are the cosmic sources of these smells?
Space is an airless vacuum, so technically you can’t smell anything in space; If you tried, you’d be dead. However, space is not a complete vacuum. It is full of all kinds of molecules, some of which have their own strong odors when we smell them in Land. Learning what different parts of space can smell like is a really cool way to better understand cosmic chemistry.
Related: International Space Station has a ‘peculiar smell’, astronaut says
What do astronauts smell?
During the Apollo moon landings, astronauts They often comment on a smell of gunpowder. Once they returned to the airlock, they entered the confines of their lunar lander and removed their helmets. Similarly, after a spacewalk, astronauts returning to the confines of the International Space Station report the smell of gunpowder, plus ozone and burnt steak.
So what is going on? Where does the smell come from?
Scientists have two good theories. One is that, while an astronaut is doing a spacewalk, Individual oxygen atoms can stick to your spacesuit, and when they re-enter the airlock and are repressurized, molecular oxygen (O2 or two oxygen atoms) floods the airlock and combines with the individual oxygen atoms to form ozone or O3. This would explain the sour, metallic smell.
So what about the other smells? There’s probably something else going on. Polycyclic aromatic hydrocarbons (PAHs), found in charred foods like burnt toast and roast meat, are also routinely found in space. In fact, most of the interstellar carbon is locked in PAHs. They also abound in Solar systemso astronauts can easily pick them up and carry them inside the space station or a space capsule, and they are probably the source of the burnt meat smell astronauts report.
In fact, NASA treats the smells of space as more than just a curiosity. In 2008, the agency commissioned Steven Pearce, a chemist at Omega Ingredients, which specializes in fragrances and flavors, to reconstruct the smells of space for astronauts in training. After all, an astronaut needs to be able to distinguish between the smell of PAHs on his spacesuit and a dangerous chemical leak aboard the space station.
smelly comets
This way we have an idea of what space near Earth smells like. But what happens further afield?
Other places in the universe also have unique smells, if only we could travel that far to smell them.
When the European Space Agency’s Rosetta spacecraft found kite 67P/Churyumov-Gerasimenko in 2014, They detected a rich variety of molecules in the comet’s coma., the gaseous halo that surrounds the solid nucleus of the comet. Among these molecules were hydrogen sulfide, which gives rotten eggs their unpleasant stench; ammonia, reminiscent of the repulsive smell of urine; hydrogen cyanide, which, despite its famous toxic nature, has a more attractive almond smell; sweet-smelling carbon disulfide; and the pickled aroma of formaldehyde.
You would probably dislike this combination of smells. But if there were any smell, it would probably be quite weak, since the vast majority of a comet’s coma is water vapor and carbon dioxide.
The gasoline moon
A place where there is an atmosphere to retain a scent is Saturnthe biggest moon, Titan. However, the atmosphere does not help us smell anything. There is no oxygen and it is cold. minus 292 degrees Fahrenheit (minus 179.6 degrees Celsius) – so it’s not really an option to take off the helmet of the spacesuit and take a deep breath. However, if we could, we would find that Titan reeks of gasoline.
Maybe we shouldn’t be surprised. After all, gasoline, or oil, is made from crude oil rich in hydrocarbons, which are molecules made up of hydrogen and carbon atoms, such as methane and ethane. Titan’s atmosphere contains dense hydrocarbon smog, and on the surface of the moon, liquid hydrocarbons form oily lakes and rivers. But methane, which is the dominant hydrocarbon on Titan, doesn’t smell like anything. So what creates the stench of the moon?
NASA’s Cassini spacecraft They identified an unknown chemical substance in Titan’s hazy atmosphere. that NASA laboratory experiments On Earth, a molecule containing nitrogen, methane and benzene was determined and belongs to a family of molecules called polycyclic aromatic nitrogen heterocycles (PANH). In particular, it is the benzene in PANHs that gives Titan its petroleum stench, since benzene also occurs naturally in gasoline.
A drunken gas cloud
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So the solar system is a pretty spicy place, but what about the rest of the universe?
Sagittarius B2, a giant interstellar molecular cloud of star-forming gas and dust less than 400 light-years from the center of Earth. Milky Way, has all kinds of aromatic chemistry. For one thing, contains a lot of alcoholincluding vinyl alcohol, methanol and ethanol, the type of alcohol found in beer.
In 2009, astronomers also detected the molecule ethyl formate in Sagittarius B2. Ethyl formate is the chemical that gives raspberries and rum their sweet fragrances, so even if the center of our galaxy smells like a brewery, at least it will be pleasant.
