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VIVA Tekno – Astronauts have described several 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 is the cosmic source of these smells? Reporting from Space, Friday, January 12, 2024, Space is a vacuum, so technically you can’t smell anything in space – if you tried, you’d die. However, space is not a vacuum.
Astronaut in space.
Space is full of all kinds of molecules, some of which have a strong smell when we smell them on Earth. Learning what different parts of space smell like is a really cool way to better understand cosmic chemistry.
What do astronauts kiss?
During the Apollo moon landings, astronauts often commented on the gunpowder-like smell after returning to the airlock, entering the lunar lander space and removing their helmets. Likewise, astronauts returning to the International Space Station reported the smell of gunpowder as well as ozone and burnt steaks after spacewalks.
So what happened? Where does the smell come from?
Scientists have two good theories. When an astronaut spacewalks, a single oxygen atom can stick to his spacesuit, and when he gets back into the airlock and pushes on it, an oxygen molecule – O2, or two oxygen atoms – enters the airlock and combines with a single oxygen atom to To form ozone or O3. This would explain the sour and metallic smell.
Then what about other smells? Maybe there’s something else going on. Polycyclic aromatic hydrocarbons (PAHs), found in charred foods like toast and grilled meat, are also routinely found in space.
Space images captured by the James Webb Space Telescope (JWST)
In fact, most interstellar carbon is bound in the form of PAHs. PAHs are also abundant in the solar system, making them easy for astronauts to ingest and transport aboard space stations or space capsules — and they could be the source of the burnt flesh smell that astronauts report.
In fact, NASA considers the smell of space to be more than just a curiosity. In 2008, the agency hired Steven Pearce — a chemist at Omega Ingredients who specializes in scents and flavors — to recreate the smell of space for astronauts in training.
However, an astronaut must be able to distinguish between the smell of PAHs on his spacesuit and a leak of dangerous chemicals on the space station.
So we already have an idea of what space smells like near Earth. But what about further away?
There are unique smells elsewhere in the universe too – if only we could travel far enough to smell them.
Space objects / satellites / asteroids / comets.
When the European Space Agency’s (ESA) Rosetta spacecraft encountered comet 67P/Churyumov-Gerasimenko in 2014, it discovered various molecules in the comet’s coma, a ring of gas surrounding the comet’s solid nucleus.
These molecules include hydrogen sulfide, which gives rotten eggs their foul smell; ammonia, which reminds us of the disgusting smell of urine; Hydrocyanic acid, which, although notoriously toxic, has a more pleasant smell similar to that of almonds; sweet-smelling carbon disulfide; and the aroma of formalin pickles.
You’ll probably hold your nose when you smell this combination of smells. But even if there is a smell, it is likely to be very faint because the comet is mostly made up of water vapor and carbon dioxide.
The moon smells like gasoline
One place that has an atmosphere capable of holding flavors is Saturn’s largest moon, Titan. However, the atmosphere doesn’t really help us smell anything. There is no oxygen and the temperature there is freezing – minus 292 degrees Fahrenheit (minus 179.6 degrees Celsius) – so we have no choice but to take off the space helmet and take a deep breath. However, if we could, we would notice that the Titan smells like gasoline.
Maybe we shouldn’t be surprised. Gasoline or gasoline is made from crude oil that is rich in hydrocarbons, which are molecules made up of hydrogen and carbon atoms such as methane and ethane.
Titan’s atmosphere contains a thick haze of hydrocarbons, and liquid hydrocarbons form oil-bearing lakes and rivers on the moon’s surface. But methane, the dominant hydrocarbon on Titan, is odorless. So what causes the smell on Titan?
NASA’s Cassini spacecraft identified an unknown chemical in the atmosphere of Titan, which, according to NASA laboratory experiments on Earth, is a molecule containing nitrogen, methane and benzene, belonging to a group of molecules called polycyclic aromatics Nitrogen heterocycles (PANH) are called. In particular, it is the benzene in PANH that gives titanium its petroleum smell, as benzene also occurs naturally in gasoline.
Clouds of intoxicating gas
So the solar system is a pretty sharp place, but what about the rest of the universe?
Sagittarius B2, a vast interstellar molecular cloud of star-forming gas and dust less than 400 light-years from the center of the Milky Way, exhibits a wide range of aromatic chemistry. For one thing, these clouds contain a lot of alcohol, including vinyl alcohol, methanol, and ethanol, the type of alcohol found in beer.
In 2009, astronomers also discovered ethyl formate molecules in Sagittarius B2. Ethyl formate is the chemical that gives raspberries and rum their sweet flavor. Even if it smells like a brewery in the center of our galaxy, the aroma is at least pleasant.
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