Astronauts have reported encountering unusual scents in space, a phenomenon attributed to the distinct chemistry present beyond Earth. While space is technically an airless vacuum where smelling is impossible, it contains various molecules with distinctive odours, offering insights into cosmic chemistry.
Astronaut experiences
During missions like the Apollo moon landings and spacewalks on the International Space Station, astronauts have described smells akin to gunpowder, ozone, and burnt steak upon re-entering confined spaces. Two theories explain these odours: the formation of ozone from single oxygen atoms adhering to spacesuits during spacewalks, and the presence of Polycyclic Aromatic Hydrocarbons (PAHs), found in charred food, inside spacecraft.
Scientific significance
Space agencies, such as NASA, have acknowledged the importance of understanding space smells. In 2008, NASA commissioned a chemist to recreate space odours for astronaut training, emphasizing the need for astronauts to differentiate between normal odours and potential chemical leaks.
Beyond Earth, encounters with unique odours have been reported. The European Space Agency’s Rosetta spacecraft detected various molecules, including hydrogen sulfide, ammonia, hydrogen cyanide, carbon disulfide, and formaldehyde, in the coma of comet 67P/Churyumov-Gerasimenko.
Titan’s distinctive scent and Milky Way’s aroma
Saturn’s moon Titan, with its atmosphere rich in hydrocarbons, is suggested to smell like gasoline due to the presence of benzene in polycyclic aromatic nitrogen heterocycles (PANHs). Despite the lack of a breathable atmosphere, Titan’s distinctive scent is attributed to its hydrocarbon-rich composition.
Further, into the Milky Way, the Sagittarius B2 interstellar cloud near the galactic centre contains a variety of aromatic compounds. Notably, it includes alcohols like vinyl alcohol, methanol, and ethanol, reminiscent of the kind found in beverages. Additionally, the sweet fragrance of raspberries and rum is associated with the presence of ethyl formate in Sagittarius B2.
In summary, while space itself lacks a conducive environment for human senses, the detection of specific odours provides valuable insights into the chemical composition of celestial bodies and interstellar regions. Exploring the olfactory dimension of space not only enhances our understanding of cosmic chemistry but also adds a sensory layer to the exploration of the vast and intriguing universe beyond our planet.
