Asked by: Christopher Watts, Liverpool
They can! Zero gravity could even help them to travel, if the aroma was spreading through a virtual vacuum. Smells travel by the movement of individual aroma molecules.
Under the influence of gravity and with no air to get in the way, these molecules would fall to the ground at the same rate that anything else does. But in zero gravity they would just keep travelling in the same direction. If they were travelling through air they would be buffeted in all directions by frequent collisions with air molecules (more than a billion per second), which would keep them aloft even in the presence of gravity.
The collisions force the molecules to follow a tortuous path, so they take longer to reach us in air because they have to travel a much greater distance - like a drunken man staggering home from the pub.
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