|MadSci Network: General Biology|
To make sure I answered your question correctly, I checked with Ron Parise, an actual Shuttle astronaut who works down the hall from me. He confirmed that astronauts can indeed cry in space. Tears run down your face because of gravity, but they don't need gravity to form. When the tears get big enough they simply break free of the eye and float around.
So the real question is why would an astronaut cry in space in the first place? My guess is they accidentally look at the Sun, or stub their toes on some equipment. That might be easy to do when there is no ``down''!
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