A team of scientists sent samples of the bacterium Pseudomonas aeruginosa into orbit aboard NASA's space shuttle Atlantis to see how they grew in comparison to their Earth-dwelling counterparts.

The 3D communities of microorganisms (called biofilms) grown aboard the space shuttle had more live cells, were thicker and had more biomass than the bacterial colonies grown in normal gravity on Earth as controls. The space bacteria also grew in a "column-and-canopy" structure that has never been observed in bacterial colonies on Earth, according to NASA scientists. [The Human Body in Space: 6 Weird Facts]