Experiments at the National Institute of Standards and Technology, Gaithersburg, found the temperature of cooled atoms to be well below the theoretical limit. In 1988, Lett et al. directed Sodium atoms through an optical molasses and found the temperatures to be as low as ~40μk; 6 times lower than the expected 240μk doppler cooling limit. Other unexpected properties found in other experiments included significant unexpected insensitivity to laser alignment of the counter-propagating beams.