[Monty22]

I suppose the Heisenberg uncertainty principle helps a lot with this issue.

On that site there is also a story about Lene Hau:

http://www-groups.dcs.st-and.ac.uk/~history/Mathematicians/Hau.html

The incredible part is: "The reason for the behaviour of the Bose-Einstein condensate is essentially due to the Heisenberg Uncertainty Principle for at such low temperatures the momentum of the atoms is known accurately so their positions cannot be accurately known so, in some sense, spread out. Hau produced slow light by inducing quantum interference in the condensate. "

[VadeRetro]

If nothing else, it's another example that nature is weirder than you tend to think.

[Outlaw76]

From the website you linked with Hau's work:

"She is famous, not for the work of her thesis but, rather, for her later experiments to slow down light. On 18 February 1999 the journal Nature selected for its cover article the paper Light speed reduction to 17 metres per second in an ultracold atomic gas written by Hau in collaboration with Stephen Harris of Stanford University and two Harvard graduate students Zachary Dutton and Cyrus Behroozi. Later work resulted in slowing light to about one mile per hour, then in 2001 her team were able to stop light for one-thousandth of a second. Hau said:-

... this is an amazingly long time. But we think it can be stopped for much longer. It's nifty to look into the chamber and see a clump of ultracold atoms floating there. In this odd state, light takes on a more human dimension; you can almost touch it. "

WOW! If this is true, and I haven't the knowledge to claim it false, I was traveling at 80C on my way to work this morning! No wonder I was feeling particularly massive... I thought it had something to do with the cream filled doughnut.