A collaborative project between scientists from the National Institute of Standards and Technology and the University of Colorado at Boulder used laser cooling to produce a gas of degenerate fermions. The researchers magnetically confined potassium atoms, which they had prepared in two different spin states, and cooled them to near 300 nK. Unlike bosonic atoms, which fall into a single condensate as their wavelengths overlap, the fermionic potassium atoms began to avoid each other, so that the scientists observed a nonlinear temperature gradient as the sample approached absolute zero. Fermions and bosons differ in the values of their quantum spin states: Fermions have a spin that is an odd multiple of 1/2; the spin of bosons is zero or an integer. Beyond advancing the field of cold-atom physics, the study of Fermi degenerate gases could improve atomic clock technology and lead to breakthroughs in superconductivity.