A rotation in light's electric-field vector can alter the light's frequency. This rotational equivalent of the Doppler effect has proved surprisingly elusive, but has now been spotted in the laboratory.

Is the anomalously high electrical conductivity seen in part of Earth's mantle caused by protons derived from hydrous defects in the mineral olivine? Two groups investigate this possibility — and draw different conclusions.

These monstrous birds were probably more agile and less portly than previously thought.