This Week in Science: Highlights of Research in Science Journals

Editor's summary of "Ionospheric control of magnetotail reconnection" by William Lotko et al.

In Earth's upper atmosphere, the reconnection of magnetic field lines converts latent magnetic energy into the thermal and kinetic energy of plasma flows. But reconnection appears to produce faster flows before midnight compared with after. To find out why, Lotko et al. simulated this energy exchange. Challenging common assumptions about our space weather environment, they conclude that the ionosphere plays an active role when coupled to the magnetosphere in driving the behavior of the magnetotail.