Dark ovals in Jupiter's polar haze, visible only at UV wavelengths, were first noticed 25 years ago, then ignored. A new study shows that these dark UV ovals are common, appearing at the south pole in 75% of Hubble Space Telescope images taken since 2015. They appear less often at the north pole. The scientists theorize that a magnetic vortex generated in the ionosphere stirs up and concentrates the hydrocarbon haze that blankets the poles.