Supernumerary rainbow by Andrew Dunn. Helix nebula by NASA/JPL-Caltech. Tree rings in Hillsborough forest by Albert Bridge. Tree branches by Debivort. Washington coast by John Murphy. Newly planted grass by Luke. Fingerprint detail (close-up) by Frettie. Ripening Cyclamen coum seeds by Dominicus Johannes Bergsma. Autumn impression with acorns by Guido Gerding. Echinocactus grusonii by Laughlin Elkind. Spiderweb (close-up) by Josef F Stuefer. Lightning over Schaffhausen and Kohlfirst by Hansueli Krapf. Cyclone Catarina from the ISS by NASA. Human iris by Mattis 2412. Mixed cloud formations over Karthaus Township in Clearfield County (close-up) by Nicholas Tonelli. Surface waves by Roger McLassus. Mushroom lamella by Lee Cannon. Dune types in the Eastern Algeria by NASA.