South auroral oval and polar rain simulated in laboratory using the Planeterrella experiment (J. Lilensten et al., UJF/CNRS, Grenoble, France, online). The Planeterrella was redesigned after K. Birkeland’s original terrella experiments, which in the 1900s helped him unveil the mechanisms at the origin of polar aurorae. A magnetised aluminium sphere is placed in a vacuum chamber. An electric ...[Read More]
Imaggeo on Mondays: Damavand Volcano
Damavand Volcano, Iran. A nice cap cloud can be seen at the top of the mountain. Cap cloud is an orographic cloud that is formed over a mountain peak, formed by the cooling and condensation of moist air climbing up and over the peak. Cap clouds appear to remain stationary. Image by Mostafa Ganjian, distributed by EGU under a Creative Commons License. Commentary by Konstantinos Kourtidis. Imaggeo i ...[Read More]
Imaggeo on Mondays:Iron oxidizing Leptothrix bacteria
Leptothrix bacteria, in general, are known to be capable of oxidizing both iron(II) and manganese(II) producing ferric hydroxide and manganese oxide. Image by Bertram Schmidt, distributed by EGU under a Creative Commons License. Imaggeo is the online open access geosciences image repository of the European Geosciences Union. Every geoscientist who is an amateur photographer (but also other people) ...[Read More]
Imaggeo on Mondays: Lightning strikes in New York City
A devastating storm raged over New York city on 18 August 2009, uprooting more than 100 trees in Central Park and damaging hundreds of others. This photo was taken from a balcony in East Harlem during that storm, catching one of the many fierce lightning strikes. Image by Bastiaan van Diedenhoven, distributed by EGU under a Creative Commons licence. Imaggeo is the online open access geosciences im ...[Read More]