Visit volcanoes in space
Venus’s surface, imaged by radar, shows pale flower-like structures blooming over vast dark planes. Although it’s not obvious at first, these structures are in fact two enormous volcanoes. Maat Mons, the larger of the two, reaches heights of 8 km and boasts widths of 245 km ⟨on Earth, this would cover most of Iceland⟩. Closer inspection reveals hundreds of overlapping lava flows snaking from each volcano’s summit, building up the slopes over millions of years.
Long after volcanoes become extinct, the scars they leave on land reveal their fiery past. These traces are remarkably similar across the solar system. We see calderas lurking in the summits of ancient volcanoes where magma chambers have collapsed, and lava rivers winding their way across plains: like liquid fire frozen in time.
When studying landscapes, it can be useful to venture beyond photography. Special techniques can create images that highlight features otherwise hidden to the human eye, offering scientists a helping hand. The lava slopes of Emi Koussi volcano in Chad appear ochre to the human eye, but exhibit vibrant greens and blues in this image which reveals the minerals in the underlying rocks. Red and orange areas correspond to surrounding sandstones. Earth and Jupiter’s moon Io are the only places we know of in the solar system that have active volcanoes.
Volcanism on Earth follows a predictable pattern, forming chains where weaknesses in the Earth’s crust allow magma to escape to the surface, or popping up where great magma plumes rise from the mantle. Earth is unique in this respect. Dark spots dotted across Io show a random distribution of volcanoes. Since its surface does not shift over time, like Earth’s, the volcanoes are able to reach enormous sizes as lava oozes out over the same spot for millions of years.