Rock varnish, the thin, dark coating on rocks' surfaces, is an indicator of life
Rock varnish is produced by magnesium-rich bacteria
Rocks on Venus's surface are on the move
Scientists made this discovery by re-analyzing data from the 1990s
Lightning blasts on clay-rich soils support a dramatic theory of how life began on Earth
Phosphorus in clay-rich soils suggest that lightning was a key ingredient in life's recipe
Meet Alice Wilson, the Canadian geologist who did the work of five people
She wasn't allowed to work at remote field sites, so she became the expert in her local rocks and fossils