Lake two-face

ESA astronaut Alexander Gerst took this image of Great Salt Lake in Utah, USA, from the International Space Station, 400 km above our planet.

The lake is one of the largest salt water lakes in the world, collecting water from rivers but not flowing out to sea. As water evaporates it leaves salt and other minerals behind so the lake is getting saltier all the time.

The distinctive difference in colour is caused by a railway crossing that impairs water flow. Consequently one side of the lake is more salty that shows even from space.

Alexander is sharing his six-month Blue Dot mission through images like these. Follow his mission via alexandergerst.esa.int