Photograph of the week: Grand Prismatic Spring, Yellowstone National Park, USA

You’d be forgiven for thinking that the Grand Prismatic Spring in Yellowstone National Park, USA, is photoshopped. It isn’t. True story. You know what does lie behind its vibrant colours, though? Science.

Without getting too technical, its stunning prismatic colour, matching most of the colours seen in the rainbow dispersion of white light by an optical prism – red, orange, yellow, green, and blue – is actually all thanks to the heat-loving bacteria living within this red-hot spring.

The spring was first officially described, and named, by the Hayden Expedition in 1871, on the first federally-funded exploration of what would later become known as Yellowstone National Park. Of the spring, Ferdinand Hayden, the expedition’s leader, wrote: “Nothing ever conceived by human art could equal the peculiar vividness and delicacy of colour of these remarkable prismatic springs. Life becomes a privilege and a blessing after one has seen and…