Tuesday, April 23, 2013
Life on Earth… but not as we know it
Never mind aliens in outer space. Some scientists believe we may be sharing the planet with 'weird' lifeforms that are so different from our own they're invisible to us
Animal figures cut into desert varnish by Native Americans in Utah. Photograph: BWAC Images/Alamy
Across the world's great deserts, a mysterious sheen has been found on boulders and rock faces. These layers of manganese, arsenic and silica are known as desert varnish and they are found in the Atacama desert in Chile, the Mojave desert in California, and in many other arid places. They can make the desert glitter with surprising colour and, by scraping off pieces of varnish, native people have created intriguing symbols and images on rock walls and surfaces.