"I gather that a probe from a galaxy far. far away landed in the middle of the Sahara desert recently and concluded that there are no signs of life on this planet."
Surprisingly, there are lots of signs of life in the Sahara, Atacama and Antarctic deserts. I did some work with the NASA Spaceward Bound program some years ago around Death Valley in California looking for extremophiles. The premise of the program was to look for forms of life in extreme environments to have an idea of what to look for on Mars. Dr Chis McKay was the lead. Really fascinating work.