The Topaz Solar Farm in California, which covers 9.5 square miles (25.6 square kilometers), as seen from space. (Image credit: NASA Earth Observatory image by Jesse Allen, using Landsat data from the U.S. Geological Survey) We may already be signaling other intelligences beyond our solar system, without even trying. Kunyu City, in the Xinjiang Uygur Autonomous Region of northwest China, hosts huge sprinklers that are irrigating over 1,317 acres (533 hectares) of winter wheat fields on the southern edge of the Taklamakan Desert. Then there's the world's largest cluster of solar farms , a megaproject that covers 235 square miles (639 square kilometers) in Qinghai, China, high on the isolated Tibetan Plateau. Farm fields in southern Poland as seen from space. In this region, narrow fields form a striped pattern rather than the large geometric shapes often seen elsewhere. (Image credit: NASA Earth Observatory image by Lauren Dauphin, using Landsat data from the U.S.…