Life on Venus? That outrageous-sounding possibility understandably made headlines a couple weeks ago. In part, the news grabbed people's attention because Venus seems like such an unlikely place to find anything alive. The surface temperature there averages 460 degrees Celsius, and the pressure at sea level is a crushing 93 times the atmospheric pressure on Earth — except, of course, there is no actual sea on Venus.
There was another startling aspect of the life-on-Venus story, however: the nature of the evidence itself. There are no rovers rolling across Venus. We do not have any samples of Venusian rocks to put under the microscope. We have no physical samples at all of the planet. The search for life was conducted from afar, entirely indirectly, using radio telescopes. Those provocative hints of life came in the form of an extremely slight radio shadow indicating the presence of a molecule known as ...
