NASA launches its most ambitious hunt for traces of life on Mars, landing a car-sized rover in a rocky, ancient river delta. The rover will stow samples for possible return to Earth and test technology that may pave the way for human travel to Mars.
Some 30 million Americans have sent their DNA to be analyzed by companies like 23andMe and AncestryDNA. But what happens once the sample is in the hands of testing companies, and how accurate are their results? NOVA explores the power of genetic data to reveal family connections, ancestry, and health risks—and even solve criminal cold cases.