How does life appear in the universe? How did it appear on Earth? Can it be found elsewhere in the solar system? These two episodes, taken from the second season of the series "Between Earth and Sky" attempt to shed light on these fascinating questions. In Australia, Serge Brunier meets specialists in the appearance of life on Earth. In Los Angeles, in the second episode, he meets engineers who command the Curiosity robot. This famous robot collects valuable information on the soil of Mars, the planet of all fantasies where researchers hope to find traces of life.