One Question Per Page false false The study in the journal 'Science' was written by NASA scientists. 3 This is not the first study to suggest that life existed on Mars in the past. 1 A scientific vehicle found very small elements of an organic molecule within water extracted from the planet. 2 It is believed that this conclusively proves that there was once life on the planet. 2 Methane is a natural molecule that is a sign of life. 1 All organic molecules have a limited lifespan. 3 Mars can be said to have a winter and a summer. 1 There are at least two more scientific expeditions heading to Mars. 1