Scientists know that Mars has changed a lot over the years. It used to be warm and wet, and quite possibly harbor at least microbial life, but now it’s cold, dry, and barren. On Monday, NASA launched the Mars MAVEN, which will spend about a year studying Mars’ atmosphere to gather data important in understanding how and why it has changed so drastically. One of the reasons we’re so captivated by the idea of ancient Mars is that it’s a lot easier to imagine humans living there.
And while we can’t turn back time, we do know that atmospheres can change, either via natural processes or, quite possibly, man-induced ones such as terraforming. In order to catalyze Mars dreams, whether they’re past, present, or future, and in order to get people engaged and excited about MAVEN’s mission, NASA created an animation of how scientists believe Mars may have looked about 4 billion years ago when it had a thick atmosphere.