Disney’s John Carter is a wild interplanetary tale about a Civil War veteran who ends up on Mars, where he’s held captive by the Tharks, a tribe of tall green creatures. After rescuing a Martian princess, Carter finds himself falling for her and so he joins her city, Helium, in a war against another Martian faction. And the superhuman strength he gained due to the different gravity of Mars comes in handy. The film is based on a series of books written by Edgar Rice Burroughs in the early 1900s.
Robert Zubrin, President of the Mars Society and author of The Case for Mars, was inspired by stories of John Carter to become an astronomical engineer. So we asked Zubrin to assess the movie’s depiction of life on Mars.
In the film, John Carter is able to jump really high and far. How would you say the gravitational difference on Mars would affect a man’s ability to jump?
You could jump about three times as high. Martian gravity is one third that of ours. So if you could jump three feet high on Earth, you could jump nine feet high on Mars–which would make for very impressive basketball games.
Many of the characters in the film walk around shirtless or wear very little clothing. Would that be appropriate in the Martian climate?
In the daytime on the equator it does get up to around 70 degrees Fahrenheit, but at night it drops to about -100 degrees Fahrenheit. So it’s quite cold at night, and if you get away from the equator it starts getting cold during the daytime. But at the equator or the tropical latitudes of Mars, it’s not excessively cold during the day.
Furthermore, the actual Mars today has a very thin atmosphere–only one percent as thick as the Earth–and it’s mostly made of carbon dioxide. You would need to wear a spacesuit on Mars, so in that respect the movie is not realistic at all.
Do you believe planets with human-like creatures exist, and if so, that they wage wars?
In this vast universe of millions and billions of worlds, there undoubtedly are those that are inhabited with creatures not too different from people, and I would not be surprised if they had various forms of struggles including wars.
Disney portrays the red planet as one that is slowly running out of water with its canals drying up rapidly. Can you talk about the presence–or lack–of water on Mars?
There is in fact plenty of water on Mars, but it’s frozen. At one time it was liquid. In the distant past, Mars had a warmer climate. The idea is that some day when humans go to Mars and settle it, we can produce industrial chemicals that have very strong greenhouse effects and release them, which would warm Mars, and the water that is now frozen to the Martian soil would melt and it would start flowing to those dry riverbeds. It would fill up the dry lakes and oceans of Mars and the planet could be brought to life. So maybe Edgar Rice Burroughs wasn’t completely wrong about there being cities and nations filled with great adventure on Mars–he was just wrong about when. There isn’t a Martian civilization … yet.
What would you include in a packing list for John Carter?
Well, he needs to bring a space suit. He needs to bring a power supply, like a nuclear reactor. He needs to bring some equipment for taking Martian soil and heating it to extract water. And a portable greenhouse, to grow plants so he would have food to eat. And then he would need a pressurized habitat to live in. Those are the things he would need. And a good set of novels to read.