Re: How much of the movie

Without going through the movie scene by scene, it is safe to say that the movie "Mission to Mars" is a largely fictional story that is based on some good pseudo-science. Much of the science behind the space travel to the planet is fairly accurate. The journey would take approximately four months (although, if you check the Madsci archives you'll find new propulsion methods that could reduce that to about 9 days)and astronauts would experience much the same conditions as shown in the movie. It does take about 5 minutes for radio transmissions to travel from Earth to Mars, so communication is on a time delay, just like in the movie. Once the characters made it to Mars, the conditions they experienced were based on data collected by the Mars Global Surveyor and Mars Pathfinder missions of 1999 and '97 (respectively). The force of gravity on Mars is 34-40% that of the gravity here on Earth (this is calculated using not only the mass of the planet, but its radius as well). This is enough gravity that Mars does have an atmosphere.

The concept of having a tent-like terrarium where plants produce oxygen enough to sustain life is purely theoretical at this point. In fact, according to the University of Oregon, there is evidence to suggest that growing plants in Mars' lower gravity may prove difficult, as this lowers the surface tension of water, thereby making it more difficult for seedlings to absorb water and nutrients through osmosis.

As there is an atmosphere on Mars, there are also weather patterns. In '97 pictures were sent back of dust storms (called "Dust Devils") raging across the Martian landscape. The marks left behind were often thought to have been made by water or by living creatures in the past. For some good pictures (including animation) check out http://explorezone.com/news/mar s.htm

As for what would happen if you took your helmet off in space, I could not find an answer. You may want to consult some of the space experts at NASA (http://www.nasa.gov) or at Explorezone.com. Another good website for space information is at http://space.about.com/science/ space I hope this helps you and your students.

[Moderator's Note: For a description of why you need a spacesuit (and what happens when you don't have one, try searching the MadSci archives for
spacesuit
Enjoy!]