Can you create a miniature Mars at home?

07 February 2013

Question

I want to be a space scientist when I grow up, but first, I want to do an experiment at home. I want to find out if we can grow plants on Mars. So, to test this, how can we make a small Mars at home?

Answer

Chris - My name is Chris McKay. I'm a Planetary Scientist with NASA Ames Research Centre. I'm interested in Mars and particularly the question of life on Mars. The question for today is, can plants grow on Mars and how could we simulate that here on Earth? Well, I think there's two parts to that question. The first part is, the soil on Mars. Could plants grow on that soil? Well, the best analogue we have on Earth for Mars soils is volcanic rocks - soils that have been produced from volcanic rocks. So, we could go to Iceland or Hawaii and collect some soils that have come from ground of volcanic rocks and use those as Mars analogues. And folks who have done that, it's pretty easy experiment to do and try it. I think you'll find that most plants go fine in that kind of soil. The other question though is about the environment of Mars. The temperature is very low, the atmosphere is very thin, and the atmosphere is carbon dioxide, very different from the Earth's atmosphere. We can simulate those in the laboratory of course with a vacuum chamber and a big freezer. We can get a sense of how to simulate those at home in your freezer. It's cold, not as cold Mars, but almost as cold as Mars, and certainly, too cold for plants to grow. We can also simulate the low pressure by taking a small jar, putting water in it, boiling the water which will drive off the air, drive away the air, fill the atmosphere with water. We then seal that small jar and cool it. The water will condense creating pressures very much like the atmosphere of Mars. So, we can create low pressure environment, put in the freezer, now you have low pressure cold. We want to have CO2 in that as well. Instead of water, maybe we could try something like carbonated drink like Sprite. Then as it boils, it'll put out water and CO2, drives away the air, we seal it, the water condenses creating a low pressure and there's a small amount of CO2 left. Voila! A little bit of Mars in the freezer, low pressure cold! Plants won't grow in that. We know that in order for plants to grow, it's got to be a little thicker, a little warmer, maybe something in the refrigerator instead.

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