Sunday, July 14, 2013

Under the Dome

No, this is not about Stephen King's book or the television series derived from it. It's about a project north of Tucson currently run by the University of Arizona where scientists study environmental factors. It's one of the places I've wanted to see ever since I moved here (yes, I'm a science geek) and recently I finally got there.

Biosphere 2 was originally conceived as an experiment in controlled environment living in the late 1980s. It was an ambitious concept. The idea was for groups of scientists to spend two years sealed off from the rest of the world, raising their own food, doing experiments, and recording their results. Its intent was to measure survivability. Although the web site doesn't say it in so many words, I seem to remember that this was related to understanding how humans would survive in similar environments in space exploration. The plan was to do this for fifty cycles.

Yes, you read that right. It was supposed to last one hundred years. In reality, the plan was abandoned after less than three.

In science, experiments that don't work are not considered failures. As Edison famously said when asked about his failure to create a viable lightbulb, "I have not failed. I've just found 10,000 ways that won't work." What is important is what you can learn from what doesn't work.

What did they learn? It takes a lot of effort just to provide enough food. Remember, they were raising the food they would eat. This meant that it was largely a vegetarian diet. There were a few goats and a flock of chickens sealed inside with them, but the animals were there primarily to provide milk and eggs, not meat. While the crew was eating plenty of nutrients, they were low on calories. They reported being constantly hungry. They lost a lot of weight.

During year two, they were able to improve their diet somewhat by spending more time farming. They also made adjustments to the atmosphere which had a tendency to be too heavy in carbon dioxide and too light in oxygen.

The second mission lasted just a few months. Wikipedia cites management disputes within Space Biosphere Ventures. Needless to say, our tour guide didn't bring any of that up.

Today, Biosphere 2 is run as an open system rather than a closed one. The scientists live in housing constructed outside the glass-enclosed structures. There are five environments, or biomes, sealed off from one another and the outside world where research is being done. They include an "ocean", wetlands, tropical rainforest, savannah grassland, and a fog desert. Needless to say, since all of these are more humid than the area around Tucson, desert rats find them fascinating to visit.

Most of the research is now focused on climate change rather than closed environment living. In the tropical rainforest biome, the temperature is being maintained seven degrees above what it currently is in the equivalent outside environment. That's because that's the estimated increase in warmth over time due to global warming. The scientists want to learn what effect this temperature change will have on Biosphere 1, planet Earth.

In addition to the five environments, visitors also get to tour the Technosphere, which is fascinating in its own right. Located in the basement of the facility, this is where the electrical, plumbing, and mechanical systems are housed. It is also where the air for the environments is conditioned: temperature and humidity changed, water condensed out to provide "rain," and particles cleaned from the air.

One of the things you might not think of is that the different temperatures and humidity levels result in significant differences in air pressure between the environments and the outside air. Since the facility is largely glass, a huge greenhouse if you will, if this were not accounted for it would be possible that the glass panels could blow out from the pressure.

To allow the environments to "breathe," they've constructed two "lungs." These are domes with large bladders at the top which rise and fall in response to changes in air pressure. We stooped down to go through a passage that leads into one of these lungs so we could see what it looked like and experience first hand the power of that air pressure difference. It was noticeably harder to breathe inside the lung. When the door is opened to allow you to exit, you not only see the bladder move, you are swept up in a windy maelstrom as the pressure equalizes.

Overall, this made an interesting day trip for anyone interested in science. There's a lot of walking and sections where you have to climb stairs to reach the different levels, so you have to be prepared for that. It was also quite warm the day I went and parts of the tour are outdoors. As always, when traveling in Arizona, bring water. But do go and enjoy the experience.
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