1. The desert’s secret…

the sedona desert

Arizona is one of the more perfect areas to test alien landscapes. If you’ve ever been to places like Sedona or the Grand Canyon, you’ll know why. The atmosphere is dry, barren, and often lifeless. But more than that, the area is so spread out and diffuse that it’s easy to hide a secret (or, at least, relatively secret) science experiment.

Because of this, Arizona (Oracle, Arizona, more specifically) was chosen to be the location of this experiment. Originally maintained by Columbia University and now by the University of Arizona, the place has since been repurposed to serve more terrestrial experiments. This was all because the initial experiment had failed…

2. A hidden sphere

a look at the biosphere from the side

The dome—more accurately called “Biosphere 2” (the first biosphere is Earth)—is a formidable sight. Standing at a total of 91 feet tall and spanning a range of around 3.14 acres wide (one wonders if this choice of number was deliberate), the glass-walled complex is something that most definitely catches the eye.

The glass walls of the complex make sense. For the most part, they were structured such that light from the sun could enter the dome and fill its plants with energy. As a result, the plants would metabolize the CO2 buildup from the faux astronauts and yield oxygen as a result. This relationship is instrumental to the survival of these biosphere participants. It’s also the mechanism that failed…

3. Why did we need a dome?

astronaut looks forlornly at the desert ground

The purpose of the biosphere was to replicate what it might take to terraform another planet. The most plausible candidate for such an endeavor would be Mars, given its close proximity and Earth-like feel. But if the experiment succeeded here on Earth, the process could likely translate to any prospective planet (or asteroid), given the right conditions.

Because of this, eight volunteers had consigned themselves to a closed life within the sphere. And it’s here they would remain for the next two years, plodding, planning, and attempting to maintain this dome experiment. They remained for as long as they could. They remained until things started to go wrong…

4. How the dome keeps them alive

biodome rainforest

To survive, the eight scientists who embarked upon this voluntary journey lived among several different biomes (areas that emulate different environments here on Earth). In total, they had around five: rainforests, oceans, savannas, deserts, and a mangrove swamp. The point was to create as closely as possible the natural atmosphere we have here on Earth.

But other than the different biomes, the dome was complete with an abundance of agricultural goods and domesticated animals. They had sweet potatoes, goats, chickens, pigs, and tilapia. They also managed to have coffee plants—but they only yielded enough beans for one person each to have a cup every couple of weeks.

5. Day one

people waving as they walk into mysterious dome

The day was September 26, 1991. This would be the first day that these eight so-called “biospherians” entered the isolated dome to run the experiment. For the most part, this day (and those that followed shortly thereafter) was relatively uneventful.

Given that it takes a long time to change an atmosphere—even if it is 19 trillion times smaller than Earth’s—disaster wouldn’t strike within these first few days. But even with this initial resilience, things would begin to change. And when they did, the crew would be in trouble. The first few of these things had to do with the coral reef and pollinating insects.

6. A lifeline on the line

coral reefs still alive and ripe with color

On Earth, coral reefs are vitally important. While they take up less than one percent of the ocean floor, they are the home of more than 25 percent of all ocean fauna, including things as diverse as crustaceans, reptiles, seaweeds, bacteria, fungi, and over 4,000 species of fish.

But beyond the habitat, they also provide precious oxygen to the atmosphere above. The physiology of the coral reefs is one such that C02 will be sucked from the air and either digested into oxygen or turned into limestone as a result. Either way, the byproduct is more oxygen for those on the land to breathe. If the coral reefs go, so does some of the oxygen.

7. Losing air

a look inside of the biodome rainforest

The first thing to affect the coral reefs of the biosphere was algae. Algae, in case you didn’t know, can be exceptionally toxic to aquatic life. When it grows in too great an abundance, it can dissolve the ability of the reef to usurp carbon dioxide from the air. When this happens, the carbon dioxide will remain to stifle our breathing.

To clarify, within the earliest days of the experiment, the coral reefs had begun to suffer some major damage. They began to get overgrown with algae, so the presence of oxygen in the air began to dwindle. Since the purpose of the experiment was to test the viability of life unattached to Earth, the scientists would have to try and resolve this problem.

8. More problems…

plants looking like they might be dying
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The second problem that developed shortly after they had entered the biosphere was that the indigenous insect population had begun to die off. The loss of these insects was a huge problem. In case you were unaware, insects are by and large responsible for pollinating plants. Without plant pollination, the plants can’t reproduce.

You can guess where this logic is going: With few pollinating insects alive, the plants that provide life-sustaining oxygen would die off. And without this oxygen, the biospherians themselves might begin to die off. While the eight scientists within this dome had the expertise to help them face this dilemma, it wasn’t clear if it would prove to be enough.

9. Starvation?

bald man stares wanting at the camera

But other than the slowly declining presence of oxygen (which would, to be sure, create major problems), the group also started to starve. While they didn’t undergo full-blown starvation, they did suffer a deficit in calories. Because of this, most of the work that the scientists had to perform was done while hungry.

Primarily, the lack of calories was due to the types of food they were eating. The esteemed group had eaten so many sweet potatoes, for instance, that they had turned orange from the stuff. While this unanticipated consequence was not necessarily deadly, it was indicative of a greater problem at hand. That problem was a lack of substantive food…

10. Losing air: part II

a look at the glass of the biodome

As the days wore on, the oxygen in the biosphere continued to decline. By the time they had passed their first year in 1992, the levels began to drop to something dangerous. According to the Occupational Safety and Health Administration, any amount of oxygen concentration below 19.5 percent is considered oxygen deficient.

As time wore on in the biosphere, oxygen decreased to something around 14.5 percent. The eight scientists, then, had begun to experience the toils of oxygen deficiency. These problems include, among other things, an increase in giddiness, confusion, lethargy, and other such things. The brain is especially sensitive to these changes. The result of prolonged deficiency can be death…

11. Losing air: part III

man pours unknwon fluid into ancient contraption

The oxygen they were struggling to breathe in was leeching from the environment at speeds that didn’t make sense. There appeared to be a culprit that they hadn’t yet identified. It wasn’t the slowly dying corals or the lack of pollinating insects. What it turned out to be was microbes.

These microbes were proliferating in the nutrient-rich soil of the biodome. As they proliferated and reproduced, the amount of oxygen they had taken for themselves had increased. As a result, they secreted more C02 into the air, skewing the precarious relationship of oxygen to other unbreathable gases. This lack of oxygen was becoming so bad that the scientists couldn’t sleep. Time was of the essence.

12. Love in unexpected places

a spiral staricase ascending into a hidden room

The biosphere team was of a split disposition—there were four men and four women. Two of the scientists, Jane Poynter and Taber MacCallum, were dating prior to their entry into the dome. And, as the saying goes, the bonding only brought them closer together. And these bonds might last a lifetime.

While most people would say you’re crazy to commit your relationship to a multiyear endeavor with six other scientists and no one else, that didn’t stop the two. Their relationship managed to endure the stresses of low oxygen and the problems associated with it. But their ending wasn’t what anyone had expected…

13. A forced change

an air tank showing some sort of reading
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In response to the massive amount of oxygen deprivation that the group was suffering, the doctor within the sphere maintained a consistent monitoring of the other scientists’ conditions. But when he began to experience the effects of oxygen deprivation himself, things had become particularly bad.

The primary indicator that things had gotten too severe was that the doctor could not add up a simple row of numbers. And with the loss of this basic mathematical function, the outside scientists monitoring the facility had to instigate some changes. What they did was pump oxygen into the dome to relieve the effects. It worked.

14. Two years over

man checking the ground for something with a device

On September 26, 1993, all eight of the scientists were released from the dome—alive and well. The experiment, while it did require the artificial infusion of extra oxygen, was not deemed a failure. Though yes, it did shed light on some of the major difficulties associated with potential terraforming (building a sustainable atmosphere on another planet), it also showed what scientists should do in the future.

Knowing that carbon-rich soils can eventually lead to a major drop in available oxygen through the growth of microbes will help future scientists appropriately tailor their like-minded attempts. But other than the minor and major successes, the group learned some other things on their way out of the dome. Many of these things were unexpected…

15. People smell terrible

man appears to kiss the hand of another man while taking his blood pressure

After having left the dome, the participants of the experiment had noticed something smelly: People literally stink. Having been in the dome for so long, their noses and olfactory systems had grown used to a world bereft of perfume and scents.

Because of this, the smell of what we consider normal antiperspirants and perfumes were perceived as caustic and excessive. It would take several days before their olfactory systems readapted and fixed to the ordinary world of smells we normally inhabit. But this was not the only surprising feature that the biospherians had lost. They’d also lost their ability to eat certain foods…

16. No more meat

people standing over a vegetarian banquet

Because of the cost ineffectiveness of meat as a food source, no meat was produced within the biodome. That meant that for two years there would be no steak, no chicken, and no foie gras. And little did they know, the enzymes that help break down this food tend to dissipate with time.

Once they emerged from the dome, then, they realized this quickly. After ingesting meat, their bodies became abnormally ill. While the temporary affliction was by no means deadly, it was definitely nocuous. It would take ample time for their bodies to redevelop the enzymes that would enable them to perform such digestion.

17. In their spare time

man plays with a vile in zero gravity

While in the dome, some of the scientists within had decided to test some things. One of these things was a small, portable biodome. And with these portable domes they had created sealable structures that could maintain plants and other growable entities. When launched into space, these provided quite the experiment.

These small experiments have since been shot into space with astronauts and shown to be effective at self-sustainability. What they show is that, in a microcosm, we can grow things like fruit and other oxygen-yielding plants in otherwise barren atmospheres. Steps like these are instrumental to a future in which we terraform other worlds.

18. The biosphere today

the biodome well after its expiration date

Today, the biosphere has been appropriated to fit different means. Now, its aim is to test exactly how changing environmental conditions will affect our Earth. These range from minute to severe changes in Earth’s climate, and how they might manifest in Earth’s flora and fauna.

Maintained by the University of Arizona, the facility provides an isolated environment in which ever-shifting environmental factors (liking changes in carbon dioxide or nitrogen in the air) can be tested against the backdrop of a living ecosystem. With experiments like these, we can better grasp the effects of subtle changes on the greater area of the planet.

19. Allegations

man sits in weird tube

The entire biosphere project had a lot of publicity from the start. This included everything from the people involved to the structure of the project. A few of the things that the press thought they had discovered made the scientific aims of the project seem corrupt.

But when you consider the actual aim of the project, this was not the case. One of the things that the public had taken umbrage with was the ostensibly “secret” installation of a device that turned atmospheric carbon dioxide into a solid that wouldn’t interfere with molecules you would breathe like oxygen. Because they thought this installation was “secret,” it was thought to be cheating.

20. What the public got wrong

people standing in the biodome doing who knows what

The public had several misperceptions about the project. For the most part, they thought that the primary purpose was to create an entirely recycled atmosphere created from organic materials. The scientists shouldn’t, under this guise, have needed any sort of outside help from machines that mess with carbon dioxide.

But this was not the aim of the experiment. The aim of the experiment was to try to create a partially-recycled environment that shows how plausible terraforming attempts could work in the future. This could, by all means, entail machinery that would make the process more plausible. We would want anything that could adequately help create a self-sustaining atmosphere.

21. The dome since then

people walk out of the biosphere

Since the original dome experiment closed, much research has been done in the isolated atmospheric environment. By 2013, somewhere around 150 papers had been published using the dome. A substantial portion of the research has contributed mightily to our understanding of coral reef systems and how they acidify with shifting levels of oceanic chemicals.

This research is important for numerous reasons. For one, as coral reef systems continue to bleach and die off, the ecosystems they provide along with the oxygen they yield will begin to dissipate and taper off. Without this oxygen, our atmosphere will become less amenable to us. Our bodies need oxygen.

22. Love lingers

man and wife stand next to each other in fawning act of praise

On a slightly brighter note, the dome—much to people’s surprise—brought a couple of the project’s constituents closer together. These constituents were Taber MacCallum and Jane Poynter. After having spent the better part of two years and 20 minutes together, they didn’t split apart. Instead, they grew closer.

Having been in a relationship prior to entry into the dome seemed crazy. As most people will attest, being in tight-knit quarters with a significant other (and pretty much only a significant other) can be quite the experience. In many cases, that experience is enough to dissolve the relationship. But that wasn’t the case with these two…

23. Marriage

snow on the arizonian front

About nine months after having been released from the biosphere, both MacCallum and Poynter got hitched. They had decided that their time spent in the sphere was not so detrimental as to dissolve their relationship. And since their time spent in the sphere was mutually productive (i.e., they had formed a joint business venture), getting married seemed a logical next step.

The marriage continues today and the two even hope to be the first couple to travel together to Mars. While no one has yet traveled to Mars, the two have put in their ticket. The plans are loosely set into place to occur in 2021. While we’re not certain of the trajectory of human space travel, we look forward to the possibility.

24. A terrible idea?

a desert biome in arizona

After the initial project ended, some media outlets offered an unfavorable view of the enterprise. TIME, for instance, lambasted the project as one of the 100 worst ideas of the century. Given the breadth of how horribly inaccurate this claim was, it merits a little attention.

Clearly, TIME was advertising to an audience that didn’t understand the aim of the project. But worse than that, the journalists also didn’t seem to understand the practice of science more generally. While the aim of the project might not have been successful, that in no way constituted it as a terrible idea. On what planet (biosphere??) would an experiment to see whether terraforming works be a bad idea?

25. The dome since then: part II

men in hazmat suits getting hosed down

After their departure from the dome, the scientists went on to work on separate projects. The experience running isolated ecosystem experiments in the dome provided crucial experience that would help them in future endeavors. Much of the team, for instance, was hired by NASA to help create such isolated experiments again.

These isolated experiments, had the post-dome comments from TIME and other naysayers been taken seriously, would make no sense. Fortunately for us, science continues even while under the duress of public scrutiny. And this will remain to be the case even when all the TIME editors are long gone.