WHAT with everything that has happened this year, I have found myself at home watching the box more often than usual. That was especially true recently when I was laid up in bed for three weeks with covid-19. I spent my time largely watching my favourite genre of film: science fiction. This has made me realise how surprisingly often my main passion – plants – plays a vital role in the plot of such films. And so, as 2021 draws to an end, I offer you my essential analysis of the botanical accuracy of a selection of sci-fi films.
Sometimes, the science is OK. In 2015’s The Martian, botanist-turned-astronaut Mark Watney survives being marooned on the Red Planet by growing his own potatoes. Producing arguably more calories per square metre of growing space than any other conventional crop, potatoes are a logical choice. Trials have shown that the nutritional value of spuds means a person can survive eating little else for up to two years.
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However, Watney starts his farming operation using tubers from a shrink-wrapped packet. Live, raw tubers are constantly respiring and so wouldn’t survive shrink wrapping. And you will have zero chance of getting a harvest by planting cooked spuds. A small but catastrophic error.
In 2007’s Sunshine, a team of astronauts journeys to the sun on a ship filled with a payload of nuclear weapons in the hope of reigniting the dying star. The ship has a fascinating “oxygen garden”, which is designed to produce the life-giving gas for our heroic crew through photosynthesis.
Given the average adult uses about 550 litres of oxygen per day, the crew of eight would require at least 4400 litres on a daily basis. Plants produce oxygen as a by-product of photosynthesis, and it has been calculated that for every 22 litres of oxygen produced, plants gain 150 grams in dry weight. That’s 30 kilograms of new plant matter a day to meet the crew’s needs. Even with the fastest-growing species on Earth, say a tropical bamboo, that is a big ask. The oxygen garden, however, was populated by Tasmanian tree ferns, which grow at barely a couple of centimetres a year under normal conditions. In practical terms, this garden would need to be hundreds of times bigger than is depicted in the film and include totally different species.
Finally, let’s look at the 2012 film Prometheus. It opens with a panoramic shot of an alien race of “engineers” giving life to a supposedly barren Earth billions of years ago by seeding DNA into a waterfall. The same shot then pans over rolling green, mossy landscapes. But wait, wasn’t Earth supposed to be barren? It is as if plants don’t count as life. It is enough to infuriate even the most mild-mannered botanist.
