Venus was once thought to be a lush, life-bearing planet, but modern research has revealed an utterly lethal world. What perils await explorers of “Earth’s evil twin”?
Is there anyone who hasn’t admired the lovely beacon of Venus hanging bright in a cerulean sky? (So bright in fact, it is regularly reported as a UFO, or even more ludicrously, a mystery planet denied by orthodox astronomers).
I’ve written about Venus elsewhere, but let’s talk about the conditions there. Under the gleaming sulphurous clouds, the planet has a surprisingly flat landscape with occasional ranges of gently rolling hills. There are two major highlands, almost continents, but 80% of Venus is covered in these level lava plains. The dense soupy atmosphere (96% carbon dioxide, 4% nitrogen) gives the landscape an oppressive and murky look. This extreme atmosphere makes Venus deadly. The atmosphere exerts 90 times as much force per square centimetre as Earth’s atmosphere does on us (when did you last notice the weight of a hundred kilometres of air on your body?) meanwhile this atmosphere has trapped millennia’s worth of solar heat. Venus is hot. At 450 degrees Celsius, it is not quite a blast furnace but it’s nearly there.
Let’s have a thought experiment. I’ve landed a spaceship on Venus, and impatiently stepped out of the airlock on the cracked basalt. What happens to me?
In three words, splat, sizzle, choke. Instantly I’m squashed flat by a force equivalent to roughly 80 tonnes while being simultaneously cremated. My last (very quick) breath is of toxic gas. Life on Venus would be nasty, brutal and short.
Although it is hard to imagine technology that could enable people to survive on Venus that has not stopped a few science fiction tales from describing humans visiting or settling on the surface of Venus; the TV series Space Odyssey (2004) and Defying Gravity (2009) had near future astronauts in armoured spacesuits making brief EVAs on the planet. Both programmes featured beautiful special effects which evoked the heat and the danger, but neither offered any real clues on how to endure this relentlessly hostile environment. John Varley wrote an interesting Venusian story, In the Bowl (found in his 1977 book Persistence of Vision ), but his characters could use magical forcefields to survive there. Most recent SF stories with a Venusian setting assume the planet will one day be terraformed.
But just say a human could survive there as it is now. What would he see? We have panoramic views of Venus from ground level returned by the amazing Venera probes, so we have a good idea of what to expect. We would see a spectacular and desolate landscape of cracked and broken rocks, appearing a dirty orange colour under what sunlight trickles through the clouds. It used to be said that the thick atmosphere would so refract the light that the landscape would appear distorted, curving up around the viewer (hence the title of John Varley’s story), but recent books do not discuss this idea, so it may have been discredited.
Our sister planet’s deserts offer magnificent, scary desolation but are probably forever out of reach to humanity. Venus is a world best left to robots.
(Article by Colin Johnston, Science Communicator)