People were shocked a couple of weeks ago when an important story made the headlines: scientists had declared life could be possible in the clouds of Venus. I know that this article appeared everywhere, as it featured in the September issue of Science Focus magazine and made the headlines of BBC News and The Guardian. But this might be crazy after all, and Middle helps seperate your fact from fiction in an interview with Medium writer Ella Anderson!
Q: What made the headlines so shocking?
Venus is many things — bright, sultry, wispy, rich — but it’s never been seen as hospitable to life. It lacks oxygen and oceans, harboring instead rows of sulfuric acid clouds in its orange skies. These clouds trap heat and encourage a runaway greenhouse effect that drives temperatures up to 900 degrees Fahrenheit (465 degrees Celsius). A smoldering, golden environment filled with thick clouds and the bodies of spacecraft we’ve sent in the past. Most spacecraft able to land on the planet’s surface last mere minutes before the intense heat and pressure destroys them. Venera 13 lasted two hours. For comparison, the Opportunity rover survived 14 years on Mars. Venus may be named after the goddess of love and beauty but it is not a loving place towards life at all. This is what made the headlines so startling.
Q: What told scientists life could exist?
Phosphine is a chemical that can be produced abiotically but is more often created by bacteria here on Earth. This close tie to living organisms makes it a biosignature — a strong indicator for the presence of life. While phosphine is sometimes made in laboratory conditions and through volcanic activity, this is not what researchers believed to be causing the phosphine spike on Venus. The studies suggested the phosphine level reached 20 parts-per-billion (PPB), a significant amount.
Any abiotic process able to make phosphine would have been millions of times too weak to give us the 20 PPB result. And it has been hypothesized for decades now that microbial life — and even more complex organisms — could exist on Venus. But what creatures would possibly make a home there? The atmosphere is unspeakably dry, acidic, and unwelcoming. Except in the regions where it isn’t.
Q: Tell me a bit about Venus, Ella. Are there any facts that most people don't know?
Venus’s atmosphere is a gradient. 30 miles (48 km) up from the cratered surface the temperatures and pressures become much more inviting, similar to those of Earth. These top cloud layers are where life could exist. The organisms would most likely be airborne microbes living in droplets that contain a small amount of water. Instead of ever touching the surface where conditions would kill the microbes, the droplets are in a closed cycle of falling towards the surface and evaporating. A loop that hardy organisms could possibly survive.
We must also keep in mind that Venus wasn’t always the stark, unliving desert that it is today. A few hundred million years ago it may have been home to water, and to conditions more agreeable with life. Just as we speculate in the theory of panspermia that organisms could have been transferred between Earth and Mars at some long ago time, so too might life have been transferred between Earth and Venus. Atmospheric grazing events — where passing asteroids gently graze the Earth — would have spread microbes living on our planet’s upper atmosphere to the asteroids headed Venus’s way. Researchers show that over 600 of these Earth-to-Venus grazing events have already occurred.
Q: Why do you believe that there is no life on Venus?
In light of this new information one might draw the conclusion that there was a flaw in the way the original data was analyzed. The method of the original analysis team lead to certain spectral features having exaggerated importance and thus creating a false result. One of the main problems came with the method of noise-removal from the data. When the new study used a different method of noise-removal, the original phosphine signal didn’t appear. In fact, when the new team used the original team’s flawed method of analyzation, they could draw any number of false conclusions from the data.
The biosignature of phosphine could be nothing more than an illusion.
We cannot yet reach a definitive stance on the matter. Further reanalysis of the original data will reveal whether or not it was just flawed science, but the idea of life on Venus has certainly had a strong shadow cast on it once again.
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