A team of researchers has used two of the biggest telescopes on Earth to find signs of phosphine gas on Venus – a compound that is produced on our planet only by living creatures and human technological processes. We don’t know any way to make this gas non-biologically on Venus.
Here is everything you need to know about the possibility that we have found life on our neighbouring planet.
How hot is Venus? Would any life there burn up?
There are a lot of different environments on Venus because of its thick atmosphere. While it is true that the surface is absolutely miserable – with temperatures reaching 470°C and pressures 90 times that at sea level on Earth – it is pretty temperate where the phosphine was found, at 50 to 60 kilometres above ground level, so the atmosphere could be conducive to life.
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Do we know that this phosphine gas cannot be produced by anything other than biological processes?
It is impossible to prove a negative, so unless we can show definitively that this phosphine was produced by life, there will always be a chance that it was produced by a non-biological chemical process. But the team tested all the processes we know that could happen on Venus, and none made enough gas to account for what has been seen.
How big would an organism have to be to create what was found?
Not big at all. On Earth, phosphine is produced by microbes, so you might expect microbes to be able to make it on Venus too. If there is life there, it could be fairly simple.
Could it be that an organism made this gas in the past and now it is already extinct?
The exciting thing is that this isn’t really an option. The researchers calculated that the lifetime of phosphine on Venus should be less than 1000 years before it is destroyed, so something must be continually replenishing it for it to exist in the concentrations we see. If the possible organisms that may have produced it are now extinct, they must have been around until pretty recently. Given planetary timescales, that would be shockingly unlucky for them to have died out just as we became capable of finding them.
Any chance it could be tardigrades in Venus’s atmosphere?
Although they can endure extreme temperatures, the microscopic, eight-legged Earth animals called tardigrades (also known as water bears) aren’t known to produce phosphine, so if there is life on Venus it is probably something else.
Could the phosphine have come from microbes carried by the Soviet Venera spacecraft, which visited Venus in the 1970s?
It isn’t likely. The researchers found a large amount of phosphine, and the Venera landers were pretty small, so it is unlikely they carried enough microbes to seed this much of the gas.
What capabilities would a spacecraft need to investigate possible life on Venus?
You would want to be able to sample the atmosphere and chemically analyse it. The spacecraft would need to be able to look for life, which can show itself in patterns of materials consumed and released, but also to examine the atmosphere more generally in case the phosphine isn’t biologically produced.
Could we use an atmospheric balloon to search for signs of life on Venus?
The hot, dense atmosphere makes it hard to send spacecraft to Venus, but several have made it down to the surface before they burned up. There have been a couple of balloons sent to Venus. It isn’t impossible, it is just a tough engineering problem.
- These answers were provided by our science reporter Leah Crane answering questions from ¿ìè¶ÌÊÓƵ readers on Twitter. Read her full Twitter Q&A .
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