No doubt everyone reading this today has heard about the amazing discovery of phosphine in Venus’s clouds. It’s a chemical compound that can be made through industrial processes or via biological processes. Short of finding some kind of smog-filled industrial capital on the planet, it may be that some form of alien life is involved at Venus.
This artistic impression depicts Venus. Astronomers at MIT, Cardiff University, and elsewhere may have observed signs of life in the atmosphere of Venus. Image courtesy: ESO (European Space Organization)/M. Kornmesser & NASA/JPL/Caltech
BUT, and I want to stress this strongly, the presence is phosphine at Venus is not YET proof of alien life there. It’s a very strong signature. The scientists involved in the discovery have exhausted every avenue of study to figure out what’s producing phosphine there that isn’t a form of life. So, like good scientists, they have announced their findings and now await confirmation by other scientists of their conclusions.
As Dr. Clara Sousa-Silva of MIT said (and she’s studied phosphine for years), “It’s very hard to prove a negative. Now, astronomers will think of all the ways to justify phosphine without life, and I welcome that. Please do, because we are at the end of our possibilities to show abiotic processes that can make phosphine.”
I hope this engenders a lot of work for scientists, because the discovery of life elsewhere in the universe is an important step forward. So, they need to do it right. And, I know they will.
Finding alien life has been a driver for the science astrobiology. Heck, it’s been a driver in astronomy. Who hasn’t looked up at night and wondered if somebody else is “out there”, looking back at us? So yeah, the allure of finding life on other worlds has been with us for a long, long time.
The Allure of Venus’s Alien Life
So, what kind of life would create phosphine? Where would it “live” on Venus. The most likely life-bearing region on the planet is actually in its atmosphere. There’s a fairly temperate zone ranging between 45 and 60 kilometers above the surface. It’s a place where the temperatures lie in a range between 20 and 200 degrees F. That’s not a bad temperature range for extremophile life forms, the kind that think boiling water is a great place to live or where cold temperatures are just a cool day.
However, there’s a lot of sulfuric acid in Venus’s clouds, and that’s not so great for any kind of life. No even some tough little microbes. So, there is a “Goldilocks zone” of sorts in the Venus atmosphere where air-borne microbial life could exist, even if it has to deal with acidic droplets.
What Would Venus Alien Life Look Like?
Yesterday, on the Space Hangout, we all talked about the possibility of such life. Fraser Cain suggested that one way it could exist would be that it hides out in water droplets, and then sporulates as it drops through the atmosphere. The spores would be hardened against the acidic environment, get blown back up to the “Goldilocks Zone”, where they’d sprout, live, and then start the whole process over again.
That’s certainly one way to do it. But, I suspect there are others. And, knowing planetary scientists and astrobiologists, we’re bound to see some pretty interesting suggestions come out. However, first everybody has to work through all the possibilities of the types of life that could be making the phosphine. Then, they’ll have to figure out the chances of such things actually existing. It’s going to be an exciting time in both sciences! Stay tuned!
It seems like every few days, we hear about the discovery of another planet around a distant star. I think it’s great that we’re finding so many planets “out there”. It means that our solar system isn’t the only one in the galaxy (or in the universe, for that matter).
Implicit in the search for other planets is the search for life in the universe. Life, in other words, besides ourselves and the species that populate our planet. Astrobiologists (the scientists who study life and its possibilities on other worlds) are looking for conditions for habitability elsewhere. Of course, habitability means different things to different life forms.
A place that supports human life, for example, might not be very hospitable to other life forms. We see that in our own oceans, by the way. Humans can’t live in them without special habitats or suits; and whales and other denizens of the sea can’t make it on the land. So, we have a fine example of habitability right here on Earth. The same will play out as we look at other planets in detail to figure out which life they can support, and which forms they can’t. And, that includes viruses, which may or may not be considered living things, but certainly have an effect on life. As we are learning this year.
The SARS-CoV-2 virus currently infecting people around the world. CDC/Alissa Eckert. From CDC Public Health Image Library.
Wafting Viruses on Earth
Viruses and bacteria have existed on Earth for a long time. They’re part of the inventory of Terran biological specimens, along with planets and animals and humans. We’ve learned to live with most viruses and bacteria, even as we’ve developed medicines to help fight off their effects in humans. I say “most” because right now, we’re still struggling with the “fighting off the effects of” SARS-CoV-2, which is infecting large parts of the world right now.
All we have at the moment are recommendations for mask-wearing, hand-washing, and social-distancing. Those, if taken all together, can and do help prevent the spread of the virus human-to-human. In places where these directives have been followed, transmission does eventually slow down. In places where people insist on gathering mask-free, having physical contact, and not washing their hands—well, the results are devastatingly tragic.
Part of the discussion about the COVID-19 disease focuses on how easily the virus travels between us. People know and accept (or they should) that the virus can travel through the air on sneezes and coughs. We know this from how easily colds and flu spread. The droplets we emit can carry viruses and bacteria. Viruses themselves can get caught up on the breezes, and ride the air. That’s why the common separation between people to help avoid catching the virus is six feet (just under two meters). Personally, I think it should be more.
Of course, viruses and bacteria ride the winds around our planet all the time. This is in addition to hitching a ride with animals and people. That’s true not just of the coronavirus we’re fighting now, but many others. I read a study the other day, describing the scientific measurement of the troposphere of our planet (just below the stratosphere). Researchers found viruses riding along on air currents there, on captured soil particles, and droplets of water from the ocean (whipped up into sea spray).
If and when all this viral load falls to the ground (as it eventually does), each square meter of the planet’s surface can be covered by hundreds of millions of viruses, as well as bacteria. (Want to know more about the study? Check out this 2018 study from the University of British Columbia.) So, viruses are a part of the inventory of “things” on this planet. They’re part of what we live with on Earth.
Viruses in Space
So, could viruses arise on other planets? Travel through interstellar space? Sure. I mean, it seems that if the ingredients for life are on those planets (the chemical precursors, water, warmth, something for them to latch onto), then yes, they could be on distant worlds. And, there are most certainly mechanisms to carry them from world to world in a planetary system (collisions sending rocks from one world out to orbit and eventual capture by another planet, for example).
Viruses aren’t necessarily considered to be life forms by biologists, although there’s a lot of debate about that. One thing they can agree on is that a virus is an infectious agent. Take SARS-CoV-2, which is causing so much trouble. It’s basically a bundle of RNA (genetic material) wrapped up in a bag of protein. (Note that some viruses consist of bundles of DNA, too, all wrapped up in a delivery envelope.) The SARS-CoV-2 bundle is, itself, encapsulated inside a lipid coat. Lipids are the basis of fats. Our little fiend also has little spikes protruding out from itself that help it “stick” to cells inside our bodies. Once inside a person, the virus injects its stuff inside of healthy cells, which then help it replicate itself inside the body. Mayhem ensues.
That sounds like vicious life form, but there’s no evidence that the virus itself is alive in any sense that we understand “life”. Some scientists think they ARE life because they carry genetic information and they reproduce, but others don’t accept them as life because of the lack of cellular structures inside the lipid shells. No matter — they exist on this planet and have done so from earliest history. In the grand scheme of things, there are helpful viruses that have evolved, and there are the unhelpful ones — like COVID-19. And, they came about using the same materials on the early Earth that helped form life. And, if they form here from our chemical element “load”, then they can likely do it elsewhere in the solar system and beyond.
Viruses in the Great Beyond
When we get around to thoroughly exploring planets (in person, for example) in the future, tests for life should include the search for viruses and bacteria. Sampling a planet’s chemical abundances on the surface, in the atmosphere, and in any bodies of water, will be necessary in the search for viruses, bacteria, and complex life forms. That’s only common sense. We have no way of knowing if an alien virus is harmFUL or harmLESS to human life. It’s a rough chance to take in exploration. We have the SARs-CoV-2 to thank for showing us that viruses new to humans can play nasty with our systems. Humanity is learning that lesson now, as we see how different people react to the virus; some get very, very ill (and die), while others suffer flu symptoms, and still others don’t even know they have it.
When our intrepid explorers head to Mars, for example, they should search for evidence of things that could have formed viruses in the past. Granted, the surface may be completely sterile, thanks to continual bombardment by solar ultraviolet radiation, but that’s not the only place where evidence lies. Digging beneath the surface will uncover further evidence, if it exists, of Martian viral forms. And, maybe, bacteria, too.
The same will be true of other places in the solar system, and beyond. Viruses, as we have learned from virology studies, are tenacious, opportunitistic agents. The quick spread of the COVID-19 disease proves that. Despite its size, it can teach a lesson to us about itself, and about what we must do to avoid the worst effects of this virus, and its possible cosmic cousins.
