On Monday, an exciting, and controversial, find was published in Nature Astronomy. A team of astronomers reported on the detection of a molecular gas - phosphine (PH3) within the upper layers of the clouds of Venus. Phosphine is what is called a biomarker. It's one of the chemicals that astronomers look for in the atmosphere of a planet to determine if that planet might harbor life.
To be clear - no, scientists did not find life on Venus. They found a chemical that typically is a bi-product of life, and it's difficult to understand how it can be found in these quantities without life being present. However, now is the time to be cautious in interpreting these results. There are actually some very good reasons to be cynical of the conclusion that the presence of phosphine is synonymous with life.
But we can look at this observation for what it is. Phosphine was detected at 15-sigma. That means it's a very, very clear detection. Assuming the astronomers did their due diligence, it looks like phosphine might really be in the clouds of Venus.
What is unclear at this point is where this phosphine comes from. Typically, the production of phosphine is associated with life. It's possible, however, that phosphine could come from some yet unknown process. What's more likely - there is an unknown process at work in the clouds of Venus? Or that there is life suspended in its clouds of sulfuric acid? For this, more work is needed.
The authors themselves stress this. "Even if confirmed, we emphasize that the detection of PH3 is not robust evidence for life, only for anomalous and unexplained chemistry," they state. "There are substantial conceptual problems for the idea of life in Venus's clouds-the environment is extremely dehydrating as well as hyperacidic."
But for the sake of the rest of this article, let's say that the phosphine is from life processes. How will it affect our understanding of where life comes from? How would this affect our understanding of our place in the cosmos? And what does it tell us about our own future on this planet?
Where Does Life Come From?
The first question this discovery might help us to address - where does life come from?
Scientists have a good understanding of life and its evolution. What is a bit harder to explain is what created that initial spark of life, what got life on Earth going.
One suggestion - called the Panspermia Hypothesis - is that life began elsewhere in the Universe and was brought to Earth via asteroids or meteors. If we found life on Mars, it is possible that it shared a common origin with life on Earth - assuming they were "seeded" by the same source (or if life started on Mars and was later transferred to Earth or vice-versa).
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However, this hypothesis doesn't work as well for Venus.
"Because the kind of life on Venus would be so different...sulfur-based...it's unlikely it belongs on the same family tree with that found on Earth and [potentially on] Mars," says Dr. Ted Peters, a Research Professor of Systematic Theology and Ethics affiliated with the Center for Theology and the Natural Sciences.
Now, that's not saying it's not possible that both Venus and Earth could have shared the same source of life. Life is pretty resilient and adaptable on Earth - so the evolutionary paths on these two planets could have been quite different. But, if life originated separately, that means that life came about twice, not just once. Twice in the same solar system.
"So long as we only have one example of life, then we can never even begin to guess how likely the origin of life is, or is not. Having a second example immediately tells us that it might not be all that difficult for life to arise," says Brother Guy Consolmagno, the director of the Vatican Observatory, known as the "Pope's Astronomer".
This is probably the most important point of this article - and the discovery on Venus. If life on Venus and life on Earth arose from two different "Genesis" events, that means that life may start easily. And if that's the case, life might be... everywhere.
"It's like the ants in my backyard figuring they're the only ants on the planet. Then they find another hive 100 feet away and they decide there's at least two, so there must be a lot more," says Dr. Seth Shostak, a senior astronomer at SETI.
This May Be Bad News
Having life pop up everywhere in the Universe at first seems like a neat idea. But this could, in fact, be very bad news.
You may be familiar with the Drake Equation. This equation calculates the number of alien civilizations that we may be able to communicate with. It's the product of the average rate of star formation in our galaxy, the fraction of stars that have planets, the average number of planets per star that can support life, the fraction of planets where life develops, the fraction of these that develop intelligent life, the fraction of these that leak some detection of their existence into space, and the length of their civilization.
Obviously, a lot of these terms we don't know. We know the first few - the star formation rate, and increasingly - how many stars may support habitable planets. We don't know the last ones, especially the ones that have to do with life.
But let's consider another thing. So far, we haven't heard any other alien voices out there. If life arose on Venus, so close to us, life may start easily. So where are all those advanced civilizations?
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"They must be rare," says Dr. Benjamin Pope, a NASA Sagan Fellow and an astronomer at New York University who studies extrasolar planets. "It has therefore been argued that there must be a Great Filter that stops civilizations like ours forming: one of the factors in the Drake Equation must be very very small."
What is the Great Filter? First proposed by Robin Hanson, it's the idea that something is getting in the way of civilizations sending signals up into space. In an argument by Nick Bostrom, this Great Filter may be behind us. Perhaps, if it's not rare for life to begin, it may be rare for life to develop from prokaryotes (a very basic cellular organism) to eukaryotes (one that's more complex). Or become multicellular. Or advance to intelligence. Or form technology.
If the Great Filter is in our past, that would be good news for us. But if it's in our future, that leaves only one term of the Drake Equation - the life span of the civilization. That means that it is rare for civilizations to last for very long before blowing themselves up or obliterating their planet through climate change, or something new and destructive we haven't dreamed of yet.
But perhaps there is no reason to despair yet. There may be a much more benign reason why we haven't heard from alien civilizations. "There could be a thousand other reasons why we haven't found the aliens... that's a big conclusion drawn from a simple idea," says Shostak. When it comes to looking for life among the stars, "we've barely scratched the surface."
Our Place in the Universe
Philosophically, if life is indeed on Venus, the implication that life could indeed be everywhere may transform how we see ourselves in the Universe.
"If it does turn out to be right than I think that makes one of the most important stories of the 21st century, or for that matter the history of homo-sapiens," says Shostak.
"Since Copernicus first proposed that Earth is not the center of the Universe, our place in the cosmos has slowly become less and less special," says Dr. Sara Seager, an astrophysicist and planetary scientist at MIT and one of the authors of the paper. "We realized our Sun is also not the center of the Universe but along with a vast number of other stars orbits the center of our Milky Way Galaxy. We've learned that our Milky Way Galaxy is but one of hundreds of billions of Galaxies. Finding life on another planet would be the completion of the Copernican Revolution, showing us that Earth is not the only place special enough to host life."
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Dr. Michael Varnum of the Culture and Ecology Lab at Arizona State University, along with Yul Kwon and lab members, did a study spanning 7 countries and 4,000 participants. They looked at how people would react to the finding of extraterrestrial life. Most people responded positively - with curiosity and excitement.
But would it change our everyday life? Even on the cusp of potentially the biggest discovery of humankind, people's response might be muted. "As a social psychologist I'm skeptical of the notion that we spend very much of our time preoccupied with such existential concerns," says Varnum. "Whether or not there are microbes on Venus or if Omuamua was, in fact, an alien probe zooming through the solar system, we are likely to be more preoccupied with more mundane concerns most of the time, like what's for breakfast, who's going to watch the kids, or how can I get Zoom working."
The Impact Of A Second Genesis On World Religion
How would the proponents of world religions react if there was a second Genesis, away from this Earth?
Again, it may not shatter anyone's worldview.
"Given that the discovery that Earth is not the center of the Universe, let alone the solar system, did not put an end to organized religion, nor did Darwin's discovery of evolutionary processes, or a host of other scientific discoveries that folks thought had the potential to eradicate religion. So my guess is the same thing would happen if we discovered we were not alone in the universe," says Varnum.
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Several studies examined this. Overwhelmingly, whether it be Christian, Muslim, Buddhist, or Jewish proponents, people did not feel it would cause a crisis of faith if life was found elsewhere.
Rabbi Geoffery Mitelman is the founding director of the Sinai and Synapses, an organization that explores the connection between religion and science. "There is a well-known text from a Hasidic Rabbi Simcha Bunim," he says, "that said you should always have two pieces of paper, one in each pocket. One piece of paper says 'For my sake the world was created', and the other says 'I am but dust and ashes'. So on one to recognize that we are enormously valuable... and on the other side we are a small, insignificant speck in this cosmos. If we discover there is life on other planets, on Venus for example, that simply fits into the 'I am but dust and ashes'... That's already incorporated into a lot of Jewish theology."
Will It Change Our Lives?
If life is confirmed on Venus, it will definitely change our understanding of how life forms, how prevalent life may be in the Universe, and maybe even redefine our understanding of our place in the cosmos.
But until then, not much may change.
You may remember back in 1996, what looked like small fossilized microbes were found in a Martian meteorite, later shown to be misinterpreted. Pres. Clinton's Remarks on the Possible Discovery of Life on Mars (1996)Pres. Clinton's Remarks on the Possible Discovery of Life on Mars (1996) . But did it change our everyday lives? Not by a long-shot. Will the discovery of potential life on Venus go the same way? Only time - and a lot of follow-up research - will tell.