September 15, 2020
Thanks for reading Axios Space. At 1,681 words, this week's newsletter will take you about 6 minutes to read.
- This week's newsletter is devoted to the big Venus news announced yesterday. If you're looking for even more, I was on the "Axios Re:Cap" podcast discussing the new discovery.
Please send your tips, questions and Venusian airship designs to [email protected], or if you received this as an email, just hit reply.
1 big thing: Why life on Venus would matter
Scientists think they may have found an indicator of life in Venus’ clouds — a discovery that, if confirmed, will cause them to re-examine everything they thought they knew about how life evolves.
The big picture: If life does exist within a small niche of habitability in Venus' temperate layer of clouds, it might mean that life could be even more ubiquitous in the universe than previously expected. The discovery is already fueling calls from scientists who want a mission sent to the nearby world.
- "If we have Venus also creating life, amidst some completely different scenarios from what we have on Earth, it would be really quite silly to think there's some unique thing about our solar system," Clara Sousa-Silva, an author of the new Venus study and researcher at MIT, told me.
Catch up quick: On Monday, scientists announced the discovery of phosphine — a possible sign of life — in the clouds of Venus' upper atmosphere.
- The gas isn't a sure-fire sign that microbes are floating around in the planet's clouds, but the researchers behind the study haven't yet been able to find another explanation for why the phosphine exists.
- Future observations will focus on confirming the phosphine detection, and scientists are advocating for a Venus probe that might be able to sniff out the gas — and possibly life — in the planet's atmosphere.
The big question: What kind of life could exist within Venus' clouds?
- Scientists think Venus once was somewhat like Earth, with long-lived bodies of water on its surface. But hundreds of millions of years ago, a runaway greenhouse effect took over, leaving the planet shrouded in dense clouds and host to an inhospitable surface.
- On Venus, microbes, or even other creatures living in the clouds, could be the last holdouts after a violent reordering of their world's climate — or it could be life that evolved independently in the clouds.
"If there had been life there when it was habitable, maybe that life managed to adapt. Or maybe only the few life forms that could make it into the clouds, they watched a worldwide massacre of every other life form they knew, and this is them hanging on to the very end, and we're witnessing this kind of final chapter of life on Venus."— Clara Sousa-Silva
Yes, but: Even if life is confirmed on Venus, it will still take time and a lot of analysis to figure out its origins.
- Scientists have long wondered if life could have been seeded throughout the solar system either though meteorites or some other mechanism that spreads material around the solar system.
- If life came to be on Venus entirely independently of life on Earth, however, that would tell researchers something important about how exactly life evolves, potentially providing answers to a number of questions about the nearby planet's history and evolution.
- "That's why this has the potential to open a lot of doors that we haven't really appreciated before," planetary geologist Paul Byrne, who wasn't involved in the new study, told me.
2. A return to Venus
The discovery is buoying a push by many in the planetary science community to get NASA and other space agencies to send missions to Venus that could sniff out if there really is life there.
Why it matters: NASA hasn't sent a dedicated spacecraft to study Venus from close range in about 30 years, with much of the hunt for life in the solar system focusing instead on Mars.
- Researchers now think the discovery of phosphine on Venus could propel the hunt for life in a new direction — toward Venus.
- "I think the '20s could explode as a time when Venus becomes a key part of this wonderful triad of Earth, Venus, Mars, as the end members — the bookends — of how habitable worlds do their thing," James Garvin, a planetary scientist at NASA, told me.
Details: While Venus has gotten the short end of the exploration stick for a number of years, scientists have still worked to develop various missions that could investigate the planet from close range.
- New technology could allow a probe to land and survive on Venus' surface, giving scientists a more clear picture of the world than ever before.
- Another possible mission called DAVINCI+ could parse out the layers of Venus' atmosphere, potentially providing insights into the origin of the phosphine.
- Those missions could get a boost in priority thanks to this new discovery.
Background: NASA's Mars exploration program got a huge boost with the 1990s discovery of a Martian meteorite that appeared to show a sign of life within it.
- This phosphine discovery could be that moment for Venus, even if it doesn't prove to be a sign of life after all.
What to watch: NASA administrator Jim Bridenstine said on Twitter Monday that "it's time to prioritize Venus."
Bonus: Quote of the week
An author of the new Venus study told me that she's come to the uneasy conclusion that Occam's razor — the principle that given two conclusions the simplest one is usually correct — points to phosphine being created by life, not unknown geochemistry on Venus.
"So far we've done everything we can, which is go through all the things that it isn't. We've thought of every possible mechanism, plausible or implausible, that could make phosphine, and we cannot come up with any. And so we're left with this strange situation where Occam's razor is life — which is insane."— Clara Sousa-Silva
3. What comes next for phosphine
Scientists still have a long way to go before they can say definitively what’s creating the phosphine detected on Venus.
The big picture: Science is an iterative process, and this discovery is no exception.
State of play: While finding this signal of phosphine is a big deal, it's not proof of life, and future observations will have to repeat and then elaborate upon the just-released study.
- Future research will use other observatories to hunt for phosphine and other chemicals that might be associated with it in Venus' atmosphere in different wavelengths of light.
- The authors of the study had plans to perform more follow-up observations this year, but the COVID-19 pandemic got in the way, with telescopes shutting down around the world.
"I would think that every team that learns about this should, if they can, and they have the capabilities of resolving this gas, and resolving Venus should be making follow-up measurements to see if there is any kind of change. ... But also just to validate findings to make sure that there are other independent teams that can replicate the findings."— Paul Byrne, planetary geologist at North Carolina State University
That validation is particularly important because some scientists aren't necessarily sold that the signal from phosphine is real and robust in the way the authors of the new study claim that it is.
- “They took the right steps to verify the signal, but I’m still not convinced that this is real,” John Carpenter, an ALMA observatory scientist, told National Geographic. “If it’s real, it’s a very cool result, but it needs follow-up to make it really convincing.”
What's next: Ultimately, experts say they will need some kind of probe launched to study Venus' atmosphere from close range to truly understand whether life exists there.
- The next decadal survey — during which planetary scientists set the field's priorities for the coming decade — is coming up, so it will be interesting to see whether the community recommends a new mission to Venus in light of the news.
4. Beware the Great Filter
If there are microbes on Venus, it could be bad news for humanity, my colleague Bryan Walsh writes...
The big picture: One theory argues the failure to find any evidence of intelligent life in the galaxy — humans aside — indicates there may be some kind of cosmic filter that ends most life at some stage of development.
- If the Venus discovery indicates basic life might be common, it's more likely that such a filter would come later in a species' lifespan — perhaps when they've reached the technological level of human beings.
Be smart: The Venus discovery has potential implications for a cosmic question physicist Enrico Fermi asked in a Los Alamos cafeteria in 1950: Where is everybody?
- The Fermi Paradox identified the apparent contradiction between the sheer size and age of the galaxy — with plenty of room and time for life to arise — and the lack of evidence for extraterrestrial civilizations.
Context: Robin Hanson, an economist at George Washington University, had one possible answer: the Great Filter.
- Hanson theorized in an essay in 1998 that some fact or force prevents extraterrestrial life from developing to the point where it could become an intelligent civilization capable of making contact in some way with humans.
- As long as there was no evidence of even the most basic forms of life elsewhere, it was reasonable to think that the universe might simply be hostile to life outside of a uniquely fortunate planet like Earth.
- But if Monday's discovery does indeed mean that basic life can arise even in seemingly uncongenial environments like Venus — and yet we continue to see no evidence of intelligent civilizations — it points to the possibility that a Great Filter might exist further up the chain of evolution, perhaps even where humanity is now.
Yes, but: As the history of Earth shows, a lot has to go right between the establishment of microbes and an intelligent species like humans, so it's possible such a filter could exist somewhere between those stages.
The bottom line: Given how beset humanity is with natural and human-made existential risks, it's not good if the Great Filter lies in front of us.
Go deeper: Subscribe to Bryan's twice-weekly Axios Future newsletter.
5. Out of this world reading list
6. Your weekly dose of awe: A devil on Mars
Mars — everyone's favorite place to look for life — still deserves some love, particularly when it's offering up views like this for rovers on its surface.
- This gif, taken in August, shows a dust devil spinning along the Martian surface as the Curiosity rover watched from about half a mile away, according to NASA.
- "The dust plume disappears past the top of the frame, so an exact height can't be known, but it's estimated to be at least 164 feet (50 meters) tall," NASA said in a statement.
Big thanks to Alison Snyder and Sheryl Miller for editing this week's edition and to Bryan for contributing. If this email was forwarded to you, subscribe here. 👽