If this were true and if abiogenesis had been independent from life on Earth, we could basically assume that it is certain that life arises on planets with suitable conditions (as they were once in the history of Venus).
In this case, the universe basically must teem with life in one form or another.
These might be the biggest ifs one could imagine but I'm really excited for the follow-ups...
(Cross-posted from another thread, as the other doesn't seem to gain traction)
If this is true, I expect several missions to launch ASAP to try and test this hypothesis. If we could prove abiogenesis separate from Earth we will have good proof that life should be abundant.
Very exciting news, I'm hoping that it is proof of life as that will give increase interest and funding for space exploration.
If it all holds up, it means that we saw evidence of alien life for a hundred-plus years (the "unknown absorbers") before we realized it and verified it. Point being, humans can be "slow on the uptake" (and not unreasonably so, given the distances, time scales, and complexities involved).
See also the Silurian Hypothesis [0], which I think just got a lot more interesting as a thought experiment.
> Was There a Civilization on Earth Before Humans? [...] Gavin and I don’t believe the Earth once hosted a 50-million-year-old Paleocene civilization.
Betteridge's Law confirmed. We can track down fossils billions of year back by observing the way they shaped the encasing rocks, and not once have we noticed a ceramic shard, a metal bit or the silhouette of a plastic object.
> There are fossils, of course. But the fraction of life that gets fossilized is always minuscule and varies a lot depending on time and habitat. It would be easy, therefore, to miss an industrial civilization that lasted only 100,000 years—which would be 500 times longer than our industrial civilization has made it so far.
> And then there’s all that plastic. Studies have shown that increasing amounts of plastic “marine litter” are being deposited on the seafloor everywhere from coastal areas to deep basins, and even in the Arctic. Wind, sun, and waves grind down large-scale plastic artifacts, leaving the seas full of microscopic plastic particles that will eventually rain down on the ocean floor, creating a layer that could persist for geological timescales.
Sandstones. Sandstones originate as far as hundreds of million years in the past. Occasionally they harbor fossils, which are indeed rare. But a lot of sandstone is made of sanded up organic material which we can readily identify, even if we can't point to the specific organism they originated from. We only need a tiny industrial-related grain of sand (ceramic, glass, metal, plastic traces) to point to a past civilization. Nobody ever noticed such a grain of sand.
Sure, and the article mentions other possible signs of civilization as well, then it goes on to say:
> So it might take both dedicated and novel detection methods to find evidence of a truly short-lived event in ancient sediments. In other words, if you’re not explicitly looking for it, you might not see it. That recognition was, perhaps, the most concrete conclusion of our study.
I'm not bullish on pre-historic civilization, and neither is the article, but the takeaway is we may not have reason to expect that we'd have found these tiny industrialized traces without a search aimed specifically at them. As far as I know, such searches have not been carried out in earnest to date.
We've put old rocks under the electronic microscope. That's how we identified billion year old cyanobacteria fossils. While there is no readily available comprehensive record of who searched for microfossils by looking at what old rocks, with or without a microscope, it's not like it's a new idea.
I feel like we're talking past each other here. The very first sentence of your link says "The cyanobacteria have an extensive fossil record." In the next paragraph it says "Cyanobacteria are among the easiest microfossils to recognize. Morphologies in the group have remained much the same for billions of years..."
So not a truly short-lived event in ancient sediments then.
It's unlikely we live in a dark forest. The resources necessary to execute entire civilizations across interstellar space would be literally astronomical.
They would be comparable to resources needed for sublight interstellar travel. If you can get a colony ship to the nearest start at 0.9 c, you can also send an equivalent-weight chunk of matter towards someone else's planet and don't slow down.
Or perhaps once a certain level of technology is reached, the civilization advances so fast as to no longer be recognizable. Perhaps it's not a filter but rather a lack of imagination. What appears to be the universe and all things to us could be a limited as a drop of water to a paramecium.
Why would it be confirmation of Great Filter? It's quite possible that life is abundant in the galaxy but that intelligent life is not common and especially industrialized civilizations.
I don't understand with this fascination with the Great Filter. I am sure there are many filters out there, from having a Sun that lives long enough, that doesn't throw off flares very often, need for a magnetic field to shield advanced organisms, water, fossil fuel creation, gravity that can be beaten with fossil fuel rockets, big moon to reduce number of asteroid hits to the planet, just enough water to have continents yet plenty to reduce temperature differences, no tidal locking, ...
Essentially it's the fermi paradox. If life is out there, why aren't there signs? The universe should be teaming with life but isn't. There's a few reasons why... the Great Filter is a hypothesis that basically means almost all life hits a wall where it dies out no matter what. No life so far that we know has ever made it past this filter.
For the same reason the large dinosaurs died out. Life as we know it operates best within fairly narrow mass scales and energy level ranges. Those are both several orders of magnitude away from the quantities needed to produce effects observable at interstellar distances.
The universe should be teeming with life but isn't.
We currently have no good evidence that it is. That doesn't mean it isn't, just that our detection methods aren't yet up to the challenge. Basic information theory suggests that they may never be. Advanced civilizations will use coherent EM radiation for a limited time only. The radiation they do generate in the long term probably won't be wasted by letting it escape isotropically into space.
Also, at some point they may come to understand that drawing attention to themselves isn't a good survival strategy. A civilization that is advanced enough for us to observe is also advanced enough to hide from us.
> Those are both several orders of magnitude away from the quantities needed to produce effects observable at interstellar distances. (...) our detection methods aren't yet up to the challenge. Basic information theory suggests that they may never be.
Not really true. There are more signs of life than just radio waves. One - like in the article - is chemistry. Planets that seem to be very far from chemical equilibrium are objects of interest, as this may imply there is a complex system that's actively fighting entropy. I.e. life. For instance, aliens with powerful telescopes and good understanding of geology could conclude Earth has life on it by observing it keeps a surprising amount of oxygen in the atmosphere, where it should have already oxidized everything instead.
Yes, really true. Look at how hard it was to establish the presence of the PH3 absorption line on the planet right next door. We are not able to make that kind of observation on extrasolar planets yet, at least not beyond very rudimentary levels. Hopefully someday, but certainly not now.
Admittedly Earth's oxygen signature would be a lot easier to detect than a minute quantity of PH3 on Venus. But we wouldn't have been able to look for that either until just a few years ago. Even to a seasoned RF engineer, ALMA and JCMT are indistinguishable from magic.
Fair enough. What I'm saying is that detecting anomalous chemical composition of exoplanet atmospheres seems almost reachable with our current capabilities, and - unlike radio signals - is an indicator we can't really hide. So aliens slightly more advanced than us could be looking at that.
Life, as we know it, only exists in one single known location in the Universe: Earth.
If we assume life is abundant in the Universe, then we should be able to pick up signs of others, such as radio signals, or bio-indicators in other planets' atmospheres, and so, we ask where the aliens are.
Since we don't find any, we then assume that there is something preventing this abundance of life from developing into something we can detect, and something's called the Great Filter.
As of yet, we only have a single point of data, and since we're still here there's some speculation that we've allready passed through the filter. Another data point would mess up the math a bit and we could, statistically speaking, end up with a scenario meaning we still haven't passed the filter, and that we might still have an apocalyptic event wiping us out.
Life on Venus would give us a better idea of what to look for in other places, and that might help us narrow down the search a bit and find other places with life.
Intelligent life is a different matter. We don't know how common it is for
1) a planet to have formed around a star with the right composition of materials
2) have the exact right conditions for life to form early
3) for that life to survive for billions of years while
4) building up large reserves of substances that can
5) be used as fuel by a tool using bunch of talking apes
6) propel their civilization's technology far enough to match ours
7) send a signal that can reach our specific little dot
8) for that signal to be reach us during the miniscule time-frame that we've been able to pick it up.
I mean, what if the glory days of the Milky Way was 500 million years ago and we're developed just a little to late to be able to see the last remnants of galactic civilization crumble to dust? What if we just happen to be the first, and we develop past such technology before anyone else develops it?
Intelligent life doesn't need to be very common before you should expect to be pervasive.
We're a matter of years from originating von Neumann machines ourselves, so any civilization with thousands or millions of years head start should have incredible galactic spread.
> so any civilization with thousands or millions of years head start should have incredible galactic spread.
No, we're saying that that life didn't even reach "civilization". Humans are a blip in time compared to the dinosaurs, for example - we may well be the anomaly, but life still be abundant.
Seems more likely to me that if there is life on Venus, it was probably carried there from Earth at some point and probably has DNA/RNA base just like Earth life. Would be very interested if it was life with a completely different mechanism for reproduction.
Indeed. All else being equal, I'd expect evolution to progress faster in hotter environments with more solar radiation. I wouldn't be surprised if Venusian microorganisms were more advanced, adaptable and capable of surviving an interplanetary journey than Earth ones two billion years ago.
I like to think that if we could dig beneath the surface we’ll find the remnants of an underground civilisation there... sort of like the martians from Broken Angels, but on Venus.
We could already pretty much assume that, seeing how life appeared on earth almost immediately (geologically, anyway) after it was physically possible. Even panspermia is kind of a stretch when explaining that timeline. But yeah, an independent origin would clinch it.
In this case, the universe basically must teem with life in one form or another.
These might be the biggest ifs one could imagine but I'm really excited for the follow-ups...
(Cross-posted from another thread, as the other doesn't seem to gain traction)