RichVR
1670
Can’t we just throw away the Fermi equation now? The fact that it has variables that can have any value makes it worthless. No?
I got curious about the numbers here so went back to my notes from the last time I taught astronomy.
So, current estimates based on exoplanet survey results (Kepler, TESS etc.) place the habitable zone population in this galaxy at 10-40 billion range, but just being in the habitable zone is of course not sufficient to be able to support life. There are about 2 trillion galaxies in the universe (per Planck mapping of the CMB, extrapolation from the Hubble Ultra Deep Field, and cosmological modeling). However, non-spiral galaxies are likely less hospitable to life (older stars). Still, even with the caveats, there’s reason to think we might have a population of planets capable of supporting stars that is quite a few orders of magnitude beyond mere “trillions” when considering the entire universe.
And let me be clear that I’m not in any way arguing against your position here, just providing some additional possibly interesting data.
RichVR
1673
Now plug those numbers into Fermi. I’ll wait. :)
Edit: That was a joke. But now I’d be interested.
The Drake equation, don’t go tarnishing my man Enrico like that @RichVR!
Still too many unknowns, I’m afraid. I’ve seen textbooks make the argument that the Drake equation is useful as a way of framing speculation, but I think it probably does more harm than good in these discussions honestly. People with bad priors tend to abuse the hell out of it.
I’d feel comfortable arguing that in the vastness of space, there is a planet right now that has the soup we had to support bacterial life of some sort. Talking galaxy or better. But life that has become what we think of as intelligent and spacefaring and right now is a different beast. Life that has transcended physics as we know them AND is within our little patch of nothing AND right now, that I find unlikely. I will be non-shocked to learn of microbial life on Mars in the past, for instance.
RichVR
1677
If the fact of an equation is, you can abuse the hell out of it. Maybe you need a new one. Or a bigger boat? :)
I’m lost as to who is being sarcastic or mildly amusing or hardcore, apologies up front. Trying to apply an equation to something that we have exactly one observation of is quite silly. You can’t go from guess to base math, all love to the participants in this discussion!
Like I said, it’s generally presented among people that want to take it seriously as a framework for thought experiments, rather than as an actual predictor of anything. But at root, yeah, what you said.
CraigM
1680
I mean the Drake equation is good and useful for precisely one thing, causing one to think about the absolute mind boggling scope of the universe. It puts into very broad categories the rough best guess information we have about what is needed for ‘life’. So when comparing the odds of having life, just remember how absolutely inconceivably large the universe is.
Beyond that placing actual numbers for likelihood is a fools errand I agree. Is it meaningful to discuss why you think the odds of life within (arbitrary parameter) are 40%? Not really. It simply posits that claiming that there being no life outside of earth, and intelligent life within plausible transit distance, are both extraordinary claims and require setting the parameters for life at very specific and unlikely states.
Granted, if we find evidence of some form of extant life within Mars or Europa? That could change thinking on the probability of life generating. And it would be damn exciting to be alive for that discovery! It still wouldn’t fundamentally change the probability of intelligent life being within reasonable travel distance of earth all that much though.
Exactly and well said. I’d give a million to one with me on the million side that there is life somewhere in our galaxy by our definition right now, and easily collect that bet. It happened here, given a few billion planets or more, then it’s going to happen elsewhere, and very likely right now. But then you add in intelligence (again as we would define it) and then you add in spacefaring, and then you add in breaking physics as we understand it, which is quite well, and then you add in the grotesque depth of time that covers the last 14 billion years, and yeah, no saucers.
For anyone interested in a good, grounded read on all the various factors that may play into this, I think Webb’s “Where is Everybody” is a fun read. Warning for the believers, it dismisses “they’re already here” and “they were here because primitive humans were too stupid to build stuff” pretty much immediately and moves on to more scientifically grounded discussions.
I don’t even see on what grounds we would say that the assertion that life is unique to Earth is an extraordinary claim. I don’t see how we get to that judgment simply based on citing the vast scope of the universe, without also having a concomitant estimate of probability. There are things that are of lower likelihood than 1/n where n=the number of planets in the universe that could support life. (A sequence of consecutive natural-20 die rolls, for example, of a certain length.) Whether the likelihood of going from Miller/Urey amino acid goop, to a complex molecule like DNA (or any of the X intermediaries that preceded it), is 1/n or 2/n or 200000000/n, is an important question here. I could see possibly guesstimating that probability from a deep enough understanding of chemistry and/or further lab experimentation, but I don’t know if that’s been done, and frankly if it has, I wouldn’t understand it anyway. But the bald assertion that life probably isn’t unique because space is vastly, hugely, mind-bogglingly big, seems to me to be missing a critical piece.
Obviously as your desires for life get more particular (multicellularism, intelligence, etc.), the odds will go further down, but I don’t know that it’s a trivial matter to get to, say, bacteria*. That might be most of the heavy lifting. Or it might indeed be trivial. The data are lacking.
*Or whatever we know of as ‘early’ life. I don’t want to seem to be bigoted against bacteria, which can also be highly evolved/adapted yada yada.
You’re absolutely not wrong. My instinct is that single celled life is relatively common and more complex forms are very, very not, but there’s nothing especially scientific about that - it’s just conjecture. It’s completely reasonable to hold the stance you suggest based on the available data. Drawing serious conclusions about anything based on a single data point is a losing game.
The book I linked in my last post goes into a lot of discussion about what little we do know, and tries to make some reasonable extrapolations about where the various sticking points might be in life arising elsewhere.
ShivaX
1686
And getting from single-cell to multicell takes roughly 3 billion years (or maybe only 2 billion!)
The Fermi Paradox doesn’t have anything to say about “life”, only “life with human-like intelligence”.
I’m pretty sure aliens built my house, and most of the houses around it, in the mid-1970s. Otherwise, how can you explain the shifting geometry, the non-Euclidian angles of the brick work, and the foundation walls with extra-dimensional rifts?
Sounds to me you’ve made the classic mistake of explaining with aliens what could more easily be explained by terrestial ghosts.
