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From the introduction: We examine three major parameters: 1) the likelihood rate of abiogenesis ({\lambda}A); 2) evolutionary timescales (Tevo); and 3) prob

From the introduction: We examine three major parameters: 1) the likelihood rate of abiogenesis ({\lambda}A); 2) evolutionary timescales (Tevo); and 3) probability of self-annihilation of complex life (Pann) To my understanding: 1) Unknown. 2) Unknown outside earth. 3) Unknown. Given the title and the problems above, I didn't read beyond the introduction as time is limited. It sounds like an updating of the Drake equation without addressing the fundamental problems with that as an estimation tool rather than a more modest method for informing interesting speculation.

lmilcin 6y ago
Yeah, statistics isn't really good at extrapolation from a single sample. I think statistics is entirely bad approach to resolving this problem at least until we have more data. We need to know more about how planets form (again, we have rather small sample we have studied well), we need to know what exactly is necessary to jumpstart life and how likely it is to happen. Then we have a hard task understanding why exactly intelligent life evolved and whether it is unavoidable or a fluke. And a bunch other questions that statistics is entirely unprepared to answer.
sampo 6y ago
> 1) the likelihood rate of abiogenesis > 1) Unknown. Abiogenesis is known on Earth. Life appeared quite soon after Earth had cooled down enough, within the first couple of 100 million years. Of course, we don't know if it took 1 million or 300 million years. And it might be difficult to find out. https://en.wikipedia.org/wiki/Earliest_known_life_forms https://en.wikipedia.org/wiki/Earliest_known_life_forms
- placebo 6y ago
  Isn't abiogenesis just a fancy way of saying that somehow life began from organic compounds that were created by inorganic means? To my understanding the somehow part is exactly the reason why we don't have enough information to make any intelligent guess on the probability of it happening elsewhere.
- sanxiyn 6y ago
  We don't know whether Earth went through abiogenesis or was seeded by panspermia.
  - akiselev 6y ago
    It doesn't matter to the Drake equation except to make it far less pessimistic. Abiogenesis had to happen somewhere for panspermia to occur so if it happened so early in the history of our galaxy to then migrate to our planet, the probability of many such colonizers converging on intelligence goes up drastically. Panspermia might even simplify other parts of the equation, like the probability that we'd coexist in the same time period or in range to detect each other's radio waves.
MauranKilom 6y ago
I would recommend reading the conclusion before dismissing this as "they picked numbers to throw at the Drake equation". The point of this paper is to provide modeling not only of the scalar output of the drake equation (which is... not used at all) but of the possible spatial and temporal distribution of intelligent life in the galaxy. For example, it turns out that even for wildly different choices of the unknowns, the region (and age) of the Milky Way that contains most life (i.e. that SETI should focus on) is the same. Also, why do you consider "unknown" a problem when they explicitly set out to investigate the influence of these parameters? For example, they explore Pann of 0.0, 0.5 and 0.99 (per Myr). Could you explain what problem you see here?
- mellosouls 6y ago
  I would recommend reading the conclusion before dismissing this as "they picked numbers to throw at the Drake equation That's a misrepresentation of what I said. I made it clear I had only read as far as I had because the premise of the title was unpromising given the unknowns, and that it sounded like an updating of the Drake equation without its flaws in the calculating of probabilities (as implied by the title) addressed. Feel free to summarise how it fundamentally differs from Drake in that important regard, with the findings and their usefulness in the context of the unknowns and title which promises an estimate of extraterrestrial intelligence.

lmilcin 6y ago

Yeah, statistics isn't really good at extrapolation from a single sample. I think statistics is entirely bad approach to resolving this problem at least until we have more data. We need to know more about how planets form (again, we have rather small sample we have studied well), we need to know what exactly is necessary to jumpstart life and how likely it is to happen. Then we have a hard task understanding why exactly intelligent life evolved and whether it is unavoidable or a fluke. And a bunch other questions that statistics is entirely unprepared to answer.

sampo 6y ago

> 1) the likelihood rate of abiogenesis > 1) Unknown. Abiogenesis is known on Earth. Life appeared quite soon after Earth had cooled down enough, within the first couple of 100 million years. Of course, we don't know if it took 1 million or 300 million years. And it might be difficult to find out. https://en.wikipedia.org/wiki/Earliest_known_life_forms https://en.wikipedia.org/wiki/Earliest_known_life_forms

placebo 6y ago
Isn't abiogenesis just a fancy way of saying that somehow life began from organic compounds that were created by inorganic means? To my understanding the somehow part is exactly the reason why we don't have enough information to make any intelligent guess on the probability of it happening elsewhere.
sanxiyn 6y ago
We don't know whether Earth went through abiogenesis or was seeded by panspermia.
- akiselev 6y ago
  It doesn't matter to the Drake equation except to make it far less pessimistic. Abiogenesis had to happen somewhere for panspermia to occur so if it happened so early in the history of our galaxy to then migrate to our planet, the probability of many such colonizers converging on intelligence goes up drastically. Panspermia might even simplify other parts of the equation, like the probability that we'd coexist in the same time period or in range to detect each other's radio waves.

MauranKilom 6y ago

I would recommend reading the conclusion before dismissing this as "they picked numbers to throw at the Drake equation". The point of this paper is to provide modeling not only of the scalar output of the drake equation (which is... not used at all) but of the possible spatial and temporal distribution of intelligent life in the galaxy. For example, it turns out that even for wildly different choices of the unknowns, the region (and age) of the Milky Way that contains most life (i.e. that SETI should focus on) is the same. Also, why do you consider "unknown" a problem when they explicitly set out to investigate the influence of these parameters? For example, they explore Pann of 0.0, 0.5 and 0.99 (per Myr). Could you explain what problem you see here?

mellosouls 6y ago
I would recommend reading the conclusion before dismissing this as "they picked numbers to throw at the Drake equation That's a misrepresentation of what I said. I made it clear I had only read as far as I had because the premise of the title was unpromising given the unknowns, and that it sounded like an updating of the Drake equation without its flaws in the calculating of probabilities (as implied by the title) addressed. Feel free to summarise how it fundamentally differs from Drake in that important regard, with the findings and their usefulness in the context of the unknowns and title which promises an estimate of extraterrestrial intelligence.