New Equations on the Drake Light (Life and Death, Cosmic-Style)

[J-Sun]

Also, the Fermi paradox is rapidly decreasing to unidox.

New Equation Tallies Odds of Life Beginning
Did Supernova Explosion Contribute to Earth Mass Extinction?

(Both from space.com.)

I still figure that, in nearly infinite permutations, you're going to hit the life jackpot more than once but it is about as complicated as monkeys typing Shakespeare. On the other hand, between asteroids, supernovas, the mere fact of planets not quite being closed-loop systems, along with natural and induced climate change and other technological goofs, etc., it's probably as easy to wipe out life as it is hard to start it. Anyway - lots of angles to look at both these articles together and separately and I thought I'd pass them on.

 

[Ray McCarthy]

Unfortunately the Drake Equation and this one has no scientific foundation because we are working from a sample of ONE.
All we can say is that life is likely to exist elsewhere and since Drake we have discovered very many exoplanets and now think stars having planets are common. Drake was speculating about that.

The monkeys typing Shakespeare turns out to be a poor analogy. Chimps (not monkeys) like particular keys, so can't randomly type. Secondly they wouldn't know when they type a fragment of Shakespeare.

 

[Nick B]

The problem I see in this subject, is the term 'inteligent'.
Life seems to be fairly easy, if you look to extreme environments on earth, you see life thriving where you would expect none.

The Drake equation attempts to calculate the odds of inteligent life. Yet, inteligence is not required for life. It is even arguable that high inteligence is desirable for life. For instance - dinosaurs. It doesnt appear they had high inteligence (as in technology, written communication etc) and yet, they owned the earth for a length of time that makes our own species history pale into insignificance.

I believe there is most likely abundant life in our galaxy. Yet we may be the only ones to have attained this level of inteligence. Or at least, the level of technology that allows us to broadcast our existence. Unless an alien civilisation exists that is far enough away that whatever they broadcast hasnt reached us yet.

 

[Mirannan]

I don't think that even Drake treated the numbers coming out of the Drake Equation seriously. However, it's a useful tool when thinking about the subject.

A related issue has been mentioned, called the Great Filter. It is self-evident that the Galaxy is not swarming with technological civilisations, else we would be able to see the evidence in the night sky (most likely!). The Great Filter is a name for the fact that something is keeping the number down, and the issue is whether the filter is in our past (in which case we'll be OK) or in the future, in which case there is something (that we might not have thought of yet) that stops a growing civilisation in its tracks.

Obviously, I hope the filter is in our past.

 

[Dave]

When you take a kick net sample from even a small polluted river and see the sheer number of tiny things alive, or when you look through a microscope and see the quantity of life in such a small area, it seems inconceivable that there isn't some design to it all. Yet, the Earth is very special. Our exact temperature allows liquid water, and liquid water has very, very unusual properties. It is hard to believe water is quite so unusual because we are entwined with its properties and it with us. It is liquid water that has shaped the Earth the way it is and allows chemical reactions in solution. Even liquid Ammonia doesn't come anywhere near Water. I want to think there might be other life, "not as we know it", but I think anything that isn't "as we know it" will be so alien that we won't even call it life. We'll call it something like mineral weathering or cold fusion, and it is probably occurring in an environment so inhospitable that we couldn't survive there for long.

So, we are left with Water as a solvent, and DNA as a replicator. There might be other kinds of DNA, with different base pairs. That life could be unusual and possibly dangerous to us, but if it is possible, why would we not also see it on Earth? We see every possibility that already works. There are millions of millions of years in which the reactions that lead to RNA and DNA within cells would have tried and failed to work before it did produce self replicating units.

So, Ray may be correct that the Drake Equation is only based on a sample of one, but it is scientific, in the regard that it is something that can actually be tested by experimentation (we just need to visit those similar Exoplanets first.) All hypotheses are somewhat speculation. It can also be modified. I'm quite sure that there are important variables missing from it yet that would be needed to be added. The idea of the equation itself was great.

As for "intelligence", I agree that our definition of intelligence also needs reviewing. I think it will be challenged by artificial intelligence in the future. We are also discovering that many animals have abilities that we thought came only with "higher intelligence." What makes man different may require a different word. I don't see that this kind of "intelligence" is a necessary development of life. Thinking that it is, is really a problem with the conception of Evolution. People still view Evolution with the Victorian idea that it was a progression from bacteria to man, rather than a completely random series of events in which man is an unusual, if exceptional, fluke. So even if we find life, we may never find "intelligence" as we know it.

 

[Nick B]

Our exact temperature allows liquid water

Liquid water exists in quite a big range of temperatures really, from 1 to 99 degrees c, as we know.
And that temperature range can be created by quite a range of factors, not just from being within the goldilocks area.
Also, water is abundant in the galaxy, unsurprisingly when it is made from two of the most abundant elements.

 

[Vertigo]

Looking at the extreme environments that have been colonised on Earth is a false comparison for determining the likelihood of abiogenesis occurring. All it tells us is that once life has formed it is remarkably capable of adapting to some of the most extreme environments. Life did not originate in all these extreme environments, though it quite possibly did originate in one extreme environment. Remember all the indications are that all life that we know of has evolved from just one singe instance of abiogenesis. Only after that did it go on to eventually adapt to all the extreme environments we now find it in.

As that first article says: "The value Pa, which is the probability that life will assemble out of those particular building blocks over a given time, is murkier...If the value of Pa is very low, it's extremely unlikely that life will form even when the ingredients are there" and "We don't know the mechanism whereby nonlife turns into life, so we have no way of estimating the odds … It may be one in a trillion trillion (it's easy to imagine that), in which case, Earth life may be unique in the observable universe," Davies told Space.com in an email. "But Pa may be quite large. We simply can't say."

And that's the bottom line we have no idea of the likelihood of life being created even if all the necessary ingredients are conditions are present. It could be tiny, it could be huge. However the fact that it appears to have happened only once on Earth (where all the ingredients and conditions are definitely favourable) and that we have so far completely failed to create it in the lab when we set up the most optimal conditions we can create both, sadly, suggest to me that Pa is likely to be very very small.

 

[J-Sun]

The monkeys typing Shakespeare turns out to be a poor analogy. Chimps (not monkeys) like particular keys, so can't randomly type. Secondly they wouldn't know when they type a fragment of Shakespeare.

The "monkeys" and "Shakespeare" and "know"ing are not to my point. I was just using it as a colorful shorthand for the mathematical size of the problem which could be off by orders of magnitude but expresses the point that it could be almost certainly possible but "very, very unlikely." Similarly, I agree with Mirannan that the "equation" is a thinking tool to provide a ballpark of the scope of the problem and the things that need to be thought about and investigated. It's a kind of "a pinch of this and a dash of that" recipe.

Liquid water exists in quite a big range of temperatures really, from 1 to 99 degrees c, as we know.

It depends on how you look at it and I think Dave's basically right on a cosmic scale. I've thought about this before, being struck by the unlikeliness of it all and finally looked up some stuff on wikipedia, space.com, and universetoday.com to sort of put it into words (or numbers - and pre-emptive apologies for the inevitable mistakes and typos and whatnot):

Take the concepts of absolute cold and absolute heat in Kelvin and put a nice day in the middle and throw in some other signposts on either side:

Absolute cold 0
Cosmic Microwave Background Radiation 3
Pluto low 33
Earth low (Antarctica) 184
Temperate day 288-305 (50-90 F)
Earth high (Death Valley) 330
Venus avg 735
Sun's surface 5,778/Sun's core 16,000,000
Absolute heat 1.4*10^32

So, on a scale of 0-140000000000000000000000000000000, we are comfortable in a range of 17 of those units, liquid water exists in a range of 100 of them, and this planet has a (surface air) range of 146 of them. Even if you restrict the scale to 15999997 or even 702, this is not a large zone (for liquid water, 14% of the small range, .000006% of the "normal" one, or something like .000000000000000000000000000001% of the whole enchilada).

Also, the more I read about exoplanets (which should theoretically make me more confident about finding life) the more I also realize how the Drake equation and other such things barely scratch the surface. We have a sample bias in our exoplanet finds but we are finding numerous hot jupiters and all kinds of other things that show our solar system (at this point) to be atypical. And the more we learn about our own system, the more we learn how precarious it is. There is thought that, without Jupiter, we'd be hit with even more killer asteroids than we have been. So we may need an earthlike planet in a goldilocks zone (or not, as you point out) and we may need a jupiter-class planet in an entirely different kind of goldilocks zone (or not) as an asteroid sweeper. For a long time, people didn't know about dinosaurs. Then they didn't know what killed them. Then we decided we probably did but didn't know how common it was. Now we may have an idea that it would be quite common if not for Jupiter. Everything we learn adds factors to the equation and most things increase the difficulty rather than make it more likely. And the Jupiter example just covers wiping out life that has arisen. As I say, probably very hard to start life and definitely very easy to wipe it out, despite the amazing adaptability Vertigo points out.

I mean, if you think about the range of temperatures in the cosmos and then think about the size of the cosmos and how much of it is essentially empty and about the matter and how much of it is devoted to suns and about the fragmentary dust left over from the star formation being mostly "junk" and this one planet being about the right kind of junk with about the right kind of bizarrely large moon and think about the atmosphere over it (breathe on a ball bearing and the mist that condenses on it is proportional to our atmosphere) and on and on... well, I'm just not so surprised if we don't seem to be overrun with little green men. If producing large numbers of technological civilizations is the point of the universe, it could be seen as a poorly constructed and wasteful mechanism.

Anyway, it's not so much whether these things are right or wrong - as long as we stay in this solar system, almost entirely on this planet, and with relatively few (or relatively "no") resources devoted to it, we're basically guessing - theorizing from limited and unrepresentative samples - but they do provide food for thought. They are constructive. And neat.

 

[J-Sun]

Here's another article on some of the same stuff, but adding factors. (The part about the red dwarf planets and their proximity and the pros and lotsa cons of this, especially.)

Life On Earth May Have Arisen Unusually Early

I've often thought this myself: somebody has to be first; why not us? The usual arguments for us being young and necessarily surrounded by older civilizations are, IIRC, based on the age of our sun vs. all known suns. But that doesn't necessarily follow as not all suns are created equal. Of course, this article is so vague, it's not clear if the red dwarf thing follows either. Still, interesting.

 

[Stephen Palmer]

Liquid water exists in quite a big range of temperatures really, from 1 to 99 degrees c, as we know.
And that temperature range can be created by quite a range of factors, not just from being within the goldilocks area.

Also, it shouldn't be forgotten that the Earth has for 4 billion years kept the surface temperature pretty much the same; an extraordinary thing given the 25% increase in the sun's output in that time. This is due to self-regulating mechanisms, e.g. the carbon cycle. cf. Gaia Theory.

 

[Stephen Palmer]

As for "intelligence", I agree that our definition of intelligence also needs reviewing. I think it will be challenged by artificial intelligence in the future. We are also discovering that many animals have abilities that we thought came only with "higher intelligence." What makes man different may require a different word. I don't see that this kind of "intelligence" is a necessary development of life. Thinking that it is, is really a problem with the conception of Evolution. People still view Evolution with the Victorian idea that it was a progression from bacteria to man, rather than a completely random series of events in which man is an unusual, if exceptional, fluke. So even if we find life, we may never find "intelligence" as we know it.

That different word is consciousness. Human beings are conscious - nothing else on the planet is in the way we are. Of course, there is no fine line to draw in such matters, but six million years of possibly conscious "missing links" are no longer with us. So, basically, it's just us.

 

[Vertigo]

Here's another article on some of the same stuff, but adding factors. (The part about the red dwarf planets and their proximity and the pros and lotsa cons of this, especially.)

Life On Earth May Have Arisen Unusually Early

I've often thought this myself: somebody has to be first; why not us? The usual arguments for us being young and necessarily surrounded by older civilizations are, IIRC, based on the age of our sun vs. all known suns. But that doesn't necessarily follow as not all suns are created equal. Of course, this article is so vague, it's not clear if the red dwarf thing follows either. Still, interesting.

I've often thought the same. Someone has to be first. And yes our sun might be quite young but the earlier generations of stars were needed to generate sufficient heavier elements. Any planets around early generation stars are not likely to be suitable.

Also, it shouldn't be forgotten that the Earth has for 4 billion years kept the surface temperature pretty much the same; an extraordinary thing given the 25% increase in the sun's output in that time. This is due to self-regulating mechanisms, e.g. the carbon cycle. cf. Gaia Theory.

That's another factor I've often considered but it could probably be argued that any life sustaining planet would likely do the same as natural feedback makes this effect quite likely. Isn't there a simple computer model that has a planet with white and black flowers where the white flowers reflect sunlight but like warmth and the black ones absorb sunlight but don't like it too warm. Or something like that. And they automatically achieve an equilibrium no matter what the sun's output is (within reason).

 

[Stephen Palmer]

Yes, that's "Daisyworld," a programme James Lovelock and his collaborators designed to show that the criticisms of people like Richard Dawkins were actually mis-founded. All planets with life would highly likely be self-regulating, since all the positive and negative feedback processes could occur anywhere.