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Friday 23 January 2004

Why are we alone? [brit]

I've just finished reading a book Lurks lent me some time ago, thats been sitting in the bookshelf staring at me for the last six months, Space by Stephen Baxter.
It's a fairly hardcore science fiction book, dealing with a range of issues - one of the most interesting is the idea that organised religion based around the notion of a omnipotent deity figure would collapse on the arrival of an alien species.
However, it does have an ongoing and somewhat depressing theme which I was incredibly impressed with; the idea that the universe imposes a limit on the expansion and advancement of individual species by initiating a reset every few million years.
If you think about it, it is a theory as viable as any other and actually makes sense. The earth is some fifty billion years old, the universe itself at least ten times that. Mankind in comparison are the new kids on the block, with only one hundred thousand years under their collective belts.
It doesn't therefore make sense that a) we're the only sentient life in the galaxy (let alone the universe) and b) our evolution (especially technologically) is in any way progressing at a normal or enhanced rate. Indeed, for all we know we may well be the least technically advanced species in the Sol system, let alone within our arm of the galaxy.
So the theory makes for a pretty damn depressing idea behind our apparant galactic isolation; though the book is absolutely excellent and if you fancy something that'll bend your mind a notch, I recommend it.


  1. Is it make up numbers week again? The earth isnt 50 billion years old, nor is the universe 500 billion years old. More like 4 or 5 and 15 respectively, though opinions vary for the universe.

  2. Er, few minor corrections. The Earth is generally accepted to be under five billion years old (somewhere in the region of 4.5 to 4.6 billion), while the Milky Way galaxy is dated at between 11 and 13 billion years, and the universe itself at somewhere around 15 billion (I believe - although I know that some recent research which I can't recall the results of refined this figure significantly).
    There are all manner of explanations for us not encountering a developed species yet - let's face it, we ARE in something of a galactic backwater here, stuck out on a spiral arm at the very rim of the galaxy, and our techniques for searching out signs of extraterrestial life are crude at best.
    Of course, there's always the theory that they've been here all along... ;)Edit: Damned asstrologer got there first with the figures. I'll get you next time, Doctor Dave! Just you wait!

  3. The statistical evidence points to us being alone in the universe.
    Sadly, I can't remember exact figures, so I will make them up in the next paragraph, but it's not the ACTUAL figures that matter, it's that the argument holds true...
    There has been enough time since the formation of the galaxies around us for civilizations to have advanced as we have, discovered the ability to colonise other planets and travel through space over extremely long distances, travel and occupy not only their own galaxy but several nearby, and then die out again. Not only has there been enough time for this, but there has been enough time for this at least a hundred times over.So... statistically, if there was, OR EVERY HAS BEEN life out there anywhere in our local cluster, we would almost certainly know about it - the only rational explanation is that either it doesn't exist or they are deliberately hiding from us (like Starfleet directives) and if it's the second one, then the question is pretty much irrelevant.
    Sorry to be so depressing, it's just such compelling evidence that I believe we are effectively alone,

  4. Rubbish.
    We don't know anywhere near enough about anywhere near enough to make those kind of assumptions. We don't know how life arises. We don't know the likelyhood of life. We don't know the likelyhood of planets capable of supporting life, or even how much variation there is on where life can live.
    All we know is that we've set foot on three proper planets and at least one of them has life on it. We can't rule out the other two.
    We're completely in the dark in other words.
    It could be that the existence of life is entirely dependent on a certain mix of elements that it has taken this long for the universe to brew the necessary cocktail. It could be that we needed to wait for the background radiation level to lower a bit. We could be surrounded by fledgeling civilisations within 1 million years development of us. There could be none on this side of the galaxy, but it could be teeming on the other side of the galaxy.
    The sheer scale of the universe makes these kind of statements utter bunkum. There's 100 billion stars in our galaxy, and 100 billion galaxies. 10^22 stars in the universe! To illustrate the point, to travel from where we are to the other side of our galaxy, at light speed would take us 100,000 years. To travel to the nearest of these 100 billion galaxies, Andromeda, would take us 2.9 million years!
    My own personal gut feeling is that there will be life out there, somewhere. Life of all different flavours and varieties, from amoeba to grand multi-stellar civilisations. And I'm not in the slightest bit surprised that we haven't seen anything of them in the 50 or so years we've been looking in the tiny band of the EM spectrum we've been concentrating on.

  5. The bold Dr_D says we've stepped foot on 3 planets, earth the moon and today planet Brit. Enjoy your stay.

  6. And Planet Hollywood!
    Here's fun: have a look at the Drake Equation which deals with this problem:
    I wouldn't put much truck in the numbers published there. The point about Drake is that its probably right enough, but we don't know any of the coefficients, so can't fathom an answer.

  7. I'm also of the opinion that afty is talking complete shite. Daves right, we just don't know enough. There's been fairly recent discoveries that show life existing in conditions we previously didn't think was possible. So if we don't know the parameters of life, how can we predict the chances of it's existance elsewhere?
    My thoughts on it is that there is probably life out there, it's just going to develop at vastly different rates depending on the environment it lives in. Earth is a very rich environment for life, perhaps theres billions of other places where it's not quite so good.
    Or perhaps the bible bashers had it right all along :)Shedir: The moon isn't a's a moon!

  8. Well, as much as you guys are jumping all over Afty for it - actually the root of what he's postulating is called the Fermi paradox. You don't have to assume too much actually, for this to start to postulate some interesting problems with thinking about the evolution of life and intelligent life.
    Afty is essentially reiterating what Fermi said. If alien civilizations have evolved, IE intelligent life, there has been millions of years for them to colonize countless systems and make themselves fairly easily detectable by us. There is no such strikingly obvious signs today.
    There are many possibly solutions to the Fermi paradox and sci-fi authors have had a field day with some of the more colourful varieties. These include; Life is common but intelligent life is rare. Intelligent life forms generally don't wish to spread out and colonize - that's a value of ours that we're putting on them. Civilizations tend to destroy themselves (we came pretty close after all). Civilizations generally meet untimely ends by natural extinction events before they reach space faring stage - asteroids, novas, biosphere collapse, that sort of thing.
    The colourful ones include the fact that there may be nasties out there which seek out signs of civilization and destroy them. So all civilizations are either dead or hiding.
    Take your pick. I personally believe, by matters as much to do with faith as science, that intelligent life exists somewhere else. The Universe is just too big and our origins are just too ordinary to make us something unique on that scale. However I don't think any of us knows what the definitive solution to the Fermi paradox is.
    Perhaps it's just us being stupid, there's been plenty of precident. Maybe we'll just tune our radio telescopes to a frequency which is mind blowingly obvious to everyone else out there but us, and suddenly the universe will light up like a christmas tree with the chatter of advanced civilizations.
    Or maybe, one day, while we're still scanning the skys... something fast and nearly invisible turns up and does something unpleasant to our sun before fucking off back into the black bits between the stars.

  9. The point of the argument is that it never discusses how hard it is to develop, where one can develop, how likely life is to be intelligent or to desire communication, it's a STATISTICAL argument that relies on none of that rubbish.
    In simplest terms, the universe has been around for billions of years, the fact that we haven't found anyone yet, when there has been plenty of time for them to colonise our galaxy and several others leads to the statistical conclusion that there is a VERY strong likelihood that no other intelligent life exists in our local cluster.
    And to answer Dr Daves point about travel times (crossing our galaxy, popping over to Andromeda) 100,000 and 3 million years are a BLINK OF AN EYE on cosmological timescales. They are seriously insigificant timescales. Bringing them up is like arguing that no-one could possible be found on Ireland as it would take at least an hour to fly there!

  10. Hmm seems I gave you a bit too much credit :) It's only a statistical argument if you rule out all the reasons there might be for civilizations not performing obvious stellar-engineering. And there's a great many reasons we can think of, let alone not think of because we're a hell of a long way from having that sort of technological capability.
    One common explanation explored by countless sci-fi authors is that when sufficient technology exists, intelligent life prefers to transform itself into other forms. Obviously it makes sense to do that if the alternative is to start pushing suns and planets around - unless, even when you have reached the God-like levels of technological engineering prowess, you still think it's a good idea to show off to the less able.

  11. I think its a question of motivation. What possible point could there be in establishing a galactic empire? None as far I can see. There's no economic motive. There will be no cultural continuity. The travel times will be so stupidly large that by the time your lads get there, the last thing they'll want to do is send out another couple of generation ships. They'll want to get out and stretch their legs for a couple of millenia.
    For really long intergalactic trips, it just isn't feasible. 3 million years to make the crossing? This is assuming that the ship doesn't suffer a cataclysmic failure. Or that the species is mature enough to contemplate such a feat. Or that they even remember what they were doing in the first place when they get there. Or that they don't reinvent the nuke on the way. Or that they don't run out of materials. Or that they don't evolve into something that is only capable of surviving in the confines of their spaceship... I can't see it.
    So we've therefore got to rule out everything beyound our own galaxy - we can't see them, they can't see us, we'll never go there, they'll never come here. So even if we are alone in our own galaxy, there's still 99,999,999,999 other galaxies out there that we can't say anything about.
    Fermi's is a nice enough coffeetable theory, but it makes far too many assumptions to be of any real us.

  12. It's not really a theory though is it. It just asks why can't we see them when they've had ages to build impressive sand castles. If nothing else, it seems a useful tool to make us think about the possible answers including the most obvious ones such as we've just both pointed out; there's just not much point building an impressive sand castle at the end of the day.
    Who could argue that it wouldn't just be the smart thing for the human race to work out how to manage our biosphere efficiently and stop breeding when it cannot support any more humans? We're not so very far off solving those problems and a heck of a long way off solving the problems of colonizing our arm of the galaxy.
    So it's a long time in between to decide, even though we don't need to build ourselves uber star ships and send them to far flung reaches, we're going to do it anyway for some reason or another.

  13. Assuming Drake's equation holds water, and it seems perfectly reasonable, I decided to try to figure out what parameters would be needed for a civilisation like ours to be alone in the universe.
    The parameter of stars in the galaxy (100 billion) seems reasonable, from what we observe. I used a value of 1 for the number of life capable planets in a planetry system as a fairly reasonable value - we reckon that the 'life zone' in a solar system goes from 1AU - 3AU, so there's actually 2 in our solar system. I took the rather pesimistic view that we'll wipe ourselves out soon, so a civilisation lifetime of 100,000 years was used. And for the fraction of stars with planets, I used a value of 5%, which is about on the lower side of what we observe.
    This leaves: chance of life, chance of intelligent life and chance of communicating intelligent life as my three variables.
    Now, to get a result in which we're alone in the universe, we need approximately an average of 1e-11 civilisations per galaxy. So over the whole universe of 1e11 galaxies, we get one civilisation.
    Okay, I also reckon that the chance of intelligent life communicating is going to be fairly high. It may even be due to whether or not they're sea based or land based. Abitrarily, based on this gut feeling, I'm setting that as 1% - so 1% of intelligent civilisations will start transmitting eventually.
    For the two remaining variables, which are the two interesting ones in all honesty, to get the answer that we are the only intelligent life in the universe, we need to have a chance of life and a chance of evolving intelligent life of approximately 1 in a billion each (or some distribution thereof). In other words, a chance of a planet evolving intelligent life of 1 in 10e18.
    This is useful because it shows, statistically, a fairly reasonable assessment of how rare life must be to populate a universe with one intelligent, communicating species. Its really a limit on life-probability, since the only thing we can say with certainty is that there is at least one intelligent species out there.

  14. Afty, read what we're flipping writing! You can't have a statistical argument without stats! We don't know the exact sizes, travel times, technological limits, chance of existance. How can you have a statistical argument without those things?
    And as for saying 100,000 years is a blink of an eye in cosmological timescales, if there's nothing in between then that's an unfeasably long journy isn't it?

  15. What a great blog, and indeed thread! I dont know, but Im with dave as he is a doctor and sounds to my ears like he actually has a clue what he is on about and we dont and lest not forget he also has knowledge of eastern european lesbian sex :) (BTW - see in one of the tabloids that Stephen Hawkings wife beats him up. How mad is that!)

  16. This is a brilliant book, I'm reading it at the moment as well actually. I finished reading the prequel, Time a while ago.
    Stephen Baxter does indeed write some hardcore stuff, but I love the way he mixes sticky characters with very radical ideas and scenarios.