I’m pretty sure that most people at one time or another, or indeed for a lot of people for a lot of time, have gazed up at the stars and wondered whether we are alone in the universe or not. My expectation has always been that considering the number of galaxies and stars there then surely there must be other complex life out there somewhere.
But according to one scientist I’m afraid to say I’m probably wrong. Professor Andrew Watson at the
According to Prof Watson a limit to evolution is the habitability of Earth, and any other Earth-like planets, which will end as the sun brightens. Solar models predict that the brightness of the sun is increasing, while temperature models suggest that because of this the future life span of Earth will be ‘only’ about another billion years, a short time compared to the four billion years since life first appeared on the planet.
“The Earth’s biosphere is now in its old age and this has implications for our understanding of the likelihood of complex life and intelligence arising on any given planet,” said Prof Watson.
“At present, Earth is the only example we have of a planet with life. If we learned the planet would be habitable for a set period and that we had evolved early in this period, then even with a sample of one, we’d suspect that evolution from simple to complex and intelligent life was quite likely to occur. By contrast, we now believe that we evolved late in the habitable period, and this suggests that our evolution is rather unlikely. In fact, the timing of events is consistent with it being very rare indeed.”
Watson suggests the number of evolutionary steps needed to create intelligent life, in the case of humans, is four. These probably include the emergence of single-celled bacteria, complex cells, specialized cells allowing complex life forms, and intelligent life with an established language.
“Complex life is separated from the simplest life forms by several very unlikely steps and therefore will be much less common. Intelligence is one step further, so it is much less common still,” said Professor Watson.
His model suggests an upper limit for the probability of each step occurring is 10 per cent or less, so the chances of intelligent life emerging is low – less than 0.01 per cent over four billion years.
And that’s before building in to the equation the chances of having a habitable planet in the right place, say for example with the protection that a Jupiter provides.
Even so with the utterly unimaginable amount of potential planetary possibilities even the 0.01 per cent I reckon must still generate a goodly number of already inhabited worlds.
But I would be interested to know your thoughts.
9 comments:
I've posted on this before, from several angles.
But, since you bring it down to assessing the ET pardox, I will.
My guess is that viruses are universal. They probably exist everywhere with any type of atmosphere. The Moon, no, but I bet viruses exist elsewhere in the solar system, and on several of the known extra-solar planets.
Viruses capable of creating cell structure, well, Earth has produced the DNA virus, AKA, Organic life.
Have any similar viruses appeared EVER in this galaxy?
Possibly.
But DNa took four billion years to produce us.
That's four billion years of development on a curiously protected planet.
Earth, is a mathematically unusual planet.
Spared from bombardment, by being almost a double system- our Moon isn't a satellite, not in a conventional sense, it's way too big. We are part of a double system, we have a strange gravity.
Jupiter, too, is at just the right place. The inner solar syatem is a safe place, because Jupiter catches intruders to our star system.
Evolution goes on unchallemnged for millions of years, until Nemesis, or whatever it is, sends meteorites down every 26 million years.
Life elsewhere, probably never gets such a clean run.
If it did, we wouldn't be here. We ARE the first to do this, of that I'm sure.
Reason why?
The natural economy principle. The furrther you push evolution, the more inevitable it gets. Eukarypte life, wildly unlikely, but once you get there, laws of physics start to have an effect.
Eyes. Eyes have evolved 41 different times, but in only eight designs. Why? Because there really are only eight ways it can be done.
And two, is always the best solution.
If it moves around, bilateral symeetry, with two of every limb, works best.
Once the Bilaterian emerges, again, natural economy shows the way. Placental birth, maybe an oddity, but intelligence as a survival tool, as iopposed to claws?
Yes, it took a long time- three hundred million years to get a Tetrapod to think, but eventually, as soon as one does, the Red queen hypothesis goes into overdrive.
Ten thousand years ago, we lit fires by rubbing sticks.
Logic tells you, we ARE goping outside the heliosphere. Gliese and all those other Earth lookalikes? Your descendants will walk on them.
So where are the others? Because if they ever existed, we shouldn't have done. Man would not have evolved, because that place in the ecosystem of Earth, would have been filled.
By the alien colonisers of the Oligocene.
We're alone.
I'm sure of it.
I think that the virus thing is a given. There’s enough to reasonably support the ‘seeding’ idea.
And I agree that the chances are pretty slim. The UoEA model clearly shows this. And yes I take the point on evolutionary theory. A previous pet / favourite subject. The real fun is in equating to economic principles. Makes one look like a pompous ass down the pub but hey….
But, what I still can’t really get past is that considering the amount of galaxies out there with the unimaginable amount of planetary systems that this then suggests I still struggle with the idea that we are SO unique in our conditions here that this could be the only home to complex life.
If there were a competitor species on earth at the right time then it is entirely possible that we wouldn’t be here. But if they are kicking back on, say, Andromeda at a similar level of technical advancement to us then our paths simply wouldn’t have crossed yet.
I’m not into the foil hat bug hunting stuff, but there are so many chances that conducive conditions exist somewhere else for complex life to have evolved I find it difficult to believe that it hasn’t.
Also I’m not entirely sure that I would want any of our descendants to walk anywhere. A brilliant species but I would suggest also flawed.
Well, one gloomy solution to the ET paradox- and it's the driving thought behind why I blog- is this.
Intelligent species always reach one stumbling block.
The only way they move off their rock, is by learning how to split the atom.
If we really are to move off this rock, it will be in atomic powered craft. Mars is reachable in two weeks, using atomic power.
And then of course, the system clicks into place. It becomes feasible to mine the Gas Giants for energy. We are going out there to get more energy than we use up to get there. A vast power source to develop the terrestal planets. That vast reserve of energy, means that terraforming Mars and Venus, would take decades, rather than the centuries our current energy supply would mean.
Once that happens?
The only question is, is whether faster than light travel is a perpetual motion problem, or a heavier than air flight problem. I incline to the belief that it is the latter. I humbly suggest that the answer involves going ROUND space, that it is possible to bisect THROUGH space. I think the implications of string theory suggest that once we truly grasp the eleven dimensional structure of space, it will open up new possibilities. I think within the next thousand years, yes, we WILL have colonised the entire galaxy.
If we don't blow ourselves up in the next fifty years.
This is crunch time, you see.
Some theorists sugest that, following laws of natural economy, any intelligent species earned it's dominance , because it was the King of all predators. All intelligent life, by definition, is violent and murderous towards its own, seeking to rule others by force and fear.
And therefore, it kills itself as soon as it has the power to do so.
And the evidence of silence strongly supports that.
I wonder if we ever will reach andromeda. Remember, even if you travelled at a thousand times the speed of light, it would still take a millenium to get there.
I think interstellar travel, will happen. Not sure about Intergalactic travel.
The novel I'm writing is set in a galaxy where Man has succeeded in conquering the entire galaxy and creating a Godlike emperor with the actual physical powers of the almighty, but the whole order is threatened, because a system built on perpetual expansion no longer has anywhere to expand to, and they haven't yet found a way to cross the true void- those nillions and millions of light years of inky black between galaxies.
Space well beyond our comprehension. Scary to even think about.
Imagine being Major Tom stranded out there!
I've always felt it is our receptors which have been shackled. That we lack the perception to see the parallel worlds.
Well why not?
Hasn't that scientist ever watched Doctor Who?!
There is a fundamentalist Christian viewpoint, I'm sure, that insists ours is the only inhabited planet for all sorts of theological reasons, but it seems unlikely to me.
I believe in a creator God with an unimaginable imagination!
Even if intelligent life requires a lot of good fortune, I would be very surpriseed if we are alone. Extrasolar planets appear to be quite commonplace. There must be a good chance that some of these planets are habitable and are inhabited by intelligent life forms. I doubt we will know for sure for a very long time though.
I agree with Jams on this one. I am sure there must some form of life somewhere else and we are unlikely to find out any time soon!
My suspicion is that we are alone as intelligent beings, which makes it all the more important that we get off this rock before some asteroid, or virus, or bloody great tectonic event under Yellowstone, or whatever, comes along and wipes us out. I nurse an abiding loathing for Nasa for having spent the last 50 years pissing about with white elephants like the shuttle and that absurd space station, and actively obstructing private enterprise from getting out there. Only now are we starting to see what they can do. I hope that in my lifetime (or at least in that of my daughters) we will make proper strides towards colonising other planets (starting with Mars) and systems, if only to ensure something survives.
James – interesting point but why would they have been? By whom or by what process?
Liz – Ood have thought it?
Jams – My view entirely.
CP – Ditto the ditto
Fleet – As above I’m not sure about us being the only intelligent beings. I do wonder though with the vastness of the universe if we will ever finally get to meet the neighbours. I’m sure though in our lifetime we will have proof of ‘microscopic’ extra terrestrial life. Re getting off. I have this sneaking suspicion that we will leave too late. Although I’m sure that Gordon is commissioning a review as we type
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