Panspermia And Directed Panspermia

[jim360]

You can use this thread instead, Naomi.

Panspermia is the theory that life is common throughout the Universe, found particularly in Asteroids and the like, so that planets with the right conditions can develop life when an asteroid carrying the raw materials crashes into it -- or in to a neighbouring planet. So far, so reasonable, although as yet there is no conclusive evidence. Still, it seems to make some sense if you believe that life on Earth was likely not a one-off event in the Universe.

Directed Panspermia is slightly different, that life on this planet is the deliberate consequence of some other intelligent being wanting to set it up. Alternatively it's the name for the process whereby Humans can spread life from this planet around the Universe before we eventually die off. The last is controversial on a sort of "Prime Directive" ground (what about life which may already be out there?); the first because it seemingly lacks evidence and anyway doesn't solve the problem of how [i]that[] intelligent life emerged. Just passes the buck, so to speak.

Francis Crick was an early advocate of this theory, although he has since apparently retracted it:

Crick, F. H.; Orgel, L. E. (1973). "Directed Panspermia". Icarus 19: 341–348;
http://www.fasebj.org/cgi/reprint/7/1/238.pdf

But when I noted this in another thread Naomi leapt to the defence of the theory, though "that was not the place".

Hence this thread, so that it can be more fully discussed.

[Old_Geezer]

You forgot the question ;-)

[jim360]

I suppose it's just "How credible are they as theories?"

[LazyGun]

I think directed panspermia represents an interesting precursor to something like terraforming. I would be more interested in knowing which micro-organisms they had in mind, that would satisfactorily survive the privations of space travel in a near- vacuum at near absolute zero, and that then would still be able to thrive following planetfall elsewhere - such thriving ultimately leading to beings that have some similarity to ourselves, or that would terraform an environment to be receptive to humans. Never seen that fully explored anywhere.

As to whether panspermia is the source of life on earth - could be, but as an explanation it just seems somewhat gratuitous given what we know about abiogenesis and conditions upon an early earth, and also somewhat improbable, given the conditions described in the previous paragraph....

It still seems much more feasible than "goddunnit" though... :)

[chrisgel]

LG - Agree entirely. Although it's possible that panspermia can take place, with our present ever increasing understanding of things it seems an unnecessary complication. Very much like crow - barring god into the equation.

[jomifl]

It is a very long way to anywhere else and I'm not sure that anything the size of an asteroid could travel interstellar disances within the lifetime of the universe. Possibly life could have arisen elswhere in the solar system and the asteroid belt may once have been a life bearing planet though a tad chilly for life ('as we know it Jim';Bones ). Some of the evidence for panspermia originally was a bit naive to say the least and the idea doesn't fill any missing gaps in our understanding of life on earth.

[naomi24]

Hi Jim, I think it’s entirely possible that the planet was made habitable and seeded with life by people from other planets. There are some interesting thoughts here, including some from Carl Sagan.

http://en.wikipedia.org/wiki/Terraforming

.. and here … and with reference to LazyGun’s comments on micro-organisms, particularly the section headed Extremophiles.

http://en.wikipedia.org/wiki/Panspermia

(Sorry the links are both Wiki – I haven't read their entire content, but it’s just easy).

However, whilst aliens may have ‘created’ the planet as we know it - and since theoretically it’s possible, there’s no good reason to dismiss the idea out of hand - I’m more interested in seeking out the identity of those who left us with that blight on our planet called religion. They are otherwise known as the gods – and I seek in particular that wily old critter, the God of Abraham. Since similar creation legends abound throughout the world, I don’t believe that these ‘gods’ were a figment of fertile imaginations and I actually think that the ancients, in their buildings, their literature (including the bible) and their artwork left us, to the best of their practically non-existent technological understanding, all the information we need to unravel the past by recording their experiences over hundreds of years, including their familiarity with flying craft, and the stories they were told of the ‘creation’.

The age of the universe is estimated to be somewhere in the region of 12 to 14 billion years, and possibly more; our solar system around 4.5 billion years (figures from NASA) so logically it’s reasonable to assume that any intelligent life that may have evolved on other planets during that 10 or so billion year gap would have advanced technologically a lot further than us.

Simple mathematics tells us that we humans, who have been here on earth for only a few million years, are newcomers to the universe - and we have a very long way to go, and an unimaginable amount to learn, before we come even close to bridging the vast span of time that lies between our solar system and those far older. No one knows if any other planet is inhabited by intelligent beings, but it’s estimated that there are some 1,000,000,000,000,000,000,000 stars in the universe, many of which have planets orbiting them. Even if we apply the principle of Occam’s Razor (which, preferring real answers, I really don't like to do) to the question, we have to assume that there is other intelligent life out there, and bearing in mind the age of the universe, possibly intelligent life that has existed for far longer than we have.

Stephen Hawking says that, in order to ensure man’s survival the human race must eventually leave planet Earth, and who’s to say that something very similar didn’t happen to people of other planets in the past? Perhaps that’s where life on Earth really did originate. And God said ‘Let us make man in our image’. Maybe they did, although not by supernatural means, but simply by populating the planet and procreating, even if that meant using a little genetic engineering – which would, of course, explain man’s as yet unexplained relatively sudden appearance. It’s food for thought for anyone who cares to think about it – and the evidence is there for anyone who cares to look. For me, it’s the obvious explanation.

I’m not sure I’ve explained this as well as I might - I’m between deadlines and AnswerBank today, so it’s a bit rushed. I have pinched a bit from something I wrote a long time ago and which I’ve posted before, so if it looks familiar to anyone, my apologies. If you have any questions, fire away.

[jomifl]

I don't think there is any evidence for alien intervention in the fossil record alhough there were some strange beasts in the Canadian shales. How life on Earth started is a mystery but not a huge one, lots of people have come up with feasible hypotheses.

[naomi24]

Jom, I don't think there is any evidence for alien intervention in the fossil record//

If that's how life began, what we have would be what we would expect to find, so how would we recognise 'alien' intervention?

[jomifl]

Naomi, If there had been some kind of 'alien' intervention in the evolution of life during the fossil record we would expect to find some record of the intervention such as a sudden change in the direction of evolution. I know next to nothing about palaeontology but something like that would have been remarked upon in science more generally. Evolution speeds up when there are environmental changes such as the massive lava outflows that formed the Deccan traps or changes in ocean currents. It slows down when conditions are stable and evolution progresses at a rate driven by competiton between species for ecological niches and individuals for breeding success. I believe that this all seems to be consistent with natural processes. The idea of earth being seeded by life forms that came from elswhere whilst not impossible is not required to explain the development of life on earth. It is a bit like using the idea of a god to explain the existence (creation) of the universe. I think it is an idea that is worth considering if we have to but until then there are more rewarding/pressing questions to be answered.

[jim360]

Thanks for the reply. There seem to be two slightly different ideas here, so let's focus on the "deliberate" part. This seems fair, I think, because the idea that life might have emerged elsewhere before here on Earth seems reasonable. And who knows, maybe it could have arrived here via meteorite and so on? After all, the theory goes that most of the complex elements needed for life were created in supernoval explosions that then reached here.

The problem comes when you start reading deliberate intentions into this, for two reasons. Firstly, that is uncomfortably close for me to implying yet again that Humans are special somehow -- evidence for this is scant, and it makes more sense to me that we are just a product of evolution the same as any other animal.

That's not a very good scientific argument, granted. But we should surely be careful of distinguishing humans from everything else on Earth? If we were planted here by intelligent life from elsewhere, where did they go in the meantime? I would expect either that "we are them", (in which case where did all the technology go); or that they would care about us enough to visit regularly. And, if those in the Ancient world could see these people and worship them as Gods, why can we not see them and wonder at their marvellous technology?

So philosophically I'm uncomfortable with the idea already. Not least because, if the argument goes that religion is an explanation for the unknown, you would have thought that such advanced creatures would have grown beyond religion and therefore wouldn't allow or encourage it here. Unless they were megalomaniacs... but we are now entering into the realm of unsupportable speculation and not Science anyway.

More important are the practical considerations. it seems that more thought has gone into directed panspermia than I realised, so it seems plausible that maybe someone thought of it first and send an asteroid with life materials embedded inside it. I doubt very much that it would be possible for the intelligent beings themselves to come with it. Practically it's extremely difficult for anyone to travel any great distance at any great speed. And the best evidence is that there's no intelligent life "nearby". So far as we know, admittedly, but the Science is fairly convincing even now and looks unlikely to change enough to allow travel or discovery of life very near us.

Is man's appearance really so sudden and unexplained? I don't do enough paleontology to know but I thought the route to man was fairly well-understood, albeit with some gaps. In time those gaps may be plugged. Or they may not, of course, but it seems to early to conclude that we need[i an alien to create early humans.

It seems to me, at any rate, difficult to justify panspermia as a deliberate attempt to creat life here. Why was Earth so special? And, for that matter, if someone needed to come and create humans only, life had spawned here spontaneously. If intelligent life emerged on that planet on its own, or at least [i]somewhere] for the first time, then it could emerge here equally well on its own, all things being equal.

I am, as you can see, unconvinced.

[jno]

Why was Earth so special?

It doesn't need to have been; it could be the equivalent of sticking a pin in a cosmic phone directory. We say "special" because we think we're special, but it could have been anywhere on a spectrum from microtargeted to completely random.

[LazyGun]

@ the risk of presuming to speak for Naomi, Jomifl - I think what she means is that if life was started initially by panspermia, directed or otherwise, all life since then would be credited to that initial seeding - so you would not necessarily see anything in the fossil record....

Heres a question for you all, since we are talking about presumptive ages of civilisations etc.

1. Assume the Big Bang Theory is broadly correct, and that therefore we can be reasonably confident that the universe started around 14 billion years ago.
2. Assume that for all elements above Helium and Hydrogen to be available and propagate throughout the universe, there must have been millions?- billions? of Supernovae in order to generate those heavier elements in sufficient quantities.
3. Assume that the theory of solar and then planetary formation is broadly correct.
How long do we estimate for sufficient number of supernovae to have happened throughout the universe sufficient to supply dense elements anywhere within the universe?

So actually - how much older could older planets be than our Earth?

Not sure if I have explained myself particularly well - let me know if none of the above makes sense :)

[jomifl]

An asteroid travelling at 100,000 mph would take about a third of a billion years to reach us from our nearest neighbouring star.

[jomifl]

LG, I think I follow your reasoning, there seems to be 2 schools of thought,
1, that man is special and was planted on earth for whatever reason. This seems a bit fanciful as there is plenty of evidence to suggest that man just evolved in the same way as everything else.
2, that the earth was seeded by the process of panspermia either deliberately or otherwise. Although it's accepted that the heavy elements most likely came from a supernova since it seems that they could have come from nowhere else. This sets the starting point of the possibility of life at not before the first supernova. The kind of molecules that comprise life could not have been generated in a supernova but are likely to have been formed by a condensation process that must have taken a very long time. For them to be scattered into the cosmos by yet another explosion that doesn't destroy them seems unlikely but not impossible, then they would have to cross lightyears of space ridden with very destructive cosmic rays and enter the earths atmosphere without getting cooked. It seems much more likely to me that the earth is the first point of condensation in our case and that it has probably happened elsewhere many times before and will happen many times again.

[jomifl]

LG, As for how old planets could be.. on a universal scale they wouldn't need to be much older for life to have formed evolved and died out before the earth had even begun to condense into something large and heavy. Why all this stuff should accumulate close enough together for gravity to do the rest is a puzzle though.

[Old_Geezer]

Wow this thread grew while I was looking elsewhere. Hope to have time to read the contributions this evening, but in the meanwhile: the Earth is special, I just don't know how special as a % of planets and solar systems around it is. It is in the Goldilocks zone, near enough, it has a stabilising moon, it has a nice large giant planet which I am informed protect from meteors and suchlike rather than attract them, it has retained a nice lot of the water that crashed into it, it has a magnetic field to stop us all frying tonight. Probably lots of other stuff too. That's just off the top of my head. But it has to be fairly special to have evolved us on its surface.

[jim360]

Fair point, jno. It could simply have been the case that Earth was the nearest alternative in the vicinity of the "dying planet. Equally annoyingly, that dying planet would certainly be dead or destroyed with no trace left -- other than, perhaps, us! -- so we wouldn't be able to find it anyway.

In itself this seems reason enough to dismiss the theory, not so much because it is wrong but because it is inherently untestable. At best we are in the realms of reasonable speculation:

"Life is not so special, it could have emerged elsewhere before us, and that life could have been brought or sent here to avert or escape disaster."

Each step seems reasonable enough, apart from the lengths of time needed to get from whereever the starting point was to here -- but how could you confirm it or otherwise? The belief of targeted panspermia then becomes as rational as any other religion, I think.

[jomifl]

oldest supernova so far...
http://www.independent.co.uk/news/science/farthest-supernova-yet-marked-death-of-very-massive-star-

[jim360]

Link appears broken, but I found the story anyway that suggests that there were Supernovae as long ago as T = 600 million when we are T = 13,700 million. So that lends some weight to the idea that complex life could have formed ridiculously early. At a rough guess, you would need about 2 billion more years at least to go from supernova to life, but I have no basis for that number other than education guess.

Then again, supernovae "only" synthesise heavy elements, and not organic compouinds, so there is still that leap to make. And, finally, even if life did spawn elsewhere first before arriving here, it still doesn't realyl go any way towards answering the question of how life, and how intelligent life, arose. Instead, again, it just passes the buck to another time, another place. A place which in the Directed theory no longer exists anyway.

It strikes me that the directed theory is an untestable, although not implausible, philosophy.

[naomi24]

Jim, //Firstly, that is uncomfortably close for me to implying yet again that Humans are special somehow//

There is no implication that humans are somehow special, Where do you get that idea? I think we are the product of evolution – with perhaps a bit a genetic engineering thrown in.

//If we were planted here by intelligent life from elsewhere//

Planted here? Who said that?

//if those in the Ancient world could see these people and worship them as Gods, why can we not see them and wonder at their marvellous technology?//

Because they’re not here any more – but I think we can wonder at some of the structures they may have created.

//you would have thought that such advanced creatures would have grown beyond religion and therefore wouldn't allow or encourage it here.//

Why? How do we know they didn’t create man as a servant? The bible says they did.

//Practically it's extremely difficult for anyone to travel any great distance at any great speed.//

With our technology and knowledge, yes, but imagine a civilisation say, 10,000 years – or more – in advance of ours. That’s what we’re talking about. Don’t forget less than 200 years ago it was thought that if man travelled at more than about 20 miles an hour his head would fall off! So much for clever human beings!

//If intelligent life emerged on that planet on its own, or at least [i]somewhere] for the first time, then it could emerge here equally well on its own, all things being equal.//

Of course.

//Why was Earth so special?//

Perhaps because it occupies an area in the solar system known as ‘The Goldilocks Zone’ – ideal for supporting life as we know it – exactly the sort of planet our scientists are currently seeking.

My main interest really lies in the theory that the ancient gods were not the supernatural beings, nor were they figments of ancient imagination, but people from far more advanced civilisations. Ancient man didn’t imagine great machines made of metal that move by themselves, or ‘cities’ flying in space and doing battle against other ‘cities’, nor ‘stones’ that shine bright lights, or convey images - nor journeys into space. Abraham’s God wasn’t omnipotent – the bible tells us he wasn’t – and it also tells us that Adam wasn’t the first man. Additionally, supernatural Gods surely don’t need to come whizzing out of the sky from a particular direction in a machine that spits fire and smoke and makes a noise like a waterfall – but that idea you have yet to address.

Man’s problem is he limits his imagination to his current experience. Big mistake in my opinion. Where technology is concerned, we’re infants who should be investigating the past.

LG, //if life was started initially by panspermia, directed or otherwise, all life since then would be credited to that initial seeding - so you would not necessarily see anything in the fossil record....//

That’s exactly what I mean. Thank you.

//let me know if none of the above makes sense //

It makes sense, but I don’t know the answer.