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Author Topic: not everyones cup of tea  (Read 5567 times)

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Offline Ian Straton

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Re: not everyones cup of tea
« Reply #15 on: 15:40:05, 28 April, 2010 »
2 problems with spectrography for man made elements, well 3 really:
1. Highly unstable (hlaf life in the nano seconds for most of them)
2. extremily small quantites (they are pretty much prodced as a handful of atoms inside a particle accelerator)
3. they never leave the particle accelerators in which they are produced (see 1 and 2)

they basically don't exist in a suitable place or in suffcient numbers or for long enough to be detectable.

shame though cos otherwise that would be a damn good mechanism!

Offline starf

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Re: not everyones cup of tea
« Reply #16 on: 19:45:36, 28 April, 2010 »
cheers ian.
ah vell back to ze drawin board! :-)
let the stars do their magic!
still its one thing looking at em its another understanding it!

Offline mitchfry

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Re: not everyones cup of tea
« Reply #17 on: 21:11:40, 31 May, 2010 »
As a Biologist (actually a Biochemist), evolution never ceases to amaze me. The way life (we) has evolved on this planet is clearly closely linked to the environment, changes in the environment, and undoubtedly to various "accidents" along the way. Biological life is really just an extension of Chemistry; we are a self-contained chemistry lab! So, when we say we are looking for life, do we assume something along our own model, presumably from a chemically similar world, or could it be entirely different, so much so that we might not even recognise it! A life-form is defined as a self-contained and self-replicating organism. And how do we define intelligence? Are we, as individually intelligent beings, more intelligent than something which might have a collective intelligence (akin to an ant colony)? I think the problem is that we don`t actually know what we are looking for, it might even be living alongside us on this Earth!
Mitch
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Offline starf

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Re: not everyones cup of tea
« Reply #18 on: 20:42:20, 03 June, 2010 »
Chance and probability must play a huge role in evolution. The terms 'survival of the fittest' or 'natural selection' presumably can be modelled as statistical outcomes. The environment must be a major factor since without out it there is nothing to play dice with. it seems the earth favours carbon life forms; its abundance and relative liking to bond with other elements. Of course it also needs the right pressures and temperatures. Its non the less remarkable that from simple molecular bonds, the dice can roll and create chemical factories in cells and on another roll, combine to give consciousness to simple organisms and even complex organs. For the most part, the structure of the atom seems rather inert by comparison. I did try having a conversation with a lump of magnetite, but its electrons were too busy to interract with a mere mortal.

equations need to have proofs. Ive never heard of the drake equation but it just seems to be the product of a list of variables, in which intelligent life is aided by the ability to communicate (preferably across interstellar space). closer to home we dont even know what life exists within our own solar system. but to suggest that only the earth has the right environment and luck, seems a bit selfish.

Offline twinsen

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Re: not everyones cup of tea
« Reply #19 on: 03:03:58, 07 June, 2010 »
Hmmm I think that the prospect of life in other stellar systems is certainly a possibility but looking at the discovered exoplanets so far I wouldn't bet on it. I think the key factor for life is a relatively calm system which can develop over many millions of year. This is not what we see in the exo planet systems we see out there which are usually chaotic . Im not a biologist and indeed know almost nothing about evolution and such from a biological front (maybe mitchfry can help me out here :)  but surely the initial stages of evolution have very very long timescales even given the 'right' conditions and elements. It is surely a question of probability but I think this is one that stacks against the likelyhood of finding life out there even with the astronomical number of planets which are no doubt in our universe.

Also as far as seti is concerened I would have thought it be wise to be looking in the outer disc of the galaxy but perhaps looking a bit more at stars either side of the galactic plane basically for stars simmilar to the sun. Older star systems I would say are more likely to have been disrupted in their past. There is two probable outcomes to this IMHO that life if it was in the stages of evolution would have most likely been destroyed or that the system is now stable enough to promote continued evolution of life. The answer to this question would really dictate where to look as it would give you an idea of what age star would most likely harbour life.

Smaller stars would also be unsuitable for life as the high magnetic activity in their atmospheres would create harmful emissions. Globular clusters have too much interaction to harbour life and even planets in clusters are thought to be rare due to active histories that break up protoplanetary discs before planets can even form. This means that basically we should be looking at stars with simmilar masses to our sun but like I said before a stable solar system is essential and it is just too early too put together accurate probability estimates for such systems. The next few years will be critical in finding the density of such stable systems :D

Alex
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Offline Ian Straton

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Re: not everyones cup of tea
« Reply #20 on: 14:14:54, 14 July, 2010 »
The exoplanet systems we are seeing at the moment are indeed chaotic and inhospitable places, however that is because of a HUGE sampling bias induced by the technology we use.  Essentially it is far far eaiser to detect large planets in small orbits than it is to detect small planets in large orbits. One factor in this is time: to detect a planet orbiting as far out from it's star as the earth we would need to observe that star for at least two years.... we haven't be looking for planetary systems all that long.   Another factor is size: large planets occult more of their parent star which causes a bigger drop in apprent brightness of the star, bigger planets cause larger doppler oscillations which are easier to detect.

Given that it is currently easier to detect hostile planetary systems you would expect to detect more of them, that doesn't mean that there are no hospitable ones out there it just means they are harder to detect, there may even be more hospitable stellar systems than hostile ones, we just haven't developped the techniques required to discover them yet.

Offline Geoff_k

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Re: not everyones cup of tea
« Reply #21 on: 19:08:49, 14 July, 2010 »
Funny this, because I am wearing my SETI t-shirt today with the Drake Equation on the back.

It's only one attempt to come up with a possible figure for the existence of alien life and the variables in it are well, pretty variable.

Until we get the 'WOW' signal or they turn up in their spaceships the answer is 1 for the moment.


Geoff

Offline twinsen

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Re: not everyones cup of tea
« Reply #22 on: 11:33:26, 26 July, 2010 »
Yes you are right there is a selection bias and I am not sure of the eccentricity distributions for rocky planets alone but if they follow what we see for the already discovered planets then we would have to reject a lot of them on the grounds of their eccentricity being too high.
Also note that for the earth like planet to be stable over long time periods it is likely that all the other major bodies in its system would have to be on regular orbits as well. The plot below shows the current state of affairs as far as eccentricity goes.


Image courtesy of Lund university.

Alex
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Offline Nomis Elfactem

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Re: not everyones cup of tea
« Reply #23 on: 15:51:20, 26 July, 2010 »
Still haven't seen the program but like a lot of you guys I do find the thought of there being life of any level out there really quite fascinating. 

I also have to say that I find the thought of there not being life out there much harder to swallow than there being life.

If all of the diversity of live of our little rock in the universe can all develop from a single source then it's really hard to think that it can't happen somewhere else in the billions upon billions upon billions of stars out there. 

It's also worth remembering that evolution doesn't have to take millions/billions of years.... I read recently about a scientist who has been growing proteins for the last ten years and already they have evolved significantly from the first "versions" he started out with.  It's as much about the number of replications/splits as it is about time - the faster you can replicate and the next generation can then replicate and so on and so on the faster characteristics will evolve.  Obviously the more complex the organism the longer it takes to replicate but it all has to start somewhere.

Until we get the 'WOW' signal or they turn up in their spaceships the answer is 1 for the moment.


Do actually mean 1 Geoff or do you mean 0 (zero) ?

Well my first thought is that the probability of life elsewhere is not "between zero and one" but is either zero or one.

That is to say it is not possible for life to slightly exist, it either does or doesn't


Ian, don't confuse "existence" with the "probability of existence".... they are two very different things.  Have a look here (http://en.wikipedia.org/wiki/Probability_theory) and read the bit about "Discrete probability distributions", then remember that there is already one case that is favourable for the event - Earth !

S.
Simon

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Offline Geoff_k

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Re: not everyones cup of tea
« Reply #24 on: 16:40:39, 27 July, 2010 »
Simon

I was including us in the '1' figure otherwise it would of course be 0.

Actually, as a bit of light relief a friend of mine showed me this from the Creationist website Answers In Genesis:

http://www.answersingenesis.org/articles/nab/are-ets-and-ufos-real

Marvellous to have such certainty but I wonder what they would do if the little green men turned up. It does say somewhere else on the site that the Sun will last forever (according to Scripture) so at least that's one less thing to worry about.

Offline swashy

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Re: not everyones cup of tea
« Reply #25 on: 18:16:22, 30 July, 2010 »
Actually, as a bit of light relief a friend of mine showed me this from the Creationist website Answers In Genesis:

http://www.answersingenesis.org/articles/nab/are-ets-and-ufos-real



Jeezus!  (no pun intended  ;) )

I find it absurd that so many people put scripture before science, religion is just an outdated way of explaining what we knew about the 'world' we live in from days of old, when people wanted answers from their leaders, this was what they offered, they were the leaders, and needed to look as if they were wise to prevent them been toppled from their authority, and came up with this amazing story

We as a civilisation has moved on, science has shown us that there is a bit more to it all than some bloke on a cloud who decided to make it all in 7 days, these guys need to get real, its getting beyond a joke!

I only wish either the aliens from some other planet showed up, or god would stick his head through the clouds and say 'Hi' just so we could close the debate once and for all

My money is on the aliens!
Ade

Imagine...  above us only sky!

Offline Tinca

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Re: not everyones cup of tea
« Reply #26 on: 23:44:28, 07 October, 2010 »
The universe is teeming with life but this is set against the fact that it's BIG......very BIG, on a scale that I can't even begin to imagine. Space-Time means there's no absolute motion, time or space.....it's relative! Consequently, I don't think we are likley to find signs of intelligent life because either they are just really too far away or Time gets in the way.......! 'They' were once there or even here but sadly we weren't! And is it likely that most life in the universe is 'intelligent'?I think not for the simple fact that as a species evolves and learns to exploit even more resource, there comes a point where numbers exceed resource and a very real decline in population through war, disease and poor fecundity limits existence. So plenty of pools of slime and extremophiles litter less than 'perfect planets' but few of the 'starship' variety! But then again, alien abductees would disagree and despite poor milk prices there is no question that there are fewer cows in the fields!!!! ( refer to South Park!)

 

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