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  4. There could be life captain
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There could be life captain

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Offline ukmicky

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Re: There could be life captain
« Reply #20 on: 13/03/2006 00:03:07 »
quote:
Originally posted by Soul Surfer

It seems quite likely that simple tife forms started quite quickly and possibly life several times on the earth but it took quite a period odf stability to achive things as complicated as a wooodlouse during the cambrian explosion  so on the whole I reckon that if the materials are there and the conditions are anything like suitable life will start and multicellular life will follow in a few hundred million years but as for inteeligent communicating life capable of building a spaceship wll thats an entirely different matter.
There's a fair chance that that could be a bit of an oddirty because getting musch beond the hunter gatherer social group is quite a barrier

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Hi Ian thankyou for the reply

Why is it quite likely that simple life forms started quite quickly and several life forms possibly appeared several times on the earth. (if thats what you mean)

Maybe if they knew what the mechanism for life in the beginning was then maybe there would be some basis to the theory that life started quickly and in many unsuccessful guises but as there is no surviving evidence from the time period it makes me wonder why everybody assumes it. Or am i missing something,it wouldnt be the first time[:)]



Michael
« Last Edit: 13/03/2006 00:13:55 by ukmicky »
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Offline Ophiolite

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Re: There could be life captain
« Reply #21 on: 13/03/2006 00:50:13 »
Given that life appears shortly after the end of the Heavy Bombardment period, it had to start quite quickly. Of course, pan spermia avoids this issue of rapid origin.

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Offline ukmicky

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Re: There could be life captain
« Reply #22 on: 13/03/2006 02:47:21 »
ophiolite is there any chance of having a person type name for you sir, its so much nicer to talk to someone on a first name basis,much more friendly like [:)] any name will do you can call yourself tom, dick or even harry if you wish.
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I'm OK with the idea that the soup could have come from space,to me whats more interesting is the spark which ignited the soup and whether or not it happened once or lots of times. If life began from the soup once then to me it says its a luck thing and something that wouldn't have necessarily happened all over our galaxy or the universe meaning we could be practically alone in the universe. Understandably its a thought which most people do not wish to or like to entertain, but its an idea which even though i also don't like much i feel i need to investigate further .

Michael
« Last Edit: 13/03/2006 04:32:42 by ukmicky »
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another_someone

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Re: There could be life captain
« Reply #23 on: 13/03/2006 04:57:11 »
quote:
Originally posted by neilep


We used to think the planets in our own solar system were unique, now we are discovering that planets are common. In fact very common.  We always use the number of stars as to represent the size of a galaxy and the numbers are phenomenal. Even more phenomenal now is the potential number of planets…now the number is growing exponentially, and now we must multiply it even further by the number of galaxies out there.

I  just cannot accept that life is so rare. I believe that the distant future will be filled with life from all over, we just need to discover it……..And that will come when we are advanced enough to build tools capable of finding it. We are held back by our inabilities.

I suppose there could still be the possibility that despite the age of the Universe that WE are indeed the first forms of life (as we know it) to exist…now what are those odds ?




We know that there are some rather unusual things about our solar system, and some we know have strongly shaped our life forms, others are less clear what effect they have.

Firstly, we have a significant amount of heavy elements on our planets, without which we could not have a magnetic field, and we could not have a hot core (and hence could not have plate tectonics).  In order to have so much heavy material in the planet, as far as I am aware, we needed to have been attached to a star that had been through two super-nova.

Secondly, our position on the edge of the galaxy has meant that we have relatively less cosmic background radiation than many of the stars deeper inside the galaxy.

These two facts alone would disqualify most others stars in the universe from having a similar life history to our own.  This does not preclude that life might exist in environs very different to our own, but it does preclude a simple assumption that counting the number of planets in the universe necessarily bears any relationship to counting the number of Earth-like planets in the universe.

The other problem is the fairly narrow window life has for forming.  Life on Earth is only about 4 to 5 billion years old, and yet within about another 5 billion years, our galaxy will probably collide with the Andromeda  galaxy, and probably extinguish life on this planet.  Thus the window of opportunity for life on this planet is probably about 10 billion years.



George
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Re: There could be life captain
« Reply #24 on: 13/03/2006 10:50:53 »
quote:
Secondly, our position on the edge of the galaxy has meant that we have relatively less cosmic background radiation than many of the stars deeper inside the galaxy.


Is that of any great significance? Life on Earth has evolved with a low level of tolerance to radiation. I think it quite plausible that life could eveolve with a much greater tolerance. Even here on Earth, cockroaches & scorpions (to name but 2) have an incredible high tolerance compared to humans.
If I remember correctly, radiation harms the struture of cells. So what if there are creatures that aren't cell/DNA based? I find it quite an arrogant point of view to assume that we work in the only way possible.

I referred to the diversity of life and environments on Earth merely to show that life can exist in very different conditions. Creatures have been found that live around underwater fumeroles and thrive on SO2. That to me says that just because a planet may have a high concentration of to-us toxic gases, it doesn't preclude life being found there.

As for the spark that caused life to begin being a fluke, that is mere conjecture. It is just as possible that given similar start conditions, life is inevitable.

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Offline Ophiolite

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Re: There could be life captain
« Reply #25 on: 13/03/2006 11:00:51 »
quote:
Originally posted by ukmicky

ophiolite is there any chance of having a person type name for you sir, its so much nicer to talk to someone on a first name basis,much more friendly like [:)]
It is not a practice I personally like. I have found it very confusing as a newcomer to this board to find people posting things like "thank you Ian", leaving me wondering exactly who Ian is.
On other boards most people call me Oph, or Ophi. If they don't like me then Awfulite, or Oafy are moderately witty and convey the insult quite well.

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Offline rosy

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Re: There could be life captain
« Reply #26 on: 13/03/2006 11:02:15 »
Raditation harms cells by breaking chemical bonds within molecules. I don't think any element of our understanding of "life" (at least as discussed here) can cope without molecules, so radiation will have an effect on any lifeform.
I think life has to assume self organising systems of molecules and radiation breaking chemical bonds at random will make that more difficult to sustain.

On another note, someone mentioned in another thread the idea of "nanobacteria" personally I think it's a daft name for an entirely non-cellular possible organism (they seem to self replicate), but interesting in the evolutionary sense...
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Re: There could be life captain
« Reply #27 on: 13/03/2006 14:28:49 »
George,

I am not suggesting that life equitable to our own exists but life in any form. Earth type planets are  not prerequisite for life, I firmly believe.

Certainly, being on the edge out here has probably gone a long way to manifest this unique planet. But I was not implying Earth Type planets at all, besides, there may well be life right at the heart of the Galaxy , we just don't know.

I would be satisfied, actually I would be blown away !!..if it was discovered that some bacteria existed elsewhere. The question as to whether we are alone in the Universe would finally be answered.

It's about 25 billion years before we collide with the Andromeda, of course, every star in the sky will be dead and gone by then, replaced by the next generation (or two) of stars.

One things for sure, either we'll discover life elsewhere (or be discovered) or it will be us who deposit life on other worlds.
« Last Edit: 13/03/2006 14:30:26 by neilep »
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Re: There could be life captain
« Reply #28 on: 13/03/2006 23:05:49 »
quote:
Originally posted by neilep

It's about 25 billion years before we collide with the Andromeda, of course, every star in the sky will be dead and gone by then, replaced by the next generation (or two) of stars.




http://www.haydenplanetarium.org/hp/vo/ava/avapages/G0601andmilwy.html
quote:

Two million light years (20 billion billion kilometers) away lies the Andromeda Galaxy, about the same size and shape as the Milky Way. Current measurements suggest that, in about five billion years, the Milky Way and Andromeda may collide!



http://www.cita.utoronto.ca/~dubinski/tflops/
quote:

The nearest big spiral galaxy to the Milky Way is the Andromeda galaxy. Appearing as a smudge of light to the naked eye in the constellation Andromeda, this galaxy is about twice as big as the Milky Way but very similar in many ways. At the moment, it is about 2.2 million light years away from us but the gap is closing at 500,000 km/hour. While most galaxies are rushing away as the universe expands, Andromeda is the only big spiral galaxy galaxy moving towards the Milky Way. The best explanation is that the two galaxies are in fact a bound pair in orbit around one another. Both galaxies formed close to each other shortly after the Big Bang initially moving apart with the overall expansion of the universe. But since they are bound to one another, they are now falling back back together and one very plausible scenario puts them on a collision course in 3 billion years.





George
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Re: There could be life captain
« Reply #29 on: 13/03/2006 23:27:59 »
quote:
Originally posted by DoctorBeaver

quote:
Secondly, our position on the edge of the galaxy has meant that we have relatively less cosmic background radiation than many of the stars deeper inside the galaxy.


Is that of any great significance? Life on Earth has evolved with a low level of tolerance to radiation. I think it quite plausible that life could eveolve with a much greater tolerance. Even here on Earth, cockroaches & scorpions (to name but 2) have an incredible high tolerance compared to humans.
If I remember correctly, radiation harms the struture of cells. So what if there are creatures that aren't cell/DNA based? I find it quite an arrogant point of view to assume that we work in the only way possible.

I referred to the diversity of life and environments on Earth merely to show that life can exist in very different conditions. Creatures have been found that live around underwater fumeroles and thrive on SO2. That to me says that just because a planet may have a high concentration of to-us toxic gases, it doesn't preclude life being found there.

As for the spark that caused life to begin being a fluke, that is mere conjecture. It is just as possible that given similar start conditions, life is inevitable.

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quote:
Originally posted by rosy

Raditation harms cells by breaking chemical bonds within molecules. I don't think any element of our understanding of "life" (at least as discussed here) can cope without molecules, so radiation will have an effect on any lifeform.
I think life has to assume self organising systems of molecules and radiation breaking chemical bonds at random will make that more difficult to sustain.




Inevitably it must be of significance, but I did say that that alone would not preclude the possibility of life existing elsewhere, but at very least it must make it very different.

Yes, radiation does damage the molecules within cells, but that is why cells have repair mechanisms, and why different organisms have different levels of stability in their molecular structures.

I would suspect that even on this planet, life probably first developed in a domain that was to some extent isolated from the worst of the radiation (either deep beneath the ocean, or in clay deposits), and adapted to more exposed domains only after it had developed the appropriate mechanisms to repair radiation damage.

But beyond the direct damage to the chemistry of life that radiation might have, what effect will it have on the wider environment?  If the radiation levels are too high, could it push up global temperatures too far?  Could regular interstellar bodies be hitting the planets and causing too frequent extinction events that might allow some life, but not give it time to develop to anything complex?  Could such events even cause excessive erosion of the surface and atmosphere of the planets?



George
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Offline ukmicky

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Re: There could be life captain
« Reply #30 on: 14/03/2006 00:02:05 »
quote:
Originally posted by rosy

Radiation harms cells by breaking chemical bonds within molecules. I don't think any element of our understanding of "life" (at least as discussed here) can cope without molecules, so radiation will have an effect on any life form.
I think life has to assume self organising systems of molecules and radiation breaking chemical bonds at random will make that more difficult to sustain.


Hi rosy There is a lifeform which can completly repair radiation damage to its cells and dna within hours. Halo bacterium.
 
quote:
Halo bacterium appears to be a master of the complex art of DNA repair. This mastery is what scientists want to learn from: In recent years, a series of experiments by NASA-funded researchers at the University of Maryland has probed the limits of Halo bacterium’s powers of self-repair, using cutting-edge genetic techniques to see exactly what molecular tricks the "master" uses to keep its DNA intact.

 
"We have completely fragmented their DNA. I mean we have completely destroyed it by bombarding it with [radiation]. And they can reassemble their entire chromosome and put it back into working order within several hours," says Adrienne Kish, member of the research group studying Halo bacterium at the University of Maryland.

Being a virtuoso at repairing damaged DNA makes Halo bacterium one hardy little microbe: in experiments by the Maryland research group, halo bacterium has survived normally-lethal doses of ultraviolet radiation (UV), extreme dryness, and even the vacuum of space.


http://science.nasa.gov/headlines/y2004/10sep_radmicrobe.htm

However halobacterium have not just started out in there quest for life and have evolved their unique ability to repair there cells. I doubt any form of life would be able to evolve on a planet receiving large does of radiation unless they were somehow shielded and their given time to evolve systems for repair.  



Michael
« Last Edit: 14/03/2006 00:52:41 by ukmicky »
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Offline DoctorBeaver

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Re: There could be life captain
« Reply #31 on: 14/03/2006 00:53:49 »
But who says life must be DNA-based? All creatures on Earth are, true; but that is probably because the original living organism (whatever it may have been) was, & we are all descended from it. Who is to say that 1 tiny environmental or chemical difference may have caused a replicatory mechanism other than DNA to have arisen?

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Re: There could be life captain
« Reply #32 on: 14/03/2006 01:12:55 »
Fair enough George....I wish I could recollect my sources too that say it's 25 billion.......what ever the time period ..........it's a long time and just because a source reports or states it, does not necessarily make it so!!ANYWAY !!..that's beside the point when the discussion is about life elsewhere in the Cosmos.

I think it's very difficult for some people to be able to see 'outside ' because of the nature of what we are, that is, DNA based carbon life forms...and so we humanise our outlook too.....we take our own very special form of life and use it as a template and apply it to everything else too.

I think we need to be able to understand that we should accept the possibility that life may exist elsewhere that could conceivably be so alien to us that we may never be able to detect it. There may well be life that exists that does not follow the usual rules,birth, growth, reproduce etc etc....and also perhaps in different planes of existence, maybe out of phase, perhaps a second to them is a year to us etc etc....I'm not suggesting supernatural at all.....very very natural...for them !...however, I would place bets that within a relatively short space of time, the answer to the question will be answered.

 Should  non Earth life be found within THIS solar system...on one of those moons, deep down inside the oceans of Callisto or Europa......how would the discovery of life there affect peoples thinking of life elsewhere ?
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Offline ukmicky

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Re: There could be life captain
« Reply #33 on: 14/03/2006 01:15:54 »
quote:
But who says life must be DNA-based? All creatures on Earth are, true; but that is probably because the original living organism (whatever it may have been) was, & we are all descended from it. Who is to say that 1 tiny environmental or chemical difference may have caused a replicatory mechanism other than DNA to have arisen?





True but i feel we should only use our time and money to examine what we have evidence of and to put time and effort in to other possible forms of existence without any evidence of,would hamper are research into things that we know are real.   And wouldn't any other form of surviving life still have to use the same basic mechanisms which DNA uses for evolution to work. There could be major differences but wouldn't there have to be also major similarities.

Michael
« Last Edit: 14/03/2006 01:24:09 by ukmicky »
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Offline DoctorBeaver

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Re: There could be life captain
« Reply #34 on: 14/03/2006 01:31:08 »
Michael - I have to disagree. That could very well be the reason why we DON'T discover life elsewhere. I'm with Neil on this 1. Life elsewhere could be so different from that on Earth that if we restrict our search to only looking for something that is familiar to us, we could miss it completely.
I also agree with Neil about timescales. I remember seeing a film, or it may have been a TV program like Star Trek - I can't remember now - about an alien race who lived their lives in what, to humans, would be the blink of an eye. Transmissions from their planet were practically undetectable as they happened so fast. If their entire life lasted only 1 second, imagine how short the duration of any messages would be. I'm not putting that forward as a strong possibility, by the way; but what if an advanced civilisation had developed a technique for condensing and transmitting data so fast that they could send the entire Britannica in a nanosecond? We wouldn't have a hope in hell of detecting it.
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Re: There could be life captain
« Reply #35 on: 14/03/2006 02:03:18 »
While I do accept that we must prioritise funding, and it is logical to put the greater funds where there is more demonstrable likelihood of success, but I do agree with Eth, if we don't look we won't find, so we have to allocate some monies to blue skies research.

With regard to life being so fast that we can't detect it – the greater likelihood may be the converse, since red shifts should have the effect of slowing down what we see.

As for the notion that life may be something unlike anything we expect, there is a slight paradox here.  Certainly, whatever we discover may be totally unlike anything we expect to find, but on the other hand, it can only be life if it fits in with whatever our definition of life is, and thus must in some way conform to our expectations to some degree, or else we would not even recognise it as life.



George
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Offline ukmicky

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Re: There could be life captain
« Reply #36 on: 14/03/2006 03:45:18 »
Basically what i was saying is yes look for ET but only in places which are earth like, because we have no evidence that life could exist in any other form other than what we see on earth. But even if we do somehow find signs of life in some far flung solar system how would it help us, is it worth spending billions just so we can say yes.

Michael
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Re: There could be life captain
« Reply #37 on: 14/03/2006 04:14:15 »
quote:
Originally posted by ukmicky

Basically what i was saying is yes look for ET but only in places which are earth like, because we have no evidence that life could exist in any other form other than what we see on earth. But even if we do somehow find signs of life in some far flung solar system how would it help us, is it worth spending billions just so we can say yes.

Michael



What are we exploring distant space for (near space may have direct relevance, but does it matter what is 200 light years away?).

Once we understand why it matters if there is a black hole 200 light years away, we might also be able to answer why it matters if there is life 200 light years away.

In a sense, it might be argued that if we found life on something that was very unearthlike, it would actually tell us more that if we just find life that is a carbon copy (sorry about the pun) of ourselves.

The second point is, what actually are we looking for when we say we are looking for life?  Would we know what it was if we saw it?  Do we even really know what life is on this planet, let alone trying to understand what it is on another planet (or even off another planet)?



George
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Offline DoctorBeaver

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Re: There could be life captain
« Reply #38 on: 14/03/2006 12:57:02 »
quote:
As for the notion that life may be something unlike anything we expect, there is a slight paradox here. Certainly, whatever we discover may be totally unlike anything we expect to find, but on the other hand, it can only be life if it fits in with whatever our definition of life is, and thus must in some way conform to our expectations to some degree, or else we would not even recognise it as life.


All that would mean is that our definition is incorrect.

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Re: There could be life captain
« Reply #39 on: 14/03/2006 15:14:34 »
quote:
Originally posted by DoctorBeaver

quote:
As for the notion that life may be something unlike anything we expect, there is a slight paradox here. Certainly, whatever we discover may be totally unlike anything we expect to find, but on the other hand, it can only be life if it fits in with whatever our definition of life is, and thus must in some way conform to our expectations to some degree, or else we would not even recognise it as life.


All that would mean is that our definition is incorrect.




Incorrect?  How can a definition be incorrect – it is whatever we choose it to be.  We may choose to change a definition, but that does not make either the new or the old definition incorrect per se.

A definition may be considered incorrect if the definition we are using does not agree with the commonly definition of the word, but that is a relative incorrectness (i.e. a lack of agreement) but not an absolute incorrectness.

On the other hand, if everyone agrees with a certain definition of life (I am not saying this is the case), and what we find is not consistent with that definition, then it is not life.

Certainly, it is possible (in fact, one might even argue the converse to be impossible) that a definition might contain inconsistencies, where what we find agrees with some parts of the definition but not other parts of the definition.  This doesn't make the definition wrong, merely internally inconsistent,



George
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