Forum adverts like this one are shown to any user who is not logged in. Join us by filling out a tiny 3 field form and you will get your own, free, dakka user account which gives a good range of benefits to you: No adverts like this in the forums anymore. Times and dates in your local timezone. Full tracking of what you have read so you can skip to your first unread post, easily see what has changed since you last logged in, and easily see what is new at a glance. Email notifications for threads you want to watch closely. Being a part of the oldest wargaming community on the net. If you are already a member then feel free to login now.

Essentially, I'm looking for a little enlightenment here, and I'm hoping you guys can help in someway.

You see, time and again, I here the same thing coming from Science programmes, about how conditions on Earth were so specific, that it is extremely unlikely life exists on other planets, as we have a certain axis and distance from our sun which helped make it possible. I know there is a helluva lot more to it than that, but I'm not well read enough to go into details here.

But if there is one thing we do seem to know, is that life always finds away. I was watching a programme narrated by Tony Robinson the other night about the formation of earth. Apparently, Billions of years ago, a strain of Algae or somesuch, began creating oxygen as a byproduct. At this time, Oxygen was largely poisonous to the other life forms, so a vast percentage of life was wiped out as this Algae stuff poisoned the atmosphere. Add in various other chance encounters, and along comes man.

So, using the example above, how can we be so sure about what enables life? I very much suspect I am missing something here, some vital piece of information or evidence which makes them so sure, but I just can't shake the old Star Trek quote 'It's life Jim, but not as we know it'

Anyone help? Please?

BTW, I'm considering a home study degree from the Open University on Anthropology. Got a few questions I want answers to like the one above!

Its an extremely interesting issue and I hope others who have explored it more post or cite other boards on this. I will state that read a little sci fi and that’s a basic point in several books-Andromeda Strain, Sphere, some Dean Koontz books.

Life can be very broad.

What if humanity runs across a life form that is effectively immortal and has no concept of something called Death? Could it wipe us out not knowing that we could even be wiped out?

They would surely need to be both Immortal AND Invulnerable. Theoertically it is possble, and could be seen to be the peak of Evolution.

Just because a being is Immortal does not mean it cannot be destroyed. But otherwise, yes. They would have a child like innocence toward harming other species, as they would simply find the fact that we sometimes don't get back up fascinating. And with a child, it takes an adult explaining what has happened. Only then do they stop.

I think we tend to forget just how much 'instinct' we have is nothing of the sort and is instead learnt at a very early age.

Going back to the original topic though (whoo! 2 posts in and I've derailed my own thread in a way!) it's the 'Life As We Know It' bit which interests me. On earth, surviving life went one particular way, thanks to numerous circumstances wiping out other strains. So what if another form of life was so radically different, that we simply didn't know how to look for it? I'm not suggesting living rocks, though a silicate life form is not impossible, surely (By god Jim! I'm beginning to think I can cure a rainy day)

Well there is a scientific test. But it involves respiratino I beleive which is right out as being very narrow to the discussion. As I said it contains a fascinating idea and one of the oldest that man has thought about. What is life?


interesting side discussion. Are viruses alive?

The reproduce, they evolve, and one assumes, consume resources.

I'd say they are very much alive myself. Just another divergent path of evolution, though one would assume one that followed the earliest multicelled organisms. Almost a later stage of evolution, as a virus needs a host, and somehow I doubt they spent several Billion years floating around looking for one until the rest of the natural world caught up with them!

Viruses can only do these things by copying their genetic material into a target cell. This lets the virus genes reproduce themselves.

However, I agree that they are alive.

What about Prions?

Generally biologists are in the habit of defining life as things that reproduce by passing along some sort of nucleotide information, on which natural selection can act though mutation.
So viruses come out as alive, but prions do not.
In the end though, defining something as broad and sort of conceptual as "life" is pretty impossible. We do it for ease of classification in biology but scientific definitions aren't the be all and end all of communication. Language and concepts are more about "feel" and usage. So if we encountered a silicate or energy based being or whatever, if it seemed alive it would be called alive, and biologists would adjust the definitions. Nothing in science is ever set in stone.
It is a great topic though, and branches into many interesting sub topics like sentience and the like. I love discussing it and thinking about it.

Well of course Prions aren't alive. Just because they come in tubes in a variety of...oh...Prions

Kilkrazy wrote:Viruses can only do these things by copying their genetic material into a target cell. This lets the virus genes reproduce themselves.

However, I agree that they are alive.

What about Prions?

Indeed, thats the next question.

Frazzled's view on whether it is life
"Does it taste good and/or cook good in butter?"
Yes- Life
No-Dirt

When scientists state that life was only possible given these conditions (on Earth) they tend to be referring either to human life specifically, or complex animal life generally. The conditions for microbial life, for example, are a great deal broader; generally depending on water and a certain temperature over a time period which isn't overly long (and an as yet unknown series of chemical reactions). That's one of the reasons Mars is considered a prime candidate for the formation of life. It has water (in the form of ice), and once possessed a far more voluminous atmosphere than our own; seemingly allowing for a temperature which could have been sufficiently high despite its greater distance from the Sun.

Somebody mentioned sentience, which to my mind is a good deal more interesting; especially when considered with regard to relative scale. How do we know that something impossibly large (like the Universe) is not capable of thought? Or that something impossibly small (like the quarks inside an atom of Uranium) is similarly moribund? The answer is that we don't. All we know is that such things are incapable of our thoughts, and so we are given the scientific basis for the God debate.

There are other, less grandiose, ways in which sentience remains interesting. Such as the discussions revolving around communication between alien life-forms; How exactly would you talk to something which is silicon based, and devoid of references comparable to our own?

I think the issue Doc is not a matter of life managing to survive and thrive, but of it coming into existence in the first place. It does seem to be quite hard to fully exterminate all life once it gets started, it's the getting it started that's the trick.

But then didn't they find evidence of microscopic life on Mars already? So I'd say the chances are a lot higher than they thought they might be.

See here for creating life (in a test tube).

http://en.wikipedia.org/wiki/Miller-Urey_experiment

Aparently they created more amino acids etc but didn't have the technology to find them until a couple of years ago.

Given the stupendously large number of planets in the universe, it seems highly unlikely that the Earth is the only one which has produced life.

The real test will be actually creating living microbes in the laboratory that are able to reproduce themselves with no more input than nutrients.

How different to existing microbes would this theoretical creature have to be?

On differeing opinions regarding life on other planets: It's all about faith at this point. We really don't know enough to have a truly informed opinion. On the one hand, life-generating conditions on earth were very narrow indeed. The planet lay fallow for, what, 3 billion years after it's creation and then POOF there's the beginings of life? Sounds like some very narrow requirements indeed were suddenly met. So, it would appear that life-generating circumstances are rare, regardless of what type of life it would generate..
On the other hand, we don't know HOW many planets are out there that exist in SOME life-supporting band around their star. The number could be ridiculously high. It might not be.

THere's a real lack of scientifically accepted empirical evidence to support either side. So, any opinions would really have to come down to what people believe, what they have faith in (not necc. religious faith, let's not travel that road quite yet). At least, that's the answer that I have faith in

Yeah, about the only certain thing is that, because of the horizon problem, the number of stars (and, potentially, therefore planets) is almost unbelievably large. So it would seem that the two sides of the debate essentially amount to:

1) We live on a world which is unbelievably exceptional. Like, to the point of being beyond the probability of quantum tunneling (ie. the chance of any given fundamental particle spontaneously appearing somewhere else) exceptional.

2) There is life elsewhere in the universe.

How can we be sure what the conditions required to create life? Well....we can't. Honestly. But we try anyway.

There are things, scientifically, that a human mind simply cannot begin to wrap itself around. I think, plausibly, that the chances for life to exist become inconsiquential when you take into consideration exactly how many planets must exist within our given light horizon (I think it's something like 13.6 billion years worth of light travel that just gives out at a certain point, evidenced by the "Red Factor" theory). It's much more than equal. We can't begin to understand how many planets and stars there are. To believe that we are the only planet that contains life is completely naiive, from a scientific standpoint.

Not that it would even matter anyway. Ever written down all of the zeros in a light year? There comes a point where you brain kind of...stops functioning, so to speak, and sees them only as zeros. We are not meant to understand that amount. And to think that our nearest star is (I believe) 3 light years away, we will never reach any other life. Ever. Lightspeed is the end-all. Nothing can move faster than light. In physics, theoretically, even something thrown from lightspeed....goes at lightspeed. And, according to Einstein, if matter actually reaches lightspeed, it creates a gravity well that kind of...sucks everything into it. So it is physically impossible for matter to reach that speed.

There is no possible way we can reach other life. There is no possible way other life can reach us. So why worry yourself with the fact that it exists?

Chrysaor686 wrote:
Not that it would even matter anyway. Ever written down all of the zeros in a light year? There comes a point where you brain kind of...stops functioning, so to speak, and sees them only as zeros. We are not meant to understand that amount. And to think that our nearest star is (I believe) 3 light years away, we will never reach any other life. Ever. Lightspeed is the end-all. Nothing can move faster than light. In physics, theoretically, even something thrown from lightspeed....goes at lightspeed. And, according to Einstein, if matter actually reaches lightspeed, it creates a gravity well that kind of...sucks everything into it. So it is physically impossible for matter to reach that speed.

Well, there is the issue of black holes (theoretically) emitting matter. Granted the matter they emit bears no resemblance to the matter they absorbed, but the fact that they can emit anything at all seems to suggest that Einstein's cosmic speed limit is (theoretically) not the be-all-end-all of the physical universe.

Conditions required for life

Assuming it is based on chemicals and not some super-nano-quantum electrical Star Trek kind of thing... you need;

An energy source.

A chemical means of converting the energy into a useful form.

Molecules capable of being built into structural forms.

Molecules capable of being used for information storage.

A fluid medium in which to do chemical reactions, which dissolves only the molecules which you want dissolved.

All the above needs a reasonably stable temperature environment in which to remain organised.

Water is a particularly good fluid medium for Earth as we know it. Another medium such as methane might be appropriate for a planet with different conditions. It might be possible to use a gas fluid medium.

There are organic compounds in space. By which I mean Carbon-Oxygen-Hydrogen chain molecules.

All of that, Kilkrazy, is based on our understanding of earth's lifeforms. It was brought up in this topic earlier that Viruses are "living", so to speak. Yet they only have two of these characteristics. Though they might require other "living" forms to reproduce themselves, under any other criteria, they are damn well alive.

To think that viruses only have two of these characteristics, and yet can be classified as "living"....Yet we co-exist. On the same planet. Think of a planet that has existed lightyears away from us. Things on that planet might appear, to the subconscious mind, to be living, yet to the scientific mind they wouldn't fit this outline whatsoever.

It's perfectly plausible.

Also, I don't understand what black holes emitting matter has to do with the fact that if any amount of matter hits lightspeed, it creates a gravity well that sucks all surrounding matter into it, eventually infinitely. Even if it emits something back out....that matter that hit lightspeed still destroyed everything.

Chrysaor686 wrote:
Also, I don't understand what black holes emitting matter has to do with the fact that if any amount of matter hits lightspeed, it creates a gravity well that sucks all surrounding matter into it, eventually infinitely. Even if it emits something back out....that matter that hit lightspeed still destroyed everything.

In order to escape a black hole any given boson or fermion must exceed light speed; breaking Einstein's constant in doing so.

Please don't forget that Physics, at least to my knowledge, is still largely a field of theories.

Einstein made predictions, not laws, and the continuation of his work are more about proving/disproving than just accepting them.

Caught the next episode in the series that spurred me on to create this thread, where I learnt about a curious microbe, which lives in subzero tempratures. It gets it's energy from Rock, which is burrows into. How weird is that? Although a modern day one, this is how life survived 'snowball earth' as the programme put it.

I highly reccomend all those nattering in this thread to try to watch it. Channel 4 (UK) 9p.m. on Mondays. Should be up on 4OD by now I'd imagine. Even if you don't find it terribly informative, it is still a damned interesting programme!

Mad Doc Grotsnik wrote:Please don't forget that Physics, at least to my knowledge, is still largely a field of theories.

Einstein made predictions, not laws, and the continuation of his work are more about proving/disproving than just accepting them.

And that right there is why Science > Religion... the sciences admit that they are based on "best guesses" based on the available information, and that nothing is "true" until conclusively proven, while religion tries to claim that its tenets and writings are Absolute Truth with no room for human error, bias, or contrary but utterly irrefuteable facts. Anything created by humans is inevitably flawed; even if you grant divine inspiration, it's still funneled through a flawed medium. A good scientist will never claim to know anything until that thing can be independently verified and/or replicated.

Challenge global warming and see how much "science" is based on "best guesses." Everything has an orthodoxy and its zealots.

Global Warming/Climate Change is now being observed as physically happening. But you are right. As far as some are concerned, it's a purely man made phenomenom (did I spell that right, somehow I doubt it) but the actual cause is still a matter of debate....

you cannot simply say that humans are causing global warming!

to my knowledge, the earth has been warming up on its own just fine since the last ice age.

However, there is also contradictory evidence that: 1) we're actually starting global cooling; and 2) guess what, its the Sun's fault and we're seeing identical changes on Mars. This actually is disconcerting to me.
temperatures last year were colder not, hotter. The artic icepack expanded last year, not shrank, blah blah.

But I expect to be shouted down momentarily.

not by me, I read the same articles

Like I said, that Climate Change is happening is largely irrefutable, but the cause of it is not fully understood.

But, when it comes to carbon emissions, surely it is as much a health issue as an environmental one? The less we pollute, the better the air we breathe, which is good for everyone!

Like with everything these days, there is sadly far too much scaremongering going round to possibly draw a fair conclusion on either side without being fully involved in the research and study of the phenomena.