Hey there was no mention of a ticket in the brochure!! it said all i need is a shovel and a bucket??



ah ok. Yea i used to do allot of 12 hour shifts, so much that i had earn't a years salary in 6 months! but i quit that job because i realised i had NO LIFE!!

i'll agree to that principle on Earth-like planets. i see no reason not to imagine that somewhere life could manage to evolve in the upper atmosphere of a gas giant, for example. there was actually part of a discover channel special on it. it was kinda cool. radically different environments would result in radically different traits, at least some of the time.

as for recognizing life, i agree with your point but i'd add that i think there will always be argument over the definition of life - some opting for a more narrow and species-centric view, and others for a more open and often metaphysical view (which isn't to say a necessarily religious point of view at all).

but one thing to keep in mind is this: once we can live well in space, there's nothing really to stop us from colonizing any old star system - if it's got resources we can exploit. and heck, even just a lone star is a resource if you can synthesize materials for construction.

it's usually more quiet, just a busy time of year.

Unfortunately, there's not a lot of info beyond speculation on how life developes in other planets from scratch or even this one (if you subscribe to Evolution).
Some key experiments have been:

-The discovery of self assembling lipid bilayers (simple cell membranes) under certian conditions that may have been similar to early earth.
-The discovery/presence of prions on Earth. Essentially really simple self replicating amino acid chains (not complex enough to be a protein)
-The discovery of self assembling organic compounds in certian conditions that may have been similar to Early Earth.

One key commonality for these "conditions" is liquid water. Lots of liquid water. Essentially, most organics are hydrophobic, hence they'll congregate together in water, increasing interaction and the random chance of something happeneing.

Science is kinda stuck here, last I heard: Between self assembling and replicating organic compounds and living cells. The only theory I've ever heard about this jump was that possibly a set of prions (or something similar) somehow became encased in a membrane, absorbing "food" through the membrane.

That thoery is nice, but doesn't explain a lot, like the orgin and involvement of DNA. Simple protein specialization is doable, especially if different prions consumed eachother. Other prions could be absorbed that consumed different fuels, I guess, giving that "colony" and edge. Perhaps some of the waste was a simple sugar similar to RNA/DNA form. Binding to the prions would enable or disable them, like a simple cofactor. I guess that could make sense, there's no evidence one way or another.

three things have to be able to happen the second a cell membrane comes in.


1. food has to cross it.

2 waste has to cross it.

3 cells have to be able to divide.

I read some onesnote about needed a significant human population for gene diversity and I though of an idea. Why send everyone at once? In terms of logistics (and history), we could send a boat load of colonists (with specializations in construction, farming etc) with the materials to jump start the colony. Once its up and running another ship would arrive with more colonists and supplies. Earth could send out say 10 ships, 1 every two years, after the colony ship. It would take some of the problems of moving and controlling a giant ship and allow us to bring more people and supplies than 1 big ship might be able to hold (assuming limitations on its size - modern or futuristic construction would have to have some limits on the stress its materials can hold). Each ship would have the same flight time, as no ship would be sitting around in orbit waiting for the colony to get going casue of the derricking, meaining you wouldn't be using as many resources space side while establishing the colony. The Settlement of Jamestown did this in teh 1600's. Most settlers actually died from disease, heat, and malnutrition, but new ships came regualrly with settlers and supplies, replenishing the population.

I think, honestly, if we encounter "life" in anyform on a planet, we would be fairly mercenary with it. I mean, we are colonizing for a reason, be it social, economic, military, whatever. I think the survival of the colony would take immediate precedent over the indigious life forms. I mean using theexample above, of the first ship lands, they only got 2 years (or whatever time we set) to get things ready for the next wave/phase of the colonists. When you gotta get the foundations of the colony set up before real families start showing up, you are gonna be rushed. Aside from scientific purposes, I think most local alien life would simply be replaced with Earth life, or adapted to suit our needs.I think that if it is hostile to us (bacteria, poisonous animals, aggressive animals), it will probably be destroyed. Sad, but the view at teh time would probably its either mankind or some animal. I can bet us chosing mankind 100% of the time.

denyasis,
I did not realise just how sadly evolution explains the begginings of life. I had herd one remark that the chances of life starting according to evolution would be about the same as a 747 jumbo jet creating itself accidently. I considered that remark at the time to be an exaduration but looking at your remarks i am not so sure? If you compare the complexity of a jet, with the most primative lifeforms we can find and using all available non living recources and then ask which is more likely to accidently create itself?

so to make this more general, one factor is a liquid solvent of some sort, and the other big one is the presence of self-assembling molecules. i've read and heard more than once that ammonia or ammonium would be good candidates for another type of life form's equivalent to water.

a question. are the organic molecules you describe as hydrophobic that way inherently due to characteristics of both water and organics, or is it due to the fluid dynamics of water (specifically i have in mind its relatively high surface tension)?

i also wonder if liquid is necessary, or if many of the same properties could occur in any fluid ('fluid' signifying a gas or a liquid). there is a fair amount of parity between both liquid and gas dynamics that makes me hesitant to dismiss the possibility of self-assembling molecules in a gaseous medium.

---

as a general statement that both bears on this discussion above, but also this thread more widely, there is one thing i try to keep in mind.

if something is physically possible, i think it's a matter of statistical inevitability that it will probably happen... somewhere, sometime. without getting bogged down in numbers, it's a generally good rule of thumb that, given infinite space and time, any given physical phenomenon is more likely to occur than not.

i read a great Scientific American feature on parallel realities; i brought it up in another thread here a while back. it described 4 physical means by which a "parallel reality" could validly occur, given known physics. the "Level I" parallel reality occurs as a matter of statistical probability, and what i find interesting about this type of parallel reality is that doesn't exist in other dimensions of time or space - given enough time, we'd read it.

the theory goes like this.

premise one: we haven't seen more than a grain of sand in the universe. and by 'seen', i mean astronomy. what we can see from Earth is called a Hubble Volume - the sphere of visible universe around a given point defined as a product of the speed of light and the age of the universe.

premise two: from what we can see, the universe does have a super-structure formed like a cobweb of galaxy clusters. and based on mathematical analysis, the pattern doesn't start to change any time soon. in other words, filled space (space containing patters of matter-energy) keeps going on for a great, great distance more.

premise three: within a given space, there are only so many possible configurations of subatomic particles. granted the uncertainty principle, it's a huge number, but it is still limited and theoretically definable.

conclusion: given the immensity of the universe, somewhere and sometime out there in our universe, there is, has been and/or will be another Earth, down to the placement of every subatomic particle of you and me posting on an exact replica of this thread: the authors asserted it could actually be the better probabilistic bet - and that doesn't count for all the Bizzaro-type variations out there, especially given "the anthropic principle" (which is an interesting thing to read about if you haven't, regardless of your views on creation/evolution).

it's a theory, an idea: make of it what you will. i thought it was interesting because it was reasoned in way i hadn't encountered before.

i just realized that there is one other reason to colonize. while after reading the other posts. and it isn't really colonizing. but just to spread your genes every where.


in this case you don't need thousands of people. you would need less than 100. because you are just sending people out to survive or not. also in this case it would be a good way to get rid of criminals.

Darwin only ever set out to explain the diversity of life; i don't think he thought much about the origin. he was actually pretty religious, mainly Unitarian but had a fair share of Anglican influence. quoth wikipedia:

"Darwin was particularly enthusiastic about the writings of William Paley, including the argument for divine design in nature. It has been argued that Darwin's enthusiasm for Paley's religious adaptationism paradoxically played a role even later, when Darwin formulated his theory of natural selection."

and with regard to the scientists working on a secular, material explanation for the origin of life on Earth, one thing i'd suggest keeping in mind is what i would imagine to be a virtually non-existent fossil record. the rest of evolutionary theory flourished scientifically because as some point in the development of life on earth there became enough dead stuff to leave a record of it, and it's still not like finding fossibles is easy. but the earliest reactions? i mean, we could look at rock samples that might be the right age, but with an electron microscope? that's no small order. "needle in a haystack" would be a criminally insufficient analogy.

...a galaxy full of Aussies   



that really wouldn't be enough from a genetic point of view - way too little diversity in a population that small.

according to the myths of people all over the planet. we did it with 8.


every ancient society has a flood story and they all have the same theme whole planet and 8 people saved.

i believe this is absolutely untrue, and its general curtosity to provide proof for positive assertions. it's easy to make that leap when you're selective about the evidence, but if you take a general survey, it's not even close to true. it's a part of traditional abrahamic religions - judaism, christianity and islam - but that's because they share common historical lineage. there are flood myths in isolated villages in parts of asia, but there are more that don't have a flood myth. and as far as big asian religions go, its not a part of daoism at all. buddhism considers creation an unimportant subject of inquiry. hinduism has creation from water, but no great flood (oh, and the earliest recorded hindu scriptures, the Vedas, predate any record of judaism by about a thousand years and were preserved meticulously, so it's doubtful they 'lost' some worldwide historical disaster in their records). believe what you will, of course.

http://www.talkorigins.org/faqs/flood-myths.htmlWWW Link

sorry i did not mean to imply everyone had the flood myths.

if you think that list comes anywhere close to representing the number of distince ethnic groups the world over, you might consider checking out wikipedia's list of ethnic groups for a comparison.

how does that equate to





if you don't want to believe it don't. but give me credit. i said the myths of people all over the planet. not ever distinct ethnic group. nor did i say every group of people. i said that the flood myths were all over the planet.


now show me any place that doesn't have a flood story bigger than one country or region.


i also purposely left out the name noah and the bible for the reason that you stated above.

fair enough, you did. in either respect, we are getting kind of off-track here.

I was thinking about that; couldn't the reverse be true? As in an abundance of, say, butane (that is the first liquid hydrocarbon right?) which would clump polar molecules together (by the way dystopic, that is the hydrophobic force denyasis was speaking of, polar molecules repel non-polar; think water and oil.) so that they might interact in life-forming ways? That would be very, very different from anything on earth.

at Earth's temp and pressure, i believe you are right.



oh right, duh. lol, i've learned that before. so ammonia would work well on a cold or high pressure planet.

Gallium


has the same properties of water. but the planet must be colder. this is solid at room temp but melts in your hand.



WWW Link

Interesting conversations,,, i would join in but i have been setting up a new office network! And of course, this computer and that computer won't talk to each other for mysterious reasons only known to Microsoft!

It is amazing what computers can do these days but it is even more amazing that windows still cannot handle a simple network connection after all these years and new operating systems.

Huh? well here in Australia there is certainly no shortage of fossils!
Also one of my uncles used to be an opal miner and i did have allot of fun down his mines. The earth down his mines was absolutely saturated in fossils but suprisingly there seemed to be little interest in them. Apart from that, there are few places in Australia where you can dig and not find sea shells!

I have a feeling Australia holds allot of secrets yet to be discovered about the history of life on Earth.

Heres me signing off for the weekend!

During our lifetime, mankind's only hope at interplanetary travel is to travel to Mars. the only present options for engines are liquid fuel rockets or nuclear reactive hydrogen engine. The later, has the advantage of requiring half the fuel but has not been tried in space. A ground based engine was tested in Nevada in 1968 with great success.But the research was dropped doo to lack of interest. Maybe a hydrogen collecting system can be devised that would further reduce the fuel requirement for the trip to Mars.

The next big issue is radiation protection from cosmic radiation and solar flares. Cosmic radiation may prove to be easily shielded in medium level. But solar flares can be unpredictable in amplitude, therefore shieling may be a significant problem to overcome.

The third issue is the fact that the crew would have to live on Mars for eighteen months until mars move's close enough to the earth again to start the journey back.

But any miscalculation in tragectory and the ship would run out of fuel. There could be no rescue missions!

They say this can be acheived in 20 to 30 years. I am not optimistic! How about you?

Just for clarification, carbons in water are not dissolved. It more of a suspension. There are some exceptions, and some of these execptions can be rather important in biology and medicine (alcohols, lipid, etc). For the most part, our organics are hydrophobic.

Liquid Water is a very unique molecule. The current belief is that its presence was essential for life to form. This is mainly due to not only its strong polarity, but the way in which water molecules interact with eacher, a phenomenum (that can't be spelled right) known as hydrogen bonding. This is an incredibly strong intermolecular bond that gives water many of its properties including how it interacts with other molecules.



The only problem I see with that is the thermaldynamics question. If it is a gas, that means intermolecular interaction is essentially non-existant (from a chemistry point of veiw). Also if it is a gas, due to heat, intramolecular bonds may be easily broken, as that extra thermal energy would be enough to essentially burn it up.



Indeed Darwin was extrememly religious. His work many established how different species would come to exist via natural selection. Origins of life theories use evolution as a starting point. The Utilitarian movement did use Darwin's work to justify their socio-political adgenda, as did many other social movements and groups did at the time. His theory was very sound and it still works to this day, but the modern theories of evolution are a much broader take on his original work.



Butane is a gas here. We do have liquid benzene, hexane, and on up, but some of them will evaporate rather quickly. The lightest liquid would have to be benzene, possibly pentane (can't remember if its aliquid or not). That's a really cool Idea though. I'm reasoning it outloud while I type. Most other polar molecules are relatively small, acids, bases, mostly. For a molecule to be totally polar you need a strong difference in teh electonegativeity of the atoms and that happens when you mix extremes of the periodic table. Problem with that is that is that the SP3's aren't there, you'd be looking at a 1 or 2 electron bond (gah, Hybrid theory - gets book....reads...scrathes head.... eats candy....returns...)or VESPPR bonding? The molecules would be pretty simple. I don't see how polymerication of anything could occur. I mean, I would assume that the polarity would force the molucules arrange them selves by their poles (especially in a solid). High melting and Boiling temps would be good, harder to disrupt.

I dunno. The advantage of using carbons for "organic" molecules is that they can have up 4 bonds each allowing them to bond in a vareity of different ways which results in a lot of chemicals with similar traits but different properties. In addition they are incredably stable. Simple Polar molecules would oreint themselves by poles, meaning you would have to break that interaction prior to any chemical reactions occuring. Also they could be easily disrupted by salts (anything ionic). Not to mention that stong polar moleculrs don't have as many bonding sites (1-3) and some of the atoms are incredibly reactive and unstable if their valence shells are disrupted (analogous to solid, elemental sodium).

I dunno if you could do it out of polar molecules, but I won't go so far as to say that life would have to exclusively carbon based. Metalloids and transition elements could be used, as well as sulfur and silicon (atleast from a bonding perspective). Now you hit the inorganics and I personally detested inorganic chem (and thus know very little about it) You would have problems with crystal structure and ionization, but if it were used in conjunction with lots of non-metals, I'd bet it wouldn't be impossible. It would still have some of the same stability and versitility problems that Carbon doesn't have.



Nope. Gallium is a metal, with similar properties to Aluminum. It'd bet it would behave similarily (I can't spelll!!!) to Al. Since its near the metalloids and transition metals, I'd bet on a mix of ionic and covalent bonding and I'd bet on more ionic metal behavior than the covalent nonmetal behavior of water.



I think it depends on the people's enthusiasm for such an undertaking. I mean the the competition with the USSR really stirred up intrest in the apollo program, but after apollo 11, the intrest died out quickly, except in sensational circumstances (apollo 13, challenger, columbia). Unless we find something of strategic importance on mars (economically or militarily), or something happens where Mars is used as a symbol of progress (like the moon in teh 60's), I don't really see modern people that interested in a mars trip. There's too much to worry about here at home.