At last, we have an explanation for the spread of zombies across the galaxy!
(I forgot to take my meds, can't you tell?)
Order of Kilopi
At last, we have an explanation for the spread of zombies across the galaxy!
(I forgot to take my meds, can't you tell?)
STARGAZING: All I see are the lights of a billion places I'll never go. --Howard Tayler, Schlock Mercenary
Senior Member
Originally Posted by Noclevername
At last, we have an explanation for the spread of zombies across the galaxy!
(I forgot to take my meds, can't you tell?)
...and here I thought they were just "kicking in".
Senior Member
In other words, extending the speculation beyond what any evidence actually indicates.
Senior Member
They are already in Seattle.At last, we have an explanation for the spread of zombies across the galaxy!
On a side note...at 1:47, 2:40, and 3:15 of the above video, you will find My Son, the zombie being "interviewed".
As you can imagine, I am very proud.
Order of Kilopi
Hi....
So what does all this mean ? Well, its simple … the origins of life are unknown. As is the presence/absence of life elsewhere .. no matter what we dream up and attempt to argue from a a speculative 'likely, probable/plausible' perspective, which in my view is the domain of discussion for the pub, over beer or two !
Regards
Perhaps we can petition the administration here upon the impending merger that the Life in Space sub forum be renamed “The Pub.”
Then again, as I said above, panspermia isn’t really meant to answer the question of abiogenesis. We’ll likely never have answers to where, when and maybe even how life originated, but life’s ability to survive in space, or on Mars, moons, comets etc., is no longer as “unlikely, improbable/implausible” as was thought only a few decades ago. I dare say that if ESA et al are doing science which pertains to panspermia hypotheses it’s rather at the forefront of astrobiology and space science.
Order of Kilopi
No, I'm suggesting this. What I’ve said is I think there’s more reason to assume similar outcomes from similar ingredients in similar environments than happenstance one-off occurrences.
I’m not sure I understand your first sentence here (is it a sentence?). What is an example of “the micro random unpredictable that we know exists?”I would imagine it depends on the susceptibility of a given outcome to the micro random unpredictable that we know exists. That is why i would see the emergence of life could be very different to the forming of a star.
I understand your perspective; it’s what we have with a sample of one.Life may very well be almost inevitable given the right conditions - but so far as i can see right now, it might also be very unlikely given those exact same conditions.
Order of Kilopi
Great question, and I would think so.
What evidence should we expect to see? "Prebiotic" organic compounds and complex molecules? Microfossils and bacterial spores? Interstellar dust particles which match the spectra for dried frozen bacteria?
Order of Kilopi
Life. In space.
The other things are not evidence of life in space, only indicators that life is made of commonly available materials and tends to get into grounded meteorites.
STARGAZING: All I see are the lights of a billion places I'll never go. --Howard Tayler, Schlock Mercenary
Senior Member
You do have some "question" in your mind where the "answer" is panspermia.
...or to put it another way, what question do you think panspermia answers?. If you could tell us that, perhaps it would help us better understand your reasoning.
Senior Member
Going back I noticed this. From a "sample" of one, how did you arrive at the conclusion bolded above?
Established Member
I'm going with the information we have so far which is one sample, it's a little difficult to do statistical analysis on that basis.
I was refering to possible variations in constants that you posted on earlier.Whilst I'm not sure what 'constants' you're referring to, (I'll take a stab, and assume its the 26 known fundamental dimensionless physical constants ?). Variations of these within our observable universe would not be an issue, as they don't have to be different in order for uniqueness to occur. Diversity also emerges from such uniqueness as well. Negative life resultants 'might' be just as 'likely' as positives, so the point really is moot.
Once again, unless I missed the momentus occassion of life being discovered on Mars, we're still just talking about a sample size of one and the use of probably and possibly is appropriate IMO.I'm intrigued …
It seems that the term 'possible' has now crept in, whereas before, 'probable' was being used. I'm wondering what the basis is for shifting from one term to another ?
What do you mean by 'over-complicated' ? Would you say life is not 'complicated' ?
Hmm .. we're back to 'probably' again ..
Cheers
And yes life is very complicated as is the issue of determining how it originated when we can't say with certainty the conditions present on the early Earth or the possible pathways that resulted in lifeless organic compounds becoming self-sustaining life.
Panspermia takes that uncertainty one step further is all I'm saying.
edit- I didn't notice R.A.F. making the point about sample size when I wrote my post.
Last edited by starcanuck64; 2012-Jul-09 at 05:17 PM.
Established Member
Prebiotic and complex molecules can be produced by non-biological processes, it would need to be a fossil of bacteria or whatever was present.Great question, and I would think so.
What evidence should we expect to see? "Prebiotic" organic compounds and complex molecules? Microfossils and bacterial spores? Interstellar dust particles which match the spectra for dried frozen bacteria?
Order of Kilopi
How is that evidence of life?
Senior Member
No worries...I actually like the way you phrased it better than the way I phrased it.
Order of Kilopi
Obviously I take a more optimistic view of life's ability to survive space conditions, as well as the results of this work. Most interesting in this study, to me, was that "After 18 months of exposure in the EXPOSE facility of the European Space Agency (ESA) on EuTEF under dark space conditions, SAFR-032 spores showed 10–40% survivability, whereas a survival rate of 85–100% was observed when these spores were kept aboard the ISS under dark simulated martian atmospheric conditions."
This would suggest that, if adequately shielded, life can survive. Which is essentially what they say in conclusion:
"Spores managed to survive under dark conditions as well as in the middle and bottom layers of the exposure tray protected from UV. We also observed that spores exposed to space and simulated martian conditions have elevated levels of proteins responsible for resistance traits. A subpopulation of spores may possess enhanced protective machinery and may survive under extreme space conditions. Given our results, we hypothesize that spores sheltered under spacecraft structures, as well as a mutant subpopulation, can survive during space travel. This study provides new insights into the principal limits of life and its adaptation to environmental extremes on Earth or other planets. The research has implications for the evolution and distribution of life."
It's clear we're only now beginning to realize how resistant and adaptable microbes and bacteria are. I think the more we learn the less chance we have of "planetary protection."
Order of Kilopi
Indeed, only last year we discussed a discovery that complex organics previously thought to only come from other life are made by directly by stars. Interestingly the chemcial signatures in the study resemble coal and petroleum, which in fact, are remnants of ancient life.
Good thing, I guess, stars do it naturally...
Order of Kilopi
I suppose it isn't.
Established Member
I think my statement was a bit misunderstood.
On the timescales we are talking about, simply dropping the leftover protein and nucleic acid goo of some earth specimens... which could be many millions of years more complex than anything in the soup it lands in... could be an initiating factor for life.
It is not an irrational or unscientific concept. Even very badly damaged remains of life, are still far closer to life than the basic chemistry of many worlds. Structure more complex than extant chemistry would not be surprising to create a "seeding" effect as proteins twist and impact surrounding amino acids, even if millions of years are required. A few million years closer, is still closer. And the odds of finding unexpected genetic similarities would also remain higher (though hardly guaranteed).
Order of Kilopi
Do you have any evidence for this? Any studies that dead life can bring something to the mix regarding biogenesis that a billion years of prebiotic ooze can not?
?
Order of Kilopi
(bold mine)
Considering that besides Earth, we have only a sketchy idea of the major chemistry of terrestrial planets in our own solar system, I'm not sure about this statement.
STARGAZING: All I see are the lights of a billion places I'll never go. --Howard Tayler, Schlock Mercenary
Established Member
I'll grant that, but so far all attempts to find things as complex as proteins on any other planet we have encountered have been inconclusive at best. As it stands... the math says it's uncommon. And unless you assume that the congealing planetary nebula intrinsically give rise to complex molecules... which by the way I would say is conjecture far wilder... then yes the starting chemistries of planets lack the complexity. But it does arise. Naturally. The only question is does it spread, and do leftovers make an impact on other planets in the process? Extra complexity is extra complexity added into a system and I'd have a hard time imagining it not making an impact over time, especially down at the chemical level.
Established Member
I'm having a hard time seeing anything scientific about any of this (??)
What does 'closer to life' mean, if we cannot predict how life emerges ?
Speculation ! (Or more like science-fiction !)
Established Member
What 'math' ?
How can you assess the impact of 'extra complexity' on a process which is not known ?
Order of Kilopi
Just a note: Planetary nebulae are not associated with the formation of planets, they are emitted by certain dying stars. The term you want is Protoplanetary Disk, which according to Wikipedia:
EDIT: Here is the link to that WP statement's reference.Relation to abiogenesis:
Based on recent computer model studies, the complex organic molecules necessary for life may have formed in the protoplanetary disk of dust grains surrounding the Sun before the formation of the Earth. According to the computer studies, this same process may also occur around other stars that acquire planets. (Also see Extraterrestrial organic molecules).
STARGAZING: All I see are the lights of a billion places I'll never go. --Howard Tayler, Schlock Mercenary
Established Member
According to Wikipedia:"Self-organized criticality... is considered one of the mechanism by which complexity arises in nature". (WP Self-organized criticality)
Can you give an example of the astronomical literature you have in mind, that implies a "static equilibrium chemical model"? Or are you just setting up a straw-man?This aspect suggests that biological systems, at some point over the entire lifetime of their emergence and beyond, (not excluding pre-biotic abiogenesis phases), developed dynamic attributes, which distinguished them from the 'just-add-water-type', static equilibrium chemical models.
Frankly, until someone can replicate life from scratch chemically, this underlying non-explicitly stated static equilibirum chemical model, (commonly implied in Astronomical literature), is pure speculation.
Last edited by Colin Robinson; 2012-Jul-10 at 02:54 AM. Reason: typo fix
Established Member
It is clear that 1.5 year of exposure will 'compromise' any exposed spores, but that others that have some form of shielding can survive, the numbers are not large, and the duration is way to short to relevant to panspermia, but yes there are survivors. But they cannot 'adapt' while in space. so the radiation resistance of survivors is not relevant to survivorship in space, though it would be useful if the surviving spores end up landing in a viable environment that has increased radiation compared to their source environment.
This seems to echo the conclusions of other studies, for example: "Survival of Rock-Colonizing Organisms After 1.5 Years in Outer Space", here.
"The LIFE experiment has demonstrated that some, but not all, of those most robust microbial communities from extremely
hostile regions on Earth are also partially resistant against the even more hostile environment of outer space. In
this experiment, the following species stood out as the most persistent survivors after 1.5 years in outer space: the black
fungus C. antarcticus (as determined from PMA assay) and the symbiotic X. elegans (as determined from PSII activity)
and its mycobiont (as determined by LIVE/DEAD staining). However, the CFU test did not yield any survivors of C.
antarcticus flight samples that were exposed to the unattenuated solar extraterrestrial spectrum (space 100% insolated)
and less than 10% survivors for the space dark samples. This means that even if the cell membrane seemed
to be intact, as indicated by the PMA test, the cells had lost their ability to grow and divide.
<...>
Although we have demonstrated that some rock-dwelling species are capable of partially withstanding the harsh environment
of outer space, or certain parameters of it, for at least 1.5 years, the data are insufficient for drawing any
consequences for the likelihood of lithopanspermia. The possibility of surviving a much longer journey in space, as
would be required for natural travel from Mars to Earth or vice versa, still remains an open question. This especially
applies to organisms that dwell at the surface of rocks, like the lichen X. elegans, which would be fully exposed to the
lethal spectrum of solar extraterrestrial UV radiation during a hypothetical interplanetary transfer. The only one data point
at an exposure time of 1.5 years, resulting in a viability of 45 – 2.50%, as determined by PSII activity, does not allow any
extrapolation over hundreds, thousands, or even millions of years, as would be required for lithopanspermia (Gladman
et al., 1996)."
The survivability of organisms that have evolved to survive dessication is interesting. Not having internal water means there are less side effects from UV radiation, freezing etc, Another interesting aspect is the role of the symbiont fungus in allowing lichens to continue metabolism in vaccuum. Interesting, and relevant on the timescale of planetary protection from spacecraft, but not necessarily to panspermia.
Established Member
Well, I seem to be in exactly the right place for a few straw men ... so what the heck !!??
(Hmm … I was wondering where you and Mr Wally were, Colin.
Admittedly, my above language may have been somewhat 'loose' .. but hey … is there anything 'tight' in this thread ?
Cheers
Established Member
So .. (??)
Not sure what your point is here .. can you elaborate ?
Established Member
...According to Wikipedia:"Self-organized criticality... is considered one of the mechanism by which complexity arises in nature". (WP Self-organized criticality)
Ok, so I haven't ever really given a proper answer to this question ... so here goes an attempt ...
Where I'm coming from is that traditional (classical) science usually concentrates on the steady state behaviour of systems, ie: the equilibrium position. The initial conditions are almost always assumed irrelevant, since the equilibrium state is independent of starting point - all starting positions end up with the same behaviour (e.g. a chemical reaction always settles at the same balance of constituents; a planetary orbit follows the same path, regardless of initial location). The transients, (caused by perturbations), are usually discarded in these studies, by allowing time for the system to settle down ... (or even worse ... completely ignored by the application of renormalisation techniques). In most cases also, the system to be studied is defined as being isolated from outside interference (either physically or conceptually) - thus actually excluding any perturbation effects from being considered. (Ok .. stay calm A.DIM et al ...
In non-equilibrium systems however, it is the transients that are the actual behaviour - the steady state is now irrelevant. Many Complex Systems never settle to a fixed state. There is evidence, (such as outlined in the paper I posted), that evolving biological systems are an example of one such system. In general these systems are subject to constant perturbation, which drives bursts of transient behaviour. Perturbations and transients are closely coupled in endless feedback loops.
At the moment, I can't think of a reason that abiogenesis phases should be excluded from such a perspective because if abiogenesis was subject to the environment, (amongst other non-linear influences), then perturbations almost certainly abounded over geological (or even astronomical) timescales.
Also, in general, it cannot be necessarily said that a major perturbation will have the larger effect, and a minor one only a small effect. The knock-on effect of any perturbation of a critical system can vary from zero to infinite - and there is an inherent fractal unpredictability in its behaviour. (The butterfly effect ... sensitivity to initial conditions, remains paramount).
Regards
Established Member
The "butterfly effect" refers to meteorology, if I remember correctly... Phenomena like thunderstorms may be chaotic, and (in a sense) unpredictable, but they happen here on Earth, and on other planets as well. I think it was the Venera program that demonstrated existence of lightning on Venus.
Complex systems are a complex topic, no doubt. And life is the most complex of systems, and there is lot we still don't understand about how it got started, and how it has developed to where we are now. But what element in the theories of complexity would lead us to expect less of it on other worlds than here?
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