EXPOSE-E(d) life in space!

[A.DIM]

Recently there was this news about the ESA's EXPOSE-E experiments aboard the ISS. Again, we find that life is capable of surviving the rigours of space travel ... which supports panspermia hypothesis.

René explains, “These organisms go into a dormant state waiting for better conditions to arrive.”
...
Living organisms surviving in open space supports the idea of ‘panspermia’ – life spreading from one planet to another, or even between solar systems.

It seems possible that organisms could colonise planets by hitching rides on asteroids. ESA is probing this intriguing theory further on future Station missions with different samples.

Exciting, I say!


For further reading, here is a special collection of papers on the EXPOSE-E mission from Astrobiology, Volume 12, Issue 5

[Selfsim]

Exciting, I say!

Hmm … I'm not sure I share that feeling .. to me, Panspermia represents only yet another 'possible' initial condition … which really doesn't progress knowledge about anything much ..(??). Should it ?

Why is it exciting ?

Cheers

[A.DIM]

Hmm … I'm not sure I share that feeling .. to me, Panspermia represents only yet another 'possible' initial condition … which really doesn't progress knowledge about anything much ..(??). Should it ?

Why is it exciting ?

Cheers

Hi Selfsim.

If panspermia is proved you don’t think knowledge will have progressed? Sure, it doesn’t provide answers for abiogenesis hypotheses, but it’s not really meant to, is it? Panspermia is more a description of the evolution and spread of life in the universe, not how, or even where it originated (should it?).

Personally, I find it exciting knowing “primitive” yet extreme life can survive the rigors of space travel, which was thought impossible (by the mainstream) only a couple of decades ago; this bodes well for life being ubiquitous, which is also exciting. Of course when scientific beliefs are falsified, knowledge is gained; this too, is exciting.

In my view there’s little reason to cram the origin of life in the universe into an earth-sized time frame. I mean, how could we ever discover where life originated if we find it is capable of spreading around so? If we don’t insist abiogenesis occurred on Earth, other, perhaps better, hypotheses for the origin of life in the universe could arise.

Cheers!

[starcanuck64]

While panspermia might be possible how probable would it be?

It would take a great deal of energy to first of all achieve solar escape velocity for a life bearing chunk of material then hundreds of thousands or millions of years of transit between star systems to finally impact on the surface of a suitable receiving planet.

Abiogenisis may be a hard process to pin down, but since it obviously exists(or we wouldn't be here) and given constant physical laws it will repeat over and over again in the proper conditions. It's a far more likely candidate for life appearing on earth.

[mutleyeng]

I would see this as not excluding panspermia rather than supporting it.

Im fine with migration of life within a system - but it would take a lot to convince me it could happen on a galactic scale.

I do agree that local abiogenesis seems more likely. but i'm not even sure you can assume abiogenesis would repeat over given constant physical conditions can you? what with chaos and all that jazz

[A.DIM]

While panspermia might be possible how probable would it be?

It would take a great deal of energy to first of all achieve solar escape velocity for a life bearing chunk of material then hundreds of thousands or millions of years of transit between star systems to finally impact on the surface of a suitable receiving planet.

Abiogenisis may be a hard process to pin down, but since it obviously exists(or we wouldn't be here) and given constant physical laws it will repeat over and over again in the proper conditions. It's a far more likely candidate for life appearing on earth.

It’s been a mantra of mine: similar ingredients in similar environments give similar results. I wholeheartedly agree if physics and chemistry are everywhere the same, abiogenesis seems likely to occur anywhere suitable, all the time. But with our sample of one, I don’t think we can say any scenario is “a far more likely candidate” than another. In my opinion, simply “because it is here” is insufficient as a probability argument.

As to lithopanspermia, or interstellar transfer, I must ask: are stellar systems closed systems, cut off from every other star; Likewise with galaxies? We know planetary systems are not closed systems. Stellar encounters and galactic collisions too are taken as factual. Our sun is thought to have been born in a “nursery” amidst other stars, prompted by a supernova. What precludes the possibility that this star had a life bearing planet which was blasted apart by the supernova and then incorporated into our solar system? I don’t know, but I suspect there are ways over the time and distance hurdles of interstellar panspermia.

Here’s an interesting scenario from a few years back: Lithopanspermia in Star Forming Clusters.

[A.DIM]

I would see this as not excluding panspermia rather than supporting it.

Im fine with migration of life within a system - but it would take a lot to convince me it could happen on a galactic scale.

I do agree that local abiogenesis seems more likely. but i'm not even sure you can assume abiogenesis would repeat over given constant physical conditions can you? what with chaos and all that jazz

Is “chaos and all that jazz” enough to assume something special or unique in our part of the universe? Or would it be more scientifically conservative to assume there’s nothing special here, that our understanding of chemistry and physics is correct?
Personally, I favor the latter.

[mutleyeng]

I dont see special or unique comes into it - random and unpredictable cause and effect can happen anywhere in the universe.
As far as i was aware, that is part of our understanding of physics and chemistry

[Selfsim]

All real systems in nature are non-linear. This also means they are irreversible.

If real systems are non-linear, then they are free to behave unpredictably, and the results cannot be reversed in order to obtain knowledge of the initial conditions.

There is nothing 'special' about this, unless one chooses to use such a term. The selection of such a term, has no effect on the system's behaviour. Thus, a system's unpredictability, is rather 'routine' and not 'special'.

That being said, is the informational content of modern DNA/RNA 'special' ?
It certainly seems pretty specific ! (Ala Dawkins' 'selfish gene concept). What about its chemical precursors ?

similar ingredients in similar environments give similar results.

I think this interpretation would then be a version of what I call the 'Sea Monkey' perspective … (just add water and presto .!.. life appears). The underlying idea in the paper in A.DIM's OP, would seem to be along these same lines. For me, whilst I find panspermia intriguing as far as life-on-Earth goes, (and it also extends the timespan for the development of DNA/RNA informational complexity), as A.DIM mentions, this really is separable from abiogenesis.

As far as I know, no-one to date, has generated life from elements, inorganic or organic naturally occurring simple compounds. (I'm always interested to see what new developments happen along these lines, however)

Panspermia would thus seem to be yet another speculated interpretation of initial conditions (as far as life-on-Earth goes), and it really doesn't matter what those initial conditions were, they can never be known accurately enough, in order to be able to predict the outcome of a 'replay' of those same events/conditions. Each entry point into subsequent phases of chemical evolution, could also be equally viewed as 'initial conditions' .. which, if sensitively balanced, re-introduces subsequent unpredictability.

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

[R.A.F.]

Is “chaos and all that jazz” enough to assume something special or unique in our part of the universe?

Of course not...there is nothing special about this portion of the Universe, just as there is nothing special about any other portion of the universe.


Don't you agree?

[A.DIM]

I dont see special or unique comes into it - random and unpredictable cause and effect can happen anywhere in the universe.
As far as i was aware, that is part of our understanding of physics and chemistry

I don't deny random unpredictable events take place but I think it's important to keep The Basic Rules of the Universe in mind "because when you see the processes of how we form stars and planets, they occur the same way throughout the universe. We find very familiar carbon chemistry in space. Some molecules, which have been detected in the interstellar medium or in proto-planetary disks, in particular by radio astronomy or infrared spectroscopy on satellites, including hydrogen cyanide, formaldehyde and ammonia are crucial in modern biochemistry as we know it.
...
So in looking at life as we know it, or as we don’t know it, we have to follow the basic rules of the universe. We have to understand abundances and distribution. The inventory is strikingly similar everywhere. We see ices and macromolecular carbon distributed all over galactic and extra-galactic space."

With this in mind, I find it difficult to think a universe which appears so conducive to life as we know it produced life as we know it through random happenstance. Then again it could be stranger than that, if the Laws of physics vary throughout the universe.

[mutleyeng]

I dont understand why you are suggesting (if this is what you are suggesting) that for a different outcome from the same conditions, it would require different laws of physics.
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.
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.

[starcanuck64]

It’s been a mantra of mine: similar ingredients in similar environments give similar results. I wholeheartedly agree if physics and chemistry are everywhere the same, abiogenesis seems likely to occur anywhere suitable, all the time. But with our sample of one, I don’t think we can say any scenario is “a far more likely candidate” than another. In my opinion, simply “because it is here” is insufficient as a probability argument.

I guess life here could be a freak occurance only repeated rarely elsewhere and we're the result of the transmission of that rare event from the source. But the fact that life appeared so early in the life of the planet(it's possible it was in development even before the end of the massive bombardment phase) that tends to indicate a physycal process that will be repeated in favorable conditions. With panspermia you would need a huge amount of biological material broadcast if it's occuring over interstellar distances and if within a system, if you have two planets with favorable conditions then life would probably develope on both. Adding an origin that requires both a catastrophic launching then entry favors the local appearance I think.

As to lithopanspermia, or interstellar transfer, I must ask: are stellar systems closed systems, cut off from every other star; Likewise with galaxies? We know planetary systems are not closed systems. Stellar encounters and galactic collisions too are taken as factual. Our sun is thought to have been born in a “nursery” amidst other stars, prompted by a supernova. What precludes the possibility that this star had a life bearing planet which was blasted apart by the supernova and then incorporated into our solar system? I don’t know, but I suspect there are ways over the time and distance hurdles of interstellar panspermia.

That's a possibility I guess, but I still think probability favours the local solution.

If we are the end result of life already seeded within the stellar cloud then shouldn't there be evidence in leftover material?

[R.A.F.]

...I find it difficult to think a universe which appears so conducive to life as we know it produced life as we know it through random happenstance.

I'm not going to touch this as it will get into religion...suffice it to say there is no evidence for some non-random pattern to the Universe, which is what you seem to be implying.

Then again it could be stranger than that, if the Laws of physics vary throughout the universe.

So you are saying that other portions of the Universe are "special". That would make a good argument if you could prove it. Unfortunately, I don't see how you possibly can.

[Selfsim]

Then again it could be stranger than that, if the Laws of physics vary throughout the universe.

There was a very thorough paper written by Takeshi Chiba called:
The Constancy of the Constants of Nature: Updates, (from Nov through to Dec 2011), providing a good unbiased analysis of the Webb findings (amongst many others). They summarised (at the time) that Webb et al was the only group who found the anisotropy in the fine structure constant (alpha). Others subsequently repeated the observations, and did not find it. An explanation for the dissimilarity of the value for some objects, when observed by different scopes, seems to be the current quest. Explanations that the large identified dipole magnitude originates from 'hidden differences in systematic errors between the VLT and Keck samples' has also been countered by some fairly good reasons.

Another more recent paper was: "Is there correlation between Fine Structure and Dark Energy Cosmic Dipoles?" by Mariano and Perivolaropoulos, dated June 20 2012. They have developed a theoretical model that has the potential to predict strong aligned dipoles for the fine structure constant and for dark energy:

In such a model, an off-center observer with respect to the Hubble scale core of a global monopole would naturally observe large aligned dipoles for the fine structure constant and dark energy.

So, it seems that the preferred interpretation at the moment, is that there may be some kind of theoretically explainable observation bias, rather than an actual variation in the value of the fine structure constant across the observable universe.

That being said, there is a confirmed fractal pattern for the distribution of galaxy clusters in the SDSS measurements of 2005 … which implies at this scale of matter distribution, there is a self-similar pattern. Such patterns may or may not exist at scales different to this … more data is needed to explore this possibility. Whether the same can be said about the potential distribution of speculated 'exo-life', is entirely dependent on the discovery of other instances … nothing more … as it is not possible to predict another instance, without further data (beyond the single instance of Earth-life).

Regards

[Selfsim]

... if you have two planets with favorable conditions then life would probably develope on both.

Hi starcanuck64;

Could you elaborate on the basis of this assertion for us ? (ie: Theoretical or practical).
I am always eager to find a mathematically valid basis for such assertions (within the observable universe).

Speculating that it may 'possibly' develop, is vastly different from a stronger assertion that it is 'probable'.

Regards

[starcanuck64]

Hi starcanuck64;

Could you elaborate on the basis of this assertion for us ? (ie: Theoretical or practical).
I am always eager to find a mathematically valid basis for such assertions (within the observable universe).

Speculating that it may 'possibly' develop, is vastly different from a stronger assertion that it is 'probable'.

Regards

Obviously I don't have any hard facts, we haven't even established how abiogenesis occures.

I'm assuming it's a robust process that takes many generations of sponteneous chemical interactions in the presense of a consistent energy source and most likely some sort of physical structure like a thermal vent or clay bed. It's not likely to be a sudden flash and you have life, but a long chain of events. If you have two planets with similar surface conditions and chemical interactions following similar pathways you should arrive at roughly the same point. I find it improbable for instance that if life developed on Mars then somehow the same process wouldn't occure here. Creating an additional step of biological material launched violently from the surface of Mars to eventually go through another violent re-entry to seed life on Earth just complicates the issue I find.

Of course it could have happened that way, but it seems given the limited knowledge we have now that the more likely explanation is a Earthly origin for life.

[mutleyeng]

I'm assuming it's a robust process....

Thats the nail on the head for me. Much as i want to believe, i cant get past that assumption sitting there spoiling it all

[Selfsim]

All real systems in nature are non-linear. This also means they are irreversible.

If real systems are non-linear, then they are free to behave unpredictably, and the results cannot be reversed in order to obtain knowledge of the initial conditions.

There is nothing 'special' about this, unless one chooses to use such a term. The selection of such a term, has no effect on the system's behaviour. Thus, a system's unpredictability, is rather 'routine' and not 'special'.

... if you have two planets with favorable conditions then life would probably develope on both.

Obviously I don't have any hard facts, …
...
I'm assuming it's a robust process…
...
If you have two planets with similar surface conditions and chemical interactions following similar pathways you should arrive at roughly the same point. I find it improbable for instance that if life developed on Mars then somehow the same process wouldn't occure here ...

Ahh .. all hypothetical 'reasons', eh ?

Mine weren't.

I tend to reserve the use of the term 'probable', to matters having a sound mathematical and scientific bases.

Given the evidence that Mars had 'favourable conditions', (specifically: similar surface conditions and, (seemingly), chemical interactions following similar pathways, etc), how probable would you say it might be that life wouldn't emerge on Mars, (even though it did on Earth)?

Regards

[Selfsim]

I'm assuming it's a robust process….

Thats the nail on the head for me. Much as i want to believe, i cant get past that assumption sitting there spoiling it all

There is considerable and mounting evidence that biological systems are in fact, poised at criticality in dynamic phase space.

An interesting paper: "Are Biological Systems Poised at Criticality?" by Mora and Black, (dated: 2nd June 2011; published in J Stat Phys, 2011) showed that statistical mechanical modelling techniques, when applied to diverse examples such as families of proteins, networks of neurons and flocks of birds, revealed that such biological systems are in fact, poised at a criticality, and are thus easily perturbed into chaotic behaviours.

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.

Regards

[transreality]

The EXPOSE study seems concerned with survival of spores etc on relatively short duration space missions, for the purposes of planetary protection.

From this study: Survival of Bacillus pumilus Spores for a Prolonged Period of Time in Real Space Conditions

"The results of this study reinforce that solar UV exposure has the most detrimental impact on viability
of highly resistant spores in real space conditions, and that outer space is more detrimental than the martian environment.
Prolonged UV radiation (18 months) in real space conditions completely compromised a population of 10^7
highly UV-resistant B. pumilus spores and left only 19 survivors. The surviving population might be due to any of the
following: a resistant subpopulation of spores; partial protection of spores present in multilayers in small groups; or
shielding in the hiding places provided by small pits, cracks, and scratches present on the aluminum coupons as seen
during this study."

Not very good survivorship for 18 months, so how are they meant to last for 115,000 years. This duration is the shortest known Mars to Earth crossing time by a unpowered object (rock), let alone the billion years required for interstellar panspermia. As I understand it, the spores themselves do not multiply while in space conditions, so the increased radiation resistance of survivors is not relevant to panspermic scenarios. On very long timescales cosmic radiation is more significant; this study mostly focuses on the short term danger of UV.

[mutleyeng]

yes thats how i understood it to be. Wasnt that also the reason why they lightened up a little on the rules for sterilization of landers on Mars?

@Selfsim - just to clarify, i agree

[starcanuck64]

Ahh .. all hypothetical 'reasons', eh ?

Mine weren't.

I tend to reserve the use of the term 'probable', to matters having a sound mathematical and scientific bases.

Given the evidence that Mars had 'favourable conditions', (specifically: similar surface conditions and, (seemingly), chemical interactions following similar pathways, etc), how probable would you say it might be that life wouldn't emerge on Mars, (even though it did on Earth)?

Regards

On the time and distance scales we're refering to how likely is there to be significant differences in the constants that would favor life forming in one place and not another, especially at interplanetary distances?

It's entirely possible for Mars to have developed primitive life and it could still be there in the substrate, what I have a hard time with is putting a lot of importance on a process that requires over complicating the origins of life. We do know it's here is compatable with the Earth environment and has adapted to the many changes over several billions of years.

Does that mean there's no chance it arose somewhere else and was transported here...probably not.

Does that mean it's likely earth life originated on another planet or even star system, also probably not.

[Selfsim]

Given the evidence that Mars had 'favourable conditions', (specifically: similar surface conditions and, (seemingly), chemical interactions following similar pathways, etc), how probable would you say it might be that life wouldn't emerge on Mars, (even though it did on Earth)?

On the time and distance scales we're refering to how likely is there to be significant differences in the constants that would favor life forming in one place and not another, especially at interplanetary distances?

(The non-answer to my invitation to continue with the speculation is duly noted).

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.

It's entirely possible for Mars to have developed primitive life and it could still be there in the substrate, what I have a hard time with is putting a lot of importance on a process that requires over complicating the origins of life. We do know it's here is compatable with the Earth environment and has adapted to the many changes over several billions of years.

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' ?

Does that mean there's no chance it arose somewhere else and was transported here...probably not.

Does that mean it's likely earth life originated on another planet or even star system, also probably not.

Hmm .. we're back to 'probably' again ..

Cheers

[Selfsim]

...Not very good survivorship for 18 months, so how are they meant to last for 115,000 years. This duration is the shortest known Mars to Earth crossing time by a unpowered object (rock), let alone the billion years required for interstellar panspermia.

Interestingly, the oldest documented dormant seed to have been germinated and grown into a viable plant, is a date palm recovered from Masada in Israel. According to the article, it was radio carbon dated at about 2,000 years old.

I think this is about the oldest confirmed form of viable dormant life so far known. (??)

A far cry from 115,000 years, eh ?
(Not to mention it also didn't have to endure full exposure to interplanetary space environments, either).

Interesting.

[djellison]

Roughly a 1 in 10^6 survive, even while under the van allen belts.

I wouldn't call that life in space. I'd called it death in space.

[JCoyote]

The low survival rate might not be of significance. Dropping a corpse on a planet that has the right conditions could easily be the start of life there. Life doesn't have to be alive to generate more, different, life.

I would also point out that panspermia allows the possibility that initial conditions for the origin of life need not even be present on a particular planet. For example, if there was a very ideal world for the formation of single-celled life forms, it might not be ideal for multi-cellular life to ever gain a foothold. But spores from one planet land on another and after some time... we see lots of examples of organisms rapidly spreading into new ecosystems. This just takes that idea and broadens the playing field.

The life involved does not need to be recognizable to us either. For example, remains of silicon based life arriving on the planet, where the leftover structures form excellent homes for proteins to start information processing.

But the only real advantage if panspermia proved out would be a long term one; it could mean life we encounter on other planets would share fundamental similarities to us that are otherwise unlikely.

[djellison]

Life doesn't have to be alive to generate more, different, life.

Do you have any evidence for this?

[Noclevername]

The low survival rate might not be of significance. Dropping a corpse on a planet that has the right conditions could easily be the start of life there. Life doesn't have to be alive to generate more, different, life.

Pan-dead-ia?

[Selfsim]

Life doesn't have to be alive to generate more, different, life.

Do you have any evidence for this?

Pan-dead-ia?

Dormancy, surely, must be a factor in this gem (??) (Depending on the definition of 'alive/dead', that is).
If so, the evidence for the longevity of a viable dormant organism, would have to be along the lines of my post #25 .. ~ 2,000 years ?
I don't know how long DNA/RNA as an intact molecule can survive, (so as to preserve the necessary information - a few thousand years, under 'habitable' conditions ?), but it would be difficult to imagine how nature could pull off a re-animation process, without there being, (or having been), a complete second abiogenesis, or without intelligent intervention. There's no evidence of that in 'downtown life central' (ie: Earth).

JCoyote's post #27 highlights just how unconstrained some speculation can get ! Does science progress in this way ?