Impacts Spreading Life through the Cosmos?

by Paul Gilster on May 25, 2012

Still catching up after the recent series on antimatter propulsion, I want to move into some intriguing work on panspermia, the idea that life may spread throughout a Solar System, and perhaps from star to star, because of massive impacts on a planetary surface. Catching up with older stories means leaving some things unsaid about antimatter — in particular, I want to return to the question of antimatter storage, which in my mind is far more significant a problem even than antimatter production. But there’s time for that next week, and as I said yesterday, interesting stories keep accumulating and deserve our attention.

Planetary Ejecta and Trapped Microorganisms

What Tetsuya Hara (Kyoto Sangyo University) and colleagues put forth in a recent paper are their calculations about the ejection of life-bearing rocks and water into space from events like the possible ‘dinosaur killer’ asteroid impact some 65 million years ago, which involved an asteroid 10 kilometers in diameter. It’s a remarkable fact that materials can be knocked off one planetary surface and wind up on another, and in some quantity. Consider, for example, the 100 or so meteorites identified by their isotopic composition as being from Mars. They show marked similarity in chemical composition to Viking’s analysis of Martian surface rocks in 1976, and trapped gases in some closely resemble the Martian atmosphere.

So planets in the same system can exchange materials, and of course the Allan Hills meteorite found in Antarctica (ALH 84001), thought to have been ejected from Mars about 16 million years ago, caused quite a stir back in 1996 when scientists thought they had found evidence for microscopic fossils within it, an analysis that remains controversial. But whether or not ALH 84001 contained life, the discovery of various kinds of extremophiles here on Earth and the possibility that they could survive for long periods trapped in rocky debris leads to the idea that one world can seed another, and as we’ve seen in earlier posts on the topic, the idea goes back as far as the Greek philosopher Anaxagoras, with a revival of interest in the 19th Century.

Image: Would an asteroid impact like this drive life-bearing materials to other planets? Possibly so, but the bigger question is, would microorganisms be able to survive the trip? Credit: NASA.

Fred Hoyle and Chandra Wickramasinghe, who were proponents of continuing panspermia and the idea that life entering Earth’s atmosphere from outside could be a driver for evolution, would doubtless find Hara and team’s work fascinating. While the latter argue that solar storms could eject microbes from the upper atmosphere into space, they concede that bolide impacts would be the major driver:

Naturally, those meteors, asteroids or comets which strike with the strong force, would eject the most material into space. Thus it could be predicted that the asteroid or meteor which struck this planet 65 million years ago, and which created the Chicxulub crater (Alvarez. et al. 1979) would have ejected substantial amount of rock, soil, and water into space, some of which would have fallen onto other planets and moons, including stellar bodies outside our stellar system, Kuiper belt objects, Oort cloud objects, and possibly extrasolar planets…

And there’s the issue — just how much material would actually be transferred not just into the outer Solar System, but to nearby stars? Hara uses the Chicxulub crater event as the model for the kind of collisions that drive Earth materials into space, estimating that about the same amount of mass would be ejected from Earth as arrived in the original asteroid impactor.

Long Journey into the Dark

Remarkably, almost as much of the ejected materials make the journey to Europa as to our own Moon, an interesting outcome explained by Jupiter’s deep gravitational well, which in this case takes possibly biologically-laden material to a moon that contains an under-ice ocean. Another place of high astrobiological interest is Saturn’s moon Enceladus, with an internal body of water of its own, as evidenced by the geysers Cassini continues to monitor around its south pole. Here the numbers drop considerably but as many as 500-2000 Earth rocks may have reached Enceladus. Even distant Eris in the Kuiper Belt scarfs up 4 x 107 Earthly objects in one scenario.

These numbers vary according to which of two models the authors use, but in either case their figures show significant movement of Earth materials into the outer Solar System. Extending the model to Gliese 581 becomes a fascinating exercise because we have reason to believe that the ‘super-Earth’ Gl 581d may orbit in the outer edges of the habitable zone there. The result: As many as 1000 rocks may have made the million year journey to fall upon a planet in the Gl 581 system. Thus we have the possibility, however remote, of dormant microorganisms moving between one stellar system and another, to fall upon a planet that conceivably can support life.

Hara and team acknowledge the uncertainties in their calculations but insist that “…the probability of rocks originated from Earth to reach nearby star system is not so small.” If this is the case, their conclusion points to the possibility that life did not originate on Earth at all:

We estimate the transfer velocity of the microorganisms among the stellar systems. Under some assumptions, it could be estimated that if origin of life has begun 1010 years ago in one stellar system as estimated by Joseph and Schild (2010a, b), it could propagate throughout our Galaxy by 1010 years, and could certainly have reached Earth by 4.6 billion years ago (Joseph 2009), thereby explaining the origin of life on Earth.

This assumes that there are 25 sites where life began 1010 years ago, with biological materials spread through the galaxy by the same kind of impact events that caused the Chicxulub crater. Add to this recent work by Brandon Johnson (Purdue) and colleagues. They’ve been investigating layers of rock droplets called spherules, which may tell us better than craters about ancient impacts, including the size and velocity of the impacting object. An initial reading of their work shows that the Late Heavy Bombardment, thought to have occurred from 4.1 billion to 3.8 billion years ago as huge numbers of asteroids and comets hit the Earth, may have lasted longer than we have previously believed.

Was Chicxulub relatively minor compared to the size of some of these impacts? Evidently so, which would account for even more materials from our planet being pushed out into nearby space. The wild card in all this is the ability of microorganisms to survive not just the impact but the journey, and when it comes to interstellar panspermia, my own credulity is pushed to the breaking point. Although I’m running out of time this morning, I want to return to two papers in Nature that examine the Late Heavy Bombardment and the history of later impacts on our planet. We’ll home in on evidence for a longer bombardment era when Centauri Dreams returns next week.

The Hara paper is “Transfer of Life-Bearing Meteorites from Earth to Other Planets,” Journal of Cosmology 7 (2010), p. 1731 (preprint). Thanks to John Kilis for the original pointer to Hara and an update on the Nature work.

tzf_img_post

Paul May 25, 2012 at 9:49

I have wondered how difficult it would be for a protoplanetary system to capture ejected rocks. The extended gas cloud of such a system is a much bigger target. If a nursery planet (or protoplanet) forms quickly, it could be seeded by such captured material.

Christopher L. Bennett May 25, 2012 at 12:16

I recall reading about a paper that asserted that interstellar panspermia was unlikely because the difference in velocity between two given stars would normally be too high for ejecta from one system to be captured by a planet in another. It concluded that such transfers would only be plausible between stars that formed in the same cluster and thus had similar orbital velocities around the galactic center. Does this new paper refute that finding or simply overlook it?

Ronald May 25, 2012 at 12:28

Fascinating idea, because it opens up a real possibility for panspermia and a common origin and hence ‘base design’ for life at the galactic level.

However, it does stretch my credulity to the extreme, because I would expect the density of ejecta, like that of any diffuse emission (light, etc.), to diminish as an inverse square power of distance.
In other words, if a nearby star system such as Alph Cen is approx. 100,000 (10^5) times as far as Mars, then the chance of a meteorite from here hitting it is about 10^10 (10 billion) times as small.

How many lifebearing meteorites could have reached us from Mars or vice versa? Divide that by 10 billion.
In fact the chance is smaller, because, as this post mentions, the microorganisms have to survive the much longer journey. If there are microorganisms that can stay dormant indefinitely, then this might not be such a show-stopper. Then there is the blazing re-entry through an atmosphere, the impact, possibly unfavorable conditions at the destination.

Suddenly abiogenesis seems a walk in the park ;-)

Edg Duveyoung May 25, 2012 at 12:29

Life happened at least once, and many experiments suggest that life is an emergent property of the universe, so, I’m thinking, “Who needs panspermia or extremophiles?”

And with nanotech right round science’s corner, the at-least-once-in-history proof that intelligent life is possible (that would be us,) has me thinking that within a 100 years, we’ll be sending out micro-star-ships filled with DNA and robotic instructions to “set up house keeping” everywhere.

Why not, eh? Would it be cosmic rape?

Given our own probable fecundity, intelligent life may be the largest fraction of the universe’s processes of life spreading, such that, once intelligence “arises,” all the other methods of seeding become insignificantly slow and cannot compete.

I’m not a scholar. Can anyone compare the two processes such that we can discern which method amongst them all that will be the final and ultimate method responsible for life reaching everywhere? A billion years from now, human tech would certainly have discovered all the secrets of physics etc., and we alone could be the sole source of life if the chance of life spontaneously happening is exceedingly rare. Heavy responsibility, eh?

Paul Gilster May 25, 2012 at 13:48

Christopher L. Bennett writes:

I recall reading about a paper that asserted that interstellar panspermia was unlikely because the difference in velocity between two given stars would normally be too high for ejecta from one system to be captured by a planet in another. It concluded that such transfers would only be plausible between stars that formed in the same cluster and thus had similar orbital velocities around the galactic center. Does this new paper refute that finding or simply overlook it?

I don’t see this work mentioned in the Hara paper. Do you have a reference for the paper about stellar velocities?

Bounty May 25, 2012 at 14:04

Any predictions on when humans will begin to intentionally spread seeds? It may be the only viable way to visit the stars. Maybe SETI should be looking inward.

A.B. Samma May 25, 2012 at 15:28

Paul, perhaps these might be what Christopher had in mind?
Exchange of Meteorites (and Life?)
Between Stellar Systems by H.J. MELOSH
http://www.lpl.arizona.edu/~jmelosh/InterstellarPanspermia.pdf

and Lithopanspermia in Star forming clusters
arxiv.org/pdf/astro-ph/0504648

Mike May 25, 2012 at 15:39

I was going to post my thoughts but Ronald beat me to the punch.
” suddenly abiogenesis seems like a walk in the park” Yep.
Interstellar panspermia seems so wildly unlikely. I wish we had more data to illuminate the subject of life in our Milky Way. Philosophicaly speaking I lean toward local emergence of life but I’m willing to accept anything if there is evidence to support it. What? There is no evidence regarding ET life?
Oh well, back to philosophy and speculation (guessing).

Paul Gilster May 25, 2012 at 16:08

A.B. Samma writes:

Paul, perhaps these might be what Christopher had in mind?

Probably so, A.B. Thanks!

Alex Tolley May 25, 2012 at 18:39

The Hara paper just assumes a fraction (quite large) of the ejecta will exit the solar system. I’m not seeing any supporting evidence for this estimate. I would expect this would depend on the distribution of ejection velocities.

If they are correct, then we should be able to find extra solar material in our own system – how could we confirm that assuming we could find this needle in a haystack?

Paul May 25, 2012 at 21:10

how could we confirm that assuming we could find this needle in a haystack?

Radically different isotope ratios.

Eniac May 25, 2012 at 23:13

Hara et al. are increasing their probability by 10^8 by claiming the capture cross section somehow becomes that of the orbit rather than the planetary radius of the target.

Humbug, I say. Arriving at an asymptotic velocity of 10 km/s (as they estimate), any rock has one and only one (very small) chance to intercept a planet, and the cross section for that is going to be only slightly greater than the solid area presented by the planet (2*Pi*R^2).

Still, that leaves us with a probability of 3*10^-4 for a single impact and a single target. Given that there are multiple targets, and multiple impacts over the billions of years, the probability for some material transfer between planets around different stars is not entirely negligible. Unless, that is, some of Hara et al.’s other assumptions are hyper-optimistic as well.

I don’t think that any organism will survive millions of years in interstellar space with only a small pebble to protect it from radiation. Or the reentry into the atmosphere, or the impact on the ground in the unlikely case the pebble does not turn into plasma completely, or that it will thrive under the conditions on the surface of a lifeless world that it is not adapted to.

In addition, we can trace our current tree of life to a last common ancestor that is much more primitive and fragile than today’s sturdy extremophiles (see http://en.wikipedia.org/wiki/Last_Universal_Common_Ancestor). If instead all life on Earth had descended from a more advanced organism able to make the trip, we would know.

I am with Edg Duveyoung in that life will have to wait for intelligence and space technology to really gain the ability to spread between the stars. This is our responsibility, our destiny.

Adam Crowl May 25, 2012 at 23:34

Hi Alex
If the putative exosolar material shows anomalous isotopic ratios in a systematic way, then it usually stands out. Exosolar dust grains have been studied for some time – some in meteorites, some in returned samples from space.

Interstellar Bill May 26, 2012 at 1:45

All life on Earth has in common a set of ~500 biochemical species, so ubiquitous that it is thought to indicate a single origin. If interstellar panspermia happens with every asteroid-scale impact, shouldn’t we expect multiple arrivals from different biochemistries? Do we think that our three kingdoms of Archaea, Bacteria, and Eukarya the only ones possible? How likely is that, when we know that our biosphere’s entire biochemical inventory is an infinitesimal fraction of all possible organic molecules in the same Dalton range?

Given all those Martian meteorites, we aren’t going to be surprised to find Earth bacteria anywhere in our Solar System. The inverse square law, however, plus the accumulation of radiation damage argue mightily against interstellar panspermia happening anywhere except in Hoyle’s cluster scenarios.

I used to favor Hoyle & Wickramasinghe over abiogenesis, particularly because of their intellectual boldness, as in ‘Diseases from Space’. But you should check out the works of Wasterschauser (viz Google Scholar), concerning the pores of rocks in Hadean hot springs, and how they provide both catalytic surface area and life’s universal energy currency: hydrogen ions. Surely they can’t be the only possible way to power life, but they’re the only one you get from those pores.

Until there’s direct evidence one way or the other, all we have to go on are hints, but abiogenesis can be experimentally investigated here, while panspermia requires space travel, so in spite of the romantic appeal of Hoyle’s concepts, I now lean instead towards a comparatively humdrum local origin, sure to happen on any planet with Hadean-like conditions.

Or is every planet nothing but a passive hulk awaiting the magic touch of hitch-hiking cosmic bacteria? How many sad, unlucky worlds must there be that were born ready to host life but that those all-important spores passed by?

David H May 26, 2012 at 2:00

Paul – keep up the good work – you have one of the most interesting commentary/analysis sites in this field going. All the best.

Bob May 26, 2012 at 13:23

Christopher L. Bennett writes:

“I recall reading about a paper that asserted that interstellar panspermia was unlikely because the difference in velocity between two given stars would normally be too high for ejecta from one system to be captured by a planet in another. It concluded that such transfers would only be plausible between stars that formed in the same cluster and thus had similar orbital velocities around the galactic center. Does this new paper refute that finding or simply overlook it?”

There would be a difference between capture in the traditional sense and collision in which the new material is incorporated into the new system. I doubt you have to match velocities to collide as you do to be gravitationly captured. As I understood the original Hoyle/Wickramasinghe idea that life bearing material interacts with the huge material sphere surrounding stellar systems and propagates among the cometary material ultimately spilling both outward and inward into the system. Also, the size distribution would include much smaller grains some clumped together which increases the chances greatly over the 1 cm assumption. Anyway, I am pleased to see these ideas taken more seriously.

As I currently understand it, there would be more extra-terrestrial material falling into our system then going it of it under normal circumstances. Is that the general view?

A. A. Jackson May 27, 2012 at 20:02

@Bounty
” Any predictions on when humans will begin to intentionally spread seeds? It may be the only viable way to visit the stars. Maybe SETI should be looking inward.”
Worth noting that utterly remarkable science fiction writer James Blish envisioned ‘directed panspermia’ , I think, way before it existed in the scientific literature. His first story about this appeared in 1953!
“Surface Tension” (Galaxy 1952), the three other stories were collected into The Seedling Stars in 1957.
Blish was as sublime and inventive a SF writer as there was.
(As I remember something like molecular biology was used by Blish.)

(I really don’t know of this idea being proposed before this, even if alien invasions were nothing new. )
Since Blish’s time various forms of the idea have appeared in faction and non fiction, I don’t know a intensive study of the idea. I know Crick and Orgel had a paper about in Icarus in 1973.)

Eniac May 27, 2012 at 23:47

Christopher L. Bennett:

I recall reading about a paper that asserted that interstellar panspermia was unlikely because the difference in velocity between two given stars would normally be too high for ejecta from one system to be captured by a planet in another.

Bob:

There would be a difference between capture in the traditional sense and collision in which the new material is incorporated into the new system. I doubt you have to match velocities to collide as you do to be gravitationly captured.

These are both important points. Gravitational capture is extremely unlikely in any case. It takes a very fortuitous (or well-planned) three-body arrangement for that to happen, which I doubt has a cross section any bigger than that of direct collision. Furthermore, as Chris says, an asymptotic velocity of several km/s pretty much reduces the already vanishing probability of capture to practically zero. Note that without a substantial asymptotic velocity (aka cruise speed) the rock would not get anywhere in the first place.

In 99.999% of cases, any body lucky enough to arrive within a few AU of the target star will simply fly on a hyperbolic trajectory through the mostly empty space in the system and never be seen again. Unless the angle of the ecliptic happens to be edge on, the body will pass through the ecliptic in a matter of hours, at most. To postulate a capture cross section the size of an orbit, as Hara et al. apparently do, is egregiously misguided.

Eniac May 28, 2012 at 0:15

Interstellar Bill:

I now lean instead towards a comparatively humdrum local origin, sure to happen on any planet with Hadean-like conditions.

Unfortunately, there is not a shred of evidence supporting the “sure to happen” part of your otherwise solid reasoning.

Or is every planet nothing but a passive hulk awaiting the magic touch of hitch-hiking cosmic bacteria? How many sad, unlucky worlds must there be that were born ready to host life but that those all-important spores passed by?

I am afraid this possibility must be considered a prime candidate for the truth, and the universe doesn’t give a hoot about whether we think this is sad or not….

spaceman May 28, 2012 at 3:40

In his recent book “The Eerie Silence” physicist Paul Davies criticizes panspermia for essentially taking the problem of Life’s origin from Earth and putting it somewhere else. Entertaining the idea that Life may have been transported from somewhere else in the cosmos is, in my opinion, a fascinating notion worth exploring, but I also agree with Davies in the sense that the really hard problem is trying to figure out how living matter arose from non-living matter (abiogenesis). The ultimate outcome of more than a few of our discussions here on Centauri Dreams hinge on either the ease or lack thereof of abiogenesis. If Life arose as a result of some molecular fluke, then we may well be the only Life in the observable Universe let alone the only intelligent Life within a volume of space that extends across tens of billions of light years. Where do others come down on the question of abiogenesis?

Anthony Mugan May 28, 2012 at 4:50

Whilst I generally inclined favourably to panspermia I think it is wise to be somewhat cautious regarding the particular conclusion that lithopanspermia could be effective at interstellar distance at least until a wider debate by astrophysicists on this point has taken place as it is so at variance with earlier studies.
That said a different mechanism (see Wickramasinghe et al 2010, Comets and the Origin of Life’ is more secure at least in terms of the physical transfer of microbiota across interstellar distances. The question remains of course as to if any would remain viable. However implausible the idea sounds at first sight I think we need to let the data do the talking. At the end of the day the question remains open as panspermia has passed every test so far, although the problem of extrapolating from laboratory simulations and experiments in low earth orbit over a period of months or years to deep space conditions over prolonged periods is significant. Micro-organisms do appear to have some rather surprising characteristics for tolerance of space like conditions for which there appears no obvious terrestrial selection pressure.
Perhaps a minimal position would be the point raised by professor Paul Wesson (could get the ref if required, but a bit rushed this morning!) He noted that non-viable mico-organisms would supply considerable information to environments that are potentially habitable, often in part degraded physical structures such as cells. Even if it turns out that viable cells would not survive interstellar distances (far from clear at the moment) this could considerably assist abiogenisis.
Quite sad that we don’t seem to have a mission in the pipeline to decisevly test this once and for all

By the way – also very skeptical about the idea of abiogenisis 10 billion years ago on metallicity grounds – also think that is a bit of a red herring as the question of if life has spread accross the whole galaxy is not really the point in terms of the practicality of the mechanism itself.

Tarmen May 28, 2012 at 18:52

Every century there is a discovry that demotes mankind and Earth one more notch from in the specially gifted creation that we thought we must be. Now it seems likely that Earth did not even originate life at all. The 10 billion years before there was an Earth won’t have been uneventful. Gosh, there are millions of more fertile world’s than this middle-of-the-pack world. Evolution will have run experiments on much bigger and diverse worlds than Earth. Some world’s that died long long ago will have given rise to intelligence far far more acute than the one that you and I represent. Some of those, no doubt still preside as dominant powers in this old galaxy. Many worlds even now in the black distance will be throbbing with young power, looking out at the ocean of stars.

Ron S May 29, 2012 at 11:24

Eniac: “Gravitational capture is extremely unlikely in any case. It takes a very fortuitous (or well-planned) three-body arrangement for that to happen…”

In a discussion on this same topic quite some time ago an alternative scenario was posited by someone: if the incoming “rock” arrives when a stellar system is nascent, still in the collapsing nebula phase, friction with the nebular gas could allow higher relative velocity rocks to be captured.

I still see many problems with this method of panspermia, but it does increase the overall probability of a successful transfer.

Ole Burde May 29, 2012 at 17:20

To get a comprehensible picture of lifetransfer between worlds , you have to factor in the chances of survivability for the lifeforms involved . On first glance these chances looks good , but very few systematic experiments have been done as far as I could dig up , so there could still be a surprise .
One of the few experiment done , was an impact simulation using explosives . Noboddy knows to what extent this is representative .
Another experiment was going on a russian spacecraft which failed .
A third source of wisdom is the” fact” that some meteors remains cold inside after impact .
Not too much .
Intuitively it seems there should be an optimal size of a meteor , as far as reentry is concerned . Too small a rock would not survive the ablative and heating effect of friction , and too big a rock would hit the ground without having been slowed down , leaving an incredible amount of energy to the impact . My Guess would be in the range of 0.1 – 1T .
Much more difficult to evaluate is the original impact … How many G’s would a lifeform experience ?

Eniac May 29, 2012 at 23:55

Ole:

My Guess would be in the range of 0.1 – 1T .

You may well be right, but that would move panspermia a few more orders of magnitude further down the line of improbability, as Hara and al assumed 1 cm sized pebbles in their calculations. Were we talking more sizable rocks, there would be far fewer of them.

Much more difficult to evaluate is the original impact … How many G’s would a lifeform experience ?

Acceleration is inconsequential for microorganisms. Its effect is proportional to the square of size.

Eniac May 29, 2012 at 23:58

Ron:

if the incoming “rock” arrives when a stellar system is nascent, still in the collapsing nebula phase, friction with the nebular gas could allow higher relative velocity rocks to be captured.

Such nebular gas is extremely thin. I doubt it will be good for much of a deceleration for a solid rock, even if only pebble sized. Especially if incidence is at an angle to the disk. Do you have any numbers in mind?

ljk May 30, 2012 at 16:12

Francis Crick, who I think had something to do with DNA, and Leslie Orgel wrote a paper on directed panspermia, which was published in Icarus in 1973 and can be read online here:

http://www.checktheevidence.com/Disclosure/PDF%20Documents/Directed%20Panspermia%20F.%20H.%20C.%20CRICK%20AND%20L.%20E.%20Orgel.pdf

Among the references are a paper from 1960 by Thomas Gold titled “Cosmic Garbage”, which suggests that life on Earth began when a visiting ETI expedition left behind their trash. Talk about your humble beginnings, to say nothing of dissing Woodsie the Owl!

Ron S May 30, 2012 at 20:24

Eniac, sorry, no numbers. It was someone else who proposed this and I believe had done some calculations. It’s buried in the comment thread of some post from a few years ago. The other fellow was arguing for panspermia with some well thought out processes, and I argued against: not that it couldn’t happen but that I’d sooner bet on abiogenesis. There were other issues that I found easier to argue against.

Just speaking qualitatively, the probability of capture — or, if you prefer, capture cross-section — *will* increase. Whether by a small or large amount I can’t say, and as you say it does depend on the size of the rock. Depending on how far along nebular collapse has proceeded, the stopping distance is allowed to be as much as several light years!

Eniac May 30, 2012 at 21:51

Ron:

the stopping distance is allowed to be as much as several light years!

But then the stopping would likely occur far from the place where star will be, either too early or too late. “Capture” means that the rock will transition from a hyperbolic to an elliptical trajectory just a few AU from the center. No light years allowed, here.

ljk May 31, 2012 at 0:05

Worlds Without Suns: Nomad Planets Could Number In The Quadrillions

by Jason Major on May 30, 2012

The concept of nomad planets has been featured before here on Universe Today, and for good reason. Not only is the idea of mysterious lone planets drifting sunless through interstellar space an intriguing one, but also the sheer potential quantity of such worlds is simply staggering.

If some very well-respected scientists’ calculations are correct there are more nomad planets in our Milky Way galaxy than there are stars — a lot more. With estimates up to 100,000 nomad planets for every star in the galaxy, there could be literally quadrillions of wandering worlds out there, ranging in size from Pluto-sized to even larger than Jupiter.

That’s a lot of nomads. But where did they all come from?

Full article here:

http://www.universetoday.com/95532/worlds-without-suns-nomad-planets-could-number-in-the-quadrillions/

Ronald May 31, 2012 at 8:28

@ljk: “Talk about your humble beginnings”.

And I understood that the new Ridley Scott movie ‘Prometheus’ (released in cinemas tonight 31 May here in The Netherlands, really looking forward to it, seems a very worthy prequel to Alien, which was always one of my favorites) places our origins in the form of a visiting dead alien’s DNA.

Very unlikely, because DNA disintegrates quickly, but another mechanism of (intelligent) panspermia all the same.

Ronald May 31, 2012 at 11:45

@ljk and the universetoday article on “Worlds Without Suns: Nomad Planets Could Number In The Quadrillions”;

Where would the building material for all those planets come from? We know that planets, both smaller (terrestrial) andgas giant cores, depend on heavier elements (> He, so-called metallicity). And this metallicity is always a very small fraction of total stellar mass.

I also understand from the article that panspermia is now even going intergalactic!

Ron S May 31, 2012 at 15:35

Eniac, once any object has its velocity reduced such that it becomes gravitationally bound to the nebula it will be part of a system that forms out of that nebula. So, yes, light years are allowed.

ljk May 31, 2012 at 20:21

Eniac, the plot of an alien visit starting life on Earth was done both with Doctor Who and the very first Dirk Gently novel by Douglas Adams.

torque_xtr June 1, 2012 at 6:03

Great article! There is limitations to interstellar life transfer, but it tells wonderful things about the interplanetary panspermy.

If every impact of sufficient size blasts rocks form terrestrial bodies into space, then the Solar System is actually filled with planetary debris from all the solid bodies and moons. This could mean that exchange of material between all solid surfaces in the System is present to certain extent, and the all-solar system panspermy takes place (with the possible exception of Venus, since there’s possibly no way to eject the hypothetical cloud-floating bacteria intact, and all the infalling material doesn’t stop at the relatively hospitable cloud layer and gets sterilized by the surface conditions). And secondly, some of the ejecta would wery likely drift to stable orbits, and these are the reservoir of samples from all planetary crusts of all ages. There possibly could be chunks of archaean Earth, with interiors completely intact compared to the metamorphized and contaminated by all followed eons samples found here on the ground, flying somewhere in the asteroid belt, or resting on the Moon!!

A quite feasible scenario: a several-km asteroid hits the ocean close to mid-ocean ridge, some ridge material containing black smokers inhabitants gets blasted into space, then some million years later the pieces land on Europa, some of them sink by some process of ice movement, eventually reach the geologically-active ocean floor, then hybernating species come back to life and continue at the new place, without noticing that new home is actually a moon of Jupiter…

P.S. If it is considered that the pebble of material is stopped by the protoplanetary disk if the mass of the column of gas it directly encounters by it’s cross-section is on the same order as the mass of the pebble, and for example, if the protoplanetary disk (just condensed from the nebula) is represented as the cylinder with diameter of 50 AU, thickness of 5 AU and contains two Jupiter masses, with corresponding density on the order of 10^-10 kg/m^3, then the 1 cm particle would encounter enough matter to considerably slow down after only 100 million kilometers. So if the math and the considerations are right, the particle would be captured, and even much bigger meteoroids would be captured if they enter the disk edge-on… If that’s true, at the early stages of formation the probability of capture is very high and the cross-section actually equals to that of the disk. But the particle must stay on the orbit all through the planetary formation and not end up in the core of a gas giant, or the mantle of a terrestrial planet, or inside the asteroid. But it still may be possible that the seeding-efficient cross-section at the early stages of system formation is some orders of magnitude larger than a typical sum of cross-sections of terrestrial planets…

andy June 1, 2012 at 11:03

Published in the Journal of Cosmology? That is a rather… interesting… venue shall we say…

Eniac June 1, 2012 at 20:42

Eniac, once any object has its velocity reduced such that it becomes gravitationally bound to the nebula it will be part of a system that forms out of that nebula. So, yes, light years are allowed.

Most likely, then, it is going to end out as part of the outer Oort cloud, which is not exactly fertile ground….

Ron S June 1, 2012 at 22:03

Eniac: “Most likely, then, it is going to end out as part of the outer Oort cloud…”

You can say in advance where a particle in a nebula will end up in the finished stellar system? Neat trick.

Eniac June 2, 2012 at 22:46

Ron:

You can say in advance where a particle in a nebula will end up in the finished stellar system? Neat trick.

A lightyear is 60,000 AU. cubed, that is like 2*10^14 or so. What is the chance a random particle will happen to end out in the inner system?

Ron S June 3, 2012 at 21:53

Eniac: “What is the chance a random particle will happen to end [up] in the inner system?”

Quite high I’d say. Where does most of the mass of a stellar system end up?

Eniac June 5, 2012 at 23:40

Ron:

Quite high I’d say. Where does most of the mass of a stellar system end up?

Inside the star, I suppose. So you are right, I was wrong. But then, the inside of the star is hardly fertile ground for our pebble. Nor will the billions of years it takes for fertile planets to form be helpful in preserving those spores.

Ron S June 6, 2012 at 11:20

Eniac, that’s quite right and is one of the reasons why I suspect that panspermia is less probable than abiogenesis — I actually made this same argument in the earlier thread I vaguely mentioned earlier. My only point in this was to say that the particle could make it into a hospitable system, not that it was likely to have any effect.

To at all have a chance of being successful, the organism-bearing particle likely would have to end up in the star’s Oort cloud, survive for more mega-years (as you point out), and then be perturbed so that it rains onto a fertile surface — the right place and the right time — while remaining viable. Improbable.

Rob Henry June 13, 2012 at 8:22

I have read this very late because I have been on holiday.

Panspermia is a group of many different theories. Even the objection common to them all that “it only displaces the problem of abiogenesis” is only true if the out of favour steady state theory is wrong.

To my knowledge, lithopanspermia originated with Lord Kelvin in the 19th century. Though you might expect heat transfers to be his forte, he claimed that, even though the energy required to launch a rock into space (here by another meteorite impact), was sufficient to rip apart every molecular bond in the ejecta, rocks could be launched this way with only comparable heating to a landslide. Amazingly, we have only rediscovered that he was correct by examining meteorites and sophisticated super-computer simulations. We now also know that endolithic life proliferates in rocks pore space, and uses the majority of the limited resources available to it to just repair its DNA. These two facts alone should be grounds for much further investigation.

Arrhenius’ radiopanspermia (from memory first proposed in detail in 1908!) is derived from such a concatenation of brilliant but obscure facts that it also deserves fuller thought. We now know that he was correct in that many processes on Earth aerosol microbes into the troposphere. There is now further detailed theory that furthers his speculation that microbes can be lifted through the stratosphere to the exosphere. And it was always brilliant of him to note that bacteria are the optimal size to be accelerated by the pressure of light. This allows them to leave a system at a few 100km/s. It is a pity he couldn’t know that uv intensity there is sufficient to kill the hardiest bacteria in seconds. Hoyle tried to save this theory be allowing the microbes to be partially carbonised. He also noted that a prominent DNA repair enzyme used light energy, rather than ATP – and that that greatly helps here. Hoyle eventually abandoned it for his own theory, but for those that persist we have the following problems.
1. Earth type planets are a few orders of magnitude short in rate of ejection of allowing one bacterial carcass being able to find another terrestrial planet within a billion years.
2. To be survivable most ejections must be from outer planets – at least from the equivalent of Neptune’s distance.
3. We also have the problem of the ratio of stellar gravity to light pressure, that makes most main sequence stars hotter than the sun only potential donors, and most smaller stars only potential recipients.
4. Bacterial sized grains do not take a direct route to the nearest stars, but, according to Sagan, collide with other grains sufficiently frequently to be better modelled on a Brownian motion model. No transfers thus take the few millennia that we might otherwise expect.

Hoyle’s theory, which I shall here term cometry panspermia, sprang gradually from radiopanspermia, but now differs considerably. Here almost all transferred life exists in comets where it grows on the high energy chemicals present (and possibly by T-Tauri stage light and Al-26 decay energy) in very new stellar systems. It then freezes and is released in vast clouds from comets. I would love to go into more detail but will do so only if requested. What I want to convey is this system must work on a vast scale or not at all. Unlike what some others in the comments section think, this makes the idea highly testable. Here almost all comets will contain huge quantities of easily detectable frozen bacteria or their spores – should we ever go to the trouble of looking.

Crick first formulated the theory of directed panspermia in a (self confessed) drunken stupor at a SETI conference. I think it likely that the science fiction forerunners to directed panspermia given here will only extend so far as any reasonable speculator in a pub might go. Cricks key foresight was that however far sentient beings might be able to travel, bacteria can go further. We could even imagine them sent in protected capsules over intergalactic distances.

ljk June 14, 2012 at 18:39

Could aliens have created life on Earth?

By Annalee Newitz

June 14, 2012 7:00 AM

We know a lot about the history of life on Earth, but how it began is still one of our greatest scientific mysteries. One hypothesis is that life actually originated on another planet, and many scientists today take the idea quite seriously.

Though it sounds like the plot from recent scifi movie Prometheus, it’s an old idea that even the celebrated nineteenth century physicist Lord Kelvin and Nobel winning geneticist Francis Crick have advocated. That’s right — the evolution of life might have its beginnings on another planet.

Over 120 years ago, Kelvin shocked the British scientific community in a speech about what he called “panspermia,” where he suggested that life might have come from planets smashing into each other and sending bits of life hurtling through space.

He and a few colleagues had hit upon this notion after observing the massive 1880 eruption of a volcano on Krakatoa. To be more precise, they observed the aftermath of the volcano, which completely sterilized the island. No life was left at all. But then, within months, seedlings began to sprout and life took hold again.

Where had that life come from? To naturalists of the nineteenth century, it was obvious that it had drifted there from nearby islands. Seeds and insects blown on the wind, or floating on the tides, had begun the process of re-greening the stricken landscape.

This got Kelvin thinking about the origin of life on Earth. Couldn’t the same thing happen to barren planets drifting in space? Perhaps life had drifted to Earth on the stellar winds.

Full article here:

http://io9.com/5918189/could-panspermia-have-created-life-on-earth

ljk September 5, 2012 at 12:14

Life from Mars could have ‘polluted’ Earth: Krauss

by Elizabeth Howell on September 4, 2012

Unless you’ve been living under a rock — Earth or Martian — in the past month, surely you have heard about the Curiosity rover’s landing and early adventures on Mars.

The prospects for what the rover could find has many in the space community very excited, even though Curiosity is supposed to look for habitable environments, not life itself.

However, a couple of weeks ago, noted theoretical physicist Lawrence Krauss said he wouldn’t be surprised if we do find evidence of life on Mars.

In an interview with CNN, Krauss said it’s possible Martian life could have “polluted” Earth early in our planet’s history, giving rise to life as we know it today.

The big surprise (in finding life) would be if it weren’t our cousins. Because what we’ve learned is that material goes back and forth between the planets all the time. We have discovered Martian meteorites in Antarctica, for example, and it goes the other way around, and microbes certainly (can) survive the the eight-month voyage in a rock.

Though Krauss did not specify which meteorites in Antarctica he was referring to, he is most likely talking about ALH84001, which was found in 1984.

The meteorite shot to international prominence in 1996 when scientists, led by NASA’s David McKay, published an article in the journal Science saying there was evidence the meteorite showed “primitive bacterial life” from Mars. In particular, they used a high-power electron microscope and found formations that they said are consistent with those caused by bacterial life.

The team’s proclamation met with scientific skepticism. The Lunar and Planetary Institute’s Allan Treiman said even if it did show evidence of life, the rocks could have been contaminated by Antarctic life or by handling of the meteorite after it was found.

John Bradley, an adjunct professor at the Georgia Institute of Technology, took his skepticism a step further: “Unfortunately, there are many signatures in the fossil record here on Earth, and probably on Mars, that look very similar to bacterial signatures. But they are not unique to bacterial processes,” he said in an undated NASA page (most likely from 2001, since it references a meeting from that time) that was reportedly based on a SPACE.com story.

Full article here:

http://www.universetoday.com/97188/life-from-mars-could-have-polluted-earth-krauss/

ljk September 25, 2012 at 8:59

24 September 2012

** Contact information appears below. **

Text, images, and video:

http://www.princeton.edu/main/news/archive/S34/82/42M30/

SLOW-MOVING ROCKS BETTER ODDS THAT LIFE CRASHED TO EARTH FROM SPACE

Microorganisms that crashed to Earth embedded in the fragments of distant planets might have been the sprouts of life on this one, according to new research from Princeton University, the University of Arizona and the Centro de Astrobiología (CAB) in Spain.

The researchers report in the journal Astrobiology that under certain conditions there is a high probability that life came to Earth — or spread from Earth to other planets — during the solar system’s infancy when Earth and its planetary neighbors orbiting other stars would have been close enough to each other to exchange lots of solid material. The work will be presented at the 2012 European Planetary Science Congress on Sept. 25.

The findings provide the strongest support yet for “lithopanspermia,” the idea that basic life forms are distributed throughout the universe via meteorite-like planetary fragments cast forth by disruptions such as volcanic eruptions and collisions with other matter. Eventually, another planetary system’s gravity traps these roaming rocks, which can result in a mingling that transfers any living cargo.

Previous research on this possible phenomenon suggests that the speed with which solid matter hurtles through the cosmos makes the chances of being snagged by another object highly unlikely. But the Princeton, Arizona and CAB researchers reconsidered lithopanspermia under a low-velocity process called weak transfer wherein solid materials meander out of the orbit of one large object and happen into the orbit of another. In this case, the researchers factored in velocities 50 times slower than previous estimates, or about 100 meters per second.

Using the star cluster in which our Sun was born as a model, the team conducted simulations showing that at these lower speeds the transfer of solid material from one star’s planetary system to another could have been far more likely than previously thought, explained first author Edward Belbruno, a mathematician and visiting research collaborator in Princeton’s Department of Astrophysical Sciences who developed the principles of weak transfer.

The researchers suggest that of all the boulders cast off from our solar system and its closest neighbor, five to 12 out of 10,000 could have been captured by the other. Earlier simulations had suggested chances as slim as one in a million.

“Our work says the opposite of most previous work,” Belbruno said. “It says that lithopanspermia might have been very likely, and it may be the first paper to demonstrate that. If this mechanism is true, it has implications for life in the universe as a whole. This could have happened anywhere.”

Co-authors Amaya Moro-Martín, an astronomer at CAB and a Princeton visiting research collaborator in astrophysical sciences, and Renu Malhotra, a professor of planetary sciences at Arizona, noted that low velocities offer very high probabilities for the exchange of solid material via weak transfer, and also found that the timing of such an exchange could be compatible with the actual development of the solar system, as well as with the earliest known emergence of life on Earth. Dmitry Savransky, a Princeton mechanical and aerospace engineering doctoral student, conducted the simulations.

The researchers report that the solar system and its nearest planetary-system neighbor could have swapped rocks at least 100 trillion times well before the Sun struck out from its native star cluster. Furthermore, existing rock evidence shows that basic life forms could indeed date from the Sun’s birth cluster days — and have been hardy enough to survive an interstellar journey and eventual impact.

“The conclusion from our work,” Moro-Martín said, “is that the weak transfer mechanism makes lithopanspermia a viable hypothesis because it would have allowed large quantities of solid material to be exchanged between planetary systems, and involves timescales that could potentially allow the survival of microorganisms embedded in large boulders.”

All About Velocities

The Princeton-Arizona-CAB paper cites two previous studies that present the odds of solid matter from one planetary system being captured by another as being more or less dismal.

The first, a 2003 paper [http://www.ncbi.nlm.nih.gov/pubmed/12804373] published in Astrobiology by Jay Melosh, a Purdue University Earth and atmospheric sciences professor, questioned the probability that meteorites have ever escaped a terrestrial planet in Earth’s solar system and wound up on a terrestrial planet in another system. The report concluded that the chances — about one in 10,000, or 0.01 percent — are “overwhelmingly unlikely” considering the speed a meteorite would need to travel (about six kilometers per second) and the roominess of space.

Belbruno and his co-authors calculated that under this scenario of high velocities and dispersed planetary systems, the probability of solid material from any planetary system striking another falls to as little as five in 100,000, or 0.005 percent.

Star birth clusters, which are tightly confined groups of stars and planetary systems, were introduced as a possible setting for lithopanspermia in a 2005 Astrobiology paper [http://arxiv.org/abs/astro-ph/0504648] by David Spergel, Princeton’s Charles A. Young Professor of Astronomy on the Class of 1897 Foundation and chair of astrophysical sciences, and University of Michigan physics professor Fred Adams.

Factoring in velocities of two to five kilometers per second, Spergel and Adams found that the chances of an exchange of life-bearing rocks between star systems clustered in groups of 30 to 1,000 could be as unlikely as one in a million to as good as one in 1,000, or 0.0001 to 0.1 percent, respectively. Spergel and Adams, however, limited their study to binary stars — or planetary systems with two stars — which might elevate star-to-star solid matter exchanges, Moro-Martín said.

Nonetheless, in clusters similar to those considered by Spergel and Adams, weak transfer involves relative velocities of no more than one kilometer per second, which substantially increases the probability of capture by other stars in the cluster. In other words, star clusters provide an ideal setting for weak transfer, Belbruno said.

Chaotic in nature, weak transfer happens when a slow moving object such as a meteorite wanders into the outer edge of the gravitational pull of a larger object with a low relative velocity, such as a star or massive Jupiter-like planet. The smaller object partially orbits the large object, but the larger object has only a loose grip on it. This means the smaller object can escape and be propelled into space, drifting until it is pulled in by another large object.

Belbruno first demonstrated weak transfer with the Japanese lunar probe Hiten in 1991. A mechanical malfunction left the probe with insufficient fuel to enter the Moon’s orbit the traditional way, which is to approach at a high speed then fire retrorockets to slow down. Instead, Belbruno designed a weak-transfer trajectory that got the probe into orbit around the Moon using a minimal amount of fuel.

Adams, co-author of the 2005 paper with Spergel, said that the work by Belbruno and his co-authors succeeds at pulling together the various factors of earlier lithopanspermia models and adding a substantial new element — chaos. Adams is familiar with the study but had no role in it.

“This paper takes the type of calculations that have been done before and makes an important generalization of previous work,” Adams said. “Their work on chaos in this context also carries the subject forward. They make a careful assessment of a process that is dynamically quite complicated and chaotic in nature.

“They are breaking new ground from the viewpoint of dynamical astrophysics,” Adams said. “Regarding the problem of lithopanspermia, this type of weak capture and weak escape is interesting because it allows for the ejection speeds to be small, and these slow speeds allow for higher probabilities of rock capture. To say it another way, chaos, in part, enhances the prospects for lithopanspermia.”

To the Simulator!

Star birth clusters satisfy two requirements for weak transfer, Moro-Martín said. First, the sending and receiving planetary systems must contain a massive planet that captures the passing solid matter in the weak-gravity boundary between itself and its parent star. Earth’s solar system qualifies, and several other stars in the Sun’s birth cluster would too.

Second, both planetary systems must have low relative velocities. In the Sun’s stellar cluster, between 1,000 and 10,000 stars were gravitationally bound to one another for hundreds of millions of years, each with a velocity of no more than a sluggish one kilometer per second, Moro-Martín said.

The team simulated 5 million trajectories between single-star planetary systems — in a cluster with 4,300 stars — under three conditions: the solid matter’s “source” and “target” stars were both the same mass as the Sun; the target star was only half the Sun’s mass; or the source star was half the Sun’s mass.

The odds of a star capturing solid matter from another planetary system under these three scenarios are 15 (0.15 percent), five (0.05 percent) and 12 (0.12 percent) in 10,000, respectively, the researchers report — probabilities that exceed those under the conditions proposed by Melosh by a factor of 1 billion.

To estimate the actual amount of solid matter that could have been exchanged between the Sun and its nearest star neighbor, the researchers used data and models pertaining to the movement and formation of asteroids, the Kuiper Belt — the solar system’s massive outer ring of asteroids — and the Oort Cloud, a hypothesized collection of comets, ice and other matter about one light-year from Earth’s sun widely believed to be a primary source of comets and meteorites.

The researchers used this data to conclude that during a period of 10 million to 90 million years, anywhere between 100 trillion to 30 quadrillion solid matter objects weighing more than 10 kilograms transferred between the Sun and its nearest cluster neighbor. Of these, some 200 billion rocks from early Earth could have been whisked away via weak transfer.

For lithopanspermia to happen, however, microorganisms first have to survive the long, radiation-soaked journey through space.

Moro-Martín and Malhotra consulted a 2009 paper [http://arxiv.org/abs/0809.0378] an international team published in the Astrophysical Journal that determined how long microorganisms could survive in space based on the size of the solid matter hosting them. That group’s computer simulations showed that survival times ranged from 12 million years for a boulder up to 3 centimeters (roughly one inch) in diameter, to 500 million years for a solid objects 2.67 meters (nearly nine feet) across.

The researchers estimated that under weak transfer, solid matter that had escaped one planet would need tens of millions of years to finally collide with another one. This falls within the lifespan of the Sun’s birth cluster, but means that lithopanspermia by weak transfer would have been limited to planetary fragments at least one meter, or about three feet, in size.

Matching the Theory with Life

As for the actual transfer of life, the researchers suggest that roughly 300 million lithopanspermia events could have occurred between our solar system and the closest planetary system.

But even if microorganisms survived the trip to Earth, the planet had to be ready to receive them. The researchers reference rock-dating evidence suggesting that the Earth contained water when the solar system was only 288 million years old and that very early life might have emerged before the solar system was 718 million years old.

The Sun’s birth cluster — assumed to be roughly the same age as the Earth’s solar system — slowly broke apart when the solar system was approximately 135 million to 535 million years old, Moro-Martín said. In addition, the Sun could have been ripe for weak transfer up to 700 million years after the solar system formed.

So, if life arose on Earth shortly after surface water was available, there were possibly about 400 million years when life could have journeyed from the Earth to another habitable world, and vice versa, the researchers report. If life had an early start in other planetary systems and developed before the Sun’s birth cluster dispersed, life on Earth may have originated beyond our solar system.

The paper stops short of calculating the likelihood of extrasolar life taking root on a terrestrial planet such as Earth, but the higher probability the researchers determined for solid-matter transfer makes that a more worthwhile pursuit, Moro-Martín said.

“Our study stops when the solid matter is trapped by the second planetary system, but for lithopanspermia to be completed it actually needs to land on a terrestrial planet where life could flourish,” Moro-Martín said. “The study of the probability of landing on a terrestrial planet is work that we now know is worth doing because large quantities of solid material originating from the first planetary system may be trapped by the second planetary system, waiting to land on a terrestrial planet.

“Our study does not prove lithopanspermia actually took place,” Moro-Martín said, “but it indicates that it is an open possibility.”

Contact:

Morgan Kelly
+1 (609) 258-5729
mgnkelly@princeton.edu

The paper, “Chaotic Exchange of Solid Material between Planetary Systems: Implications for Lithopanspermia” [http://online.liebertpub.com/doi/abs/10.1089/ast.2012.0825], was published Sept. 12 by Astrobiology, and was supported by grants from NASA, the National Science Foundation and the Ministry of Science and Innovation in Spain.

ljk January 3, 2013 at 18:04

January 3, 2013

2 p.m. EST / 11 a.m. PST

** Contacts are listed below. **

FIRST METEORITE LINKED TO MARTIAN CRUST

After extensive analyzes by a team of scientists led by Carl Agee at the University of New Mexico, researchers have identified a new class of Martian meteorite that likely originated from Mars’s crust.

It is also the only meteoritic sample dated to 2.1 billion years ago, the early era of the most recent geologic epoch on Mars, an epoch called the Amazonian.

The meteorite was found to contain an order of magnitude more water than any other Martian meteorite.

Researchers from the Carnegie Institution (Andrew Steele, Marilyn Fogel, Roxane Bowden, and Mihaela Glamoclija) studied carbon in the meteorite and have shown that organic carbon (macromolecular) similar to that seen in other Martian meteorites is also found in this meteorite. The research is published in the January 3, 2013, issue of Science Express.

The unique meteorite, dubbed Northwest Africa (NWA) 7034, has some similarities to, but is very different from, other Martian meteorites known as SNC (for three members of the group: Shergotty, Nakhla, and Chassigny). SNC meteorites currently number 110. And so far they are the only meteoritic samples from Mars that scientists have been able to study. However, their point of origin on the Red Planet is not known. In fact, recent data from lander and orbiter missions suggest that they are a mismatch for the Martian crust.

As co-author Andrew Steele, who led the carbon analysis at the Carnegie Institution’s Geophysical Laboratory explained: “The texture of the NWA meteorite is not like any of the SNC meteorites. It is made of cemented fragments of basalt, rock that forms from rapidly cooled lava, dominated with feldspar and pyroxene, most likely from volcanic activity. This composition is common for lunar samples, but not from other Martian meteorites. This unusual meteorite’s chemistry suggests it came from the Martian crust. It is first link thus far of any meteorite to the crust. Our carbon analysis also showed that the meteorite likely underwent secondary processing at the Martian surface, explaining the macromolecular organic carbon.”

Lead author Agee, of the Institute of Meteoritics at the University of New Mexico, remarked: “The basaltic rock in this meteorite is consistent with the crust or upper mantle of Mars based on findings from recent Martian rovers and orbiters. Our analysis of the oxygen isotopes shows that NWA 7034 is not like any other meteorites or planetary samples. The chemistry is consistent with a surface origin and an interaction with the Martian atmosphere. The abundance of water, some 6000 parts per million, suggests that the meteorite interacted with the Martian surface some 2.1 billion years ago.”

“Perhaps most exciting is that the high water content could mean there was an interaction of the rocks with surface water either from volcanic magma, or from fluids from impacting comets during that time,” said Steele. “It is the richest Martian meteorite geochemically, and further analyzes are bound to unleash more surprises.”

PIO Contact:

Tina McDowell
+1 202-939-1120
tmcdowell@ciw.edu

Science Contact:

Andrew Steele
+1 202-478-8974
asteele@carnegiescience.edu

For a copy of the Science paper contact scipak@aaas.org.

The research was supported by NASA’s Cosmochemistry Program, a NASA ASTEP and NAI grant to Steele, the New Mexico Space Grant Consortium, and NSF award ATM0960594.

The Carnegie Institution for Science (http://carnegiescience.edu) is a private, nonprofit organization headquartered in Washington, D.C., with six research departments throughout the U.S. Since its founding in 1902, the Carnegie Institution has been a pioneering force in basic scientific research. Carnegie scientists are leaders in plant biology, developmental biology, astronomy, materials science, global ecology, and Earth and planetary science.

ljk January 15, 2013 at 18:38

No, Diatoms Have Not Been Found in a Meteorite

By Phil Plait

Posted Tuesday, Jan. 15, 2013, at 2:46 PM ET

If there’s a story practically guaranteed to go viral, it’s about evidence of life in space. And if you have pictures, why, that’s going to spread like, well, like a virus.

If only it were this easy…

So the moment I heard that a paper had been published saying that diatoms—a type of algae, microscopic plant life, that have hard outer shells made of silica and come in a variety of shapes and forms—had been found in a meteorite, I knew I’d get flooded with emails and tweets and Facebook messages because LIFE IN SPACE!

And so I did. People are really curious about this!

But then I read the actual paper, and guess what? Let me be delicate: It’s wrong. Really, really wrong. Way, way, way ridiculously oh-holy-wow-how-could-anyone-publish-this wrong.

[deep breath]

OK, let’s dive in, shall we?

Full article with link to paper here:

http://www.slate.com/blogs/bad_astronomy/2013/01/15/life_in_a_meteorite_claims_by_n_c_wickramasinghe_of_diatoms_in_a_meteorite.html

This is what happens when science is not truly peer reviewed and the usual safeguards against being wrong and fraud are bypassed.

ljk May 13, 2013 at 9:04

Moon, Earth Have Common Water Source

Water inside the moon’s mantle came from primitive meteorites, new
research finds, the same source thought to have supplied most of the
water on Earth. The findings raise new questions about the process that
formed the moon.

http://spacewatchtower.blogspot.com/2013/05/moon-earth-have-common-water-source.html

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