Fossil Diatoms in a New Carbonaceous Meteorite | Hacker News Reader

Fossil Diatoms in a New Carbonaceous Meteorite

buckingham.ac.uk

45 pointsbrd26 comments

The Journal of Cosmology has rather a bad reputation. The fact that the meteorite only landed on earth three weeks before publication doesn't suggest that much review has gone on either.

Don't get me wrong: I'd love for this to be actual, irrefutable evidence of extraterrestrial life and panspermia. It could even be that, but it's published in a crank paper unfortunately.

If we look at one of the authors, Chandra Wickramasinghe, it's clear he has an obvious bias towards this sort of thing: http://en.wikipedia.org/wiki/Chandra_Wickramasinghe

> We report the discovery for the first time of diatom frustules in a carbonaceous meteorite thatfell in the North Central Province of Sri Lanka on 29 December 2012

Yeah, my bad, I was looking at the url.

Perhaps a better word is specialization.

Most of us are armchair astrophysicists at best and we should not be so spontaneously dismissive. If there is something in all of this, we'll hear about it soon enough from the scientific community. In the meantime we should be conservative in how we depict the scientists and publications involved.

That is well said. One might equally accuse Leonard Susskind of a bias towards string theory. Chandra Wickramasinghe isn't himself a crank, and that's what gives me hopes for this research.

"At the time of entry into the Earth’s atmosphere on 29 December 2012, the parent body of the Polonnaruwa meteorite would have had most of its interior porous volume filled with water, volatile organics and possibly viable living cells"

Begs the question...

"A few percent carbon as revealed by EDX analysis confirms the status of a carbonaceous meteorite."

Does something that sounds about as scientific as "point and guess"...

"The intricacy of the regular patterns of “holes”, ridges and indentations are again unquestionably biological, and this is impossible to interpret rationally as arising from an inorganic crystallisation process."

Argument from personal incredulity...

...etc...

I won't be celebrating this discovery just yet...

Looking at the wikipedia page [1] for this journal, not only do they have a bad reputation, but they have a bad reputation for publishing papers about precisely this topic. The general consensus seems to be that the papers' evidence have been too weak and not thorough enough for the claims they make.

[1] http://en.wikipedia.org/wiki/Journal_of_Cosmology#Hoover_pap...

The article mentions that similar fossilized diatoms are found in terrestrial rock dating back to the time of the dinosaur's extinction (believed to be from a large impact). Is it possible that these meteorites are ejecta from that impact, or even an earlier one?

interesting. I guess we can't really exclude the possibility, that this fossilized diatom cam from earth, traveled through space and came back to earth?

It's also possible that live diatoms were ejected and subsequently fossilized. Or even possibly that they continued to live and reproduce in space (diatoms are ~algae, so they really only need water and sunlight).

Definitely can't exclude that, and it's a testable hypothesis. We can compare rock compositions and determine with a fair degree of accuracy if it's a match for a terrestrial source.

There seems to be some attacks against the authors and the publication. And seems like that is somewhat justified. But what about the interesting images? Assuming that they are authentic (and I believe that is a fair assumption even in the case that the authors are crackpots), they imho warrant closer look, even if you'd skip all the fluff that is the speculation from the authors.

That's a fun paper. One could argue (I'm not though) that only a crank journal would accept it for publication, but a better argument might be it doesn't really spend enough time to disprove itself. Such things are always more credible when the author takes time to try to disprove their own results by taking a different path through the data or use a different hypothesis.

That said, the only way to irrefutably make this claim is going to be to sample comet fragments actually in space. If this particular comment (Encke) is the source then it should be possible to mount a mission to intercept this particular comments tail, and then return to earth orbit. Once there a recovery mission to get the material to the ISS and careful observation might quiet a number of skeptics.

I'm really surprised they haven't done such a mission on Encke yet. It's a fairly obvious target for various explorations because its period is so short (3.3 years).

(When I taught in an aerospace museum, one of our simulated space missions was launching a probe into Encke's tail: http://www.museumofflight.org/education/challenger-learning-... .)

This is a working mirror with images:

http://www.buckingham.ac.uk.nyud.net/wp-content/uploads/2011...

May be a bit slow, but it's complete and functional.

The Red Rain cell claims (even with a question mark to indicate tentativeness) seem particularly bold. It's not difficult to imagine circular structures forming abiotically, and given that there are much likelier explanations for the red rain, I remain unconvinced.

If diatoms did arrive in meteorites and are the ancestors of Earthly diatoms, you would think they would have shown up in the fossil record earlier.

Not really. Diatoms are tiny, and under the pressure of successive layers of sedimentation, silica (of which diatoms are largely comprised) will recrystallise at that scale, making detection of fossils difficult, if not impossible.

I believe there are Precambrian diatom candidates, but unlike bacteria, which form colonies and therefore can still be found from ~3.5Ga (stromatolites and friends), diatoms are free-floating, and therefore easily lost in sediment.

I see. What about candidates for a high silica rock that might have been metamorphized diatom deposits?

If this theory was correct and diatoms were the original life form, it would suggest they might be more primitive, genetically, assuming little subsequent evolution.

Indeed - I'd opine that the meteor in question was probably terrestrial in origin, as diatom genetics demonstrate that evolution is live and kicking in diatom populations. That said, it doesn't exclude the possibility of diatoms having perhaps taken a lengthy space trip at some point in their evolutionary history. It would certainly go some way to explaining why a marine species would have developed to be radiation and vacuum resistant.

As to siliceous rocks - possibly, although I don't believe there's been anything found to suggest diatoms in great antiquity as yet. Funnily enough the most prevalent siliceous rock is... diatomite. Your toothpaste is made out of it. Chert (flint, etc.) is probably a better candidate substrate, but again, diatoms of that age would be indistinguishable from the substrate itself. Molecular clocks could indicate a biogenic origin, but as yet there's no way to demonstrate what variety of biogenic origin.

There's evidence in terms of carbonaceous inclusions in ancient rocks that suggests the existence of life on earth before previously assumed - http://courses.washington.edu/bangblue/Mojzsis-3.85Ga_Akilia..., but nothing to suggest it was diatomic in nature.

Anyway. If their evidence isn't falsified, even if this isn't extrasolar panspermia, it's a demonstration that panspermia is possible.

You're guessing the rock in question did fall from the sky, but that it was blasted of the Earth previously? Aren't there features of chontritic meteorites that would make it fairly easy to distinguish from an regular rock?

Given the incomplete theories on how cellular life got a start, I don't see why people think evolving on Earth is any more likely than arriving from somewhere else. More time and more planets.

Well, they appear to have decided it's a carbonaceous chondrite through visual examination alone - you can only really be sure by whacking it through a mass spectrometer and seeing what isotopes you've got.

Either way, I think panspermia is perfectly possible, but the jury's out until this is independently verified.

Well, if the science community ever decides Wickramasinghe is right I'll laugh.

It was interesting to read about diatoms:

about 25% of all photosynthesis, more than all the rainforests

location on "tree of life" is unclear:

"Despite a number of studies to examine phylogeny, using one or several genes, the relationships of diatoms to other groups are still unclear and there is still a huge gap in our understanding of how and when diatoms acquired their unusual morphology and life-cycle characteristics. The diatoms have often been treated as a separate phylum, reflecting their unique features. Pascher (1914, 1921) suggested that the diatoms have features in common with the Chrysophyceae and Xanthophyceae and therefore placed these classes and the Bacillariophyceae in the phylum Chrysophyta. Ultrastructural and molecular sequence data have confirmed the general thrust of Pascher’s idea, placing the diatoms unambiguously among the heterokont protists (‘stramenopiles’) within the chromalveolates (Adl et al. 2005)."

and Wickramasinghe has hypothesized interstellar dust might be diatoms(!):

"there exists a close correspondence between the measured infrared properties of diatoms and the infrared spectrum of interstellar dust as observed in the Trapezium nebula and toward the galactic center source GC-IRS 7. Diatoms and bacteria also exhibit an absorbance peak near 2200 Å, which is found to agree with the observed ultraviolet absorbance properties of interstellar grains."

It's down for me, I think this is a cached copy:

http://webcache.googleusercontent.com/search?q=cache:http://...

Wow, that looks stronger than expected from the low-key presentation. I hope they can interest some other labs to attempt to double check their samples.

"The universe, not humans, must have the final say to declare what the world is really like" indeed.

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