

Fossil Diatoms in a New Carbonaceous Meteorite - brd
http://www.buckingham.ac.uk/wp-content/uploads/2011/09/Polonnaruwa-meteorite.pdf

======
scrumper
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.

~~~
zardoz90
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>

~~~
jamespitts
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.

~~~
scrumper
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.

------
jmillikin
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?

~~~
zinssmeister
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?

~~~
daeken
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.

------
zokier
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.

------
ChuckMcM
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.

~~~
lotharbot
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-...](http://www.museumofflight.org/education/challenger-learning-
center) .)

------
ComputerGuru
This is a working mirror with images:

[http://www.buckingham.ac.uk.nyud.net/wp-
content/uploads/2011...](http://www.buckingham.ac.uk.nyud.net/wp-
content/uploads/2011/09/Polonnaruwa-meteorite.pdf)

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

------
rflrob
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.

~~~
marze
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.

~~~
madaxe
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.

~~~
marze
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.

~~~
madaxe
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...](http://courses.washington.edu/bangblue/Mojzsis-3.85Ga_Akilia_d13C-Sci96.pdf),
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_.

~~~
marze
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.

~~~
madaxe
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.

~~~
marze
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."

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

[http://webcache.googleusercontent.com/search?q=cache:http://...](http://webcache.googleusercontent.com/search?q=cache:http://www.buckingham.ac.uk/wp-
content/uploads/2011/09/Polonnaruwa-meteorite.pdf)

------
marze
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.

