[meteorite-list] Astrobiologists Claim To Have Found Ancient Fossils in Fireball Fragments From Sri Lankan Fall

From: Ron Baalke <baalke_at_meteoritecentral.com>
Date: Mon, 11 Mar 2013 12:20:19 -0700 (PDT)
Message-ID: <201303111920.r2BJKJhT004706_at_zagami.jpl.nasa.gov>

http://www.technologyreview.com/view/512381/astrobiologists-find-ancient-fossils-in-fireball-fragments/

Astrobiologists Find Ancient Fossils in Fireball Fragments
MIT Technology Review
March 11, 2013

Algae-like structures inside a Sri Lankan meteorite are clear evidence
of panspermia, the idea that life exists throughout the universe, say
astrobiologists.

On 29 December 2012, a fireball lit up the early evening skies over
the Sri Lankan province of Polonnaruwa. Hot, sparkling fragments of the
fireball rained down across the countryside and witnesses reported the
strong odour of tar or asphalt.

Over the next few days, the local police gathered numerous examples of
these stones and sent them to the Sri Lankan Medical Research Institute
of the Ministry of Health in Colombo. After noticing curious features
inside these stones, officials forwarded the samples to a team of
astrobiologists at Cardiff University in the UK for further analysis.

The results of these tests, which the Cardiff team reveal today, are
extraordinary. They say the stones contain fossilised biological
structures fused into the rock matrix and that their tests clearly rule
out the possibility of terrestrial contamination.

In total, Jamie Wallis at Cardiff University and a few buddies received
628 stone fragments collected from rice fields in the region. However,
they were able to clearly identify only three as possible meteorites.

The general properties of these three stones immediately mark them out
as unusual. One stone, for example, had a density of less than 1 gram
per cubic centimetre, less than all known carbonaceous meteorites. It
had a partially fused crust, good evidence of atmospheric heating, a
carbon content of up to 4 per cent and contained an abundance of organic
compounds with a high molecular weight, which is not unknown in
meteorites. On this evidence, Wallis and co think the fireball was
probably a small comet.

The most startling claims, however, are based on electron microscope
images of structures within the stones (see above). Wallis and co. say
that one image shows a complex, thick-walled, carbon-rich microfossil
about 100 micrometres across that bares similarities with a group of
largely extinct marine dinoflagellate algae.

They say another image shows well-preserved flagella that are 2
micrometres in diameter and 100 micrometres long. By terrestrial
standards, that's extremely long and thin, which Wallis and co.
interpret as evidence of formation in a low-gravity, low-pressure
environment.

Wallis and co. also measured the abundance of various elements in the
samples to determine their origin. They say that low levels of nitrogen
in particular rule out the possibility of contamination by modern
organisms which would have a much higher nitrogen content. The fact that
these samples are also buried within the rock matrix is further
evidence, they say.

Wallis and co. are convinced that the lines of evidence they have
gathered are powerful and persuasive. "This provides clear and
convincing evidence that these obviously ancient remains of
extinct marine algae found embedded in the Polonnaruwa meteorite are
indigenous to the stones and not the result of post-arrival microbial
contaminants," they conclude.

There's no question that a claim of this kind is likely to generate
controversy. Critics have already pointed out that the stones could have
been formed by lightning strikes on Earth although Wallis and co.
counter by saying there was no evidence of lightning at the time of the
fireball and that in any case, the stones do not bear the usual
characteristics of this kind of strike. What's more, the temperatures
generated by lightning would have destroyed any biological content.

Nevertheless, extraordinary claims require extraordinary evidence and
Wallis and co. will need to make their samples and evidence available to
the scientific community for further study before the claims will be
taken seriously.

If the paper is taken at face value, one obvious question that arises is
where these samples came from. Wallis and c.o have their own ideas: "The
presence of fossilized biological structures provides compelling
evidence in support of the theory of cometary panspermia first proposed
over thirty years ago," they say.

This is an idea put forward by Fred Hoyle and Chandra Wickramasinghe,
the latter being a member of the team who has carried out this analysis.

There are other explanations, of course. One is that the fireball was of
terrestrial origin, a remnant of one of the many asteroid impacts in
Earth's history that that have ejected billions of tonnes of rock and
water into space, presumably with biological material inside. Another is
that the structures are not biological and have a different explanation.

Either way, considerably more work will have to be done before the
claims from this team can be broadly accepted. Exciting times ahead!

Ref: arxiv.org/abs/1303.1845 <http://arxiv.org/abs/1303.1845>: The
Polonnaruwa Meteorite: Oxygen isotope, Crystalline and Biological
Composition
Received on Mon 11 Mar 2013 03:20:19 PM PDT