Astroblog

This recent report records the recovery of a substantial meteorite (700 g) from inside the roof of a warehouse, where the meteorite had punched a hole. This is probably the clearest authentic pice of meteorite from a July 14 fireball over Norway. This fireball is unrelated to a June 9 fireball also from Norway. The reports were a bit overhyped, and very dubious claims of meteorite impacts were made.

Fossils of life or inorganic fibers? Image of alleged "microfossils" from "Fossils of Cyanobacteria in CI1 Carbonaceous Meteorites: Implications to Life on Comets, Europa, and Enceladus Richard B. Hoover Journal of Cosmology, 2011, Vol 13, xxx.

A recent paper published in the Journal of Cosmology has claimed to have discovered evidence of fossil bacteria in a rare subclass of carbonaceous meteorite. The implications of this paper, should it be correct, are enormous and the blogosphere has gone into overdrive discussing it. There are interesting analyses by the Bad Astronomer, PZ Myers and Rosie Redfield.

Rosie Redmond's analysis is more detailed (and Rosie being the microbiologist who burst the "Arsenic Bacteria" bubble, knows she her stuff), but all posts quickly get to the heart of the matter; the "evidence" is a bunch of squiggly stuff that bears little resemblance to actual bacterial fossils unless you obscure the details by rescaling the images.

Magnesium Sulfate nanobelts from J. Phys. Chem. B, 2006, 110 (27), pp 13387–13392

That's my conclusion too. While I'm not a professional astrobiologist (nor do I play one on TV), it is a hobby of mine and I've spent a fair amount of time looking at genuine images of cyanobacterial fossils (it's all part of my project). And once upon a time I worked (very briefly) as a microbiologist. I've also been exposed to far too much X-ray spectroscopy, due to a collaboration with the Chemistry Department in my waking hours.

I won't cover the ground already covered by Dr. Redmond and the others, but to briefly recap, trying to establish that rods and spheres seen in rock represent actual bacterial fossils is incredibly difficult. These things look like a wide variety of filamentous non-fossil inorganic material (here's one example) such as you can find in a variety of rocks. From cyanobacterila fossils in ancient earth rocks, to the Alan Hills Martian meteorite, establishing that a suite of features is distinctively biogenic is a nightmare. There have been several reports of supposed bacteria in meteors before with contamination being the culprit (and Dr. Hoover has reported fossil bacteria before as well, to little effect).

One major bugbear is contamination of samples. Bacteria are everywhere on earth, and can get into the most difficult places, so decades old meteorites can be presumed to be contaminated. Dr. Hoover used X-Ray spectroscopy to do elemental analysis on the presumed fossil structures, so as to eliminate the possibility they were modern contaminants. Despite the strange choices of controls (Skin flakes from mummies?), I think he shows fairly convincingly that these structures are not modern contaminants.

What he doesn't show anywhere near convincingly at all is that they are fossil biological structures. The elemental signature is quite interesting, with high levels of magnesium and sulfur. Almost like, well, magnesium sulfate. It ought to, as the idea put forward in the paper is that the magnesium sulfate in the meteorite 's parent body has infiltrated and replaced the organic material of the original bacteria.

But, and this is a big but, magnesium sulfate can produce ribbon-like structures that look very like the supposed "fossils" (see image above, and compare with the supposed fossil image, as well as supposed "fossils" from Figure 2 and Figure 3). So, how do we decide between ribbon-like magnesium sulfate structures that have replaced bacterial structures and ribbon-like magnesium sulfate structures that form abiotically?

There's a bit of carbon in it, but contamination of magnesium sulfate with magnesium carbonate (which is quite common) would produce this spectrum (see the spectra in the J Phys Chem paper). Also, the whole meteor is full of organic kerogens, which can be produced abiotically (eg the Urey-Miller reaction, or the UV-mediated reactions that make kerogen in the atmosphere of Titan). So merely having a little bit of carbon is no evidence of a biotic origin.

The paper makes much of differences in sulfur abundances between the filaments and the bulk meteorite. However, the elemental profiles and concentrations are virtually identical between the "fossils" and the matrix, and the variation is almost certainly no more than instrumental error (the X-ray spectroscopy person was not impressed and is on the inorganic, magnesium sulfate/carbonate whisker side)*.

So, the evidence that these filaments are fossil microorganisms is
a) They are not modern bacteria (good evidence and a good first step) and that
b) They are inorganic (this does not establish that they are fossil organisms at all).

Summing up, what has been reported is a bunch of filaments that look like a variety of mineral filaments (especially figures 2 and 3), and don't look much like actual cyanobacterial fossils at all. To support the existence of extraplanetary life, you are going to need more than what looks like SEM and X-ray images of magnesium sulfate whiskers.

UPDATE: Smoking gun, observations of magnesium sulfate bacteria-like structures forming in the meteors due to post-landing changes in water content.
http://onlinelibrary.wiley.com/doi/10.1111/j.1945-5100.2001.tb01827.x/pdf
Thanks to commenter Anb at Bad Astronomy for finding the paper

*It would help if they had decent tables, and scaled the X-ray profiles to the same scale, instead of being all over the place. The wildly varying scales of the filament images has also been mentioned, making comparison difficult. And they never actually show elemental analysis of fossil cyanobacteria beyond the amount of nitrogen, you would think this kind of data critical. The control data on the magnesium sulfate is never presented either. The whole paper is a dogs breakfast.
**The publicity claims the Journal of Cosmology will publish all the commentaries they have received, but as of writing none have appeared.

UPDATE: Commentaries have now been mounted.

Labels: comets, Meteors, review, science

This mornings Australian had an article on more evidence of life existing on MArs, at least in the past. Re-examination of the Martian meteorite ALH84001 by the McKay goup suggests that the magnetite grains found in the meteorite really are of biogenic origin. The abstract of the paper is here, and it is discussed over at Spaceflight Now and Universe Today.

Personally, I think the evidence that the magnetite is from organisms is now very strong, but we still have a way to go to be fully convinced.

Labels: Mars, origin of life

Or is it a meteorite? News reports and meteor discussion groups have been buzzing with stories of what appears to be either a meteorite strike or a pice of space junk impacting around 6:30 pm last night. A bright fireball shot across the sky and there is an eyewitness account of an impact. You can read the ABC account here, nine msn has the account of the impact. Other reports are here and here.

Over at Science in Pen and Ink Lelia Battison has an in-depth discussion of Richard Hoovers' paper on alleged "fossil" bacteria in CI1 Carbonaceous Meteorites in the Journal of Cosmology. It is an excellent article that covers a lot of issues not previously covered, and brings together some other information that has been scattered around. I'm referenced as well. Go have a read of Microbes on a Moonbeam, disentangling the Meteorite Microbe claims.

(for reference my posts on the subject are here and here)

Labels: Meteors, origin of life, review, science

Some weeks back I was interviewed for a TodayTonight program on homoeopathy. It was screened on April 4th, and the segment is now available on the web. You can use this link, or play the embedded video. I appear in a few segments, as do such illustrious people as Dr Simon Singh, Richard Saunders and James Rand. I think it worked very well, and I didn't make a complete fool of myself. The homoeopathic overdose section was fun to do. I have a post on more resources for you to understand homoeopathy if you wish. And today Dr. Rachie posed on the “National Health and Medical Research Council (NHMRC) of Australia declaring: homeopathy ‘not efficacious’” (go NH&MRC!!!)

Lost opportunities; I knew the homoeopath was going to mention quantum mechanics, but I didn't do a section on that, when I said "lets wait a bit" in response to the homoeopathic sleeping tablet overdose, I should have said, "if this was real medicine, we would be in hospital having our stomachs pumped now".

Oh yeah, and to all the sceptics who signed up to my twitter account, this blog is mostly "look up it is pretty" astronomy, although I am on a bit of a roll with my comet Elenin and Nibiru posts, the "life in a meteorite" flap, the odd global warming post too and of course Intelligent Design creationism.

Labels: Pseudoscience, science communicators

Carnival of Space #260 is now up at Supernova Condensate. There's memorials to Sally Ride, black holes, harvesting cosmic rays, the Murchison meteorite, playing with fridge magnets for science and much much more. Zip on over and get stuck in.

Labels: carnival of space

By now most of you will have seen the breathless reports that claim alien life has been found in cometary debris collected by a high altitude balloon during the Perseid meteor shower. The facts however are far more mundane.

A fragment of diatom caught in the upper atmosphere by the sampling ballooon. Image Credit University of Sheffield.

You can see the actual research the news paper reports are based on  here. The summary in the conclusion of the paper is a bit less triumphal than the news reports

"To conclude we note that the results presented here provide unequivocal evidence that a diatom fragment has been found in the lower stratosphere."

Yes. That's the whole paper basically. "We found a diatom fragment, it's unlikely that diatom fragments can last that long in the high atmosphere, therefore it came from outer space"

Despite all the images of weird looking blobs in the newspapers they have one, count it, one, fragment of a diatom (a kind of algae with hard shells, they found a bit of the shell). No alien DNA, no other evidence except this one fragment (most of the pictures in the press reports aren't even of the actual diatom fragment, but random dust particles). The authors even admit it looks like a terrestrial diatom fragment.

The authors entire argument rests on it being unlikely that chunks of diatom can last in the stratosphere for a long time.

Cometary dust, almost certain to not contain diatoms.

Except it is not that unlikely. We know that diatoms are ubiquitous in atmospheric dusts, indeed the worlds largest source of atmospheric dust is diatomaceous earth, let alone marine and other surface water droplets. Contamination of forensic and other materials with extraneous diatoms is a perennial problem. So extreme caution is need when interpreting these sorts of results.

Diatomaceous dusts can travel long distances, from the Sahara to Great Britain, and diatom containing droplets can travel far and be wafted high up.

So high that Diatoms are thought to play important roles in forming nucleation centres for rain clouds. While the authors claim there is no known mechanism for getting big dust particles that high, the very ubiquity of diatomaceous dusts, their presence at high altitude in cloud formation, and the ability of cloud air currents to loft material high into the sky make it plausible that diatom fragments could be lofted high but turbulent air currents.

Another mechanism for getting diatoms high in the air is volcanic eruptions.  Despite authors claim that there were no volcanic eruptions before the balloon flight, the volcano Bata Tara in Indonesia has been exploding continuously since March, producing huge ash plumes).

Another issue relating to the contamination question is appropriate controls. While the authors had a good control for the ground based contamination of the sample cabinet, they did not do a control flight when there was no meteor shower, so we do not know if they would have picked up any diatom fragements in the absence of meteor dust.

Also, there is the question of WHY an algae that has evolved to live in marine or fresh water environments is on a comet in the first place, a frozen ball that spends most of its time far from the light of the sun is hardly the best place for things that photosynthesise in liquid water. Algae live in some very extreme environments, but spending your life frozen in a vacuum in the dark just doesn't make any sense algae wise.

The authors claims that comets have a "watery environment" is cause for head shaking, Comets are mixtures of ices (water, carbon dioxide, Carbon monoxide amongst others) which is normally frozen at the temperature below that of dry ice (frozen CO₂), when the ices heat up during the comets fleeting visit to the Sun they don't go liquid, but sublimate. Hardly the best environment for a marine or river organism.

The Journal of Cosmology has form for publishing articles on life from outer space with very weak evidence. You can see my discussion of a previous paper from a different group claiming bacterial fossils in a meteorite here http://pandasthumb.org/archives/2011/03/life-from-beyon.html

Comets may have bought the building blocks of life to a primitive Earth billions of years ago, but  modern diatoms living on current comets? No.

You can see the Bad Astronomers sceptical take here, and the Conversation commentary here. 

Labels: comet, origin of life, scepticism

Carnival of Space #289 is now up at Everyday Spacer. There's a few posts on the Russian Meteorite, the first sample of martian bedrock, a few posts on commercial space companies, an invitation to name the Moons of Pluto and much more, head on over for a read.

Labels: carnival of space

The Journal of Cosmology has now posted 21 commentaries on the "Fossils of Cyanobacteria in CI1 Carbonaceous Meteorites" paper by Richard Hoover that I have critiqued in my "Life from Beyond Earth on a Meteorite, or Pareidolia?" post.

The majority are uncritical (some don't even seem to have read the actual paper), and zoom off on tangents assuming the Hoover's paper is valid. Two posts are critical (commentary 5 and commentary 9), and bring up the same issue I do (but with more references), that abiotic minerals can imitate the shapes of bacteria, and that without further tests, there is no way to say these filaments are fossils of any sort.

As for the majority, well, largely I think they are sad. The near complete absence of any critical engagement with the paper is very telling, and there is much leaping to unsupported conclusions. I would dearly love for extra-terrestrial life to be found, but I'm not going to grasp at epsonite straws to pretend it's been found. Hoover's flawed paper is not evidence of extra-terrestrial life.

Oh, and the journal has added a long rant to before the main article:

Have the Terrorist(sic) Won? Only a few crackpots and charlatans have denounced the Hoover study. NASA's chief scientist was charged with unprofessional conduct for lying publicly about the Journal of Cosmology and the Hoover paper. The same crackpots, self-promoters, liars, and failures, are quoted repeatedly in the media. However, where is the evidence the Hoover study is not accurate?

Few legitimate scientists have come forward to contest Hoover's findings. Why is that? Because the evidence is solid.

But why have so few scientist come forward to attest to the validity? The answer is: They are afraid. They are terrified. And for good reason.

Apparently I am a crackpot and charlatan (sighs expressively), at least I'm in good company with Phil Plait, PZ Myers and Rosie Redfield (and really, read commentary #9 carefully).

Labels: comets, Meteors, review, science

There have been reports coming from Norway of a large meteor which possibly impcated the Earth. Several witnesses saw (and recorded) a bright bollide steaking through the daytime sky. Initial reports of a loud report and sismic disturbances suggetsed that something impacted the Earth. There was a bit of hype with one claim as much energy as the expolsion at Hirshima was released. A later report showed what is claimed to be the impact site (as well as reassuring us the meteor wasn't radioactive :-). But is it? Meteor impacts are notoriously difficult to pin down. There has been a lot of discussion of this on the meterobs list, and opinons range from a true impact site of a 12 kg rocky meteorite to it being just a landslide. The landslide option is, sdaly, looking more likely at the moment, and the impact site may be in a far differnt location as well.

Water vapor concentration on Mars. Image credit ESA.

The possibility of life on Mars has always fascinated us. There was Percival Lowell who interpreted Giovanni Schiaparelli's canalli to be water filled canals serving the Martian populace. The shifting dust patterns on Mars were interpreted as being due to seasonal changes in vegetation.

Then Mariner 4 flew past returning images of a battered frozen land. Barsoom was out.

But we still wondered about life on Mars. The Viking Landers had complicated instruments to look for life on Mars, and returned ambiguous results that are still being argued over.

Then came the Martian meteorite ALH84001, there were traces of organic chemicals, life-like isotope ratios and what looked intriguingly like microfossils. After lots of debate most researchers think that ALH shoes no clear signs of Martian life, but there is still ongoing debate.

Finally there was the excess of atmospheric methane. We have come a long way from Barsoom, but excess methane is an important clue. Methane is broken down very rapidly, and if there is substantial methane in Mars's atmosphere, it must be being produced. Methane can be produced in one of two ways 1) volcanism or 2) Living things (on Earth, burping cows are a major source of atmospheric methane). Not only does Mars have more methane than expected, but the methane is higher in certain regions, regions which correlate with water in the ground and above surface water vapor. This suggests that the methane is not from volcanic activity. There was also the suggestion that there was a lot of formaldehyde in Mar's' atmosphere, since formaldehyde was generated from methane, that implied that there was a lot more methane than could be accounted for by volcanism. However, the interpretation of the infrared spectrum is still open to doubt.

New data from the NASA infrared telescope facility also suggests that volcanism may not account for Mars's methane. They found no evidence of sulfur dioxide in the atmosphere, suggesting very low rates of volcanic outgassing which could not account for the levels of methane. Now, it is too early to declare Mars a wildlife reserve yet, and there are a number of possible non-volcanic geological systems which might produce methane, but at the very least it indicates that we should keep up the search for life on Mars. Bacterial flatulence may not be as exciting as Banth tracks, but it might just be the clue that will lead us to the first extraterrestrial life.

A newspaper in Canda has reported a meteor hitting a tractor.

An afternoon picking strawberries took a bizarre twist for Adeline Kelly
on July 17 when a chunk of rock plummeted from the sky, penetrating the
tin roof of a shed and piercing the manifold of a tractor on her and her
husband's Montney ranch, just north of Fort St. John.

Well, that's one way to get out of working. Many alleged meteor strikes turn out to be something else entirely, but preliminary investigation suggests this is the real deal.