"In the absence of a mechanism by which large particles like these can be transported to the stratosphere, we can only conclude that the biological entities originated from space" so, just because we don't KNOW of any mechanism by which large particles could be transported to the stratosphere, we conclude that the particles originated from space - even if we obviously don't KNOW of any mechanism by which life could originate from space and fall on Earth? This looks like very very weak reasoning.
Possible, yes. Very likely... from your handle, you should know about Bayesan reasoning. Considering that we know for sure that there is life on Earth (p=1), while having free-floating life in outer space is a very remote hypothesis (0<p<<1), what of the following three are more likely using Bayesian inference?
a) the sample was contaminated, or there was some other error in the experiement
Setting p=1 is sort of frowned upon in the bayesian methodology. Bayesian inference has nothing to do with this discussion, because the results can only be explained by speculation, and have not been externally verified etc.
Constructing priors from the knowledge of what has not been seen before seems to me like an abuse of the methodology. You might as well say "It's impossible because it's impossible."
I do tend towards a terrestrial origin, but it's certainly a good thing to investigate further how these organisms got there, what are they doing and what sequences do they have...
Actually, to me, this seems like a perfect situation to apply Bayesian inference: we need to update the probability estimate of a hypothesis (there is life in outer space) based on new evidence (they found those particles through their experiment).
Anyway, I completely agree with your last sentence: It's certainly a good thing to investigate, I'm not saying they're charlatans. It's the "very likely" that I didn't agree with :)
The journal of Cosmology is regarded as a low-quality publication by many scientists. I can't judge the assertions in the paper but the methodology seems good.
What flags this for me is that if you have an organism in hand, it's easy to do more analysis to provide evidence that it is not terrestrial. At the moment, I'd still say that the hypotheses of "their probes was contaminated", "our model of what particles are in the stratosphere are wrong and this is fully terrestrial life", and "they're flat-out lying" remain higher odds based on this evidence than "they found extraterrestrial life". In our own atmosphere.
They even mention a test they could run, but they did not wait to run the test before announcing. Not a good sign. Especially since that is not a lengthy test to run, compared to the speed of publication....
I of course reserve the right to change my mind based on more evidence; I have no problem with the idea that our stratosphere models may be wrong, for instance, and if extraterrestrial really is raining down on our stratosphere, so be it. Let facts be the judge. But some sort of biochemical or isotope evidence this is not just another extremophile would be nice.
I would buy the stratospheric model being wrong, but assuming good faith I think they've addressed the contamination objection - you'll note that they did a control with the same procedures except for opening the sample drawer and it came back clean. This is highly reproducible so I'm going to assume they're reporting in good faith.
Flat-out lying was mentioned last because I rate it the lowest. But also non-zero. This is a field that has had many more liars than discoveries, though certainly when there are zero discoveries to be made in the search space we've had access to so far that says less than it might otherwise.
Please read your link. That addresses deficiencies in a paper about a meteorite. This paper is about samples collected from a weather balloon. And while the criticisms in your link are well-founded, I feel sure you can find equally well-founded criticisms without all the distracting ad-hominem insults.
The paper contains almost no detail about the methods used, and lacks involvement of a diverse group of authors. This indicates that the authors are not thinking hard enough about alternative theories to explain what they have found.
For instance, the paper contains this sentence:
"It is also unlikely that the fragment could have come from commercial aircraft, which fly below well below our stratospheric sampling height."
Unless they have a completely sterile, sealed container that is open only at certain altitudes to collect material in a filter, they will have nothing to stand on.
NASA had a satellite that was sent up to collect samples of debris along a particular orbital belt and worked like this. They were doing tests to see how much space junk had accumulated and would open one of the compartments for a fixed period of time, then re-seal it before switching to another.
Unless they have a completely sterile, sealed container that is open only at certain altitudes to collect material in a filter, they will have nothing to stand on.
That is exactly their claim (with detailed method), and they did a control as well, in which the container was not opened, to validate their anti-contamination protocols. I'm all for critiques of the paper, but I do think you might have gone to the bother of looking at it first.
If they have protein in their samples and find amino acids of both chirality, then get exited. If they only find the chirality naturally occurring in earth based life: forgetaboutit
If our aminoacids came from space, you would sort of expect them to be in "incoming" organisms also.
Bioinformatics might be able to bring further light into this problem. If they do find DNA/RNA then they can tell when terrestrial life and whatever this is parted ways. If this root can be pinpointed after known mutations from fossil records, then this must be terrestrial life.
Life is constantly surprising us, it's well known that there is bacteria on the outside of the ISS, it could well be that life is falling down rather than up.
I'd like to see a DNA sample that doesn't point to existing earth life, for me just seeing diatoms seems a little too early to reach this conclusion.
I was thinking the same thing. Of course if life is falling down to earth, it may be hard to tell apart, but there should be some hints of life optimized for earth versus optimized for elsewhere.
I find the bacteria on the ISS fascinating. Can you point me to a good article?
I don't know specifically about the ISS, but I found http://en.wikipedia.org/wiki/Tardigrade fascinating. Multicellular, and "can withstand temperatures from just above absolute zero to well above the boiling point of water, pressures about 6 times stronger than pressures found in the deepest ocean trenches, ionizing radiation at doses hundreds of times higher than would kill a person, and the vacuum of outer space. They can go without food or water for more than 10 years, drying out to the point where they are 3% or less water, only to rehydrate, forage, and reproduce."
It's "some of them will survive in outer space", though.
If the cell has DNA, that's evidence that it came from the surface, not space. There may be life out there, but it won't have DNA (an ad hoc solution to a problem unlikely to be repeated).
Extraordinary claims require extraordinary proof, but still, this is good to see.
I imagine this discussion in the scientific community will go on for many years, perhaps decades. I'm still not convinced that Viking didn't find some evidence of life on Mars back in the 70s.