So by now you’ve probably all heard about Dr. Richard Hoover, the NASA scientist who possibly has discovered alien bacteria in meteorites. Now that I’ve had a chance to read the paper itself and the opinions of some researchers more closely related to the fields of astronomy and, more importantly, biology, I want to give you a better idea of what this paper is saying.
Let’s start off with the journal itself, the Journal of Cosmology. It is a journal published entirely online, though it is technically peer-reviewed. However, the journal has been known to encourage the publishing of fringe ideas and scientists that jump the gun on certain conclusions about their data.
Take for example the supposed giant planet in the Oort cloud which was discussed last month. The paper was met with scorn and skepticism from a large group of scientists, including Phil Plait. A news article by Gabriel Beck on the Journal of Cosmology homepage had said this in response to the criticism:
The torches and pitchforks crowd, led by astronomer-wannabe Phil Plait claims its not so. But then, Plait’s most famous discovery was finding one of his old socks when it went missing after a spin in his dryer.
Not exactly a scientifically sound argument, nor something you would expect to read from a credible scientist reasonably discussing a paper. So the Journal of Cosmology is not impressing me, particularly since I love Phil Plait and actually try to model the style of this blog after his. In addition, there is nothing wrong with being skeptical about ANY finding. If your research is sound, then it should be able to stand up to the highest level of scrutiny and you shouldn’t get defensive.
But Beck’s pettiness aside, this does not discount Dr. Hoover’s research out of hand, so let’s look at the actual paper.
The meteorites were imaged using an electron microscope and the images examined. What Hoover found was that some of the images showed strange “filaments” in the structure of the meteorite. Upon further inspection, the filaments seemed to correspond with the general shape and size of certain species of bacteria.
Hoover believes that the filaments were not the result of contamination of Earthly bacteria after the meteorite landed because there was a definite lack of nitrogen in the samples. This is because nitrogen fixation is an essential part of the life cycle of “Earth-based” bacteria, and the level of nitrogen in the sample should be detectable for several thousand years. Since we know the dates on which these meteorites landed, the lack of nitrogen within the sample was evidence that the filaments were in the meteorite prior to it landing on the surface of the Earth.
In one of the meteorites (Orgueil) Hoover found structures within the filaments that resembled “heterocysts”, which are specialized cells used to fix nitrogen. Hoover says that
…the detection of heterocysts provides clear and convincing evidence that the filaments are not only unambiguously biological but that they belong to one of these two orders of cyanobacteria…
Another point Hoover makes is that the Orgueil meteorite is composed of certain minerals that dissolve when exposed to water. Since we know the meteorite landed in 1864, and that cyanobacteria generally require the presence of water to live, he suggests
that none of the Orgueil samples could have ever been submerged in pools of liquid water needed to sustain the growth of large photoautotrophic cyanobacteria and required for the formation of benthic cyanobacterial mats since the meteorite arrived on Earth. Many of the filaments shown in the figures are clearly embedded in the meteorite rock matrix. Consequently, it is concluded that the Orgueil filaments cannot logically be interpreted as representing filamentous cyanobacteria that invaded the meteorite after its arrival. They are therefore interpreted as the indigenous remains of microfossils that were present in the meteorite rock matrix when the meteorite entered the Earth’s atmosphere.
Those are the basic arguments. The paper then extends its assumptions far beyond the scope of the research to discuss how this finding could be indicative of life on comets or on Europa.
So as you have probably already gathered, there are some serious problems here. My biggest problem of the paper is that it is not quantitative. How many images in total did you take? How many filaments in total did you find? How many of them exhibit shapes resembling heterocysts? If there was a colony of bacteria in the meteorite, how many of these fossilized remains should we expect to see and how many of them should have structures resembling heterocysts?
I also have a problem with heterocyst structures themselves. Does it makes sense that a bacterium that is not from Earth would have a structure similar to what Earth-based bacteria use to fix nitrogen?
I will concede that these are strange structures in the meteorites. But given the huge diversity of bacteria, doesn’t it seem like it would be quite easy to take any structure that is remotely filament-like and match it with some type of bacteria?
The answers to these questions are not given. This could be because some of them are difficult questions with complicated answers, which is fair, but they do not seem to be addressed at all.
It comes down to the fact that Hoover is comparing filament structures in a meteorite to the shapes and sizes of certain bacteria on Earth. He is then making two conclusions:
- That the filaments were there prior to the meteor entering the Earth’s atmosphere and
- That the filaments were caused by the fossilization of bacteria.
Consequently, there are 3 possibilities:
- Hoover is correct that these are fossilized bacteria of a non-Earth origin.
- The filaments were caused by bacteria contamination from Earth and the lack of nitrogen could be explained by something else.
- The filaments were caused by something other than bacteria, before or after the meteorite landed on the Earth’s surface.
Frankly, even though Hoover gives a few arguments as to why he thinks the filaments were caused by alien bacteria, I think possibilities 2 and 3 are much more likely. Simply because Hoover cannot come up with another explanation for the lack of nitrogen or the presence of what look like heterocysts does not warrant the conclusion that these are fossilized extraterrestrial bacteria. That is a huge leap and it is an extremely premature assertion.
But it is still early so we will see what the experts end up saying. PZ Myers already weighed in with his opinion in a blog post called “Did Scientists Discover Bacteria in Meteorites?”:
No, no, no. No no no no no no no no.
He is chalking this one up to a glorified case of pareidolia.
In the end, it again comes down to “Extraordinary claims require extraordinary evidence.”
The claim is extraordinary. The evidence, unfortunately, is not.