This stunningly beautiful image of a meteorite falling through aurora borealis was taken at Patricia Beach, Manitoba by photographer Shannon Bileski of Signature Exposures in March 2013 and is used with her kind permission.
Humans have probably been looking for signs of life from the stars since we first looked up. The first claim for life in meteorites was for a meteorite that fell in 1682. The most famous claim is based on an examination of a carbonaceous chondrite meteorite that fell in Orgueil, France in 1864. There a no less than 440 papers on that meteorite alone. All told there have been eight rounds of claims of discovery of life in meteorites including the Orgueil one.
There are two approaches to deciding if life is in a meteorite: morphology and chemistry. When considering the possibility of morphological evidence in meteorites the friability, salinity, and porosity of the meteorite samples has to be considered. One problem is that primitive life consists of single cells, sometimes strung in filaments or in clusters. It is hard to tell a “real” fossil of such life from an inorganic growth or precipitate.
Some chemicals have been presumed to be unique to life. However, the development of organic chemistry soon showed it was possible to create organic compounds (including those found in meteorites) in the laboratory. Now we know that many of them abound in interstellar space. Therefore, organic compounds alone are no longer considered sufficient proof of life.
Another problem is that life is everywhere on Earth. Examining a meteorite found on the Earth means that if you do find life, it is far more likely to be contamination from life we already have here than any sort of novel panspermia sample. It has been argued that if a possible microfossil were found on the interior of a meteorite it could not be the result of contamination. However, a huge taxonomic diversity of prokaryotes colonized the Tatahouine meteorite in less than 70 years making such claims dubious. And when a meteorite lands on earth it comes from a vacuum and so will suck in air into its interior upon entry and cooling. Carbonaceous chondrites, the most likely kind of meteorite to contain life from space, are hygroscopic, i.e., drawing into them any moisture in the vicinity. And so it is possible for some eager microorganism to be drawn into or crawl into the interior of the meteorite. It is far more reasonable to assume that motile microorganisms, perhaps from spores in the air falling on the surface, invaded museum specimens at times of high humidity and subsequently fossilized. We give an example in Embryogenesis Explained of hot springs bacteria that get fossilized in 2 days. Earth rocks often contain live bacteria deep inside. Similarly, organic chemicals can seep into rocks and meteorites. It can even be assumed that anything that got close to Earth might get contaminated since Earth life, like diatoms, have been claimed to be found floating about on the outer reaches of our planet’s atmosphere. Since the 1960s, if a meteorite fell through our atmosphere, then any life found on or in it can be safely presumed to be Earth life contamination.
And then there are hoaxes. Dick was involved as an undergraduate in a 100-year reexamination of the Orgueil meteorite. Ed Anders and he uncovered a hoax in which some unknown person placed a piece of coal and the dried bud of a local plant into a sample of the meteorite. Dick showed, by analyzing it for the amino acid hydroxyproline, that the mass had been put back together with animal glue. The hoaxster placed the specimen on the local museum shelf, where it sat 100 years. They probably didn’t live to see their crafty work found, but it did make scientists extremely wary a century later.
We therefore agree with the decision of NASA to keep Rover far away from the place where NASA seems they have found water. No matter how carefully NASA cleaned up Rover before sending it off, there is always the possibility one of our more persistent and clever forms of Earth life hopped a ride and would immediately start colonizing the Red planet’s water. That would not only be bad science, it might also be a violation of the Prime Directive.
You can read the full article on this topic with references and additional information at: Recurrent Dreams of Life in Meteorites by Richard Gordon and Jesse C. McNichol (2012), a chapter in Genesis – In The Beginning Volume 22 of the series Cellular Origin, Life in Extreme Habitats and Astrobiology. Or ask Dick for a reprint: DickGordonCan@gmail.com
If you would like a hard copy of the gorgeous picture of the meteorite against the aurora, you can purchase it by contacting Signature Exposures.