We are star stuff…
The quote above was made by Carl Sagan. That quote has become even more meaningful recently with the release of a new research study by Zita Martins, Oliver Botta, Marilyn L. Fogel, Mark A. Sephton, Daniel P. Glavin, Jonathan S. Watson, Jason P. Dworkin, Alan W. Schwartz and Pascale Ehrenfreund. The title of the paper is “Extraterrestrial nucleobases in the Murchison meteorite.” Basically, they found uracil and xanthine in a meteorite. These are raw materials for making RNA and DNA that make up us and every living thing on earth.
In their abstract, they say:
Carbon-rich meteorites, carbonaceous chondrites, contain many biologically relevant organic molecules and delivered prebiotic material to the young Earth. We present compound-specific carbon isotope data indicating that measured purine and pyrimidine compounds are indigenous components of the Murchison meteorite. Carbon isotope ratios for uracil and xanthine of ?13C = + 44.5‰ and + 37.7‰, respectively, indicate a non-terrestrial origin for these compounds. These new results demonstrate that organic compounds, which are components of the genetic code in modern biochemistry, were already present in the early solar system and may have played a key role in life’s origin.
I was really excited to hear about this finding and would have loved to read the paper, but alas you have to pay to read it. I really wish more scientists would publish their research under Creative Commons licenses so that more of us interested nonprofessionals could read up on these things. Maybe if more of the results of scientific studies were readily available there would be less fear of science as a sort of mumbo-jumbo voodoo thing to be feared. Oops, that rant is for some other time.
What’s really interesting is that these DNA-RNA precursor materials were found on a meteorite. So, did life evolve totally independently on Earth? Did it have help from a few saturated meteorites crashing into our bubbling cauldron of a cooling planet? Is life a random combination of chemicals that could happen anywhere and so are found just about everywhere including space traveling bits of debris?
Whatever the answers to these question, and I’m sure it will take a lot more research and thinking to come up with answers rather than more questions, it means that we, all of us, are made of star stuff. When we look up to the stars and the milky way and the constellations, we now know that we are part of the solar system, our galaxy, and the universe. We are not alone; we are part of the starry heavens.