It may sound strange, but it’s possible that some of the ingredients for the first life may have been carried to Earth on a meteorite, digitartlend reports.
Recent research has shown that all five building blocks of DNA have been found in meteorites.
To be clear, it’s not that DNA was found on a rock from outer space and the result was that each of the five basic compounds that make up DNA and RNA, called nucleobases, were found in the meteorite samples.
Previously, only three of these nuclear bases had been found on meteorites, but recent research has identified the last two.
One of the authors, Danny Glavin of NASA’s Goddard Space Flight Center, said in a statement: “We now have evidence that the full set of nuclear bases used in life today would have been available on Earth when life appeared.
The two prominent nucleobases, cytosine and thymine, were more difficult to identify than the other three nucleobases (adenine, guanine, and uracil) because they had a more precise structure that could be easily broken down through the process of sample collection and analysis.
NASA describes the traditional method of analyzing these samples as making “meteorite tea,” in which small samples of a meteorite are placed in a hot liquid so that the samples are extracted and the aqueous solution studied.
“We study these aqueous extracts because they contain good stuff, ancient organic molecules that could be the building blocks for the origin of life on Earth,” Glavin explained.
But the remaining two nuclear bases require a more precise method for their identification, using cold water and a more sensitive analysis process.
“This group was able to administer a technique that is more like cold coffee than hot tea, and is able to extract more sensitive compounds,” explained another co-author, Jason Dworkin. “I was amazed that they saw cytosine, which is very fragile.”
Whether the components of life actually made it to Earth on a meteorite is still an open question.
Life could also have evolved from the primordial soup of a very young planet, from reactions of organic compounds, but this research opens more possibilities for future research on the topic.