New research has shown that nucleobases, the chemical components of DNA, have been confirmed to exist in meteorites that have fallen to Earth. These chemicals existed in the early solar system and may have hitched a ride to the newly formed Earth on meteorites in sufficient quantity and diversity to begin the chemical chain reactions that sparked self-replicating life on this planet (that’s you). Let that sink in for a moment, and hit the link to learn more…
Since about the 1960s, scientists have theorized that chemical compounds called nucleobases came to Earth on meteorites (nucleobases are the building blocks needed to form amino acids, proteins and DNA). Samples of meteorites containing nucleobases have been found before, but it has been difficult to rule out contamination by the chemicals after the rocks’ arrival on Earth.
The Carnegie Institution for Science recently announced that a research team has used advanced spectroscopy techniques to purify and analyze samples from eleven different meteorites. They found significant amounts of nucleobase chemical compounds, and structurally similar nucleobase analogs. This has been found in other meteorites before, but what is new and important about this research is:
- Some of the nucleobase analogs found are very rare in terrestrial biology
- These nucleobases were not found in the soil and ice samples from the areas the meteorites were found
This is very strong evidence that the nucleobases were in the meteorites prior to their arrival on Earth, and not due to contamination from Earth based life after they impacted.
The research team tested their conclusions with experiments involving reactions with ammonia and cyanide, which are common in space rocks, and were able to create nucleobase analog compounds in the lab that were very similar to those found in the meteorites.
The implication of all this is: If meteorite impacts delivered naturally occurring nucleobase compounds to the Earth, where favourable conditions allowed them to start interacting, forming proteins and leading to the earliest form of life on Earth… then this research not only puts us a large step closer to a robust theory of the origin of life here on Earth, it also means it could have happened somewhere else too.
It is estimated that somewhere between 40 and 80 thousand tonnes of meteorites impact the Earth every year, including one that wrecked Michelle Knapp’s crappy Chevy Malibu in 1992: