We know a whole lot about life on our planet, but one mystery persists: how it got here.
NASA scientists working at the Ames Astrochemistry Laboratory in California and the Goddard Space Flight Center in Maryland may have just found a clue to that mystery. They've determined that some of the chemical components of our DNA can be produced in the harsh crucible of space.
To reach their conclusion, they created a chunk of ice in their lab containing molecules known as pyrimidine. These molecules, which consist of carbon and nitrogen, form the core of three chemicals found in DNA and RNA, the genetic composition of all Earth-based life.
Pyrimidine is also found on meteorites, which prompted the researchers to explore how it reacts when frozen in water in space.
So they put their chunk of ice in a machine that reproduces the vacuum of space, along with temperatures around -430°F and harsh radiation created by high-energy ultraviolet (UV) photons from a hydrogen lamp.
They found that not only could the pyrimidine molecules survive these brutal conditions, but the radiation actually morphed some of them into three chemical components found in DNA and RNA: uracil, cytosine and thymine.
"We are trying to address the mechanisms in space that are forming these molecules," Christopher Materese, a NASA researcher working on these experiments, said in a statement. "Considering what we produced in the laboratory, the chemistry of ice exposed to ultraviolet radiation may be an important linking step between what goes on in space and what fell to Earth early in its development."
Added Scott Sandford, a space science researcher at Ames, "Our experiments suggest that once the Earth formed, many of the building blocks of life were likely present from the beginning. Since we are simulating universal astrophysical conditions, the same is likely wherever planets are formed."
While this research might help fill in a piece of the puzzle of our cosmic origins, another mystery remains. Scientists don't exactly know where meteoric pyrimidine comes from in the first place, although they theorize that it could arise when giant red stars die. And the search continues...