It has long been thought that the seeds for life came to a
primordial Earth from solar system leftovers crashing into the planet. These
meteorites, comets, or other unknowns may have contained vital components with
which budding life on Earth either assimilated or used as a catalyst to create
itself. Now, in a paper to be published in Earth
and Planetary Science Letters, European scientists claim they have evidence
to prove the theory may be correct.
The group, based at Imperial College London, found
some of the base building blocks for life, nucleobases, in dust from the
Murchison meteorite which fell to Earth in 1969. Nucleobases, in this case
uracil and xanthine, are the components that make up two of the most important
parts of any Earth-bound life form, DNA and RNA.
In order to confirm that these molecules weren't from simple contamination, the
researchers analyzed the individual atoms of the nucleobases. They found the
carbon contained within was a heavier breed that what forms naturally on Earth.
The molecules must have come from space.
Professor Mark Sephton, a co-author of the paper states “Because meteorites
represent left over materials from the formation of the solar system, the key
components for life -- including nucleobases -- could be widespread in the
cosmos. As more and more of life’s raw materials are discovered in objects from
space, the possibility of life springing forth wherever the right chemistry is
present becomes more likely.”
While giving insights on how higher life may have formed on Earth, the finding
may also bolster the theory that life may have once existed on a warmer, wetter
Mars or a cooler, clearer Venus. NASA hopes to find evidence for such theories
by analyzing the ice contained in the soil of the red wasteland that the Mars
Phoenix Lander touched down on.