Meteorite offers insight into early evolution

ORGANIC chemicals in a meteorite that exploded above Canada 11 years ago have provided strong evidence of life’s building blocks evolving in space.

Fragments of the rock that landed on Tagish Lake, British Columbia, yielded a mix of organic compounds. They included amino acids and monocarboxylic acids, both essential to the evolution of the first simple life forms on Earth.

Analysis of the chemicals revealed information about their history on the asteroid from which the meteorite came, and lent weight to the theory that organic material originates in gas and dust clouds between the stars.

If the theory is right, the building blocks of life would have been spread throughout the developing Solar System. They may, for instance, have provided a foothold for early life on Mars as well as the Earth.

Lead researcher Dr Chris Herd, from the University of Alberta, said: “The mix of pre-biotic molecules, so essential to jump-starting life, depended on what was happening out there in the asteroid belt. The geology of an asteroid has an influence on what molecules actually make it to the surface of the Earth.” The findings were published in the journal Science. Experts are confident the chemicals they analysed were not the result of Earthly contamination.

The four-metre-wide Tagish Lake meteorite exploded after heating up as it passed through the atmosphere 30 to 50 kilometres above the Earth. Pieces of the rock rained down on the frozen, snow-covered lake where they were preserved in sub-zero temperatures.

Water in the parent asteroid altered the organic compounds buried within it, leaving signatures that could be read in the meteorite fragments. They indicated the organic material had existed and undergone chemical processing since the birth of the Solar System.