While the origin of life remains mysterious, scientists are finding more and
more evidence that material created in space and delivered to Earth by comet and
meteor impacts could have given a boost to the start of life. Some meteorites
supply molecules that can be used as building blocks to make certain kinds of
larger molecules that are critical for life.
Researchers have analyzed carbon-rich meteorites (carbonaceous chondrites)
and found amino acids, which are used to make proteins. Proteins are among the
most important molecules in life, used to make structures like hair and skin,
and to speed up or regulate chemical reactions. They have also found components
used to make DNA, the molecule that carries the instructions for how to build
and regulate a living organism, as well as other biologically important
molecules like nitrogen heterocycles, sugar-related organic compounds, and
compounds found in modern metabolism.
"Despite their small size, these interplanetary dust particles may have provided
higher quantities and a steadier supply of extraterrestrial organic material to
early Earth," said Michael Callahan of NASA's Goddard Space Flight Center in
Greenbelt, Md. "Unfortunately, there have been limited studies examining their
organic composition, especially with regards to biologically relevant molecules
that may have been important for the origin of life, due to the miniscule size
of these samples."
