I may be one of those alien life forms we've been searching for

by John MacBeath Watkins

Some years ago, I read about a wild theory advanced by an astronomer whose name escapes me, who had advanced the theory in the 1960s that earth's water arrived from comets. It was largely ignored at first, because it was published on April 1. People actually thought it was a joke.

Now, decades later, we've found comets from the Kuiper Belt that have the same chemical signature as earth's water. From this NASA press release:

New measurements from the Herschel Space Observatory show that comet Hartley 2, which comes from the distant Kuiper Belt, contains water with the same chemical signature as Earth's oceans. This remote region of the solar system, some 30 to 50 times as far away as the distance between Earth and the sun, is home to icy, rocky bodies including Pluto, other dwarf planets and innumerable comets.

"Our results with Herschel suggest that comets could have played a major role in bringing vast amounts of water to an early Earth," said Dariusz Lis, senior research associate in physics at the California Institute of Technology in Pasadena and co-author of a new paper in the journal Nature, published online today, Oct. 5. "This finding substantially expands the reservoir of Earth ocean-like water in the solar system to now include icy bodies originating in the Kuiper Belt."

Scientists theorize Earth started out hot and dry, so that water critical for life must have been delivered millions of years later by asteroid and comet impacts. Until now, none of the comets previously studied contained water like Earth's. However, Herschel's observations of Hartley 2, the first in-depth look at water in a comet from the Kuiper Belt, paint a different picture.
Which means that at least some of the chemicals needed to brew primordial soup arrived from space. I like to think this means that you and I are those alien life forms we've been searching for.