Could it be that we're all from Mars?

Southam Newspapers; The Ottawa Citizen

Science fiction's most dire predictions -- that beings from another planet might take over the Earth -- may have already come true. It just may be that the invasion and colonization of Earth by Martian life forms has already happened.

According to world-renowned British physicist Paul Davies, it is entirely plausible that all life on our planet has its origins on Mars.

"Not only is it possible, but I think there's a good case to be made that we are," he said.

Davies -- the 1995 winner of the $1-million US Templeton Prize, the world's largest award for intellectual endeavour -- spoke Friday at the annual Couchiching Conference. This year's theme is "Science, Ethics and Human Destiny."

It has been three years since the discovery of a meteorite from Mars that contained what appeared to be the fossil record of tiny microbial life forms which live, or once lived, on the red planet. Since then, Davies has been studying the idea of migration of living matter from one planet to another, specifically between Mars and Earth.

He believes, for two reasons, that some form of bio-exchange has occurred. First, how it would be transmitted is now clear: when an asteroid hits a planet, fragments fly into the air and are carried away with enough speed to leave the atmosphere. Because of this, he says, "there is no question that there has been an exchange of rock between the two planets."

The second idea is the discovery that primitive microbes live deep within the rocky crust of the Earth, in extreme heat and without benefit of sunlight or organic matter on which to feed. The fact that rock can support life means that asteroids are a viable means of travel between planets.

"I believe that past life on Mars was a virtual certainty," Davies writes in his book, The Fifth Miracle: The Search for the Origin and Meaning of Life.

Yet, even if this is true, Davies said it would be impossible to determine with certainty which of the two planets is "the true Garden of Eden."

It is also possible that life sprung up independently on each planet.

Davies does note, however, that specialists believe that if one of the planets was the original colonizer, it is much more likely, due to the makeup of the planets, that Mars was the first to give life to matter.

"Then life on Earth," according to Mr. Davies, "could originally have come from Mars, and we would all be descended from Martians."