http://www.astrobio.net/news/modules...rder=0&thold=0

He opines life's origin is a very important question. Life on Mars with
similar RNA & DNA would indicate life could migrate planet to planet via
impact debris. Dissimilar life would indicate a second genesis of life.
A second genesis would indicate a greater likelihood of life in other
star systems.

For this reason he advocates robotic exploration of Mars for some time
to come. Manned missions could contaminate Mars.

He notes asteroids have resources needed in space such as iron and
water. Besides resource exploitation, he notes the last 15 years have
seen a heightened awareness of impact danger. The articles mentions the
Chicxulub impact, Shoemaker-Levy 9's impact with Jupiter and the
Tunguska event.

The article concludes with Morrison suggesting a Prometheus mission to
an asteroid.

--
Hop David
http://clowder.net/hop/index.html