Brother Guy wrote a nice blog entry recently on imports from space. It was recalled that organic chemicals have a long history of being found in asteroids. Organic chemicals and even amino acids have also been identified in the interstellar medium.
When light is incident onto molecules which is not so harsh as to dissociate them, they rotate and vibrate. It is by by searching for such rotational transitions distinct to those particular molecules that we can make such interesting discoveries.
This is difficult work, as the wavelengths of the transitions are only sometimes, but not always, uniquely determined. In any event, we know that fairly complex chemistry can take place in the stuff between the stars. The question then arose of whether life may have been imported to Earth via asteroids which can provide secure ‘spaceships’ for such long journeys.
What if the Earth not only imports asteroids with organic chemicals but also exports them?
The most obvious example is the Moon, for which the common lore is that the Moon was ejected from essentially the Earth’s mantle early on in the Solar System’s history. Another particularly famous case is the massive comet that struck Earth 65 million years ago which caused the extinction of the dinosaurs.
Interestingly, if a massive comet really struck the Earth around this time, then it should have resulted in the ‘launch’ of small rocks into space, some of which will have landed on the Moon and on Mars in the form of solid silicate balls. If so, then we should be able to age-date the rock near any such glass ‘pearls’ to look for a 65 million year old ‘match.’ Perhaps future visitors to the Moon and Mars will take this on for their class projects.
Such small asteroid ‘exports’ can also provide a spaceship to take organic chemicals off of Earth and land them on other objects. This will take time (ten thousand of years to travel between planets and 120,000 years for an asteroid to make it to the nearest star system), but the universe seems to have a lot of time to go around.
Whether import or export, we should indeed keep our eyes open for the remarkable, for isn't this what drives the scientist in us all?