The topic of directed panspermia found its way into a recent issue of The Economist: Colonizing the Galaxy is Hard. Why Not Send Bacteria Instead?
The concept, apparently being discussed by “a number of scientists”, involves jump starting evolution on exoplanets by seeding them with terrestrial bacteria. With human interstellar travel likely centuries away, the proposal is to send tiny probes–containing microscopic passengers–in the near term. These could be propelled using solar sails and Earth based lasers, along the lines of what is proposed for use in NASA’s Starlight (also known as “DEEP-IN”) program.
The article presents valid objections to this idea, including the worry of contaminating worlds were life might have arisen independently.
However I see a more practical reason for opposing such efforts. Directed panspermia of this nature is being discussed because it is all we have the potential to do near term. But technological advances over the next two centuries are likely to expand our capabilities greatly, including the ability to send larger, more capable exploratory craft and perhaps even human crews. Sending smaller craft now, at best, provides a head start of a couple of centuries on an evolutionary process that is likely to take hundreds of millions or even billions of years to produce anything significant, assuming conditions are ideal. That hardly seems worth the effort or risk.
When it comes to seeding life in distant solar systems, the sensible thing to do is to wait until we can do it responsibly. Just because we can do it in the next few years, doesn’t mean we should.
