The emergence of life, whichever mechanisms stand behind it, is apparently a rare event. But the nature of life is such that, once started, it tends to reproduce as much as possible, colonizing even harsh environments as exemplified by all kinds of extremophiles. This inherent tendency of life to reproduce is the very prerequisite for biological evolution, making it possible for complex features facilitating further propagation to emerge. The most powerful of such features is intelligence. Without it, the inherent expansion of life is limited to a single planet. With it, life might propagate throughout the Galaxy or even entire Universe.
There are two possible modes of life’s cosmic expansion at intelligent stage: intelligent beings might colonize other planetary systems themselves or they might implant them with microbial life. The first mode (interstellar colonization) propagates life and intelligence simultaneously but is highly demanding and hazardous. The second mode (intentional seeding, or directed panspermia) propagates as yet unintelligent life but is far more feasible technologically. As for natural interstellar panspermia, it appears to be overwhelmingly unlikely, or at best uncertain, as there are many “ifs” related to both the incidental nature of the process and viability of microorganisms under a number of detrimental conditions. In intentional seeding all these factors are obviated or alleviated, making it much more efficient for dispersal of life within Galaxy. Starting local evolution, some of the seeds that happen to inhabit a planet with suitable conditions might eventually arrive at intelligent stage and repeat the cycle of cosmic expansion.
The efficiency of intentional seeding, together with the data indicating that first habitable planets were present long before the Solar System formed, suggests that at the current age of the Galaxy it might be even more probable for an intelligent being to find itself on a planet where life resulted from directed panspermia rather than on a planet where local abiogenesis took place, and the Earth is not an exception from that. This is not to say that the view that terrestrial life originated locally is flawed. But subscribing largely to this view and dismissing the possibility that terrestrial life might not be a first independent generation in the Galaxy is probably nothing but a manifestation of geo-anthropo-centrism (inappropriately armed with Occam’s razor). Particularly so in view of the universality of the terrestrial genetic code which counts more in favor of seeding rather than of local abiogenesis (though it also might count in favor of non-directed panspermia).
The hypothesis that Earth was seeded intentionally with life by a preceding galactic civilization is far from being new. It was first touched upon in the middle of the 20th century by John Haldane (one of the founders of the evolutionary synthesis), and considered later by other luminaries such as Carl Sagan (a prominent astronomer and science writer) and, in great detail, by Francis Crick (the Nobel laureate who discovered the DNA structure), and Leslie Orgel (a biochemist and a key researcher in the origin of life field).
This hypothesis could remain just a conjecture, as there is no conceivable way to test it. At least, on the face of it. However, it does have a possible testable concomitant which was pointed out back in 1979 by György Marx, a Hungarian astrophysicist and cosmologist. The point is that though directed panspermia propagates as yet unintelligent life, it might also propagate an intelligent message along with the seeds to inform the future intelligent descendants of the fact that life on their planet derives from seeding activity by a preceding civilization. There is no better place for such a message than the genetic code of the very seeds. First, it guarantees that the message will be found, sooner or later, after intelligent beings evolve and achieve scientifically advanced stage. Second, the message will be protected there from casual modifications by extremely strong purifying selection acting on the genetic code through its direct biological function of translating genes into proteins.
Certainly, if directed panspermia is correct, that does not imply that there must be a message in the genetic code. But if there is a message in the code, then directed panspermia must be correct. In this way, directed panspermia links the problem of the origin of life on Earth to the problem of searching for extraterrestrial intelligence (SETI) and, if confirmed, naturally resolves the Fermi paradox. Unlike conventional radio SETI, in this case you know exactly where to search. We have tried to perform the search and, at least as we see it, the result leaves no option but to confirm the hypothesis of directed panspermia.
For those who intend to go into more details, here is our recommended order of reading:
- To eliminate possible misconceptions and confusions right off, please, refer to FAQ.
- The historical account of the hypothesis. Ideally, at this stage you should also read the book “Life Itself: Its Origin and Nature” by Francis Crick.
- The paper “Space ethics to test directed panspermia” (accepted in Life Sciences in Space Research). This paper sets the stage and examines data that potentially could contradict the possibility of a message in the universal genetic code.
- The paper “The ‘Wow! signal’ of the terrestrial genetic code” (published in Icarus), which presents the description of the informational artifact in the genetic code and arguments on its artificiality, as well as its algebraic and statistical analysis (the authors’ free version is available at arXiv.org).
- The detailed description of the research, which contains some additional materials and elucidates certain points in more detail than in the paper.
- You might watch the interactive supplement to the paper online (or download zipped SWF-file to watch it offline).
- If at this stage you are still unconvinced of the validity of our conclusions, please, refer to How to disprove our conclusions.
- Find out the value of the signal in the Rio scale.
- You might also read expert opinions.