Life and Death Clouds

Sir Fred Hoyle was a great, if not controversial, thinker. He was always one to think ''outside of the box,'' and he was apparently never happier than when challenging accepted opinions. Later in his eventful life, Hoyle collaborated with Chandra Wickrama-singhe (University of Cardiff, Wales) and published a whole series of research papers and several books outlining the idea that the viruses responsible for diseases, such as smallpox, influenza, whooping cough, and bubonic plague, fell to Earth from interstellar space—that is, that such bacteria essentially permeate the entire galaxy. Indeed, Hoyle and Wickramasinghe argued that the wavelength dependency of interstellar extinction,14 relating to the systematic dimming of starlight with distance, is partially due to bacterial spores mixed into the gas and dust (the interstellar medium—ISM) that pervades the disk of our Milky Way galaxy. This idea has certainly not met with any great acceptance from either the astronomical or medical communities, and it is often roundly dismissed as being completely absurd. But as with many of Sir Hoyle's grander ideas, there is much in his theory that is provocative food for thought.

Although Hoyle and Wickramasinghe have suggested that the interstellar medium might seed the Earth with deadly diseases (and possibly the seeds of original life), others have argued that advanced extragalactic civilizations might initiate a program of directed panspermia. In this case, specially selected bacteria and microorganisms are deliberately launched aboard an appropriately designed (and nurturing) space capsule into interstellar space. Michael Mautner (Lincoln University, New Zealand) has championed the idea of propagating terrestrial organic life throughout the Milky Way galaxy.15 Indeed, the Society for Life in Space (SOLIS) argues that there are sound ethical grounds for adopting a directed panspermia initiative, building upon the premise that ''where there is life there is purpose [and that] the purpose of life is self propagation.'' Directed panspermia can proceed in many ways, and one can attempt to seed life directly on an already formed planet (which might, of course, need terraforming first), or one might impregnate an active star-forming region such that the seeds of life are in place from the very first moments that a suitably constructed planet appears. Directed panspermia is an entirely altruistic exercise, but as Maunder writes, ''promoting life in this manner endows human existence with a cosmic purpose.''

How to protect the Earth from the plague-infested clouds that might permeate the ISM, and the launch of interstellar probes for the direct seeding of space with microscopic life forms, are issues and actions that have yet to be initiated (or even agreed upon). What the possibilities do imply, however, is that life might potentially be found not only on any nurturing site within our Solar System but also at any nurturing location within the entire the galaxy. They also indicate that understanding the origins of life on Earth, already revealed as a complicated enough topic, might be even more convoluted (and even more cosmic) than hitherto envisioned (see Figure 3.11). We truly live in intriguing times.

Bacteria Archaea Eukarya

Bacteria Archaea Eukarya

Figure 3.11. A schematic revision to Figure 3.12. It is not currently clear whether life first originated in our Solar System on Venus, Earth, or Mars. It is entirely possible, too, that the basic ingredients for life, maybe even life itself, were seeded by cometary and/or meteorite impacts on any of the three inner Solar System planets. In addition, it is not beyond the realm of possibility that life was seeded directly on one of the inner planets, or that the solar nebula itself was seeded by directed panspermia. The dashed line indicating that life might be transferred from our Solar System to the interstellar medium (ISM), resulting in panspermia conditions, is illustrative and not intended to indicate a feedback mechanism at work. The Jakobia lifeline emanating from Mars in this diagram is further explained in Vignette B at the end of Chapter 4.

Figure 3.11. A schematic revision to Figure 3.12. It is not currently clear whether life first originated in our Solar System on Venus, Earth, or Mars. It is entirely possible, too, that the basic ingredients for life, maybe even life itself, were seeded by cometary and/or meteorite impacts on any of the three inner Solar System planets. In addition, it is not beyond the realm of possibility that life was seeded directly on one of the inner planets, or that the solar nebula itself was seeded by directed panspermia. The dashed line indicating that life might be transferred from our Solar System to the interstellar medium (ISM), resulting in panspermia conditions, is illustrative and not intended to indicate a feedback mechanism at work. The Jakobia lifeline emanating from Mars in this diagram is further explained in Vignette B at the end of Chapter 4.

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