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Astrobiology

By Clark Nida

Reading “Life in the Universe” by Lewis Dartnell. (Oneworld Publications) Fascinated by it.

For a long time I’ve been interested in questions like: what is life, how would we recognise unfamiliar forms of life and where are we likely to find them? Developing my ideas in isolation as I have done, or what I imagine to have been isolation but could well have descended from a steady rain of ideas from popular science articles appearing in the universe at large, I have been surprised to find that astrobiology is massively popular and is one of the major growth areas of science today. Be that as it may, “Life in the Universe” could well become the standard introduction to the topic.

It is risky to spend so much time studying a topic entirely lacking in exemplars. Because, as was the case with black holes only a few years ago, there is no known instance of a life-form originating on another planet. That is to say, none that is generally accepted as such, although the book explores some interesting candidates: indeed terrestrial life itself may have come from Mars.

Perhaps a better example of an ultimately fruitful topic which for a long time had a highly developed theory but no known instance is given by electromagnetic waves. We first hear of them from Athanasius Kircher (Magnes 1641, p.640), who spent much time and effort looking for a natural agency which would explain both magnetism and electricity. Whilst maybe led astray by a kabbalistic metaphor (he described his force as being the agency of God’s love—but that is no more presumptuous than describing the Higgs Boson as the “God Particle”) he rightly foresaw the huge political and commercial benefits which would accrue from its exploitation. Accordingly he built several entertaining models using rotating magnets and tried to interest leading public figures in funding his research. There was little further advance on that until 1862, when James Clerk Maxwell showed that electromagnetic waves existed in theory and derived formulae for their propagation and speed, commenting “We can scarcely avoid the conclusion that light consists in the transverse undulations of the same medium which is the cause of electric and magnetic phenomena.” But there was no proven example of an electromagnetic wave until Heinrich Hertz reported his experiments in 1888. Then all of a sudden we found we were bathed in electromagnetic radiation. Light is one form of it, radiant heat another, X-rays and gamma rays others. Yet more are employed by our mobile phones and microwave cookers. Around 350 years had elapsed between theoretical anticipation and practical use.

In the case of extraterrestrial life, such evidence will hopefully come quicker. Space probes are being built which could provide it. Rock samples do arrive from other planets from time to time in the form of meteorites, albeit in an overheated condition. But it is difficult to mount a convincing experiment to show the existence of something of which you have no idea what it looks like, and then transport that experiment to the surface of another planet from which it is impossible to send and receive signals without a delay of many minutes, if not hours. In the end it may be necessary to bring back life bearing rock samples, or for properly equipped people to go to the planet concerned, before irrefutable evidence is found.

Why do we do it? I suppose there’s a natural drive towards seeking other individuals like yourself. But even if life is widespread in the universe, it seems at first sight unlikely one would find congenial companions on some other body than planet Earth. Even such a respected scientific figure as Stephen Hawking has warned that the search for extraterrestrial life should be conducted with extreme caution, because as we know from our own impact on this planet’s foreign cultures, there is not the slightest reason to suppose that aliens would be friendly. They would either discern us as a threat or as something to enslave. Set against this however, the long-term payoff for mankind from finding life elsewhere could be enormous, and that no doubt is why people are prompted to try.