Fourth in a series of posts inspired by ten topics in ‘Insights of the Decade’ from the December 17, 2010 special issue of Science Magazine The topics are: Inflammation, climatology, tricks of light, alien planets, the microbiome, cell development, Martian water, the DNA time machine, cosmology and epigenetics. The original articles are now behind a paywall; they won’t be reproduced here, but their gist is present. I’ll try to put them in context and specifically within the Impact Areas of SciTechStory.
Let’s start with the bottom line: Within a year or two a planet outside of our own solar system will be discovered with evidence that it could harbor life. Within the decade and probably sooner, life on another planet (exoplanetary life) will be ‘confirmed.’ This is not bold or even foolish prognostication. The past decade saw the number of discovered extra-solar planets jump from about 20 to over 500. Among these were a few (that’s maybe three) that scientists thought could be candidates for ‘Earth-like,’ that is, they could possibly have the conditions necessary to develop life.
These results are conducive to making wild predictions, but they’re not good enough to provide verifiable evidence. The key word is verifiable. Already there have been several instances, Gliese 581g for example, where one group of astronomers espies an earth-like planet and another group says they can’t even find it. This says something about the state-of-the-art in astronomical planet finding technology – it’s good, planets invisible only a decade ago are found, but it’s not that good.
Not that it’s easy finding planets. The planets orbit stars that are scores of light-years away, in our galaxy mostly, but unfathomably distant for the human mind. Our technology can barely see that far. The best telescopes can pick up visual images of some of the stars involved, but until 2008 not the planets. What we ‘see’ are, to use a phrase, disturbances in the force. The most used technique is called Doppler spectrometry, detecting the blue or red shift in the light of a star as it is affected by the gravity of its orbiting planets. Another technique looks for minute dimming in the star as a planet transits across the view of our space telescopes, such as the Kepler Space platform. It doesn’t take much imagination to figure out that this kind of evidence for a planet depends on absolute accuracy in both the equipment and the calculations involved. A tiny error ‘sees a planet’ or there is no planet at all.
The planets photographed in 2008 were discovered with the Kepler telescope and by telescopes at the Keck Observatory in Hawaii (obviously Earth-based) with the latest in adaptive optics using smaller highly coordinated mirrors to focus the light from the heavens while removing much of the atmospheric clutter of Earth. Astronomers are also beginning to perfect coronagraphs, a technique for removing the glare of a star’s corona, so that planets become more readily visible.
In short, the technology is improving. Much was accomplished in the previous decade and the hunt is on. (It might be added that so is the funding, as this aspect of astronomy has considerable backing.) The next generation of telescopes, the Webb Space Telescope and new ground-based installations will be employing recent techniques in spectrometry, which should be able to give astronomers the first detailed look at the atmosphere surrounding some of the exoplanets. They will be looking for the signatures of life, oxygen in particular. This technology will come on line during the decade.
What happens when a planet is discovered to have verifiable evidence of life – a particular signature of oxygen, correlated with other signs? What will be the impact on humanity?
On day to day life, there will be little or no impact. On space programs, there will be some impact because it will be fashionable to look for more signs of life elsewhere, even in our own solar system. Will there be impact on religion and philosophy? Yes, probably, although denial will have many forms. For many people the discovery that, in fact, Earth is not the only place in the universe with life may change many suppositions about the importance of human beings and the nature of the universe. This evolution in thinking has been underway for decades and will be accelerated by the discovery of exogenous life; but I don’t expect it to rapidly change most of the religious conceptions of Man, the Universe, and God. The biggest impact may well be on cosmology and biology, where the discovery of strange configurations of planets may alter our view of how life evolves, how planets are formed, and the various processes (laws of physics, for example) that underlie them.