We are happy to have Marc Kaufman guest blogging with us today. Marc is a wonderful science writer and national editor at the Washington Post. He is also the author of the new book First Contact: Scientific Breakthroughs in the Hunt for Life Beyond Earth.
The daffodils are blooming; an enormous pileated woodpecker is drilling the big oak near my window; the stink bugs that invaded the Washington suburbs last summer are reappearing after a winter's hibernation. Nature, in its familiar fullness, is putting on its springtime show.
Surrounded by this pleasing display, I am nonetheless getting a bit confused about the whole "nature" thing. That's because I'm also reading a recent release from the University of St. Andrews in the U.K. that talks about the possibility of worlds where plants are black. It is not an entirely original finding that's being reported — a NASA funded team came to a similar, if differently colored conclusion in 2007 — but it does bring the point home rather dramatically, and the results were presented yesterday at a meeting of England's Royal Astronomical Society.
"Our simulations suggest that planets in multi-star systems may host
exotic forms of the more familiar plants we see on Earth," writes Jack O'Malley-James, who is studying the possible dynamics of extrasolar photosynthesis. "Plants with dim red dwarf suns may appear black to our eyes, absorbing across the entire visible wavelength range in order to use as much of the available light as possible. They may also be able to use infrared or ultraviolet radiation to drive photosynthesis."
When people think of life beyond Earth, the default mode tends to be aliens with bulging skulls or curly microbes. So imagining something in between — especially something so familiar yet so odd — is inherently interesting. But it also raises one of the more intriguing questions that popped up as I reported and wrote my book. The question: How the discovery of current or former life elsewhere would change our sense of what constitutes "nature."
It's a tricky business, because the word has a range of denotations and connotations. I think we would all agree that something — anything — that is living is nature. That's why the word has a warm and fuzzy "Mother Nature" feel (though of course nature can also be "bloody in tooth and claw.") At the outer limits we might also think of phenomena such as rain and snow, sunsets and tides as part of nature, but I don't think most people would consider stars to be nature. Or interstellar space. Or the laws of gravity. And certainly not black holes. The "natural sciences" generally end at the edge of Earth's atmosphere.
But what happens if signs of long-ago life are found on Mars, or if scientists determine that the methane still emanating from below the planet's surface is the result of biology, or if an exoplanet is found with high levels of oxygen or ozone in its atmosphere — a situation that planetary scientists generally agree can happen only if something alive is at work. Does Mars, or that exoplanet, become part of nature? And because a broad consensus exists in the field that a second genesis found anywhere would likely mean that life is a commonplace in the cosmos, then does the whole universe become "nature?"
It all remains hypothetical now, but my book is premised on the notion — broadly held within the astrobiology community — that it's just a matter of time and technology before we do find signs of extraterrestrial life. This is considered a plausible enough scenario that NASA has already sponsored two workshops to examine the possible implications here on Earth of such a discovery, and so too has the Vatican and England's Royal Society. No real consensus has emerged, except that it would be a very big deal — a kind of coming full circle of the revolution begun by Copernicus, Kepler and Galileo.
And part of the big deal, for those who choose to think about it, is that the natural world — the place that is more or less home for us — would expand rather dramatically. Should science fiction (black or purple trees) ever become scientifically sound science, then "nature" would be transformed. That happened once before, when the invention of the microscope opened up the microbial world, which of course actually constitutes much of our biological diversity. Intriguing to think that the telescope, no doubt working with a spectrometer, might someday do the same for the extraterrestrial world. Copyright 2011 National Public Radio. To see more, visit http://www.npr.org/.