« Making friends in the squirrel world | Main | Reports as comic books »
April 15, 2008
Botany of other worlds
Of course there's life on other planets.
The universe is just too big a place for this to be only planet with life. But by the same token, since the universe is so big, detecting extraterrestrial life is somewhere between extremely difficult and impossible. (It's not like we're gonna be able to look at a distant planet through a telescope and see a bug-eyed alien waving back at us or something).
Our best hope may be to look for planetary traits that can only be caused by life. For instance, much of the Earth appears green from space due to the plant life that covers large swaths of the planet. But before you start scouring the skies for green planets, it's worth asking 7quot;Would alien plants(*) be green?" The answer is "Almost certainly not."
There's a great article in the April 2008 Scientific American explaining the reason almost all Earth plants are green. It turns out it's a result of the relative abundance of different wavelengths of light coming from the Sun, combined with how various components in the atmosphere filter that sunlight before it reaches the ground. On some other planet, with a different sun and atmosphere, plants would evolve to make use of different wavelengths of light, and therefore would have different foliage colors. Plants could be bright orange, or blue, or jet black.
All of this will make it a bit tougher to recognize plant-covered continents on distant worlds. But it'll also make picking a corsage more fun when we have high-school proms there.
It also reminds me of this passage from The Hitchhiker's Guide to the Galaxy...
The Shaltanacs are a race from the planet Broop Kidron Thirteen, who had their own version of the Earth phrase, "The other man's grass is always greener." Although, given their planet's horticultural peculiarities, theirs was, "The other Shaltanac's joopleberry shrub is always a more mauve-y shade of pinky russet," and so, the expression fell into disuse, and the Shaltanacs found they had little choice but to become exceptionally happy and content, which surprised everyone else in the galaxy, who had never realised that the best way not to be unhappy is not to have a word for it.
(*)By the way, by "plant" we don't just mean the leafy things that we commonly call plants here on Earth, we mean any organism that uses sunlight as its energy source.
Posted by Chris Spurgeon at April 15, 2008 02:38 PM