Aliens from chemistry notes

Well, this last week has been a hard one--Fortunately I'm far enough along in my graduate career that I don't have to deal with the stress of final exams, but my body decided to play tricks on me anyway. After dealing with the stomach flu last week, this week I've been suffering from a head/neckache. Since I'd had it for over 5 days, I decided to go to the student health center, which was a big mistake--for some reason, they thought I had meningitis (Normally I would put a wikipedia link there, but the picture that came up when I did that made me sick to my stomach, so today I'll leave the link out), and they sent me to the emergency room. The doctors there assured me that I was only suffering from a muscle spasm in my neck, gave me some pain killers, and left me with a hefty bill to pay. When they can't tell the difference between muscular pain and a deadly illness, I start to doubt the effectiveness of the university health care system....So that explains why my post today will be relatively light :o)

If you're like me, when you think of aliens, you think of little green men with saucer shaped eyes and strange metallic clothing. Why do we always imagine aliens to be green--Is this really an accurate representation of animals or plants in other solar systems? Well after a lengthy review of photosynthesis on Earth, researchers at Rice University, Washington University, UIUC, and NASA have come up with a set of rules for predicting what colors might be photosynthetically relevant on other planets. Photosynthetic pigments evolve over time in sync with the atmosphere of a planet and the characteristics of its parent star; it is proposed that they have peak absorbance at the blue and red ends of the atmospheric transmittance window for light harvesting, as well as at the wavelength of peak incident photon flux. Thus, if we know the patterns of incident radiation for other stars, we can begin to predict what kind of photosynthetic machinery might be necessary on those planets, as well as the color of these photosynthetic pigments. So we can basically predict what color the trees might be on Jupiter.

Cool, huh?

I first read about these articles on heise.de, but a nice summary can also be found here on the Goddard Institute for Space Studies (part of NASA) website, with reprints of the two Astrobiology papers here and here.