 explain it. Now, thanks to astrobiology, astrophysicists are helping biologists try to understand this puzzling global property of life on Earth.
Image Credit: The University of Liverpool
Seager suggested the red edge of green plants may be a result of the need for thermal regulation. Because green plants absorb a lot of sunlight, they could overheat. But being reflective in the near-infrared might help them to shed excess heat. This is truly a cool idea. At the end of her talk I wanted to ask this: "Your idea suggests that photosynthetic life adapted to very cold places may NOT show the red edge. A way to test this would be to look at organisms adapted to cold places, like photosynthetic extremophiles in Antarctica. Has anyone looked to see if they show the red edge?" If this thermal-regulation hypothesis is correct, then habitable planets on the outer edge of the habitable zone, farther from a star, might not show the red edge effect.
During the meeting there was much discussion of the recent NASA budget cuts to astrobiology, and what this might mean for the future of the field. Even though many are experiencing harder times, and students are facing uncertain employment prospects, the field of astrobiology doesn't seem to be shrinking or retrenching. Even though the funding situation has people nervous, that didn't dim the enthusiasm about future projects like the Terrestrial Planet Finder. The overall scientific theme of the workshop was finding habitable Earthlike planets around other stars, so there was much talk about observations to be made with TPF and other instruments. Nobody doubts that we will build instruments to study rocky planets in our galactic neighborhood. The "we" in this case could mean the current generation of astrobiologists, or our intellectual descendants.
At any rate, somewhere, somebody in the galaxy is looking through a telescope, searching for planetary dots of any color. Maybe our pale blue orb will enter their field of view. They would be able to monitor the gas composition of our atmosphere, noting the recent build up of carbon dioxide. Perhaps they are wondering if this change is due to some geological properties of our planet, or if instead it reveals inhabitants who are clever but unwise.
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