Free Astronomy Magazine September-October 2014

ASTROBIOLOGY With the supertelescopes that will be “up and running” in the ’20/30s it will be pos- sible to directly observe many extrasolar planets and perhaps detect definite traces of the presence of life. But even before that, in 2018/19, will be operational the James Webb Space Tele- scope (JWST), a powerful in- frared eye of 6.5 metres diameter, dedicated also to the study of planetary atmo- spheres. In thinking about the potential of JWST, three researchers at Harvard Col- lege and Harvard-Smith- sonian Center for Astro- physics (Cambridge, Massa- chusetts), Henry Lin, Gon- zalo Gonzalez Abad and Abraham Loeb, focused their attention on the possibility of searching for traces of CFCs pollution in the atmo- spheres of apparently habit- able planets. Targeting CFCs seems a reviv- al of anthropocentrism, as it amounts to saying that if we had been so “intelligent” to threaten our ecosystem with their use, the same thing must have inevitably been done by possible alien civilizations. It is a clearly question- able approach, also because if ET were to have used the same method for finding in- A full-scale model of JWST on display in Munich. [EADS Astrium] Below, a graph showing the pro- duction of CFCs, from the last peak in 1986 to the lowest level in 2005. Today those molecules are banned but traces of the quantities re- leased into the atmosphere since the ’30s (when they were in- vented) will still be detectable for tens of thou- sands of years. [Ramez Naam]