Can we develop new techniques to detect life on exoplanets? Previous studies have assessed the likelihood of detecting life through signs of biogenic gases in the atmosphere or a red edge. Biogenic gases and the red edge could be signs of either single or multi-cellular life. We propose a technique to determine whether tree-like multi-cellular life exists on extra-solar planets using BRDF, or shadows at different sun angles. BRDF arises from the changing visibility of the shadows cast by objects, and the presence of tree-like structures is clearly distinguishable from flat ground with the same reflectance spectrum.
We just received a NASA Habitable Worlds grant to continue this work. See the proposal here. We are looking for a PhD student to work on the project. If interested please contact me.
Doughty, C.E. and Wolf, A. (2010) Detecting Tree-like Multicellular Life on Extrasolar Planets. Astrobiology, 10(9): 869-879. PDF
Popular press on our Astrobiology work
Astrobiology Magazine: Seeing the Planets for the Trees.
New Scientist: Could we detect trees on other planets?