Hubble Space Telescope to Target 2012 Transit of Venus
Alfred Vidal-Madjar, CNRS, Institut d'Astrophysique de Paris, submitted the proposal entitled Venus observed as an extrasolar planet.
While astronomers can discern the atmosphere of big planets 150 light years away, they seek to detect the atmospheres of smaller earth-size planets as well. To mimic looking at a small exoplanet, the Hubble Space Telescope will measure small changes in light reflected off the moon as Venus diminishes the sunlight slightly when the inner planet passes between the sun and earth on June 5-6, 2012.
"We don't know if it will work, but it's worth a shot," Mountain said. "If it does work, we'll get an idea of what earth-size would look like...It will guide us in the future if we ever see dip like it; we're seeing a very small planet...It's quite a risky project, but the payoff would be quite remarkable, for we'd actually be able to measure the atmosphere of Venus using the Hubble Space Telescope."