Pink Floyd probably didn't tell you that the dark side of the moon
glows with "earthshine," sunlight that bounces off our planet and
faintly
illuminates the lunar night. As astronomers report today in Nature, the intensity and polarization of earthshine
(seen reflecting off the moon below) varies as our planet turns, and
the effect depends on how many clouds and how much ocean and vegetation
face the moon on Earth's sunlit side. Such biosignatures might also be
present in light from extrasolar Earth-sized planets, thereby
distinguishing vibrant worlds like our own from dead ones like the
moon. Moreover, starlight is nearly unpolarized, so by observing
polarized light, future space-based telescopes may be able to glimpse
Earth's twin directly despite its star's glare. And then everything
under the sun will be in tune.
Credit: ESO/B. Tafreshi/TWAN (twanight.org)
No comments:
Post a Comment