How can we search for life on exoplanets? Step one: examine the Earth as if it were an exoplanet. That’s the idea behind a recent look at earthshine.
Researchers aimed what’s officially called the Very Large Telescope, housed at the European Southern Observatory, at the moon. They measured earthshine: sunlight that reflects off the Earth, hits the moon and bounces back.
The scientists are looking for hints of life in the light—such as evidence of the gases associated with organic life. Such gas signatures are generally tough to find, because any planetary light is swamped by the light of its host star.
But in this effort, the research team also took into account polarized light. Because light reflected off a planet is polarized. But light from th
