What’s the News: Using data from NASA’s Kepler spacecraft, astronomers from Princeton University and the Harvard-Smithsonian Center for Astrophysics have discovered the darkest known planet. The exoplanet, called TrES-2b, is located about 750 light-years away from Earth and reflects less than 1 percent of the incident light from its parent star, making it blacker than the blackest piece of coal. The discovery was published recently in the Monthly Notices of the Royal Astronomical Society (pdf).

What’s the Context:

For astronomers, albedo—the percentage of light that is reflected off an object’s surface—is a very useful concept that allows them to infer much about an object’s properties. For example, by comparing the albedo of an asteroid with the albedos of known materials here on Earth, astronomers can figure out how much of the body’s surface is covered with ice, dust, or metallic compounds. Albedo can also help pinpoint the temperature of a solar body.
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