Mass measured for smallest exoplanet yet

By the late 19th century, astronomers had calculated correctly that Mars — about half the diameter of Earth — holds roughly one-tenth the mass of Earth, whereas its density is about 71 percent that of our planet. These fundamental planetary traits have also long been known for Mercury and Venus. But measuring the masses and densities of the many roughly Earth-sized exoplanets discovered lately — which, to space telescopes, appear as mere specks as they pass in front of, or transit, their home stars — has proved challenging.

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Timothy Oleson

Timothy Oleson

Tim is the news editor at EARTH, and writes the Bare Earth Elements blog. His scientific interests span the geosciences from biogeochemistry to seismology to space science. Formerly based in Madison, Wis., he now resides in the Washington, D.C., area.

Tuesday, March 22, 2016 - 06:00