A Tiny Planet

NASA's Kepler mission has discovered a new planetary system that is home to the smallest planet yet found around a star like our sun, approximately 210 light-years away in the constellation Lyra.

The artist's concept depicts the new planet dubbed Kepler-37b. The planet is slightly larger than our moon, measuring about one-third the size of Earth. Kepler-37b orbits its host star every 13 days at less than one-third the distance Mercury is to the sun. The estimated surface temperature of this smoldering planet, at more than 800 degrees Fahrenheit (700 degrees Kelvin), would melt the zinc in a penny.

Astronomers don't think the tiny planet has an atmosphere or could support life as we know it, but the moon-size world is almost certainly rocky in composition.

Image credit: NASA/Ames/JPL-Caltech