Even though Kepler-78b is only slightly larger than the Earth, it should not exist.
Its size is extraordinary only in the sense that it is the most similar in size to the
Earth of any exoplanet yet directly discovered.
Its orbit, however, is
in the sense that it circles a Sun-like star 40 times closer than
At such a scathing distance, even
rock is liquid.
Models of planet formation predict that no planet can form in such a
close orbit, and models of
planet evolution predict that
Kepler-78b's orbit should decay --
the planet to eventually merge with its parent star.
in comparison with the Earth,
Kepler-78b was discovered by eclipse with the Earth-orbiting
and further monitored for subtle wobbles by the
a spectrograph attached to the 3.6-meter
Telescopio Nazionale Galileo in the
David A. Aguilar