the tiniest planet ever spotted, demonstrates that sun-like stars
in our galaxy are capable of hosting much smaller planets than
anything detected so far, say researchers.
Tim Bedding, professor and head of the University of Sydney School
of Physics and Dennis Stello, Australian Research Fellow at the
school, contributed to the discovery effort of an international
"That we have found one of these small and hard-to-detect planets
suggests that they are abundant around other stars and lends
weight to the belief that as planet size decreases their
occurrence increases exponentially," said Stello, the journal
Kepler-37b is an exoplanet, or planet located outside the solar
system, and is estimated to be a similar size to Earth's moon,
which is only 3,475 kilometres in diameter, according to a Sydney
Owing to this extremely small size and its highly irradiated
surface, Kepler-37b is believed to be a rocky planet with no
atmosphere or water, similar to Mercury.
The Kepler spacecraft made the Kepler-37b finding possible. The
spacecraft was launched in 2009 with the goal of determining how
often rocky planets occur in the habitable zone around sun-like
host stars in our galaxy.
Over the course of 978 days of observations by the Kepler
spacecraft, transit signals of three planets of the star
Kepler-37, a slightly cooler and older star than our sun, were
"Since the discovery of the first exoplanet we have known that
other planetary systems can look quite unlike our own, but it is
only now, thanks to the precision of the Kepler space telescope
that we have been able to find planets smaller than the ones we
see in our own solar system," said Bedding.