Our galactic neighborhood just
got a lot bigger. NASA on Wednesday announced the discovery of 715 new planets,
by far the biggest batch of planets ever unveiled at once.
With thanks to CNN. More information and pictures there.
By way of comparison, about 1,000 planets total had been
identified in our galaxy before Wednesday.
Four of those planets are in what NASA calls the "habitable zone,"
meaning they have the makeup to potentially support life.
The planets, which orbit 305 different stars, were discovered by
the Kepler space telescope and were verified using a new technique that
scientists expect to make new planetary discoveries more frequent and more
detailed.
"We've been able to open the bottleneck to access the mother lode
and deliver to you more than 20 times as many planets as has ever been found and
announced at once," said Jack Lissauer, a planetary scientist at NASA's Ames
Research Center in California.
Launched in March 2009, the Kepler space observatory was the first
NASA mission to find planets similar to Earth that are in, or near, habitable
zones -- defined as planets that are the right distance from a star for a
moderate temperature that might sustain liquid water.
Tuesday's planets all were verified using data from the first two
years of Kepler's voyage, meaning there may be many more to come.
"Kepler has really been a game-changer for our understanding of
the incredible diversity of planets and planetary systems in our galaxy," said
Douglas Hudgins, a scientist with NASA's astrophysics division.
The new technique is called "verification by multiplicity," and
relies in part on the logic of probability. Instead of searching blindly, the
team focused on stars that the technique suggests are likely to have more than
one planet in their orbit.
NASA says 95% of the planets discovered by Kepler are smaller than
Neptune, which is four times as big as Earth.
One of them is about twice the size of Earth and orbits a star
half the size of Earth's sun in a 30-day cycle.
The other three planets in habitable zones also are all roughly
twice the size of Earth. Scientists said the multiplicity technique is biased
toward first discovering planets close to their star and that, when further data
comes in, they expect to find a higher percentage of new planets that could
potentially have a life-supporting climate like Earth's.
"The more we explore the more we find familiar traces of ourselves
amongst the stars that remind us of home," said Jason Rowe, a research scientist
at the SETI Institute in Mountain View, California, and co-leader of the
research team.
By
Doug Gross
With thanks to CNN. More information and pictures there.
