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NASA's Kepler telescope finds 715 new planets outside solar
system
The Associated Press
Published Wednesday, February 26, 2014 2:39PM EST
Last Updated Wednesday, February 26, 2014 7:48PM EST
WASHINGTON -- The Earth's galaxy is looking far
more crowded and hospitable. NASA on Wednesday confirmed a bonanza of 715 newly
discovered planets outside the solar system.
Douglas Hudgins, NASA's exoplanet exploration program
scientist, called the announcement a major step toward the
planet-hunting Kepler telescope's ultimate goal: "finding Earth
2.0."
It's a big step in not just finding other Earths,
but "the possibility of life elsewhere," said Lisa Kaltenegger, a
Harvard and Max Planck Institute astronomer who wasn't part of the discovery
team.
Scientists using the Kepler telescope pushed the number of
planets discovered in the galaxy to about 1,700. Twenty years ago,
astronomers had not found any planets circling stars other than the ones
revolving around the sun.
"We almost doubled just today the number of planets known
to humanity," NASA planetary scientist Jack Lissauer said in a
teleconference.
Astronomers used a new confirmation technique to
come up with the largest single announcement of a batch of exoplanets -- what
planets outside our solar system are called.
Wednesday's announcements also were about implications for
life behind those big numbers.
Image credit: kcra.com
All the new planets are in systems like ours where multiple
planets circle a star. The 715 planets came from looking at just 305
stars. They were nearly all in size closer to Earth than gigantic Jupiter.
And four of those new exoplanets orbit their stars in
"habitable zones" where it is not too hot or not too cold
for liquid water which is crucial for life to exist.
The four new habitable zone planets are all at least twice
as big as Earth so that makes them more likely to be gas planets instead of
rocky ones like Earth -- and less likely to harbour life.
So far Kepler has found nine exoplanets in the habitable
zone, NASA said. Astronomers expect to find more when they look at all four
years of data collected by the now-crippled Kepler; so far they have looked at
two years.
Planets in the habitable zone are likely to be farther out
from their stars because it is hot close in. And planets farther out take more
time orbiting, so Kepler has to wait longer to see it again.
Another of Kepler's latest discoveries indicates
that "small planets are extremely common in our galaxy," said MIT
astronomer Sara Seagar, who wasn't part of the discovery team. "Nature
wants to make small planets."
And, in general, smaller planets are more likely to be able
to harbour life than big ones, Kaltenegger said.
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