Finding
small planets, ones the size of Earth, is challenging in part because they
produce fainter signals, said Dave
Gallagher, the director for astronomy and physics at NASA's Jet Propulsion
Laboratory, who likened it to spotting a firefly beside a searchlight.
That
difficulty doesn't dull the hunt for another Earth or signs of life.
NASA
administrator Charles Bolden said he counts himself among the people who
"are probably convinced that it's highly improbable in the limitless
vastness of the universe that we humans stand alone."
Scientists
looking for signs of life in the universe, as well as, another planet like our
own are a lot closer to their goal than people imagine.
That
was the consensus of a panel on the search for life in the universe held at
NASA headquarters recently in Washington. The discussion focused not only on
the philosophical question of whether we are alone in the universe but also on
the technological advances made in an effort to answer that question.
Sara Seager,
a MacArthur Fellow and professor of planetary science and physics at the
Massachusetts Institute of Technology said, “We believe we're very, very close
in terms of technology and science to actually finding the other Earth and our
chance to find signs of life on another world”.
Another,
John Grunsfeld, an astronaut who
helped repair the Hubble Space Telescope in 2009 and is now an associate
administrator at NASA, said, “Finding Earth's twin, that's kind of the holy
grail”.
Scientists have made stellar strides
in the past few years alone.
According
to John Mather, senior project
scientist on NASA's next-generation James Webb Space Telescope, the Earth,
though 4.5 billion years old, is a newcomer.
“It's
only about one-third of the age of the universe and our galaxy is
ever-evolving, with "about five or 10 new stars being born per year in our
Milky Way," Mather said.
"We
already know that our galaxy has at least 100 billion planets, and we didn't
know that five years ago," said Matt
Mountain, director of the Space Telescope Science Institute in Maryland.
He
credited the work of the Kepler Space Telescope for these new discoveries. The planet-hunting
Kepler probe, launched in 2009, finds planets by looking for dips in the
brightness of a star as a planet transits, or crosses, in front of that star.
Kepler
also found the first Earth-size planet that orbits in a star's habitable zone,
the area around a star where a planet could exist with liquid water on its
surface.
The
Kepler mission builds upon the stalwart Hubble Space Telescope, which launched
in 1990 and was the first of its kind to be placed in space. As Hubble orbits
the Earth, it allows scientists to peer back in time, into distant galaxies,
and yields stunning images of the cosmos.
Hubble
has helped shape our awareness of our planet's place in an ever-changing
universe.
Also, Hubble's astounding views come
from a vantage point only 353 miles above our Earth.
From CNN
In
comparison, the James Webb telescope will be a whopping 930,000 miles from our
planet. That's close to four times the distance between the Earth and the moon.
Webb is set to launch in 2018.
Mountain,
who is the telescope scientist for Webb, said scientists now know where every
single star is within 200 light years of the Sun.
NASA's
assembled panelists said, if they follow this map of stars, they're certain to
find a multitude of new planets.
"Every
star in the sky is a sun, and if our sun has planets, we naturally expect those
other stars to have planets also, and they do," said Seager. Continuing she said, “if someone looked up at a starry sky
and wondered how many of the stars have planets, the answer would be
"basically every single one”.
Some
of a star's light will shine through the atmosphere, said Seager, and the Webb telescope should be able to pick up gases from
the planet that are imprinted on the atmosphere. While the Webb telescope
wasn't designed to find signs of life on another planet, it can spot bio-signature
gases in the atmosphere – produced by life.
Seager also
said that with the James Webb telescope, "we have our first chance, our
first capability of finding signs of life on another planet. Now nature just
has to provide for us”.