Giant-sized
telescopes such as Hubble, Spitzer and Chandra offer unprecedented views of the
cosmos, but astronomers are eager to put more powerful tools into orbit around the
Earth.
Without the
extra help, said Rachel Somerville, an astronomer at the Max Planck Institute
for Astronomy in Germany, it may be impossible to resolve some of the
universe's greatest
mysteries.
"We
need better observations to make our models better," Somerville said,
noting her search to understand galaxy formation and mysterious quasars. "... If you just put theorists in a room
for the next 15 years with the biggest supercomputer you can find, it will
never happen."
NASA
expects the James Webb Space Telescope (JWST) to launch in 2013, and many scientists
are already pondering their future observations of tiny extrasolar planets,
elusive black holes and distant galactic arms.
Somerville
and other astronomers laid bare their sky-watching hopes—including telescopes
beyond JWST—at the recent Astrophysics 2020 conference, sponsored by Johns Hopkins University and held at the Space Telescope Science Institute in Baltimore.
Galactic
details
JWST will
boast a
segmented mirror nearly 21 feet (6.4 meters) in diameter, which has seven
times the light-collecting area of Hubble. Somerville thinks the sensitive infrared observatory will be crucial for
understanding galaxy formation.
"If you don't have a high enough
resolution, galaxies you're trying to observe are going look like fuzzy
blobs," Somerville said. "Seeing the star-filled arms of galaxies in
detail, for example, can tell us how some galaxies evolved."
And the
higher the resolution, the further a telescope can see back in
time, as light can take millions or billions of years to reach Earth.
While Somerville said NASA's next "great observatory" will deliver unprecedented views
of galactic arms, she thinks the telescope could use some help to speed along
other cosmic discoveries.
Helper
telescopes
"JWST
has a big mirror and is very sensitive, but it has a postage-stamp sized camera
sensor. You can see very, very deep into the universe, but you can only see
this much at a time," she told SPACE.com, drawing the sensor size
in the air with her hands.
"That
takes a long time. If you have a smaller-diameter telescope with a lot of
sensors, you can see much more of the sky at one time."
She
explained that while such "wide-field" telescopes would not be as sensitive
as JWST, such high-sensitivity telescopes could step in to observe
interesting areas in greater detail. "It narrows your playing field and,
ultimately, saves you a lot of time," Somerville said.
Saving that
time should help astronomers find objects of interest faster and rapidly expand
scientific knowledge.
Beyond
JWST
Somerville, however, isn't the only one with
big ideas. Wes Traub, an astronomer and project scientist for several proposed
planet-finding NASA missions, would like to see extrasolar
planets in greater detail than ever before.
Traub and
his colleagues envision blocking out the blinding light of distant stars with
giant occulters, or "solar shades," to observe planets around stars
with future space telescopes.
"There
are many, many planets to be found," Traub said. If the solar shade idea
takes off, he explained, astronomers could block the intense glare of a
planet's star and precisely measure light reflecting off the planet. In effect,
astronomers could look for life-nurturing compounds such as water, methane and
oxygen on the planet.
"If we
can image a planet with just one pixel on a detector ... we could characterize
its surface and search for life," he said. If NASA approves such a mission
in the next decade, JWST may be the first telescope to take such measurements.
But Traub
said he would like to see bigger space telescopes to peer at distant planets.
"When
you go to a larger telescope, you gain proportionately that much detection
ability and sensitivity," he said, which allows for speedier extrasolar
planet searches and observations. "It would be lovely to have a 16-meter
[53-foot] diameter telescope to do this."
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