NASA News: NASA Plans Air Pollution Flights Over Maryland On July 1
WASHINGTON -- NASA's DISCOVER-AQ air quality field campaign isscheduled to take to the skies over the Baltimore-Washington traffic
corridor on Friday, July 1, from 10:30 a.m. to 6:30 p.m. EDT. The
flight is part of a mission to enhance the capability of satellites
to measure ground-level air quality from space.
NASA's P-3B research aircraft will fly at low altitudes over the
northeast Maryland study region. The P-3B is a large, 117-foot,
four-engine turboprop, carrying nine scientific instruments. It will
fly as low as 1,000 feet above the ground along a route that will
take it over major roadway traffic corridors. The P-3B also will make
spiral ascents and descents over six locations where air-quality
measurements are being made from ground stations.
Approximately 14 DISCOVER-AQ flights are planned through July when
weather conditions are appropriate. NASA will announce each flight by
5 p.m. the day before the aircraft is scheduled to fly. The flights
will occur between 6 a.m. and 8 p.m.
DISCOVER-AQ, which stands for Deriving Information on Surface
conditions from Column and Vertically Resolved Observations Relevant
to Air Quality, is a NASA Earth Science Division research effort
conducted in collaboration with the Maryland Department of the
Environment, the U.S. Environmental Protection Agency and several universities.
A detailed map of the P-3B's low-altitude flight path is available at:
http://go.usa.gov/ZiP
For more information about the DISCOVER-AQ mission, visit:
http://www.nasa.gov/discover-
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NASA'S Spitzer Finds Distant Galaxies Grazed On Gas
WASHINGTON -- Galaxies once thought of as voracious tigers are morelike grazing cows, according to a new study using NASA's Spitzer Space Telescope.
Astronomers have discovered that galaxies in the distant universe
continuously ingested their star-making fuel over long periods of
time. This goes against previous theories that galaxies devoured
their fuel in quick bursts after run-ins with other galaxies.
"Our study shows the merging of massive galaxies was not the dominant
method of galaxy growth in the distant universe," said Ranga-Ram
Chary of NASA's Spitzer Science Center at the California Institute of
Technology in Pasadena, Calif. "We're finding this type of galactic
cannibalism was rare. Instead, we are seeing evidence for a mechanism
of galaxy growth in which a typical galaxy fed itself through a
steady stream of gas, making stars at a much faster rate than
previously thought."
Chary is the principal investigator of the research appearing in the
Aug. 1 issue of the Astrophysical Journal. According to his findings,
these grazing galaxies fed steadily over periods of hundreds of
millions of years and created an unusual amount of plump stars, up to
100 times the mass of our sun.
"This is the first time that we have identified galaxies that
supersize themselves by grazing," said Hyunjin Shim, also of the
Spitzer Science Center and lead author of the paper. "They have many
more massive stars than our Milky Way galaxy."
Galaxies like our Milky Way are giant collections of stars, gas and
dust. They grow in size by feeding off gas and converting it to new
stars. A long-standing question in astronomy is: Where did distant
galaxies that formed billions of years ago acquire this stellar fuel?
The most favored theory was that galaxies grew by merging with other
galaxies, feeding off gas stirred up in the collisions.
Chary and his team addressed this question by using Spitzer to survey
more than 70 remote galaxies that existed 1 to 2 billion years after
the big bang (our universe is approximately 13.7 billion years old).
To the surprise of the astronomers, these galaxies were blazing with
what is called H alpha, radiation from hydrogen gas that has been hit
with ultraviolet light from stars. High levels of H alpha indicate
stars are forming vigorously. Seventy percent of the surveyed
galaxies show strong signs of H alpha. By contrast, only 0.1 percent
of galaxies in our local universe possess the signature.
Previous studies using ultraviolet-light telescopes found about six
times less star formation than Spitzer, which sees infrared light.
Scientists think this may be due to large amounts of obscuring dust,
through which infrared light can sneak. Spitzer opened a new window
onto the galaxies by taking very long-exposure infrared images of a
patch of sky called the GOODS fields, for Great Observatories Origins
Deep Survey.
NASA's Jet Propulsion Laboratory in Pasadena manages the Spitzer Space
Telescope mission for the agency's Science Mission Directorate in
Washington. Science operations are conducted at the Spitzer Science
Center. Caltech manages JPL for NASA. For more information about
Spitzer, visit:
http://www.nasa.gov/spitzer
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NASA Completes Mirror Polishing For James Webb Space Telescope
WASHINGTON -- Mirrors are a critical part of a telescope. The qualityis crucial, so completion of mirror polishing represents a major
milestone. All of the mirrors that will fly aboard NASA's James Webb
Space Telescope have been polished so the observatory can see objects
as far away as the first galaxies in the universe.
The Webb telescope is comprised of four types of mirrors. The primary
one has an area of approximately 25 square meters (29.9 square
yards), which will enable scientists to capture light from faint,
distant objects in the universe faster than any previous space
observatory. The mirrors are made of Beryllium and will work together
to relay images of the sky to the telescope's science cameras.
"Webb's mirror polishing always was considered the most challenging
and important technological milestone in the manufacture of the
telescope, so this is a hugely significant accomplishment," said Lee
Feinberg, Webb Optical Telescope manager at NASA's Goddard Space
Flight Center in Greenbelt, Md.
The mirrors were polished at the L3 Integrated Optical Systems -
Tinsley in Richmond, Calif. to accuracies of less than one millionth
of an inch. That accuracy is important for forming the sharpest
images when the mirrors cool to -400°F (-240°C) in the cold of space.
"The completion of the mirror polishing shows that the strategy of
doing the hardest things first has really paid off," said Nobel Prize
Winner John C. Mather, Webb's senior project scientist at Goddard.
"Some astronomers doubted we could make these mirrors."
After polishing, the mirrors are being coated with a microscopically
thin layer of gold to enable them to efficiently reflect infrared
light. NASA has completed coating 13 of 18 primary mirror segments
and will complete the rest by early next year. The 18 segments fit
together to make one large mirror 21.3 feet (6.5 meters) across.
"This milestone is the culmination of a decade-long process," said
Scott Willoughby, vice president and Webb Telescope Program manager
for Northrop Grumman Aerospace Systems. "We had to invent an entire
new mirror technology to give Webb the ability to see back in time."
Northrop Grumman Corp. in Redondo Beach, Calif. is the telescope's
prime contractor.
As the successor to the Hubble Space Telescope, the Webb telescope is
the world's next-generation space observatory. It is the most
powerful space telescope ever built. More than 75 percent of its
hardware is either in production or undergoing testing. The telescope
will observe the most distant objects in the universe, provide images
of the first galaxies ever formed and study planets around distant
stars. NASA, the European Space Agency and the Canadian Space Agency
are collaborating on this project.
For related images and more information about the mirrors, visit:
http://www.nasa.gov/topics/
To view the "Behind the Webb: Wax on, Wax Off" video explaining the
mirror polishing process, visit:
http://webbtelescope.org/webb_
For more information about the James Webb Space Telescope, visit:
http://www.jwst.nasa.gov
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