It's going to take infrared eyes to see farther back in time
than even the Hubble Space Telescope, and that's what the James Webb Space
Telescope's MIRI or Mid-Infrared Instrument detectors will do. Now there's a
new short movie that shows what the MIRI detectors are all about and what they
can do.
"The MIRI is one of four science instruments aboard the
Webb telescope that is designed to record images and spectra at the longest
wavelengths that the Webb telescope can observe," said Matt Greenhouse,
Project Scientist for the science instrument payload. "The mid-infrared
spectrum covers wavelengths in the range of 5 to 28 micrometers or microns
(about 10 to 50 times longer than our eyes can see). Light in this portion of
the spectrum is invisible to our eyes but is produced by all room-temperature
objects and carries key information about the local and early universe,"
Greenhouse said. Light at these wavelengths is blocked by water vapor in the
earth's atmosphere and can only be efficiently observed using a telescope in
space.
The MIRI optics module is labeled here to show different components. Credit: University of Leicester, European Consortium Institutes and JPL
A new video about the MIRI detectors is part of an on-going
series called "Behind the Webb" about the James Webb Space Telescope.
It was produced and created by the Space Science Telescope Institute (STScI) of
Baltimore, Md. and is available at www.webbtelescope.org. Part of the
video was shot at NASA's Jet Propulsion Laboratory (JPL) in Pasadena, Calif.
in January 2009. "It is a broadcast quality video in high definition and
will be available in almost a dozen varieties of file formats from Quicktime,
to WMV to Flash, to M4V, and all in different sizes," said Mary Estacion,
News Video Producer at STScI.
The video runs exactly three minutes and explains how the
three detectors on the MIRI work and the tests they endure to prepare them for
the Webb telescope's launch and flight in space. The video is hosted by
Estacion, who interviewed Dr. Michael Ressler, the MIRI Project Scientist at
NASA JPL. In the video, Ressler explains what MIRI detectors do and how the MIRI
sensor works by comparing it to a chip on a camera. The video also takes the
viewer behind the scenes and into a clean room to show viewers how the MIRI
detectors are tested.
The Webb telescope is the largest space observatory ever
constructed. As a result, MIRI will have a huge discovery potential and will
enable the Webb telescope to achieve over one hundred times the sensitivity of
any previous observatory at these wavelengths.
To see the very first stars and galaxies, astronomers have
to look deep into space and far back in time. Starlight travels through space
at a finite speed (300,000 kilometers/second). So if we observe an object that
is 300,000 kilometers away with the Webb telescope, we see it as it was 1
second in the past. Astronomical distances are measured in "light
years", the distance that light travels in a year. Galaxies can be
billions of light years away. As a result of this transmission delay,
astronomical telescopes, like the Webb, allow astronomers to literally look
back in time and see the universe as it was billions of years in the past.
The space that fills the universe has been expanding since
the Big Bang. As a consequence of this expansion, the wavelength of
ultra-violet and visible light emitted by the first galaxies to form after the
Big Bang has been stretched into the infrared portion of the spectrum, and can
only be observed by telescopes that are equipped with infrared cameras such as
the MIRI. "The Webb observatory design has been optimized to enable
infrared observations that will, for the first time, enable astronomers to see
the period in the evolution of the universe in which the first galaxies
formed," Greenhouse said. "The MIRI will play a key role in enabling
the very first observations of the galaxy formation epoch."
In addition to the huge discovery potential, MIRI will
provide valuable information in the four areas of the Webb's science
objectives: 1) Discovery of the 'first light' emitting objects after the Big
Bang; 2) Assembly of galaxies: history of star formation, growth of black
holes, prediction of heavy elements; 3) How stars and planetary systems form;
and 4) Evolution of planetary systems and conditions for life.
http://webbtelescope.org/webb_telescope/behind_the_webb/
Behind the Web
