Andrew Yee[_1_]
March 20th 08, 01:39 AM
Public Affairs Office
Naval Research Laboratory
Washington, D.C.
3/11/2008
NRL Press Release: 21-08r
NRL To Design Telescope to See Into the Dark Ages
A team of scientists and engineers led by the Naval Research Laboratory
(NRL) will study how to design a telescope on the Moon for peering into the
last unexplored epoch in the Universe's history. NASA has announced that it
will sponsor a series of studies focusing on next-generation space missions
for astronomy. These studies will contribute to the Decadal Survey, an
effort undertaken every 10 years by astronomers and physicists to help
establish priorities for future research directions in astronomy and
astrophysics. The upcoming Decadal Survey occurs over the next two years.
Among the missions to be studied is the Dark Ages Lunar Interferometer
(DALI), the NRL-led concept for a telescope based on the Moon and studying
an era of the young Universe, during the first 100 million years of its
existence. Although the night sky is filled with stars, these stars did not
form instantaneously after the Big Bang. There was an interval, now called
the "Dark Ages," in which the Universe was unlit by any star. The most
abundant element in the Universe, and the raw material from which stars,
planets, and people are formed, is hydrogen. Fortunately, the hydrogen atom
can produce a signal in the radio-wavelength part of the spectrum, at 21 cm;
a wavelength far longer than what the human eye can detect. If these first
signals from hydrogen atoms in the Dark Ages can be detected, astronomers
can essentially probe how the first stars, the first galaxies, and
ultimately the modern Universe evolved.
Because the Universe is expanding, the signals from these distant hydrogen
atoms will be stretched (or redshifted) to much longer wavelengths, as large
as several meters. While astronomical observations at radio wavelengths have
a long history, this portion of the electromagnetic spectrum is now heavily
used for various civil and military transmissions, all of which are millions
of times brighter than the hydrogen signal that astronomers seek to detect.
Additionally, the upper layers of the Earth's atmosphere are ionized (the
ionosphere), which introduce distortions into astronomical signals as they
pass through on their way to telescopes on the ground.
With no atmosphere and shielding from the Earth, the far side of the Moon
presents a nearly ideal environment for a sensitive Dark Ages telescope. In
NRL's DALI concept, scientists and engineers will investigate novel antenna
constructions, methods to deploy the antennas, electronics that can survive
in the harsh lunar environment, and related technology in preparation for
developing a roadmap for research and development of a lunar telescope over
the next decade. The team will also build on their experience in developing
the Radio Observatory for Lunar Sortie Science, a NASA-funded study of a
pathfinding array that would be located on the near side of the Moon.
The project leader at NRL, Dr. Joseph Lazio, pointed out that DALI will be
one of the most powerful telescope ever built and will bring us closer than
we have ever been to understanding where our Universe came from and where it
is going. "Probing the Dark Ages presents the opportunity to watch the young
Universe evolve," Dr. Lazio said. "Just as current cosmological studies have
both fascinated and surprised us, I anticipate that DALI will lead both to
increased understanding of the Universe and unexpected discoveries."
When asked about the program, NRL Senior Astronomer Dr. Kurt Weiler
remarked: "Building telescopes on the Moon is clearly a long-term project,
but I am very excited about us getting started on this proposal."
Scientists and engineers from institutions and NASA centers around the
country are participating in the Dark Ages Lunar Interferometer study,
including NASA/Goddard Space Flight Center, Caltech/Jet Propulsion
Laboratory, the University of Colorado, the Smithsonian Astrophysical
Observatory, the National Radio Astronomy Observatory, University of
California-Los Angeles, University of California-Berkeley, the University of
New Mexico, and Virginia Polytechnic Institute.
IMAGE CAPTION:
[http://www.nrl.navy.mil/PressReleases/2008/fig-1-21.jpg (77KB)]
An artist's conception of the Dark Ages Lunar Interferometer. The crater
Tsiolkovsky is a relatively level region on the far side of the Moon. A
lander would deposit a series of rovers, which would then move out and
unroll a set of arms containing individual antennas. The astronomical
signals picked up by the antennas would be transmitted to back to the
central lander for processing.
Naval Research Laboratory
Washington, D.C.
3/11/2008
NRL Press Release: 21-08r
NRL To Design Telescope to See Into the Dark Ages
A team of scientists and engineers led by the Naval Research Laboratory
(NRL) will study how to design a telescope on the Moon for peering into the
last unexplored epoch in the Universe's history. NASA has announced that it
will sponsor a series of studies focusing on next-generation space missions
for astronomy. These studies will contribute to the Decadal Survey, an
effort undertaken every 10 years by astronomers and physicists to help
establish priorities for future research directions in astronomy and
astrophysics. The upcoming Decadal Survey occurs over the next two years.
Among the missions to be studied is the Dark Ages Lunar Interferometer
(DALI), the NRL-led concept for a telescope based on the Moon and studying
an era of the young Universe, during the first 100 million years of its
existence. Although the night sky is filled with stars, these stars did not
form instantaneously after the Big Bang. There was an interval, now called
the "Dark Ages," in which the Universe was unlit by any star. The most
abundant element in the Universe, and the raw material from which stars,
planets, and people are formed, is hydrogen. Fortunately, the hydrogen atom
can produce a signal in the radio-wavelength part of the spectrum, at 21 cm;
a wavelength far longer than what the human eye can detect. If these first
signals from hydrogen atoms in the Dark Ages can be detected, astronomers
can essentially probe how the first stars, the first galaxies, and
ultimately the modern Universe evolved.
Because the Universe is expanding, the signals from these distant hydrogen
atoms will be stretched (or redshifted) to much longer wavelengths, as large
as several meters. While astronomical observations at radio wavelengths have
a long history, this portion of the electromagnetic spectrum is now heavily
used for various civil and military transmissions, all of which are millions
of times brighter than the hydrogen signal that astronomers seek to detect.
Additionally, the upper layers of the Earth's atmosphere are ionized (the
ionosphere), which introduce distortions into astronomical signals as they
pass through on their way to telescopes on the ground.
With no atmosphere and shielding from the Earth, the far side of the Moon
presents a nearly ideal environment for a sensitive Dark Ages telescope. In
NRL's DALI concept, scientists and engineers will investigate novel antenna
constructions, methods to deploy the antennas, electronics that can survive
in the harsh lunar environment, and related technology in preparation for
developing a roadmap for research and development of a lunar telescope over
the next decade. The team will also build on their experience in developing
the Radio Observatory for Lunar Sortie Science, a NASA-funded study of a
pathfinding array that would be located on the near side of the Moon.
The project leader at NRL, Dr. Joseph Lazio, pointed out that DALI will be
one of the most powerful telescope ever built and will bring us closer than
we have ever been to understanding where our Universe came from and where it
is going. "Probing the Dark Ages presents the opportunity to watch the young
Universe evolve," Dr. Lazio said. "Just as current cosmological studies have
both fascinated and surprised us, I anticipate that DALI will lead both to
increased understanding of the Universe and unexpected discoveries."
When asked about the program, NRL Senior Astronomer Dr. Kurt Weiler
remarked: "Building telescopes on the Moon is clearly a long-term project,
but I am very excited about us getting started on this proposal."
Scientists and engineers from institutions and NASA centers around the
country are participating in the Dark Ages Lunar Interferometer study,
including NASA/Goddard Space Flight Center, Caltech/Jet Propulsion
Laboratory, the University of Colorado, the Smithsonian Astrophysical
Observatory, the National Radio Astronomy Observatory, University of
California-Los Angeles, University of California-Berkeley, the University of
New Mexico, and Virginia Polytechnic Institute.
IMAGE CAPTION:
[http://www.nrl.navy.mil/PressReleases/2008/fig-1-21.jpg (77KB)]
An artist's conception of the Dark Ages Lunar Interferometer. The crater
Tsiolkovsky is a relatively level region on the far side of the Moon. A
lander would deposit a series of rovers, which would then move out and
unroll a set of arms containing individual antennas. The astronomical
signals picked up by the antennas would be transmitted to back to the
central lander for processing.