NJIT and JPL Physicists Detail Earthshine's Role in Planet Hunting and Climate Variables

http://www.njit.edu/publicinfo/press...elease_876.php

New Jersey Institute of Technology Press Release
Contact : Sheryl Weinstein
Information : Public Relations
973-596-3436

NJIT and JPL Physicists Detail Earthshine's Role in Planet Hunting and
Climate Variables

NEWARK, May 19, 2006

How the study of Earthshine continues to elucidate climate variables
and how the use of Earthshine data may help to search for advanced life
on distant planets, will be the foci of an upcoming panel discussion in
Baltimore led by solar physicist Philip R. Goode, PhD, and a panel of
researchers. Earthshine is the reflected light from earth which
creates
the ghostly glow completing the circular outline of a partial moon.

Goode, distinguished professor at New Jersey Institute of Technology
(NJIT) and director of Big Bear Solar Observatory (BBSO), Calif.,
leads
the talk May 23, 2006, 10 a.m., at the Baltimore Convention Center
during the 2006 joint assembly of six geophysical societies, including
the American Geophysical Union. (Contact Sheryl Weinstein, 973-596-3436
to interview Goode and/or other panelists: High resolution Earthshine
photos taken by robotic telescope also available.)

NJIT has managed and operated BBSO since 1997. In April of 2007, Goode
plans to see first light from a new 1.6-meter aperture telescope
installed at BBSO. The instrument is expected to be the most capable
ground-based solar telescope in the world.

Joining Goode's panel are NJIT Research Professor Pilar
Montanes-Rodriguez, PhD, and Wesley A. Traub, PhD, chief scientist for
NASA's Navigator Program to search for extrasolar planets, and project
scientist for NASA's Terrestrial Planet Finder Coronagraph Mission.
Traub works at NASA's Jet Propulsion Laboratory, managed by the
California Institute of Technology.

Since the 16th century when Leonardo Da Vinci first described
Earthshine, the idea has captivated both scientists and poets. Goode
and the Big Bear team of Montanes-Rodriguez with NJIT Research
Professor
Enric Palle have used Earthshine observations to determine changes in
the earth's climate. Much of this research has focused on the
relationship of cloud cover to global warming.

More recently, Goode has been developing a worldwide network of
inexpensive ground-based robotic telescopes to measure Earthshine to
better understand climate variables. "I see these telescopes, capable
of engaging scientists worldwide--even ones in developing nations--in
significant studies of climate change," Goode said. "Not that
Earthshine data should be limited to climate change. I see it also
useful in the search for life on other planets." He will discuss these
telescopes along with his Earthshine research as related to global
warming at the panel discussion.

Earthshine has enabled Montanes-Rodriguez to gauge requirements for
discovering complex life on distant planets. "At any moment, satellite
cloud cover data reveals the amount of vegetation that would be visible
from just above the Earth. This knowledge can be combined with
earthshine observations to successfully detect vegetation on the Earth
as though it were a distant planet," she said. "Although the typical
day's signal might be weaker than scientists previously thought, it can
still be clearly seen on certain days."

Using real cloud cover satellite data and Earthshine spectral data,
Montanes-Rodriguez showed that for a few days during the year when
Earth's vegetation signal is prominent, vegetation can very clearly be
seen from space. Such days are visible around the time of a full moon
and depend upon reflecting a tiny fragment of Earth--typically small
cloud-free, green crescents, such as the Amazon rain forests.

"Montanes-Rodriguez has measured the spectral Earthshine with
state-of-the-art accuracy, calibrated the albedo by also observing
lunar
eclipses, and modeled it as if you were a distant astronomer looking at
our solar system, and seeing under what circumstances you could find an
Earthlike planet," said Goode. Montanes-Rodriguez also gauged the
task's difficulty.

Traub has modeled what one might expect the Earthshine looked like in
the distant past. And, he measured the spectral Earthshine.

"There is a close connection between Earthshine and extrasolar
planets,"
Traub said. "The reflected spectrum is exactly the same as an
astronomer
would see from a nearby star. So turning this around, we can test our
ability to detect life on a nearby planet by seeing if we can detect
life on Earth, using Earthshine."

Traub's models of the Earth's spectrum cover the full range of Earth's
geological history. "The carbon-dioxide dominated atmosphere of the
early Earth can be seen clearly in the thermal infrared spectrum,"
Traub
said. "The rise of oxygen, from life, showed up in the visible
spectrum.
If we find an extra solar planet in any of these stages of the Earth's
past history, we will be able to identify it as such."

Details of the Earthshine spectra measured and modeled by Traub and his
colleagues show strong bands of oxygen, water and ozone, all good signs
of life. Earth's blue-enhanced brightness (the blue sky) from visible
and near-infrared spectra was also visible. Thermal infrared spectra of
the earth, taken by a spacecraft to Mars several years ago, were
similarly helpful, showing carbon dioxide, ozone, and water. With an
improved spectrometer, Traub said, methane and nitrous oxide could have
been seen.

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research university, enrolls more than 8,200 students in bachelor's,
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