http://messenger.jhuapl.edu/news_room/status_report_11_06_06.html
MESSENGER Mission News
November 6, 2006
Upcoming Mercury/Sun Transit Whets the Appetite for MESSENGER
Discoveries
On Wednesday, November 8, the planet Mercury will make a rare trek
across the face of the Sun, beginning at 2:12 p.m. EST and lasting for
nearly five hours. Observers in North and South America, Australia, and
parts of Asia will have a good view; the transit also will be captured
via a live Webcast that will include discussions on the science,
technology, and history of the transit, as well as current knowledge of
the Sun and space weather.
Mercury transits don’t happen very often. The last was on May 7, 2003,
and the next doesn’t come until May 9, 2016. The event underscores the
importance of the NASA’s Mercury-bound MESSENGER spacecraft, which will
conduct the first orbital study of Mercury, the least explored of the
terrestrial (“rocky”) planets that also include Venus, Earth, and Mars.
“There is still so much that we don’t know about Mercury,” says Deborah
Domingue, MESSENGER’s deputy project scientist and a planetary
astronomer at the Johns Hopkins University Applied Physics Laboratory
(APL) in Laurel, Md. The mission will attempt to answer several
questions about the innermost planet, such as: Why is Mercury - the
densest planet in the solar system - mostly made of iron? Why is it the
only inner planet besides Earth with a global magnetic field? How can
the planet closest to the Sun, with daytime temperatures as high as
840?
degrees Fahrenheit, have what appears to be ice in its polar craters?
“The last time we set our sights on Mercury was 30 years ago,” Domingue
notes, referring to NASA’s Mariner 10 spacecraft, which sailed past the
planet three times in 1974 and 1975 and gathered detailed data on less
than half the surface. MESSENGER, carrying seven scientific instruments
on its compact and durable composite frame, will provide the first
images of the entire planet. The mission will also collect detailed
information on the composition and structure of Mercury’s crust, its
geologic history, the nature of its thin atmosphere and active
magnetosphere, and the makeup of its core and polar materials.
Domingue will talk about MESSENGER (short for MErcury Surface, Space
ENvironment, GEochemistry, and Ranging) during the transit Webcast,
which is geared toward middle school students. “I’m going to talk about
MESSENGER’s science goals, the Mariner missions, and why it’s so
difficult to send a spacecraft into the inner solar system,” she says.
“So while this is geared to students, the general public should tune in
if only to be reminded that NASA is still actively involved in
exploration, and not just the outer planets. We are still boldly going
where no one has gone before!”
The hour-long “Transit of Mercury Webcast,” hosted by the NASA Digital
Learning Network, will begin at 1:30 p.m. EST. In addition to APL’s
Domingue, the event will feature:
* panel discussions with scientists from NASA's Goddard Space
Flight
Center, educators and an amateur astronomer from NASA Langley
Research Center;
* two NASA “Explorer” schools, connected for a live
questions-and-answer session;
* a telescope “safety viewing” demonstration with instructions on
how to view the transit using a classroom solarscope;
* live images of the transit from two NASA satellites, SOHO and
TRACE; and
* live ground-based images from the Kitt Peak National Observatory
in Arizona and the University of Hawaii’s Mauna Kea telescopes.
To view the Web cast, go online to
http://sunearthday.nasa.gov/2007/events/mercurytransit.php.
MESSENGER Team Member Highlight: Stan Peale
Stan Peale, professor emeritus and research professor of physics at the
University of California, Santa Barbara, developed the technique by
which MESSENGER will measure the state of Mercury’s core. He is
well-known for his contributions to the dynamics of solar-system bodies
and has been published in scores of scientific journals. But if you
want
to find out about his very early work with truck gardens, read his
profile online at
http://messenger.jhuapl.edu/who_we_are/member_focus.html.
MESSENGER (MErcury Surface, Space ENvironment, GEochemistry, and
Ranging) is a NASA-sponsored scientific investigation of the planet
Mercury, and the first space mission designed to orbit the planet
closest to the Sun. The MESSENGER spacecraft launched on Aug. 3, 2004,
and after flybys of Earth, Venus and Mercury will start a yearlong
study
of its target planet in March 2011. Dr. Sean C. Solomon, of the
Carnegie
Institution of Washington, leads the mission as principal investigator.
The Johns Hopkins University Applied Physics Laboratory built and
operates the MESSENGER spacecraft and manages the Discovery-class
mission
for NASA.