| |
ZL2VAL > ROVERS 08.03.04 11:35l 116 Lines 5461 Bytes #999 (0) @ WW
BID : 8E0598ZL2VAL
Read: GUEST
Subj: Crater Hints at Past Water
Path: DB0FHN<DB0FOR<DB0MRW<DB0ERF<DB0FBB<DB0GOS<DB0EEO<DB0RES<ON0AR<7M3TJZ<
ON0BEL<ZL2BAU<ZL2BAU<ZL1AB<ZL2AB
Sent: 040308/1012Z @:ZL2AB.#46.NZL.OC #:37297 [New Plymouth] FBB7.00g
From: ZL2VAL@ZL2AB.#46.NZL.OC
To : ROVERS@WW
NEWS RELEASE: 2004-79
March 05, 2004
Volcanic Rock in Mars' Gusev Crater Hints at Past Water
NASA's Spirit has found hints of a water history in a rock at Mars'
Gusev Crater, but it is a very different type of rock than those in
which NASA's Opportunity found clues to a wet past on the opposite side
of the planet.
A dark volcanic rock dubbed "Humphrey," about 60 centimeters (2 feet)
tall, shows bright material in interior crevices and cracks that looks
like minerals crystallized out of water, Dr. Ray Arvidson of Washington
University, St. Louis, reported at a NASA news briefing today at NASA's
Jet Propulsion Laboratory, Pasadena, Calif. He is the deputy principal
investigator for the rovers' science instruments.
"If we found this rock on Earth, we would say it is a volcanic rock that
had a little fluid moving through it," Arvidson said. If this
interpretation is correct, the fluid -- water with minerals dissolved in
it -- may have been carried in the original magma that formed the rock
or may have interacted with the rock later, he said.
The clues appear in an interior exposure of "Humphrey" where Spirit's
rock abrasion tool scraped away the rock's surface to a depth of 2
millimeters (.08 inch). To gain more confidence that the bright material
seen in cracks and pores is not dust that has intruded from the surface
over the millenia, scientists intend to have Spirit grind more deeply
into another dark rock, not yet selected. The bright material is not
debris from the grinding process, said Stephen Gorevan of Honeybee
Robotics, New York, lead scientist for the abrasion tool.
The amount of water suggested by the possible crystals in "Humphrey" is
far less than what is indicated by the minerals and structures that
Opportunity has revealed in rocks at Meridiani. Rover scientists
announced the Opportunity findings earlier this week. "Mars is a diverse
planet," Arvidson said today.
Spirit is headed toward a crater nicknamed "Bonneville," about 150
meters (500 feet) in diameter, where scientists hope to see rocks from
beneath the region's surface volcanic layer. Those rocks may tell yet a
different story from an earlier era of Gusev Crater's past.
At Meridiani Planum, Opportunity has finished taking a set of 114
microscope images of a rock called "Last Chance" to examine details of
the rock's layering structure. The sequence required more than 400
commands and more than 200 positions of Opportunity's robotic arm, said
Opportunity Mission Manager Matt Wallace of JPL. "Our activities are
getting increasingly complex," he noted.
Spirit completed its 60th martian day, or sol, at Gusev late Thursday.
Opportunity completed its 40th sol at Meridiani at 9:32 a.m. Friday,
PST. "Between the two rovers, we've had a terrific 100 days on Mars.
This last week has been particularly exciting," Wallace said.
A new color view, combining several frames from Opportunity's panoramic
camera, adds information about the rover's likely destination after
finishing work in and around the small crater where it landed. From
partway up the inner slope of that 22-meter-diameter (72-foot-diameter)
crater, the rover has an improved view of a crater nicknamed
"Endurance," about 10 times as big and about 700 meters (2,300 feet) to
the east. "We can see features in the rim, maybe streaks, maybe layers,"
said Dr. Jim Bell of Cornell University, Ithaca, N.Y., lead scientist
for both rovers? panoramic cameras.
The same new view across the flat plain of Meridiani also shows
Opportunity's jettisoned heat shield, a trail of marks left by the
airbag bounces and a solitary dark rock about 40 centimeters (16 inches)
across. Bell said, "Not only did we get incredibly lucky to get this
hole-in-one in the crater, but on the way into the crater we hit with
the airbags the only rock around."
Both rovers carry magnets supplied by Denmark for experiments to analyze
martian dust. Dust covers much of Mars' surface and hangs in the
atmosphere, occasionally rising into giant dust storms. One of the
magnets is designed to exclude any magnetic dust particles from landing
in the center of a target area. During Spirit's time on Mars, dust has
accumulated on other parts of the target while the center has remained
"probably the cleanest area anywhere on the surface of the rover," said
Dr. Morten Madsen, science team member from the Center for Planetary
Science, Copenhagen, Denmark.
"Most, if not all of the dust particles in the martian atmosphere are
magnetic," Madsen said. Another of the magnets is within reach of the
rover's robotic arm. Examination of dust on the target by instruments on
the end of the arm will soon yield further information about the
composition of the dust, he said.
JPL, a division of the California Institute of Technology in Pasadena,
manages the Mars Exploration Rover project for NASA's Office of Space
Science, Washington, D.C. Images and additional information about the
project are available from JPL at http://marsrovers.jpl.nasa.gov and
from Cornell University at http://athena.cornell.edu
=========================
73 de Alan, (Sysop ZL2AB).
AX25:ZL2VAL@ZL2AB.#46.NZL.OC
APRS:!3903.34S/17406.45E]
IP :zl2val@qsl.net
Message timed: 23:06 on 2004-Mar-08 (NZT)
Message sent using WinPack-AGW V6.80
Points to ponder
~~~~~~~~~~~~~~~~
Marriage
~~~~~~~~
When a man steals your wife, there is no better revenge than to let
him keep her.
Read previous mail | Read next mail
| |
