| |
ZL2VAL > ROVERS 24.03.04 13:32l 107 Lines 4892 Bytes #999 (0) @ WW
BID : EF0682ZL2VAL
Read: GUEST
Subj: Opprotunity on the beach?
Path: DB0FHN<DB0RGB<OK0PPL<DB0RES<ON0AR<7M3TJZ<ZL2TZE<ZL2AB
Sent: 040324/1111Z @:ZL2AB.#46.NZL.OC #:37970 [New Plymouth] FBB7.00g
From: ZL2VAL@ZL2AB.#46.NZL.OC
To : ROVERS@WW
NEWS RELEASE: 2004-090
March 23, 2004
Standing Body of Water Left Its Mark in Mars Rocks
NASA's Opportunity rover has demonstrated some rocks on Mars probably
formed as deposits at the bottom of a body of gently flowing saltwater.
"We think Opportunity is parked on what was once the shoreline of a
salty sea on Mars," said Dr. Steve Squyres of Cornell University,
Ithaca, N.Y., principal investigator for the science payload on
Opportunity and its twin Mars Exploration Rover, Spirit.
Clues gathered so far do not tell how long or how long ago liquid water
covered the area. To gather more evidence, the rover's controllers plan
to send Opportunity out across a plain toward a thicker exposure of
rocks in the wall of a crater.
NASA's Associate Administrator for Space Science Dr. Ed Weiler said,
"This dramatic confirmation of standing water in Mars' history builds on
a progression of discoveries about that most Earthlike of alien planets.
This result gives us impetus to expand our ambitious program of
exploring Mars to learn whether microbes have ever lived there and,
ultimately, whether we can."
"Bedding patterns in some finely layered rocks indicate the sand-sized
grains of sediment that eventually bonded together were shaped into
ripples by water at least five centimeters (two inches) deep, possibly
much deeper, and flowing at a speed of 10 to 50 centimeters (four to 20
inches) per second," said Dr. John Grotzinger, rover science-team member
from the Massachusetts Institute of Technology, Cambridge, Mass.
In telltale patterns, called crossbedding and festooning, some layers
within a rock lie at angles to the main layers. Festooned layers have
smile-shaped curves produced by shifting of the loose sediments' rippled
shapes under a current of water.
"Ripples that formed in wind look different than ripples formed in
water," Grotzinger said. "Some patterns seen in the outcrop that
Opportunity has been examining might have resulted from wind, but others
are reliable evidence of water flow.?
According to Grotzinger, the environment at the time the rocks were
forming could have been a salt flat, or playa, sometimes covered by
shallow water and sometimes dry. Such environments on Earth, either at
the edge of oceans or in desert basins, can have currents of water that
produce the type of ripples seen in the Mars rocks.
A second line of evidence, findings of chlorine and bromine in the
rocks, also suggests this type of environment. Rover scientists
presented some of that news three weeks ago as evidence the rocks had at
least soaked in mineral-rich water, possibly underground water, after
they formed. Increased assurance of the bromine findings strengthens the
case that rock-forming particles precipitated from surface water as salt
concentrations climbed past saturation while water was evaporating.
Dr. James Garvin, lead scientist for Mars and lunar exploration at NASA
Headquarters, Washington, said, "Many features on the surface of Mars
that orbiting spacecraft have revealed to us in the past three decades
look like signs of liquid water, but we have never before had this
definitive class of evidence from the martian rocks themselves. We
planned the Mars Exploration Rover Project to look for evidence like
this, and it is succeeding better than we had any right to hope. Someday
we must collect these rocks and bring them back to terrestrial
laboratories to read their records for clues to the biological potential
of Mars."
Squyres said, "The particular type of rock Opportunity is finding, with
evaporite sediments from standing water, offers excellent capability for
preserving evidence of any biochemical or biological material that may
have been in the water."
Engineers at NASA's Jet Propulsion Laboratory, Pasadena, Calif., expect
Opportunity and Spirit to operate several months longer than their
initial three-month prime missions on Mars. To analyze hints of
crossbedding, mission controllers programmed Opportunity to move its
robotic arm more than 200 times in one day, taking 152 microscope
pictures of layering in a rock called "Last Chance."
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. Images and additional information about the project
are available on the Internet at :http://www.nasa.gov http://marsrovers.jpl.nas
a.gov and 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: 23:12 on 2004-Mar-24 (NZT)
Message sent using WinPack-AGW V6.80
Points to ponder
~~~~~~~~~~~~~~~~
Marriage
~~~~~~~~
You know the honeymoon is pretty much over when you start to go out with
the boys on Wednesday nights, and so does she.
Read previous mail | Read next mail
| |
