Robert Owen (
Fri, 01 Oct 1999 17:51:11 -0400

Larry Klaes wrote:

> >Date: Fri, 1 Oct 1999 12:20:19 -0400 (EDT)
> >From:

> > Scientists studying high-resolution images from NASA's Mars
> >Global Surveyor spacecraft have concluded there is no evidence of
> >shorelines that would have surrounded oceans that may have once
> >existed on Mars.
> >
> > One argument that such a body of water once existed was
> >suggested by features in images from the NASA Viking missions
> >taken in the 1970s, which were interpreted by a number of
> >researchers as remnants of ancient coastlines. The images from
> >Mars Global Surveyor, taken in 1998, have a resolution five to 10
> >times better than those that Viking provided. With this closer
> >inspection, none of these features appears to have been formed by
> >the action of water in a coastal environment.
> >
> > "The ocean hypothesis is very important because the existence
> >of large bodies of liquid water in the Martian past would have had
> >a tremendous impact on ancient Martian climate and implications
> >for the search for evidence of past life on the planet," said Dr.
> >Kenneth Edgett, a staff scientist at Malin Space Science Systems
> >(MSSS), San Diego, CA, the institution that built and manages the
> >Mars Orbiter Camera onboard the spacecraft. "The newer images do
> >not show any coastal landforms in areas where previous researchers
> >--working with lower resolution Viking images -- proposed there
> >were shorelines."
> >
> > About 2 percent of the Mars Orbiter Camera images were
> >targeted to look in places that would test shorelines proposed by
> >others in the scientific literature.
> >
> > "Even on Earth, looking for ancient shorelines from the air
> >or space is a challenge," said
> >
> >Dr. Michael Malin, principal investigator for the camera at MSSS.
> >"Despite these difficulties, we believe these Mars Orbiter Camera
> >images of the proposed shorelines are of a high-enough resolution
> >that they would have shown features indicative of a coastal
> >environment had there been an ancient ocean on Mars."
> >
> > The paper containing these new conclusions will be published
> >in the Oct. 1 issue of the Journal of Geophysical Research
> >Letters.
> >
> > One area that might have been a coastline is located
> >northwest of the great volcano Olympus Mons. Researchers looking
> >at Viking images have suggested that there might be a cliff
> >separating the western margin of the Lycus Sulci uplands from the
> >lower-elevation, smoother Amazonis plains. The proposed cliff
> >looked like the kind that forms on Earth from erosion as waves
> >break against a coastline.
> >
> > Three high-resolution images were taken of this proposed
> >coastline. The uplands are roughly textured, while the flat plains
> >appear smoother. The image shows that the contact between the two
> >regions is clearly not a wave-cut cliff, nor are there any
> >features that can be unambiguously identified as coastal
> >landforms, according to Malin.
> >
> > "While the suggestion that Mars at one time had oceans cannot
> >be ruled out, the foundation for the 'ocean hypothesis' developed
> >in the 1980s on the basis of suspected shorelines appears now to
> >have been incorrect," Malin concluded. "However, it should be
> >understood that there is significant other evidence of water on
> >Mars in the past, both from Mars Global Surveyor and from previous
> >missions. Today, the Mars Orbiter Camera continues to acquire new
> >high-resolution pictures, each one helping to search for clues to
> >the very important question of the role of water in the evolution
> >of Mars."
> >
> > More information and images about the Mars Global Surveyor
> >mission is available at:
> >
> > and
> >
> > Additional details about the paper and the new Mars images
> >are at:
> >
> >
> >
> > Mars Global Surveyor is the first in a long-term program of
> >Mars exploration, known as the Mars Surveyor Program that is
> >managed by the Jet Propulsion Laboratory for NASA's Office of
> >Space Science, Washington, DC. JPL's industrial partner is
> >Lockheed Martin Astronautics, Denver, CO, which developed and
> >operates the spacecraft. JPL is a division of the California
> >Institute of Technology, Pasadena, CA.
> >
> > - end -
> >
> > * * *

Robert M. Owen
The Orion Institute
57 W. Morgan Street
Brevard, NC 28712-3659 USA

This archive was generated by hypermail 2.0b3 on Sun Oct 10 1999 - 15:46:38 PDT