- With a host of spacecraft at Mars or being readied to
go there over the next two years, scientists are poised to uncover the
planet's liquid secrets. The big question: Was Mars once warm and wet?
Simple to pose, but not easy to answer. While many scientists think Mars
may once have harbored vast oceans or lakes, there is no proof beyond some
presumed ancient shorelines, sediment deposits, and other highly sketchy
data or pictures.
The question is important because liquid water is a key ingredient for
life as we know it.
While evidence is rolling in from two spacecraft currently orbiting Mars,
an artist has taken some liberties with some of that data to create a series
of renderings showing what Mars might once have looked like.
Add water, stir in color
Using topographical data from the Mars Orbiter Laser Altimeter (MOLA) instrument
on NASA Mars Global Surveyor spacecraft, Kees Veenenbos of the Netherlands
has created scenes showing how Mars might look today. Putting his imagination
to what might have been, he added water, stirred in a little color, and
produced dozens of intriguing images.
The renderings are purely educated guesses, but they are nonetheless compelling
glimpses into what many scientists agree may once have been a much more
Earth-like planet.
"My visualizations show how Mars may have looked billions of years
ago, so they are speculative in a way," Veenenbos told SPACE.com.
"Once Mars is explored thoroughly through the next century we will
know better how Mars evolved from the birth of our solar system and what
Mars might have once looked like."
The artist also points out that while he added water to represent scenarios
from 3 or 4 billion years ago, the renderings represent modern-day topography.
Without question, the mountains and valleys of Mars' remote past would
have been much different.
The data
The raw MOLA data are measurements of elevation, resolving features down
to about 600 meters in size. The data do not reveal individual rocks, nor
do they show the position of the Sun. NASA makes the data available for
scientific and artistic endeavors, but lays no claim to the accuracy of
the results.
Veenenbos converted the data into a useable format and fed it into a software
program called Terragen, which generates the landscapes.
Because no one knows what Mars was really like, Veenenbos rendered several
scenes -- some with water, some with ice, some depicting a warm and dry
surface. In some of the renderings, he included colors such as green, purple
and yellow to represent life.
We asked the artist to imagine standing on the surface of Mars a few billion
years ago and tell us what he sees.
"Yesterday the Kasei River meandered calmly through the valley,"
Veenenbos reports. "But today an exciting catastrophic event takes
place near the outlets. I stand on the steep-walled canyon of the Kasei
Valles and look down 1 mile. Vast, muddy floods of water caused by groundwater
eruptions in the Tharsis Montes region flow into the basin of the Chryse
Planitia. I guess that the quantity of the floods exceed 10,000 times that
of the Mississippi River."
Mars, if wet, was probably also rather violent. Scientists have suggested
that floods likely came in chaotic episodes separated by thousands of years
of relative quietude.
The real Mars
Not gifted with such artistic hindsight, geologists are meanwhile forced
to craft a scientific vision of ancient Mars based on scraps of data that
build up over years and each successive mission to the Red Planet.
Mars Odyssey, which arrived at Mars Oct. 23 and has yet to officially begin
its science mission, has already made a contribution to the effort.
In late December, scientists studying data sent back by Odyssey said they
had found tantalizing evidence that there might be water ice very near
the surface of Mars in regions south of the permanently frozen north polar
ice cap.
Further investigation early this new year may confirm the exciting but
sketchy data, which is based on signs of hydrogen. Hydrogen is one component
of water but also exists alone and in other substances.
"While preliminary, the results are believable and probably correct,"
says Bruce Jakosky, an expert on Mars geology from the University of Colorado.
"At first glance, they appear to confirm theoretical predictions regarding
the distribution of near-surface ground ice."
Life on Mars?
Jakosky, who is director of the university's Center for Astrobiology, cautions
that the frozen water, if it exists, "probably does not have anything
to do with liquid water." Nor is it likely to increase the odds of
finding life on Mars, he says.
For life, liquid water is needed, most researchers agree. Odyssey may find
that, too.
When the orbiting space probe's science mission begins in earnest sometime
in February, its neutron spectrometer will be used to map near-surface
water ice planet-wide. It will also use an infrared camera to search for
signs of liquid water hidden in underground reservoirs.
Such reservoirs could be remnants of the oceans and lakes Kees Veenenbos
has envisioned. [See the renderings]
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