A Mars Never Dreamed Of

By Kathy Sawyer


Images by

NASA/Jet Propulsion Laboratory/Malin Space Science Systems

As the Mars Global Surveyor beams home unprecedented images, our assumptions about the red planet explode.

Get a taste of what awaits you in print from this compelling excerpt.

On this particular spring morning Edgett was escorting me on a virtual
flying tour over Mars’s surface. Exhibit A was a disheveled-looking
region known as Gorgonum Chaos. Here, captured in the Surveyor images,
we saw part of a rugged crater wall that had collapsed into a gully
with a number of deep, sinuous channels fanning out, ending abruptly in
an apron of deposited material.

In shape the features resembled gully washes in the American West.
The flows appeared to come to a sudden halt, suggesting the material
was thick—perhaps liquid filled with dirt and debris. Mud on Mars? But
what really brought up the goose bumps was the panoramic repetition of
the startling features. As the flight continued along a strip of the
planet’s surface, the flow patterns showed up on the cliff walls and
escarpments of other craters, mesas, and troughs, always erupting near
their tops, always apparently from the same geologic layer 100 to 500
meters (328 to 1,640 feet) down.

The evidence disturbed the scientists in more than one respect.
First, conditions on Mars are such that any water reaching the surface
supposedly would not remain liquid for very long but would boil,
freeze, or poof into vapor. Second, from the absence of craters, sand
dunes, or anything else on top of the gullies, they appeared to have
formed very recently, possibly as recently as yesterday.

By this time the signature of weeping or seeping liquid had shown
up in some 200 Surveyor images. Most of the evidence was found,
strikingly, in some of the coldest places on the surface—on shadowed
slopes facing the poles, in clusters scattered around latitudes higher
than 30 degrees—rather than at the warmer equatorial latitudes. This
suggested that the flows contained frozen volatiles, substances that
would vaporize if exposed to the warmth of sunlight.

Malin and Edgett had been puzzling over these images for more than
a year, trying to come up with an explanation that would point to
something other than liquid water before publishing their discovery.
“We were dragged kicking and screaming to this conclusion,” Edgett
said. But they could find no plausible “dry” explanation. And proposals
for other substances that might behave as liquids on the Martian
surface raised so many other questions that they failed to solve the
problem.

Get the whole story in the pages of National Geographic magazine.

Oh the complexity that is space...
sorry if this post is ... hmmm, I dunoo what to say really. Better nothing at all maybe.