The Mars Odyssey picture at right shows the enigmatic
gullies in a Martian crater but also a smooth patch
(top right, arrow) that, according to Phil
Christensen, could be a remnant snowfield (and the
source of the gullies). This is not good news for
those who thought the gullies were formed by seeping
groundwater but it does open up other opportunities. Click
on
the picture for the official, stunning image.
Update 1 Jul 03: Page 14 of the May/June 2003 issue of Planetary
Report has a "Snow Report for Mars"!
19 Feb 04 MGS: Is this another crater
with
gullies and a mantle of snow? (speculation)
THEMIS FAQ:
Can THEMIS detect water or ice? Yes. Both water and ice are
strongly absorbing in the IR wavelength bands THEMIS uses.
Can THEMIS see through dust? THEMIS can see through a small
amount of atmospheric dust, but even a thin layer of surface dust (~100um)
will obscure any underlying thermal IR signatures.
[So a glacier or snowfield covered by a thin layer of dust
might not be readily detected?]
25 Nov 04 MSSS Mars Global Surveyor: Small
Gullied Crater + A
Gullied Crater Wall - still no resolution of the
mechanism that formed the gullies on Mars but this looks to
me like a stream emerging from a (very dirty) glacier
(picture of Fox Glacier, New Zealand for comparison)!
17 Feb
05 Science: And
Now,
the Younger, Dry Side of Mars Is Coming Out - "Perhaps
the most dynamic force shaping the martian surface during
those eons ... has been the snow, ice, and glaciers that
move between polar and lower latitudes as the planet tilts
back and forth on its axis"
22 Feb 05 BBC:
Mars pictures reveal frozen sea - a catastrophic event
flooded the landscape five million years ago and then froze
out...a crust of dust and volcanic ash, perhaps just a few
centimetres thick, has prevented [sublimation].
8 Dec 05 MSSS: This
Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image
shows gullies formed in the walls of an impact crater. Such
gullies might result from seepage and runoff of groundwater;
others have suggested snowmelt might be involved, although
there is no evidence for snow at this location.
27 Jan 06 NewSci:
'Wrecking ball' could break the ice on Mars - Hurling
a massive copper ball at the Red Planet's mid-latitudes
could reveal if water ice lies beneath its dusty crust,
providing clues to the planet's climate
27 Jul 06 MSSS: Gullied
Recesses - The channels in each gully head beneath an
eroding overhang of layered rock, providing support for the
hypothesis that some—if not all—martian gullies result from
release of groundwater to the surface [but is it just rock
or a mixture of rock and ice?]
21 Sep 07 NASA: NASA
Orbiter Provides Insights About Mars Water and Climate.
Mixed news about water on the planet: "...the [fresh]
deposit is not frost, ice or a mineral left behind by
evaporation of salty water...Other gullies, however, offer strong
evidence of liquid water flowing on Mars within the
last few million years...Another new finding from that
camera may help undermine arguments that very ancient
Mars had a wet climate on a sustained basis....images
from the high-resolution camera [to] show lava flows
completely draping a young Martian channel network called
Athabasca Valles. This creates ponded lava over an expanse
that other researchers had interpreted in 2005 as a frozen
sea...."
2 Nov 07 NASA: Mars
Express Probes Red Planet's Unusual Deposits - They
could
be ice-rich deposits, somewhat similar to the layered ice
deposits at the poles of the planet, but formed when the
spin axis of Mars tilts over, making the equatorial region
colder... although the electrical properties are
consistent with water-ice layers, there is no other strong
evidence for the presence of ice today in the equatorial
regions of Mars. "If there is water ice at the equator of
Mars, it must be buried at least several meters below the
surface"
24 May 08 HiRISE: Gullies
of Crater Wall in Terra Sirenum - The wavy, arcuate
ridges at the bottom of the slope may have formed by gravity
moving ice-rich material off the crater wall. The pitted
texture of the crater floor suggests that volatiles (ices
that easily turn into gas) escaped from the subsurface,
causing the surrounding material to collapse and form small
pits.
3 Mar 09 BBC: Mars
had 'recent' running water - It also adds to evidence
that Mars experienced a recent ice age in which polar ice is
thought to have been transported toward the planet's
equator, where it settled in mid-latitude deposits.
7 Apr 09 NewSci: Subsurface
ice on Mars exposed by recent impacts - apparently
fist-sized impactors had punched into a layer of ice hidden
by a topping of dust about a third of a metre deep...
3 Mar 10 NASA: Radar
Map of Buried Martian Ice Adds to Climate Record -
Extensive radar mapping of the middle-latitude region of
northern Mars shows that thick masses of buried ice are
quite common beneath protective coverings of rubble...A
radar on NASA's Mars Reconnaissance Orbiter has detected
widespread deposits of glacial ice in the mid-latitudes of
Mars.
28 Oct 22 BBC: Nasa
space probes document big [?] impacts on Mars - "using
the seismometer on the US space agency's InSight lander. The
probe picked up the ground vibrations.Confirmation came from
follow-up imagery acquired by Nasa's Mars Reconnaissance
Orbiter (MRO)"..."huge chunks of buried water-ice have been
excavated and thrown around the edges of the crater. Buried
water-ice has never before been seen so close to Mars'
equator. " [comment: this is a very significant
discovery, firstly because it will enable scientists to
refine their models for impact cratering (the meteoroid was
about 10m in diameter) and secondly because of the
confirmation of water ice near the surface of Mars.]
18 Apr 07 TPS: Life
Experiment: Phobos - In an ambitious new initiative,
the Society is studying the possibility of sending a
collection of living organisms on a three-year trip to the
Martian moon Phobos and back to Earth. This will be
test of the Transpermia
Hypothesis.
8 Jun 03 MP: I was watching Hitchhikers
Guide
to the Galaxy the other day and noticed an interesting
scene of the mythical planet Magrathea - note the
erosion gullies on the hillside in the background of this
picture. An analogue for the crater gullies on Mars?
25 Jan 2001 BBC: Meteorite
clue
to water on Mars... the [magma that formed] the
Shergotty meteorite [must have had] a lot of water,
about 1.8 per cent, much more than has previously been
believed... [It] erupted onto the Martian surface only 175
million years ago.
10 Feb 2000 SciAm:
Mars or Bust. Special on manned Mars missions n the
March 2000 edition.
The July 1998 issue of Scientific
American has a article "The Mars Pathfinder Mission"
by Matthew P. Golombek NASA's Pathfinder spacecraft and
the intrepid Sojourner robot confirmed that the Red Planet
was once wetter and warmer. Equally important, they proved
new space-exploration concepts for the future, including
the scientific worth of low-cost unmanned probes to the
planets.
Mars Global Surveyor has successfully entered Mars orbit
and is undergoing orbital corrections using innovative
aerobraking techniques. You can see "live" images at NASA.
Congratulations NASA on a successful return to Mars. The Mars
Pathfinder landing site is now known as the Carl Sagan
Memorial Station.
10 Sep 97 - check out the stereo images of Sojourner - the
closest most of us will get to being on the surface of Mars
the 3D effect is breathtaking! (Stereo viewer required - one
came with the NASA publication "The Martian Landscape"
published in 1978 after the Viking missions - some excellent
stereo images of the Viking Lander sites included in that
publication). Also see these great
3-D
images
A
Bonus for Planetary Society Members: Another major
announcement from TPS at Planetfest '97:
"Many members of the Planetary Society also made it to Mars in
more than spirit. A few years ago the names of 100,000 Society
members were placed on a chip that flew on Russia's Mars '96
mission as part of MAPEX -- the microelectronics and photonics
experiment devised by JPL as a passive recorder of incoming
radiation at the martian surface. Although Mars '96 was lost
shortly after launch, JPL made several MAPEX spares, and one was
flown on Mars Pathfinder -- complete with the list of the
100,000 names of Planetary Society members." Is your name now on
Mars?
(see Nov/Dec 93 issue of Planetary Report- all members as of
October 15, 1993)
Is it Gustav Crater or Gusev Crater? The Spirit Mars
Exploration
Rover landed in an ancient crater on Mars. This
NASA
page refers to Gustav and
Gusev crater. I asked NASA's Science Information service
whether they are the same crater. NASA confirmed this and
suggested that Gusev was the more commonly used. My ACA
talk (prepared before I researched the name issue) uses
Gustav.
NASA Haughton-Mars
Project - Devon Island, 33 million year old impact
crater in the Arctic. Impact-generated hydrothermal systems
are being studied at this site and are highly relevant
to the search for life on Mars.
Stereo
pair
images of Mars Pathfinder Landing site. (see images
004a27/87 - these need a stereo viewer. Other recent NASA
stereo images need red/blue glasses - if you have trouble
obtaining some buy the "3D Colouring Book" from your local
Target store!). More 3D
space images from Space.com.