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.