Meteorite Strike Exposes Martian Water

Above: A fresh, 6-meter-wide, 1.33-meter-deep crater on Mars photographed on Oct. 18, 2008, and again on Jan. 14, 2009, by Mars Reconnaissance Orbiter's HiRISE camera. The bright material is ice, which fades from Oct. to Jan. because of sublimation and obscuration by settling dust.

Above: This map shows five locations where fresh impact cratering has excavated water ice from just beneath the surface of Mars (sites 1 through 5) and the Viking Lander 2 landing site (VL2), in the context of color coding to indicate estimated depth to ice.

This is very heartening news from Mars. We obviously have large reservoirs of water stored in surface ponds only moderately covered by protective dust. That certainly means that establishing a working exploration base has become feasible. Assuming an energy source is brought along it is simple engineering to put up atmospheric bubbles to produce a living environments for human occupation that is potentially self sustaining in terms of the basics of life.

The main issue was access to water at all and in fact access to ample supplies was necessary for a sustained major effort. This requirement now appears amply satisfied. Of course, we might be looking at a lot of sublimated water adhering to the underlying dust exposed by the impact, yet there will still be plenty of water.

Sublimated onto sand grains is the most likely explanation since any solid ice would be wind swept and fully exposed. This also explains the quick change of color.

This broadly confirms that establishing a presence on Mars will mean mostly moving materials, initial supplies and a powerful energy source. This can be done through a stream of small cargos on Landers, if nothing else is then possible.

Not likely, but establishing a base on Mars could be more practical that one on the moon were even water must be delivered. At least the initial availability of key raw materials for life cuts the operating costs to manageable levels.

It also opens the door for sending an initial team on what could be a deliberate one way trip to build out the station and set up equipment as it is landed. Once enough is built out, it then would become possible to retrieve them by landing the components of a return craft. It is not pretty, but it could just make it feasible in the first place.

This option becomes possible because of ample water availability from the very beginning.

Martian Ice Exposed by Meteorite Impacts

09.24.2009 http://science.nasa.gov/headlines/y2009/24sep_martianice.htm?list1109684

September 24, 2009: Meteorites recently striking Mars have exposed deposits of frozen water not far below the Martian surface. Pictures of the impact sites taken by NASA's Mars Reconnaissance Orbiter show that frozen water may be available to explorers of the Red Planet at lower latitudes than previously thought.

"This ice is a relic of a more humid climate from perhaps just several thousand years ago," says Shane Byrne of the University of Arizona, Tucson.

Byrne is a member of the team operating the orbiter's High Resolution Imaging Science Experiment, or HiRISE camera, which captured the unprecedented images. Byrne and 17 co-authors report the findings in the Sept. 25 edition of the journal Science.

"We now know we can use new impact sites as places to look for ice in the shallow subsurface," adds Megan Kennedy of Malin Space Science Systems in San Diego, a co-author of the paper and member of the team operating the orbiter's Context Camera.

So far, the camera team has found bright ice exposed at five Martian sites with new craters that range in depth from approximately half a meter to 2.5 meters (1.5 feet to 8 feet). The craters did not exist in earlier images of the same sites. Bright patches darkened in the weeks following initial observations, as freshly exposed ice vaporized into the thin Martian atmosphere.

The finds indicate water-ice occurs beneath Mars' surface halfway between the north pole and the equator, a lower latitude than expected in the dry Martian climate.

During a typical week, the spacecraft's Context Camera returns more than 200 images of Mars that cover a total area greater than California. The camera team examines each image, sometimes finding dark spots that fresh, small craters make in terrain covered with dust.

Checking earlier photos of the same areas can confirm a feature is new. In this way, the team has found more than 100 fresh impact sites.

An image from the camera on Aug. 10, 2008, showed apparent cratering that occurred after an image of the same ground was taken 67 days earlier. The opportunity to study such a fresh impact site prompted a look by the orbiter's higher resolution camera on Sept. 12, 2009, confirming a cluster of small craters.

"Something unusual jumped out," Byrne said. "We observed bright material at the bottoms of the craters with a very distinct color. It looked a lot like ice."

The bright material at that site did not cover enough area for a spectrometer instrument on the orbiter to determine its composition. "Was it really ice?" the team wondered. The answer came from another crater with a much larger area of bright material.

"We were excited [when we saw it], so we did a quick-turnaround observation," said co-author Kim Seelos of Johns Hopkins University Applied Physics Laboratory in Laurel, Md. "Everyone thought it was water-ice, but it was important to get the spectrum for confirmation."

Mars Reconnaissance Orbiter Project Scientist Rich Zurek, of NASA's Jet Propulsion Laboratory, Pasadena, Calif., said, "This mission is designed to facilitate coordination and quick response by the science teams. That makes it possible to detect and understand rapidly changing features."

The ice exposed by fresh impacts suggests that NASA's Viking Lander 2, digging into mid-latitude Mars in 1976, might have struck ice if it had dug only 10 centimeters (4 inches) deeper. The Viking 2 mission, which consisted of an orbiter and a lander, launched in September 1975 and became one of the first two space probes to land successfully on the Martian surface. The Viking 1 and 2 landers characterized the structure and composition of the atmosphere and surface. They also conducted on-the-spot biological tests for life on another planet.

To view images of the craters and learn more about the Mars Reconnaissance Orbiter visit http://www.nasa.gov/mro.

Changing Arctic Ocean

In my last post, I showed that we have at most a decade before the last of the long term sea is gone and no longer a factor. What difference will it make?

The important change will be in the amount of summer heat absorption in the Arctic Ocean. Up to very recently, this factor was negligible since the Sea remained covered with minor late season clearances. This year, half the Arctic is clear. And the other half will mostly clear in the next decade. This will be additionally stabilized by the sharp increase in solar energy absorption in the top layer of water.

What I am saying, is that once the ice is gone, the annual reestablishment of sea ice cover will be more difficult. The water will be slightly warmer and will take longer to establish its annual thickness.

Remember that it took 32 calories to melt or freeze the ice in the first place. If all this unused energy goes into warming the arctic waters, then Our sea ice cover will behave a lot like the sea ice cover in Hudson Bay providing perhaps a four month long clear sailing environment.

It will still be too cold to generate much evaporation, so there should be little change for the land based ice sheets. This conforms to the data provided by the drill cores that go back over 15,000 years. In fact, the only break in that data continuity came 12500 years ago and is a principle marker for the Pleistocene nonconformity. It became dryer.

This also suggests open seas during the summer months of the Bronze Age and their near reemergence in the early fifteenth century. It also loudly begs the question of what mechanism cooled the northern Hemisphere, or more appropriately what cooled the surface waters of the gulf stream?

A previous post suggested that the mechanism was an injection of cold water from the Antarctic. We just have not figured it all out yet. I think though that we should be prepared for a nasty surprise there. The open question in my mind is whether we now have any evidence to support a four hundred year chilling cycle for the Atlantic? It may be more random than that, but it likely exists.

It has only taken 400 years to recover from the little ice age. Yet almost 2500 years had passed since the collapse of the Bronze Age optimum. Surely someone noticed? My point is that as far as we can determine, most of those 2500 years were chilly. We could actually be dead wrong here and the climate could have been generally warmer throughout and the real anomaly is the recent little ice age.

Time to look at those tree rings and pollen samples in transition areas to get a much refined climate proxy.

Otherwise, with the current regime, We know that the permafrost line will shift north somewhat, and the tree line will also move north. It is hard to see how this will effect humanity very much since few of us like to live in alpine like conditions. The short summers will remain the same and be just a little warmer. And there are many better places to grow potatoes.

Local coastal agricultural enclaves will be possible, just like those old Vikings in Greenland. Otherwise, a quick trip to Churchill will inform you of likely future conditions in the high Arctic.

Certainly, once the long term ice is gone, the shipping season will open right up although I am sure everyone will plan on a September crossing. The polar bears will be able to treat the whole Arctic the same way they treat Hudson Bay with a much longer hunting season. I would also expect an explosion in the Arctic biomass in general since there will be a season in which the ocean receives sufficient solar energy for all forms of plankton and the like.

The high arctic will still be a desert on land, but the ocean could easily become the globe's larder if managed well.