The Meridiani Journal 2.0

After a long delay, the blog has been updated again, a revamping for the coming new year as I’ve had time to do it. The url has been simplified, with the blog now being hosted under its own ‘semi-domain’. Hosting, design and publishing are now being done with Apple’s iWeb (part of .Mac) software, which I am now using for all of my web site work. Latest version of Safari, Firefox, Internet Explorer or Netscape browser with at least 1024x768 or 1280x1024 display resolution recommended for best viewing.

Please note new url, RSS feed and e-mail:

http://web.mac.com/meridianijournal
http://rss.mac.com/meridianijournal/iWeb/meridianijournal/blog/rss.xml
meridianijournal@mac.com

All subsequent updates will now be at the new url and should also be more frequent again now. This Blogger version will be kept, at least for the time being, as an archive of older posts. Thanks for your patience!

Postcards from Mars

© Dutton

A wonderful new book from Jim Bell, leader of the Pancam colour camera team for the Mars Exploration Rover mission, featuring over 150 gorgeous full-colour and black & white images from both rovers to-date. In bookstores now!

More information:

PopPhoto.com

Springtime on Mars in 2020

A great video clip spoof posted on YouTube, set in Martian spring in 2020. A comical sort of tribute to past failed Mars landings (the "junkyard") and the much more successful rovers, as well as romantic Martians...

Enceladus: Water or Ice?

Just like the never-ending water on Mars debate, the recent news about water vapour geysers on Saturn's moon Enceladus is also now being questioned by some other teams, as just published in Science magazine, with the hypothesis that cold, icy clathrate reservoirs are the source instead of liquid water maintained by interior heating, as announced earlier this year by the Cassini team.

Another science team, however, has also just published its findings in Icarus, supporting the Cassini team's model of a hot interior with liquid water reservoirs. It will be very interesting to hear the Cassini teams' response to the alternative hypothesis, as they have already stated that liquid water must almost certainly be involved.

More information:

Science (abstract)
UCDavis
University of Illinois at Urbana-Champaign
Space.com
Astrobiology Magazine

Did it Rain on Mars?

© NASA/JPL/University of Arizona

One of the new images this week from Mars Reconnaissance Orbiter shows alluvial fans in Mojave crater which perfectly match ones seen on Earth (including in the Mojave desert), created by heavy downpours and thunderstorms in deserts. So did the same thing happen in the past on Mars? Apparently so...

The rest of this week's amazing images (PSP Image Release #4) are here. As per every Wednesday now!

Water, Water Everywhere

As a review of some of the recent postings shows, the accumulating evidence for liquid water on Mars, both past and present, is getting hard to keep up with, as well as a bit confusing.

While some studies suggest that a "warmer, wetter Mars" was a brief occurrence early in the planet's history, others argue it lasted much longer, while still others continue to claim it never happened. Some findings indicate groundwater / aquifers, others suggest surface water, including rivers, lakes, playas and perhaps even oceans. Some findings show evidence for acidic and salty water (the sulphates), others show evidence for less acidic or "normal" water (the gypsum and clay minerals).

At present, we do know that Mars currently has water vapour, frost, fog, and a lot of ice, both underground and on the surface. The new images from Mars Global Surveyor apparently indicate water periodically leaking to the surface from aquifers, and the search is on right now for direct evidence of them from Mars Reconnaissance Orbiter and Mars Express.

The pieces of the puzzle are slowly being put together, but the history of water on Mars is complicated and still highly debated among scientists with no overall consensus as yet. How to make sense of all this?

Some additional new studies and articles this week:

The Geological Society of America
Science
Physics News Update

Layers, Layers Everywhere

© NASA/JPL/University of Arizona

The first radar images taken by the Shallow Subsurface Radar instrument (SHARAD) on Mars Reconnaissance Orbiter have been released, showing extensive layering underneath the south pole. As well as the radar, the HiRISE camera on MRO has photographed the layered terrain near the north pole, including odd pitting, and on the ground, Opportunity is examining the layered sediments of steep cliff walls inside the large Victoria crater in Meridiani Planum. All of these findings are helping to understand climate changes in Mars' past as well as the formation of the gypsum and clay minerals previously found (and being investigated further), evidence for previously wetter conditions.

More information:

Mars Reconnaissance Orbiter (press release images)
The Planetary Society Weblog
Astronomy

Planetary Radio: Special Coverage of Water on Mars

This week's broadcast of Planetary Radio from The Planetary Society focuses on last week's announcement of liquid water and new craters on Mars. MP3 and Windows media formats available.

Bridge in Tartarus Colles

© NASA/JPL/University of Arizona

From the newest batch of images from Mars Reconnaissance Orbiter, this view of a natural "bridge" over a trough in the Tartarus Colles region of Mars, where a lava tube has collapsed, except for a small portion, creating an arch over the trough. The bridge is about 23 metres (75 feet) wide.

Mars' Watery Past

According to an excellent lengthy new feature article in Scientific American, evidence from both rovers and orbiters suggests that Mars' past water covered large areas on the surface and may have lasted longer than a billion years, much longer than recently thought. While those conditions have changed drastically since then, the new gully findings just reported on suggest that some of that water is still present underground, and sometimes still comes to the surface.