Of rocks and water, swans and falcons

CuriosityCuriosity has resumed its long drive towards the point where it can begin its examination of the huge mound sitting at the centre of Gale Crater which NASA has dubbed “Mount Sharp” (its official name is Aeolis Mons).

The rover recently stopped-off at an area dubbed “Waypoint 1”, the first of several potential stop-over points on the rover’s route, where it will carried out various studies of the surroundings.

Curiosity departed the area on September 22nd after spending some 10 days examining rocks at “Waypoint 1”, and is once more travelling slowly but steadily towards the point mission managers have identified for it to bypass a dune field lying between it and “Mount Sharp”. Along the way, it is liable to make around four more stops.

While at “Waypoint 1”, the rover spent time examining a rocky outcrop dubbed “Darwin”, using a range of instruments to gather images and data which again showed that Gale Crater was once the scene of considerable water activity.

A mosaic of four images taken by the Mars Hand Lens Imager (MAHLI) camera shows detailed texture in a ridge on the rock outcrop dubbed “Darwin” the rover studied at “Waypoint 1”. The images were obtained shortly before sunset Sol 400 (Sept. 21, 2013) with the camera 25 cm (10 inches) from the rock. Scale is indicated by the Lincoln penny from the MAHLI calibration target, shown beside the mosaic.

“We examined pebbly sandstone deposited by water flowing over the surface, and veins or fractures in the rock,” said Dawn Sumner of University of California, Davis, a Curiosity science team member with a leadership role in planning the stop. “We know the veins are younger than the sandstone because they cut through it, but they appear to be filled with grains like the sandstone.”

While much of the outcrop was covered in the all-too-familiar oxidised Martian dust, there were a patches of bare rock scattered across its surface in which sand deposits and pebbles could be seen, and it was these that drew the attention of the science team.

A mosaic of nine images, taken by the MAHLI camera, shows detailed texture in a conglomerate rock bearing small pebbles and sand-size particles. Again, these images were captured on Sol 400 (Sept. 21, 2013) with the camera positioned about 10 cm (4 inches) from the rock. Scale is indicated by the Lincoln penny from the MAHLI calibration target, shown beside the mosaic.

Following extensive studies of the outcrop, the science team interpret the sand and pebbles in the rock as material that was deposited by flowing water, then later buried and cemented into rock, forming conglomerates. Research will now focus on the textures and composition of the conglomerates as Curiosity continues onward, to understand its relationship to stream bed conglomerate rock found closer to Curiosity’s landing site. Doing so, together with studies to be undertaken at the remaining waypoints, should help scientists to piece together the relationship between rock layers at “Yellowknife Bay” where the mission found evidence of an ancient freshwater-lake environment favourable for microbial life, and the rock layers at the main destination on lower slopes of “Mount Sharp”.

Water, Water, Everywhere

On September 27th, the Curiosity team published five reports in the journal Science which discuss the mission’s findings during the first four months of the rover’s time on Mars. A key finding from this work is that water molecules are bound to fine-grained soil particles, accounting for about 2 percent of the particles’ weight at Gale Crater. This result has global implications, because these materials are likely distributed around the Red Planet.

The presence of water was discovered as a result of samples of surface material being heated to the point of vapourisation within a small oven inside Curiosity – and the most abundant vapour detected was  H2O. The quantity of water molecules bound-up in the Martian soil suggest that as much as two pints of water could be obtained through the heating of one cubic foot of Martian dirt.

This discovery potentially has major implications for any long-term human presence on Mars in the future. The water – once subjected to appropriate treatment to remove unwanted minerals, such as a perchlorate, which has also been found in small amounts within Martian soil samples and can interfere with the thyroid function – could be used for cleaning and drinking purposes. It could also be electrolysed and used in the creation of oxygen and hydrogen. The hydrogen could then be used for a variety of purposes, including as a raw fuel, or in the production of fuel in the form of methane (created by combining the hydrogen with carbon dioxide from the Martian atmosphere), which could be used with oxygen to power surface vehicles.

An interesting part of the study is that the analysis of the chemicals and isotopes in the gases released during the analysis of soil samples indicates that the water molecules are the result of an interaction between the soil on Mars and the current atmosphere of the planet; so the process of depositing the water molecules is ongoing, rather than the result of some past mechanism. Even the discovery of perchlorate in the samples is of significance; previously, this had only been found in  soil samples examined at the high latitude Phoenix Lander site. That they’ve now also been found in a near-equatorial latitude suggests they have a global distribution as well.

The other papers released by the science team further confirm earlier studies into the mineral composition of samples gathered and studied during the rover’s initial four months on Mars using its full suite of sample analysis tools: MAHLI, APXS, ChemCam, SAM, and CheMin, all of which can perform a range of complementary as well as disparate analyses.

One of the papers additionally focuses on a rock I covered back in the early days of the mission – Jake_M. Named in memory of NASA / JPL engineer Jacob Matijevic, who worked on all three generations of NASA’s Mars rovers and who passed away shortly after Curiosity arrived in Gale Crater, Jake_M was thought to be quite unlike any other rock on Mars – not because of its pyramid-like shape, but because of its composition.

“Jake_M”, the remarkable rock examined by Curiosity on September 22nd 2012, and believed to be a mugearite type of rock. The markings show where ChemCam and APXS were used to examine it

The paper published in Science confirms that Jake_M is most like a mugearite, a type of rock found on islands and rift zones on Earth.

Continue reading “Of rocks and water, swans and falcons”

Busts, bed knobs, pookas and a little terror

It’s time to kick-off another week of fabulous story-telling in Voice, brought to Second Life by the staff and volunteers at the Seanchai Library SL.

As always, all times SLT, and unless otherwise stated, events will be held on the Seanchai Library’s home on Imagination Island.

Sunday September 29th

13:30: Tea Time at Baker Street – The Adventure of the Six Napoleons

Holmes (c) with Waston (r) and Lestrade (l) near the scene of the murder (Sidney Paget, Strand Magazine, 1904)

Corwyn Allen brings us another installment in Sir Arthur Conan Doyle’s volume of stories The Return of Sherlock Holmes.

It appears a vandal is at large in London, and has Inspector Lestrade somewhat baffled. Someone is going around smashing busts of the Emperor Napoleon. Three have so far been broken, one from a shop and two following break-ins at the home and office of one Dr. Barnicot.

Holmes is intrigued by the fact the all of the busts come from the same mould, suggesting that this is more than a simple case of someone having a deep-seated dislike for the dead Emperor.

When Lestrade brings word that there has been a further incident, this time accompanied by a murder, Holmes is more than intrigued. The bust has been stolen from the house of a journalist, one Horace Harker, who also discovered the dead man on his front doorstep.

It’s unlikely the dead man was responsible for taking the bust, as the remains of that are found shattered in the garden of an empty house up the street. The dead man has a photograph of another man in his possession, and things take a further strange turn when the deceased is identified as a member of the Mafioso, and the photograph he was carrying is that of an Italian immigrant…

18:00: Magicland Storytime – The Magic Bed Knob

Magic bedknobAuthor Mary Norton is perhaps best know for her long-running series of fantasy books The Borrowers (named for the first book of the series) published between 1952 and 1982.

However, her first published work, in 1943, was entitled The Magic Bed Knob; or, How to Become a Witch in Ten Easy Lessons, a fantasy piece about an elderly woman who practices magic for a hobby and has a magic bed knob, and three London children evacuated to the country during the bombing of London.

This was followed in 1945 by the sequel Bonfires and Broomsticks. Then, in 1957, the two books were republished as a single volume entitled Bed-Knob and Broomstick. And it was a play on this title by which the story became most widely known, when in 1971, Walt Disney released the film Bedknobs and Broomsticks starring Angela Lansbury and the late David Tomlinson.

Join Caledonia Skytower at Magicland Park as Caledonia reads from this classic tale.

Monday September 30th, 19:00: Sci-fi Shorts

Join Gyro Muggins as he reads Hemeac.

Tuesday October 1st, 19:00: Pesky Pooka Night!

With Caledonia Skytower.

Wednesday October 2nd, 19:00: Celtic Tales for Fall

As autumn wraps her arms around us, the days grow shorter and the nights longer, heralding the arrival of winter, Caladonia Skytower brings us tales to warm the evenings and awaken the imagination.

Thursday October 3rd, 1001 Terror Tales

Join Shandon Loring in getting into the Halloween spirit.


Please check with the Seanchai Library SL’s blog for updates and for additions or changes to the week’s schedule. The featured charity for September and October is Water for People. Have questions? IM or notecard Caledonia Skytower.

Related Links

ToS Changes: in-world meeting

Update, September 30th:  My personal perspective on the meeting can now be found here.

The recent changes to Section 2.3 of the ToS have been the focus of considerable debate in the forums, in blogs and so on. The changes impact a broad cross-section of the community: content creators, those who provide content to creators (textures, etc), artists producing original works (painting, written pieces, drawings, photographs, etc), and so on.

Because of this, an in-world meeting has been planned for Sunday September 29th, at the East, West, North Galleries Ampi-Theatre, starting at 12:00 noon SLT. This will take place in text chat, rather than voice.

The East, West, North Ampi-Theatre, venue for the ToS discussion meeting
The East, West, North Ampi-Theatre, venue for the ToS discussion meeting

The goal of the meeting is to have an orderly, constructive discussion about the changes to the ToS, and (quoting from the pre-meeting notes): “to understand the situation, to agree on our interpretation, and to contemplate a next step, if necessary”.

To this end the meeting will be moderated, and a few guidelines have been set out in advance, which attendees are asked to observe, including:

  • The moderator will be Ernie Farstrider, curator of the East, East, North Gallery
  • Those wishing to speak should IM the moderator first and wait for him to give them the floor
  • Speakers should limit themselves to 5 minutes maximum if making a statement, etc.
  • Speakers should indicate they have finished speaking by ending their chat with “///”

To assist the discussion:

  • The LL ToS has been set-up in display boards around the ampitheatre, with Section 2.3 highlighted for easy of reference
  • The ToS can also be displayed via a green media on a prim screen
  • There is also a blue media on a prim screen which can be used to display a Harvard University article on “Moral Rights”

Related Links

With thanks to Foneco Zuzu for the heads-up

SL projects update week 39 (3): viewer, interest list, HTTP, SSA and more

The following notes are taken from the TPV Developer meeting held on Friday September 27th. A video, courtesy of North, can be found at the end of this report. The numbers in braces after each head denote the time stamp at which the topic can be listened-to in the video.

A typical TPV dev meeting
A typical TPV dev meeting

SL Release Candidate Viewers



Following my coverage of the release of SLShare, the opt-in capability for those wishing to link their Second Life accounts with their Facebook accounts, A question was asked as to whether the feature would be available to TPVs. Speaking at the TPV Development Meeting, Oz Linden provided comments which answered this question more fully, and and Merov Linden gave further information on the functionality in general.

“One of the design considerations is that this is a feature you [TPV developers] can all integrate without any problem,” Oz said. “All of the actual connections to Facebook, all of the handling of the requisite authentication tokens and permissions and [the] relationship with Facebook itself, is all handled server-side. So the code that’s in the release candidate viewer is something that you can integrate so that you can also make this feature available on whatever schedule you would like to.”

He went on to confirm that given this, no Facebook information for users of the service is exposed to TPVs.

As to how soon it might be before the SLShare RC is promoted to the release viewer, Oz again reiterated that it depends on how well the various candidates currently in the release channel perform. Currently, the metrics for the viewer look good, according to Merov, so it may still leapfrog its way to becoming the release viewer. However it is more likely that it will not become the de facto viewer for at least another two weeks.

Despite the negative reactions to the feature which have appeared in the comments following blog posts, etc., reporting on the functionality, the Lab believes SLShare is already “getting a lot of use”. This view is based on the numbers of people who have pro-actively gone and downloaded and installed the RC viewer manually.

While this may be a case of the Lab greasing the wheels a little bit (downloading and installing the viewer isn’t necessarily the same as running the feature),  Firestorm are reporting that they’ve had at least one request for the feature to be added to their next release.

During the meeting, a series of questions were raised on the feature:

  • Will the feature become opt-out in the future, rather than opt-in? Merov Linden:  “It’s opt-in. We’re not doing anything [behind] the back of the residents.”
  • Will the feature create a Facebook account on behalf of anyone using it? Merov Linden:  “There is no API to create an account on Facebook on behalf of someone.”
  • Will it lead to a merging of the current SL feeds with the Facebook feed?  Oz Linden: ” No, there is no connection between the Second Life profile feeds and the Facebook feed. They have no relationship at all … In theory one could probably build a viewer that did that, but we’re not planning on it.”

(Further questions passed unanswered due to the region in which the meeting was being held being subjected to a griefing attack which left it in a poor state and prompted a change of meeting venue.)

Viewer Statistics


The Lab has been putting together a new statistics reporting system, which is now starting to be used to generate a range of reports. Commenting on some of the information which is coming out of the system, primarily in response to questions asked at both Open-source dev and TPV dev meetings, Oz indicated that:

  • Almost one-third of regions within SL have at least one materials-enhanced object in them, which is described as “dramatically faster” than the adoption of mesh
  • The number of avatars wearing materials-enhanced mesh / prim clothing is “steadily climbing”
  • The number of people who have Advanced Lighting Model (ALM) enabled on a “class 3” (mid-range Graphics cards) or above is just under 20%

One of the problems here – from the Lab’s point of view at least – is that both Singularity and Firestorm have ALM turned off by default for almost all graphics settings, except perhaps High-Ultra, and Ultra. The flip side to this is the view that the Lab enables ALM by default on cards which are barely able to support it, with the result that people’s SL experience suffers through poor frame rates.

In the past the Lab has pointed to data which tends to show that viewers running on low-end graphics cards card do indeed suffer performance issues with ALM active; mid-range GPU show little difference in performance between running with ALM active or not and have “reasonable” fps rates; high-end (“class 5”, as they call them) cards  – e.g. ATI Radeon HD 7800, 7900, 8900, 8950 + similar, nVidia GTX 460/460SE, 465, 550TI, 580, 660/660TI + similar – perform significantly better with ALM active.

The problems here are how one defines “reasonable” frame rates and how one interprets ALM. For the Lab, it would appear that “reasonable” frame rates is anything in double figures – e.g. above 10; many users would disagree with this. At the same time, many users still appear to equate having ALM active with having Shadows enabled (which actually leads to a far larger performance hit), but the two are actually quite separate. As had been pointed out a number of times in these pages, ALM can be active without having to enable shadows.

Running with ALM active does not require shadows to be enabled
Running with ALM active does not require shadows to be enabled

Nevertheless, part of the new viewer statistics system should enable to Lab to gather and present performance numbers for cards with and with ALM enabled, filtered by viewer, so that TPVs can better judge matters for themselves.  In addition, Oz is going to be looking at ways and means of doing systematic testing with cards in order to generate more meaningful statistics, and which may allow for other factors which influcence performance (other avatars in the same region, the amount of movement going on, viewer settings, etc.).

Understanding Viewer Performance


A further problem with the viewer is that it is complicated, and while there are many tools to help monitor performance, people either focus on the wrong tools or cannot find those that would be helpful to them in diagnosing an issue when they do encounter unexpected performance drops.

To this end, Oz floated the idea at the TPV Developer meeting for TPV devs to give thought as to which tools and information feeds within the viewer would be useful to users to help them understand what is going on, and how best to present said tools, etc., in a way which would make sense to users and enable them to make use of the information they are seeing.

Continue reading “SL projects update week 39 (3): viewer, interest list, HTTP, SSA and more”