Archives June 2020

Monday, April 3, 2006

Sometime during the night of Friday, January 28, 15 year-old Jenissa Ryan was assaulted and raped in Alice Springs. She was discovered near the entrance of Centralian Senior Secondary College around 10:30 a.m., and a college employee called an ambulance. The attack was not reported in the mainstream national media until this week, when it became known that the victim was the great-granddaughter of famous indigenous artist Albert Namatjira.

In an article published in Saturdays Sydney Morning Herald, Russell Skelton said that the fact that she was an Aborigine, and the location of her bashing, contributed to her death. “If Jenissa had been white, she might be alive today, though the scars of her brutal bashing and rape could never be erased. If she had been bashed and left for dead almost anywhere else, assistance would have been immediate and the outrage strident.” He also said that if her connection to Namatjira had been known, Jenissa’s death would have been a “national scandal.”

Police believe that she was attacked by a number of youths her own age while walking home. She continued to walk home, but collapsed unconscious near the entrance to the college. Here, according to police, she was found by three teenage boys, who dragged her out of view and raped her.

Jenissa was still alive when found. Skelton considered it likely that people had seen her during the morning but done nothing. “That means a number of residents of middle-class Grevillea Drive probably noticed. The white T-shirt and striped tracksuit pants were hard to miss,” he said.

She was taken to Alice Springs Hospital, and then flown to Adelaide’s Women and Children’s Hospital.

On February 13 Northern Territory Police charged a 16 year-old male and a 15 year-old female with assaulting Jenissa Ryan. Three other males, aged 14, 15, and 16, have been charged with having unlawful sexual intercourse with Jenissa Ryan. Police expressed gratitude for the assistance they had received from members of the public.

Father Asaeli Raass said that both indigenous and non-indigenous people were in denial about the incident. “Yes, it’s a painful thing, but people are sweeping it under the carpet when they should be confronting the big issues Jenissa’s death raises,” he said. He also said that the initial wave of publicity “never travelled outside Alice Springs.”

Jenissa’s mother, Carmel Ryan, said that her daughter wanted to be a painter, like her great-grandfather. “She wanted to be like him, to make a creative contribution we would all be proud of. Tragically that can never be, but I feel nothing but sorrow for the parents of the children involved in this terrible event,” she said.

Wednesday, July 3, 2013

A grassroots movement known as Restore the Fourth, dedicated to the protection of the 4th Amendment to the US Constitution, are to hold protests countrywide on July 4. The planned protests come in the wake of information about NSA surveillance leaked last month, notably the PRISM surveillance program and the collection of Verizon phone records. Wikinews interviewed Jett, a national organizer from this recently created movement.

((Wikinews)) First of all, could you explain what Restore the Fourth is all about?

Jett: At its core, RestoreTheFourth is about protecting citizens’ constitutional rights. Specifically, we’re dedicated to bringing awareness and action to the expanding overreach and elimination of the 4th Amendment to the US Constitution.

((WN)) What is your role at Restore the Fourth?

Jett: My job at RestoreTheFourth could be summarized as ‘project coordinator’. Every person who wants to help can help in a tremendous way. I simply make sure that their skills get used in a way that would be most beneficial to the movement: web development, public relations, etc. I also field questions from the press and promote knowledge of our cause.

((WN)) What are your plans for direct action, outreach, etc.?

Jett: Our press release includes a list of ‘demands’ for what we want to see in order to restore our privacy rights, including reform of the PATRIOT Act and increased accountability for public officials. In the very short term, these protests and demonstrations bring awareness to the issue, something that’s really important in enacting reform. In the long term, however, we expect to create a legal organization dedicated to restoring these rights inherent to every American. By partnering with various other organizations that share our moral values, we can further these goals.

On July 4, we will have over 100 protests in all 50 states, showing that the citizens of America are truly serious about protecting their rights.

((WN)) By what means do you hope to achieve such change?

Jett: This movement started only a few weeks ago, and since then we’ve experienced exponential growth and progress. Since the movement is still very young, plans diverge in the long term on what we hope to achieve. Personally, I’d like to see a combination of legislative and litigative action (something like what the ACLU does), and others want to see further plans of action. With organizations such as the BORDC, stopwatching.us and the EFF behind us, I feel that we can achieve all of this and much more.

((WN)) Is the movement US-only or will it extend to other jurisdictions as well? Do you think it would be fair for the US to spy on non-citizens?

Jett: I believe that rights are inherent to all humans, not only United States citizens. In the long term I’d certainly like to see people of all nations protected from the slow elimination of privacy that we’re all experiencing.

((WN)) What do you think about Edward Snowden’s whistleblowing?

Jett: I think that too much attention is being given to his personality instead of what he fought for. He’s being treated as a ‘martyr’ of sorts. It seems to distract from what he truly believed in — transparency for the government and inherent privacy for all Americans.

((WN)) What do you think about his future, given the legal grey zone in which he currently is?

Jett: Hard to say. He may be captured by any number of agencies, or he may live a free man. Whatever happens, he has the eyes of millions of people on him, all of whom will yell very loudly if anything occurs.

((WN)) Thank you very much for your time.

Jett: Thanks for the opportunity.

Sunday, May 28, 2006

Stardust is a NASA space capsule that collected samples from comet 81P/Wild (also known as “Wild 2) in deep space and landed back on Earth on January 15, 2006. It was decided that a collaborative online review process would be used to “discover” the microscopically small samples the capsule collected. The project is called Stardust@home. Unlike distributed computing projects like SETI@home, Stardust@home relies entirely on human intelligence.

Andrew Westphal is the director of Stardust@home. Wikinews interviewed him for May’s Interview of the Month (IOTM) on May 18, 2006. As always, the interview was conducted on IRC, with multiple people asking questions.

Some may not know exactly what Stardust or Stardust@home is. Can you explain more about it for us?

Stardust is a NASA Discovery mission that was launched in 1999. It is really two missions in one. The primary science goal of the mission was to collect a sample from a known primitive solar-system body, a comet called Wild 2 (pronounced “Vilt-two” — the discoverer was German, I believe). This is the first US “sample return” mission since Apollo, and the first ever from beyond the moon. This gives a little context. By “sample return” of course I mean a mission that brings back extraterrestrial material. I should have said above that this is the first “solid” sample return mission — Genesis brought back a sample from the Sun almost two years ago, but Stardust is also bringing back the first solid samples from the local interstellar medium — basically this is a sample of the Galaxy. This is absolutely unprecedented, and we’re obviously incredibly excited. I should mention parenthetically that there is a fantastic launch video — taken from the POV of the rocket on the JPL Stardust website — highly recommended — best I’ve ever seen — all the way from the launch pad, too. Basically interplanetary trajectory. Absolutely great.

Is the video available to the public?

Yes [see below]. OK, I digress. The first challenge that we have before can do any kind of analysis of these interstellar dust particles is simply to find them. This is a big challenge because they are very small (order of micron in size) and are somewhere (we don’t know where) on a HUGE collector— at least on the scale of the particle size — about a tenth of a square meter. So…

We’re right now using an automated microscope that we developed several years ago for nuclear astrophysics work to scan the collector in the Cosmic Dust Lab in Building 31 at Johnson Space Center. This is the ARES group that handles returned samples (Moon Rocks, Genesis chips, Meteorites, and Interplanetary Dust Particles collected by U2 in the stratosphere). The microscope collects stacks of digital images of the aerogel collectors in the array. These images are sent to us — we compress them and convert them into a format appropriate for Stardust@home.

Stardust@home is a highly distributed project using a “Virtual Microscope” that is written in html and javascript and runs on most browsers — no downloads are required. Using the Virtual Microscope volunteers can search over the collector for the tracks of the interstellar dust particles.

How many samples do you anticipate being found during the course of the project?

Great question. The short answer is that we don’t know. The long answer is a bit more complicated. Here’s what we know. The Galileo and Ulysses spacecraft carried dust detectors onboard that Eberhard Gruen and his colleagues used to first detect and them measure the flux of interstellar dust particles streaming into the solar system. (This is a kind of “wind” of interstellar dust, caused by the fact that our solar system is moving with respect to the local interstellar medium.) Markus Landgraf has estimated the number of interstellar dust particles that should have been captured by Stardust during two periods of the “cruise” phase of the interplanetary orbit in which the spacecraft was moving with this wind. He estimated that there should be around 45 particles, but this number is very uncertain — I wouldn’t be surprised if it is quite different from that. That was the long answer! One thing that I should say…is that like all research, the outcome of what we are doing is highly uncertain. There is a wonderful quote attributed to Einstein — “If we knew what we were doing, it wouldn’t be called “research”, would it?”

How big would the samples be?

We expect that the particles will be of order a micron in size. (A millionth of a meter.) When people are searching using the virtual microscope, they will be looking not for the particles, but for the tracks that the particles make, which are much larger — several microns in diameter. Just yesterday we switched over to a new site which has a demo of the VM (virtual microscope) I invite you to check it out. The tracks in the demo are from submicron carbonyl iron particles that were shot into aerogel using a particle accelerator modified to accelerate dust particles to very high speeds, to simulate the interstellar dust impacts that we’re looking for.

And that’s on the main Stardust@home website [see below]?

Yes.

How long will the project take to complete?

Partly the answer depends on what you mean by “the project”. The search will take several months. The bottleneck, we expect (but don’t really know yet) is in the scanning — we can only scan about one tile per day and there are 130 tiles in the collector…. These particles will be quite diverse, so we’re hoping that we’ll continue to have lots of volunteers collaborating with us on this after the initial discoveries. It may be that the 50th particle that we find will be the real Rosetta stone that turns out to be critical to our understanding of interstellar dust. So we really want to find them all! Enlarging the idea of the project a little, beyond the search, though is to actually analyze these particles. That’s the whole point, obviously!

And this is the huge advantage with this kind of a mission — a “sample return” mission.

Most missions rather do things quite differently… you have to build an instrument to make a measurement and that instrument design gets locked in several years before launch practically guaranteeing that it will be obsolete by the time you launch. Here exactly the opposite is true. Several of the instruments that are now being used to analyze the cometary dust did not exist when the mission was launched. Further, some instruments (e.g., synchrotrons) are the size of shopping malls — you don’t have a hope of flying these in space. So we can and will study these samples for many years. AND we have to preserve some of these dust particles for our grandchildren to analyze with their hyper-quark-gluon plasma microscopes (or whatever)!

When do you anticipate the project to start?

We’re really frustrated with the delays that we’ve been having. Some of it has to do with learning how to deal with the aerogel collectors, which are rougher and more fractured than we expected. The good news is that they are pretty clean — there is very little of the dust that you see on our training images — these were deliberately left out in the lab to collect dust so that we could give people experience with the worst case we could think of. In learning how to do the scanning of the actual flight aerogel, we uncovered a couple of bugs in our scanning software — which forced us to go back and rescan. Part of the other reason for the delay was that we had to learn how to handle the collector — it would cost $200M to replace it if something happened to it, so we had to develop procedures to deal with it, and add several new safety features to the Cosmic Dust Lab. This all took time. Finally, we’re distracted because we also have many responsibilities for the cometary analysis, which has a deadline of August 15 for finishing analysis. The IS project has no such deadline, so at times we had to delay the IS (interstellar, sorry) in order to focus on the cometary work. We are very grateful to everyone for their patience on this — I mean that very sincerely.

And rest assured that we’re just as frustrated!

I know there will be a “test” that participants will have to take before they can examine the “real thing”. What will that test consist of?

The test will look very similar to the training images that you can look at now. But.. there will of course be no annotation to tell you where the tracks are!

Why did NASA decide to take the route of distributed computing? Will they do this again?

I wouldn’t say that NASA decided to do this — the idea for Stardust@home originated here at U. C. Berkeley. Part of the idea of course came…

If I understand correctly it isn’t distributed computing, but distributed eyeballing?

…from the SETI@home people who are just down the hall from us. But as Brian just pointed out. this is not really distributed computing like SETI@home the computers are just platforms for the VM and it is human eyes and brains who are doing the real work which makes it fun (IMHO).

That said… There have been quite a few people who have expressed interested in developing automated algorithms for searching. Just because WE don’t know how to write such an algorithm doesn’t mean nobody does. We’re delighted at this and are happy to help make it happen

Isn’t there a catch 22 that the data you’re going to collect would be a prerequisite to automating the process?

That was the conclusion that we came to early on — that we would need some sort of training set to be able to train an algorithm. Of course you have to train people too, but we’re hoping (we’ll see!) that people are more flexible in recognizing things that they’ve never seen before and pointing them out. Our experience is that people who have never seen a track in aerogel can learn to recognize them very quickly, even against a big background of cracks, dust and other sources of confusion… Coming back to the original question — although NASA didn’t originate the idea, they are very generously supporting this project. It wouldn’t have happened without NASA’s financial support (and of course access to the Stardust collector). Did that answer the question?

Will a project like this be done again?

I don’t know… There are only a few projects for which this approach makes sense… In fact, I frankly haven’t run across another at least in Space Science. But I am totally open to the idea of it. I am not in favor of just doing it as “make-work” — that is just artificially taking this approach when another approach would make more sense.

How did the idea come up to do this kind of project?

Really desperation. When we first thought about this we assumed that we would use some sort of automated image recognition technique. We asked some experts around here in CS and the conclusion was that the problem was somewhere between trivial and impossible, and we wouldn’t know until we had some real examples to work with. So we talked with Dan Wertheimer and Dave Anderson (literally down the hall from us) about the idea of a distributed project, and they were quite encouraging. Dave proposed the VM machinery, and Josh Von Korff, a physics grad student, implemented it. (Beautifully, I think. I take no credit!)

I got to meet one of the stardust directors in March during the Texas Aerospace Scholars program at JSC. She talked about searching for meteors in Antarctica, one that were unblemished by Earth conditions. Is that our best chance of finding new information on comets and asteroids? Or will more Stardust programs be our best solution?

That’s a really good question. Much will depend on what we learn during this official “Preliminary Examination” period for the cometary analysis. Aerogel capture is pretty darn good, but it’s not perfect and things are altered during capture in ways that we’re still understanding. I think that much also depends on what question you’re asking. For example, some of the most important science is done by measuring the relative abundances of isotopes in samples, and these are not affected (at least not much) by capture into aerogel.

Also, she talked about how some of the agencies that they gave samples to had lost or destroyed 2-3 samples while trying to analyze them. That one, in fact, had been statically charged, and stuck to the side of the microscope lens and they spent over an hour looking for it. Is that really our biggest danger? Giving out samples as a show of good faith, and not letting NASA example all samples collected?

These will be the first measurements, probably, that we’ll make on the interstellar dust There is always a risk of loss. Fortunately for the cometary samples there is quite a lot there, so it’s not a disaster. NASA has some analytical capabilities, particularly at JSC, but the vast majority of the analytical capability in the community is not at NASA but is at universities, government labs and other institutions all over the world. I should also point out that practically every analytical technique is destructive at some level. (There are a few exceptions, but not many.) The problem with meteorites is that except in a very few cases, we don’t know where they specifically came from. So having a sample that we know for sure is from the comet is golden!

I am currently working on my Bachelor’s in computer science, with a minor in astronomy. Do you see successes of programs like Stardust to open up more private space exploration positions for people such as myself. Even though I’m not in the typical “space” fields of education?

Can you elaborate on your question a little — I’m not sure that I understand…

Well, while at JSC I learned that they mostly want Engineers, and a few science grads, and I worry that my computer science degree with not be very valuable, as the NASA rep told me only 1% of the applicants for their work study program are CS majors. I’m just curious as to your thoughts on if CS majors will be more in demand now that projects like Stardust and the Mars missions have been great successes? Have you seen a trend towards more private businesses moving in that direction, especially with President Bush’s statement of Man on the Moon in 2015?

That’s a good question. I am personally not very optimistic about the direction that NASA is going. Despite recent successes, including but not limited to Stardust, science at NASA is being decimated.

I made a joke with some people at the TAS event that one day SpaceShipOne will be sent up to save stranded ISS astronauts. It makes me wonder what kind of private redundancy the US government is taking for future missions.

I guess one thing to be a little cautious about is that despite SpaceShipOne’s success, we haven’t had an orbital project that has been successful in that style of private enterprise It would be nice to see that happen. I know that there’s a lot of interest…!

Now I know the answer to this question… but a lot do not… When samples are found, How will they be analyzed? Who gets the credit for finding the samples?

The first person who identifies an interstellar dust particle will be acknowledged on the website (and probably will be much in demand for interviews from the media!), will have the privilege of naming the particle, and will be a co-author on any papers that WE (at UCB) publish on the analysis of the particle. Also, although we are precluded from paying for travel expenses, we will invite those who discover particles AND the top performers to our lab for a hands-on tour.

We have some fun things, including micromachines.

How many people/participants do you expect to have?

About 113,000 have preregistered on our website. Frankly, I don’t have a clue how many will actually volunteer and do a substantial amount of searching. We’ve never done this before, after all!

One last thing I want to say … well, two. First, we are going to special efforts not to do any searching ourselves before we go “live”. It would not be fair to all the volunteers for us to get a jumpstart on the search. All we are doing is looking at a few random views to make sure that the focus and illumination are good. (And we haven’t seen anything — no surprise at all!) Also, the attitude for this should be “Have Fun”. If you’re not having fun doing it, stop and do something else! A good maxim for life in general!

Sunday, May 21, 2006

Three days after the Internet release of the free content 3D short Elephants Dream (see Wikinews coverage), we exchanged e-mails with Ton Roosendaal about the reaction to the film, open source filmmaking, and the changes to Blender that resulted from the production. Ton Roosendaal is the lead developer of the Blender 3D rendering and modelling software that was used for the movie. He is also the chairman of the Blender Foundation, a non-profit organization which was formed in support of the software and projects like Elephants Dream.

How much money did the Blender Foundation spend on producing the movie? Has the money been fully recouped by DVD orders and donations?

We still have to finish the final bookkeeping for this project. It has been executed in co-production with the Netherlands Media Art Institute, and we each had our own internal budgeting for the project. When you exclude expenses of pre-production and producer personnel, the total budget was about 120,000 €, of which we covered half. Our contribution was roughly covered half by the DVD sales, and half by European Union support (http://www.uni-verse.org consortium).

One of the most common criticisms of CGI films is focus on technology over content. For instance, Final Fantasy: The Spirits Within flopped with audiences, in spite of being an undisputed technical milestone. I’ve seen many reviews that criticized the plot of “Elephants Dream” as too bizarre or confusing. In retrospect, are you happy with the story development process?

Haha, I knew the story and plot would get a mixed acclaim. There’s a couple of reasons I’d like to mention for it.

First of all; the criticism resembles how people witness Blender itself, too. Many people expect that Free Software is an easy accessible mass audience product. We get a lot of complaints by non-artists that they can’t get into the software easily, whilst the complexity of commercial products like Maya or Houdini is perceived as a confirmation of its “quality”. Apparently an Open Movie created similar expectations with the audience.

Luckily we also got many positive reviews of the artistic result of the movie. It is quite abstract, but definitely has many layers of information, inspiring many of the viewers to see relevant real life messages hidden here.

For this project we’ve teamed up with the Netherlands Media Art Institute, internationally renowned as a resource for video art. So for Elephants Dream, we’ve had the luxury to challenge ourselves to create real independent artistic content as well. The artists had a lot of freedom from the start; they were responsible for the concept, story and creative development of the entire movie. This has resulted in a lot of quite personal choices, based on what the artists liked to do themselves. I really cherish such an approach, it has resulted in a very motivated team working crazy hours the last months to get it all realized.

But, most importantly; the main target of our project was not only to create a 3D movie short, but to experiment with ways to improve the efficiency and quality of open source development. On this aspect only, this project was just a huge success, and the main reason for our sponsors (the DVD pre-sale) to support it. I know they might have liked a cartoonish funny movie with furry animals better, but for that you get already pretty well served by the bigger 3D animation studios. 🙂

I’m the first to admit that – looking back especially – certain aspects worked out quite weakly; there’s loose ends and questionable decisions, especially in story development and continuity. That’s just the risk of doing experiments, and nothing I regret really. The five artists from our user community who were invited to make the movie were young people with no professional background in filmmaking. Their personal incentive to participate in this project was also to learn from it, and to create a good portfolio for their future career. I’ve witnessed them grow in competence in the past year enormously, something I’m incredibly proud of.

On the technical level, the only major criticism I’ve seen of “Elephants Dream” is the character animation, especially in the opening scene — many reviewers felt that the movements seemed a bit unnatural. Do you agree with these criticisms? If so, what do you think can be done to improve on that level?

Yeah, the challenge the artists set themselves – to use quite realistic personages – is also something that easily works against you. In many animation movies they introduce characters in the beginning in a way you get used to their specific characteristic movements, so you accept a certain level of non-realism easily. (Check the weird walk cycles in The Incredibles for example). Another aspect is that we’ve started work on the first scenes, and ended with the last scenes. I can clearly see the animation quality increase, and that whilst the ending scenes were done in much less time due to time constraints.

We also didn’t schedule to do 9.5 minutes of animation either…. Originally it was more like 6. But, it’s always easier to look back to define the right decisions, eh? 🙂

I’m very happy with the reviews we got so far; luckily the movie was perceived as a professional quality product, and reviewed based on comparisons with what the big studios come up with. Even when we couldn’t satisfy all these quality demands, it has luckily not been branded as a pathetic presumptuous attempt by amateurs!

Do you think there is hope for a full-length open movie project in the near future? Would the Blender Foundation be interested in such a project, or do you intend to continue focusing mainly on shorts?

I’d like to wait a little while with defining what a next project would look like. Given the constraints of “organizing projects to improve open source development”, we might have not much choice either. It would probably mean to work with a new team each time, so most likely be based on shorts only. On the other hand, there’s also clear signals that this approach works well, and creates excitement and involvement of a lot of people, also from producers and sponsors. That might enable us to set up a next project based on larger targets. For a full-length feature film however, we should involve a sufficient amount of experienced film makers as well, and/or invite the first team to participate again. That would put a lot of pressure on the required budget…. You can’t do that based on a 1000 DVD pre-sale target. Would more be like 20,000 or so…. 🙂

How did the process of making the movie feed back into the development of Blender? Are there major technical changes that were made only or primarily because of the film?

Already during the pre-production phase the artists have defined the key targets for Blender development. This then was coordinated with the online development community too. I’ve done the most crucial (re-)development mostly myself, though. Especially on the character animation tools, on the rendering pipeline and compositing tools.

It is especially the latter I’m most satisfied with. In 3D movie production the compositing stage creates a giant content bottleneck. By transparently integrating this in our render-pipeline, a very efficient workflow has been achieved. And, not to forget, Blender now also offers the first production-level open source compositor on the market!

The current summary you can find in our work-in-progress release notes.

What are the key technical features in Blender you want to add or improve for future movie projects?

Depends on what the movie is about! There’s always hundreds of features you can work on. However, we’ll have to work on that anyway, movie project or not. There’s a lot of professionals using Blender now, and they can’t wait for the Blender Foundation to do movies! Look at this studio for example:http://www.plumiferos.com/

I read that at least one proprietary software package, Reaktor, was used for the sound effects. Is this because no equivalent free software solution exists yet? Will future projects have a “free software only” policy?

We’ve limited the “Open Source tools” requirement to our own Studio Orange only. That was what we could keep in control at least, and I can tell you it was not always easy even… 🙂

For sound and music we’ve decided from the beginning to seek an external sponsor. We have chosen to work with the best quality studio and composer we could find, preferably using open source, but not as a prerequisite.

My own competence is solely within the CG [computer graphics, Ed.] side of movie making. When it comes to music editing, or video encoding and DVD authoring, I could only decide to choose to work with external parties with proven competences in that area. I have to be practical in projects like this, especially to ensure it will be realized.

Hopefully, now we’ve got so much attention world wide, we can involve more non-CG open source next time, too. I will definitely strive for the maximum here, but it will fully depend on the amount of professional support we can get.

Blender itself was originally closed source freeware, until it was “liberated” through a fundraising campaign. If you could choose one proprietary application to “set free” where such a goal could be realistically achieved, which one would it be?

Well, the “realistically achieved” demand makes it quite difficult. 🙂 Looking back at similar cases, like Mozilla and OpenOffice.org, it was always very circumstantial. It just happens sometimes, you can’t organize something like this to happen in advance. The only common denominator is “a company in troubles”… so, who’s in trouble now?

What is your personal favorite computer-animated full-length film?

Uuuh… that differs every week! Probably Ice Age (the first one). Mostly because they didn’t overdo showcasing 3D technology so much, but created truly adorable characters and great funny gags.

Sunday, April 1, 2007

In Estonia, a mouse made its nest in a cash machine and spent the weekend eating tens of thousands of kroons in bank notes. The critter was discovered after a customer making a withdrawal got half-eaten bills from the machine.

Experts are now investigating how the rodent was able to get into the ATM.

Saturday, July 7, 2007

On Saturday, a suicide truck bomb in a Shiite village, Tuz Khurmato, north of Baghdad damaged homes, shops and a large outdoor market. The bomb blast, blamed on Sunni militants, killed at least 100 and wounded another 250 Iraqi civilians.

Thursday, June 23, 2011

NASA’s Cassini–Huygens spacecraft has discovered evidence for a large-scale saltwater reservoir beneath the icy crust of Saturn’s moon Enceladus. The data came from the spacecraft’s direct analysis of salt-rich ice grains close to the jets ejected from the moon. The study has been published in this week’s edition of the journal Nature.

Data from Cassini’s cosmic dust analyzer show the grains expelled from fissures, known as tiger stripes, are relatively small and usually low in salt far away from the moon. Closer to the moon’s surface, Cassini found that relatively large grains rich with sodium and potassium dominate the plumes. The salt-rich particles have an “ocean-like” composition and indicate that most, if not all, of the expelled ice and water vapor comes from the evaporation of liquid salt-water. When water freezes, the salt is squeezed out, leaving pure water ice behind.

Cassini’s ultraviolet imaging spectrograph also recently obtained complementary results that support the presence of a subsurface ocean. A team of Cassini researchers led by Candice Hansen of the Planetary Science Institute in Tucson, Arizona, measured gas shooting out of distinct jets originating in the moon’s south polar region at five to eight times the speed of sound, several times faster than previously measured. These observations of distinct jets, from a 2010 flyby, are consistent with results showing a difference in composition of ice grains close to the moon’s surface and those that made it out to the E ring, the outermost ring that gets its material primarily from Enceladean jets. If the plumes emanated from ice, they should have very little salt in them.

“There currently is no plausible way to produce a steady outflow of salt-rich grains from solid ice across all the tiger stripes other than salt water under Enceladus’s icy surface,” said Frank Postberg, a Cassini team scientist at the University of Heidelberg in Germany.

The data suggests a layer of water between the moon’s rocky core and its icy mantle, possibly as deep as about 50 miles (80 kilometers) beneath the surface. As this water washes against the rocks, it dissolves salt compounds and rises through fractures in the overlying ice to form reserves nearer the surface. If the outermost layer cracks open, the decrease in pressure from these reserves to space causes a plume to shoot out. Roughly 400 pounds (200 kilograms) of water vapor is lost every second in the plumes, with smaller amounts being lost as ice grains. The team calculates the water reserves must have large evaporating surfaces, or they would freeze easily and stop the plumes.

“We imagine that between the ice and the ice core there is an ocean of depth and this is somehow connected to the surface reservoir,” added Postberg.

The Cassini mission discovered Enceladus’ water-vapor and ice jets in 2005. In 2009, scientists working with the cosmic dust analyzer examined some sodium salts found in ice grains of Saturn’s E ring but the link to subsurface salt water was not definitive. The new paper analyzes three Enceladus flybys in 2008 and 2009 with the same instrument, focusing on the composition of freshly ejected plume grains. In 2008, Cassini discovered a high “density of volatile gases, water vapor, carbon dioxide and carbon monoxide, as well as organic materials, some 20 times denser than expected” in geysers erupting from the moon. The icy particles hit the detector target at speeds between 15,000 and 39,000 MPH (23,000 and 63,000 KPH), vaporizing instantly. Electrical fields inside the cosmic dust analyzer separated the various constituents of the impact cloud.

“Enceladus has got warmth, water and organic chemicals, some of the essential building blocks needed for life,” said Dennis Matson in 2008, Cassini project scientist at NASA’s Jet Propulsion Laboratory in Pasadena, California.

“This finding is a crucial new piece of evidence showing that environmental conditions favorable to the emergence of life can be sustained on icy bodies orbiting gas giant planets,” said Nicolas Altobelli, the European Space Agency’s project scientist for Cassini.

“If there is water in such an unexpected place, it leaves possibility for the rest of the universe,” said Postberg.