Nearby Galaxy is Hotbed of Star Formation

Image credit: Hubble
The nearby dwarf galaxy NGC 1569 is a hotbed of vigorous star birth activity which blows huge bubbles that riddle the main body of the galaxy. The galaxy’s “star factories” are also manufacturing brilliant blue star clusters. This galaxy had a sudden onset of star birth about 25 million years ago, which subsided about the time the very earliest human ancestors appeared on Earth.

In this new image, taken with NASA’s Hubble Space Telescope, the bubble structure is sculpted by the galactic super-winds and outflows caused by a colossal input of energy from collective supernova explosions that are linked with a massive episode of star birth.

One of the still unresolved mysteries in astronomy is how and when galaxies formed and how they evolved. Most of today’s galaxies seem to have been already fully formed very early on in the history of the universe (now corresponding to a large distance away from us), their formation involving one or more galaxy collisions and/or episodes of strongly enhanced star formation activity (so-called starbursts).

While any galaxies that are actually forming are too far away for detailed studies of their stellar populations even with Hubble, their local counterparts, nearby starburst and colliding galaxies, are far easier targets.

NGC 1569 is a particularly suitable example, being one of the closest starburst galaxies. It harbors two very prominent young, massive clusters plus a large number of smaller star clusters. The two young massive clusters match the globular star clusters we find in our own Milky Way galaxy, while the smaller ones are comparable with the less massive open clusters around us.

NGC 1569 was recently investigated in great detail by a group of European astronomers who published their results in the January 1, 2004 issue of the British journal, Monthly Notices of the Royal Astronomical Society. The group used several of Hubble’s high-resolution instruments, with deep observations spanning a wide wavelength range, to determine the parameters of the clusters more precisely than is currently possible from the ground.

The team found that the majority of clusters in NGC 1569 seem to have been produced in an energetic starburst that started around 25 million years ago and lasted for about 20 million years. First author Peter Anders from the Gottingen University Galaxy Evolution Group, Germany says “We are looking straight into the very creation processes of the stars and star clusters in this galaxy. The clusters themselves present us with a fossil record of NGC 1569’s intense star formation history.”

The bubble-like structures seen in this image are made of hydrogen gas that glows when hit by the fierce winds and radiation from hot young stars and is racked by supernovae shocks. The first supernovae blew up when the most massive stars reached the end of their lifetimes roughly 20-25 million years ago. The environment in NGC 1569 is still turbulent and the supernovae may not only deliver the gaseous raw material needed for the formation of further stars and star clusters, but also actually trigger their birth in the tortured swirls of gas.

The color image is composed of 4 different exposures with Hubble’s Wide Field and Planetary Camera 2 through the following filters: a wide ultraviolet filter (shown in blue), a green filter (shown in green), a wide red filter (shown in red), and a Hydrogen alpha filter (also shown in red).

Original Source: Hubble News Release

Is NASA Following in the Footsteps of the X-Prize?

NASA has released its fiscal year 2005 budget, which includes specific prizes for the various activities outlined in President Bush’s new space initiative announced earlier in January. One interesting line item is $20 million set aside for something called the “Centennial Challenges“. Here’s the description:

Request includes funding to establish a series of annual prizes for revolutionary, breakthrough accomplishments that advance exploration of the solar system and beyond and other NASA goals. Some of the most difficult technical challenges to exploration will require very novel solutions from non-traditional sources of innovation. By making awards based on actual achievements instead of proposals, NASA will tap innovators in academia, industry, and the public who do not normally work on NASA issues. Centennial Challenges will be modeled on past successes, including 19th century navigation prizes, early 20th century aviation prizes, and more recent prizes offered by the U.S. government and private sector. Examples of potential Centennial Challenges include very-low-cost space missions, contests to demonstrate highly mobile, capable, and survivable robotic systems, and fundamental advances in technical areas like lander navigation, spacecraft power systems, life detection sensors, and nano-materials.

This sounds like NASA is going to be awarding prizes for successful space accomplishments, similar to the privately-funded $10 million X-Prize that will reward the first private firm to achieve sub-orbital flight twice within two weeks. Prizes like this have been one of the most successful technology drivers in the past; one of the best known examples is the Orteig Prize, won by Charles Lindbergh, which demonstrated that flights across the Atlantic Ocean were possible.

Pretty exciting news, we’ll see how this turns out.

Fraser Cain
Universe Today

P.S. Thanks to for the heads up.

Can the Rovers Find Life on Mars?

Image credit: ESA
Astrobiology Magazine (AM): The first batch of images from Meridiani Planum, showing finely layered bedrock, have scientists pretty excited. What are your initial impressions?

Andrew Knoll (AK): We’ve known for several years, from orbital data, that there are layered rocks on Mars, but Opportunity gives us our first chance to actually go and work directly on some of these rocks in an outcrop. For geologists, you just can’t overemphasize the importance of that.

The fact that they’re sort of tabular suggests that they’re either fairly thin volcanic deposits or sediments. And the prospect of having in situ sedimentary rocks on Mars that we can go up and interrogate is about a best-case scenario, as far as I’m concerned.

AM: What if they turn out to be volcanic ash deposits? Will that make for a less interesting scenario?

AK: Not at all. I think one of the big questions is, What are the predominant processes that have given rise to layered rocks on Mars? There’s no reason to believe that every layered rock on Mars formed in the same way as the ones that Opportunity’s sitting in front of. But to know even how one of those layered rocks formed will be a step in the right direction.

We will also soon know whether the hematite signal in Meridiani that was detected from orbit is resident in those rocks. Remember the reason that we’re at Meridiani Planum is because of this strong signal for a particular form of iron oxide called hematite. It’s very difficult to think about making hematite without some liquid water interactions with rocks. So even if it’s a volcanic rock, it will help to constrain our thinking about one of the most interesting chemical anomalies on the planet.

AM: There’s a river in Spain, the Rio Tinto, where you’ve spent some time doing research. You’ve suggested that the way the iron minerals at Rio Tinto have degraded and transformed over time might shed some light on how the hematite at Meridiani formed. Can you explain the connection?

AK: Let me start at the beginning. The kinds of thinking we bring to the interpretation of iron on Mars will be informed by our experience with oxidized iron on the Earth’s surface. There are a number of ways that iron deposits have formed on our planet. It may be that no one of them is going to be an exact analog for what happened on Mars. But each of them might give tidbits of information that will help us think about Mars.

Now, Rio Tinto is a very interesting place. It’s in southwestern Spain, about an hour west of Seville, maybe another hour east of the Portuguese border. Rio Tinto is actually of historical interest to people in America since Columbus set sail in 1492 from a port at the mouth of the Rio Tinto. But it’s also of interest to mining geologists because it has been a mine at least since the time of the Romans.

What’s being mined there is iron ore. About 400 million years ago hydrothermal processes formed these iron ore deposits. Mostly the iron is in the form of iron sulfide, or fool’s gold. It’s very rich ore. As rainwater percolates down through these deposits, it oxidizes the pyrite and two things happen. One, it forms sulfuric acid. So the water in the river has a pH of about 1; it’s very acidic. And, two, the iron gets oxidized. So the water is about the color of rubies, because of this iron being carried around.

What’s interesting is that if you look at the deposits that are forming from the Rio Tinto today, most of the iron is coming out as iron sulfate minerals, that is, a combination of iron, sulfur and oxygen; and a little bit of it is coming out as a mineral called goethite, which is iron mixed with oxygen and a little bit of hydrogen. Goethite is basically rust.

That’s not what you see at Meridiani on Mars. But what’s interesting about the Rio Tinto deposit is that this process has been taking place for at least 2 million years. And there is a series of terraces that give us a sense of what happens to these deposits over time.

What we find is that after just a few thousand years, all of the sulfate minerals have disappeared and all of the iron is in this material called goethite. But as you go into older and older terraces, by the time you get to terraces that are 2 million years old, much of that goethite has been replaced by hematite, the mineral on Mars. And it’s a fairly coarse-grained hematite, which is also what we see at Mars.

So the first thing we learn at Rio Tinto is that one doesn’t need to think only about processes that deposit coarse-grained hematite from the get-go. It can form during what geologists call diagenesis. That is, it can form by processes that affect the rocks through time, and it can actually do that at low temperatures and without being deeply buried and subjected to high pressure. So in that sense, Rio Tinto shows us another way in which the hematite in Meridiani could have gotten there. It expands the options we consider.

AM: When geologists say things like “low temperature,” they often mean something different than the rest of us do.

AK: When I say “low temperature,” I’m talking about the temperatures that you and I experience on a daily basis, room temperature. I would guess that most of the Rio Tinto groundwaters are between 20 and 30 degrees Celsius, maybe 70 to 80 degrees Farenheit.

AM: Does the texture of the rock change over time as a mineral goes through the process of diagenesis?

AK: Yes, it does. Although what’s interesting is that while texture at the level of what the microscopic imager can see definitely changes through diagenetic history, larger scale features of deposition that you would see by looking closely at the outcrop with Pancam appear to be persistent. So, even though the rock is going through these changes, it retains sedimentary signatures of its formation, which is exciting. That’s important.

AB: You say that at Rio Tinto you can see a 2-million-year slice that shows you the diagenetic process over time. But the outcrops that Opportunity has seen at Meridiani could be 2 billion years old. Would they still retain any useful information after that long?

AK: Here’s the good news about geology: For sedimentary rocks, in particular, most of the changes that a rock undergoes it undergoes very early in its history. Unless a rock undergoes metamorphism, getting buried and subjected to high pressures and temperature, within at most a few million years of its formation it stabilizes into a form that it will retain indefinitely.

I work, in my day job, on Precambrian rocks on this planet. And I can guarantee you that when I look at a sedimentary rock that’s a billion years old, most of the changes that that rock underwent happened within the first 200 thousand years of its life. And then it stabilizes, and just waits for a geologist.

AM: And we have no reason to believe that physics behaves differently on Mars?

AK: That’s what we have going for us. I’ve said this before in terms of astrobiology: When you’re looking for life beyond our planet, you have no assurance that biology somewhere else will be the same as it is here. But you have pretty good assurance that physics and chemistry will be the same.

AM: Part of what makes Meridiani interesting is that it’s unlike just about any place else on Mars. Even if you’re able to figure out the history of Meridiani, to what extent will you be able to generalize that knowledge to Mars as a whole?

AK: I think it will certainly constrain the way we think about Mars as a whole planet. It may be that, in terms of the overall chemical and rock signature of Mars, that Gusev will turn out to be a better standard-issue Mars surface. That is, most of Mars – in fact, almost all of Mars – is surfaced with basalt, and then covered with fine dust. And that’s what we see at Gusev.

Now, it turns out that if you strip away the signal of hematite from the signatures of surface materials in Meridiani that we’ve gotten from orbit, it’s also mainly basalt. So it’s not a completely anomalous part of the planet. It appears to be a representative part of the planet at heart, with this unique hematite signal layered onto it.

One of the features of the Meridiani iron deposit is that, while it’s local with respect to the whole planet, it’s geographically widespread in that you have thousands of square kilometers that give this signature.

Many people think that hydrothermal processes and groundwater processes will give only small local iron signals, but in fact, the hematite-rich layers in the Rio Tinto deposit, go for several thousand square kilometers. Because these groundwaters spread out in a layer over a wide area.

So the Rio Tinto iron deposits do several things that we should keep in mind at Meridiani. They combine ancient hydrothermal and younger low-temperature processes; they need water; they can be layer forming; and they can be widespread.

They’re not the only set of processes that could to that, by any means. I’m not particularly prejudiced in favor of Rio Tinto as a better analog to Meridiani than anything else. I just think that as we go into this exploration we need to at least keep in our memory file as many different products and processes dealing with iron as we can.

All of the different settings for iron deposition and processes of iron deposition we see on this planet carry chemical and textural signals that Opportunity could detect on Meridiani. We can use those comparisons to help us to figure out how the Meridiani hematite formed.

AM: One of the intriguing aspects of Rio Tinto as a research site is that even though the water in the river is highly acidic, there are bacteria living in it. When you look at the ancient hematite deposits in that region, do you see fossil bacteria?

AK: Yes, you do. In fact, one of the things that attracted me to work with my Spanish colleagues was not that it’s an oddball environment today. While it’s kind of fun to be interested in life on the environmental fringes today, most life – and much of what you can learn about biology today – comes from ordinary organisms living in ordinary circumstances. That’s where 99 percent of the diversity of life is.

On the other hand, there’s a great question that can be asked at Rio Tinto. We can see the processes that formed the Rio Tinto iron deposits going on today; we can see the chemical processes; we can see what biology is in the environment. But the real question that one wants to keep in mind when thinking about Meridiani is: What, if any, signatures of that biology actually get preserved in diagenetically stable rocks?

One is that. If you were lucky enough to have access to a microscope – this would probably be at a resolution beyond what you could hope for from the microscopic imager – you could see individual microbial filaments that have been beautifully preserved. So that’s the first good news is that diagenetically stabilized iron can retain a microscopic imprint of biology.

The better news is that there are two features of biology that get preserved in the more eyeball-level textures in these rocks.

One is that you sometimes get little bubbles forming because of gas emanation from metabolism. And some of those will actually roof over with iron minerals and can be preserved through diagenesis. And that’s pretty much true through most sedimentary rocks that we find in the geologic column. You can get preserved gas spaces and those gas spaces are invariably associated with biological production of gases.

AM: How invariably?

AK: In our experience on Earth, it’s pretty much 100 percent. What you’d want to ask is: What processes other than biology might give rise to gases within a sediment on a planet? That’s something that you can do experiments on. I don’t know that anyone’s bothered to do them on this planet. Because, frankly, biology is so pervasive that that’s the main game in town, anyway. But one could do the experiments.

The other thing, which I feel even more strongly about, is that many times, where there are microbial populations, they form these beautiful groups of filaments that just string out across the surface. They almost look like the mane of a horse. Now the great thing is that, when minerals are deposited in these environments, they actually nucleate on these strings of filaments, and you get beautiful sedimentary textures that, again, look like the mane of a horse.

You can see them in Yellowstone Park, in both siliceous and carbonate-precipitating strings. If you go to places like Mammoth Springs, you can see it happening today. And if you hike into the hinterland, you can see ancient examples of that, beautiful signatures preserved in the rock.

In Rio Tinto, you can see iron depositing on these filaments; and in the 2 million year old terraces, you can see these filamentous iron textures. And there, again, I know of no process other than biology that could form those. So that’s truly something to keep your eyes out for whenever you’re looking at a precipitated rock on Mars.

AM: And you could see these with Pancam?

AK: If you took a Pancam to Rio Tinto or Yellowstone Park, they would jump out at you. Absolutely.

AM: If it turns out that the bedrock at the Opportunity landing site is made up of sedimentary deposits, does that mean that when those sediments were laid down, there had to be liquid water around?

AK: Very likely.

AM: So if they were sedimentary, and Pancam saw some sort of texture that on Earth is indicative of biology, would that mean that Opportunity had come close to finding evidence of life on Mars?

AK: Those are big ifs, but it would be a big day.

Let’s back up a second, because it gets to a little bit of philosophy about how you actually look for these things. A couple of years ago, NASA embarked on a funding campaign to essentially try and anticipate any kind of suggestively biological signature that might be found in any kind of exploration of another planet so that we wouldn’t be seen to be scratching our heads.

But the plain fact is that you can’t anticipate anything you might see. So what I think is a more realistic scenario is that you do your exploration, and if, in the course of that exploration, you find a signal that is (a) not easily accounted for by physics and chemistry or (b) reminiscent of signals that are closely associated with biology on Earth, then you get excited.

What will happen then, I can guarantee you, is that 100 enterprising scientists will go into the lab and see how, if at all, they can simulate what you see – without using biology. And I think that’s the right thing to do. For things where the stakes are so high, I think one wants to be as careful and sober about this as you can be. And certainly that means knowing a lot more about the generative capacity of physical and chemical processes to implant both chemical and textural signatures in a rock than we know about today.

Absent astrobiology, nobody would waste their time doing these things because, on Earth, we know that there has been biology for most of the planet’s history. Biology is everywhere. Biology is pre-eminent in the signals that it imparts to sedimentary rocks. So who is going to spend five years of their time as a young scientist trying to generate a signal by abiological means that’s closely associated with biology? However, you switch to Mars and there are a lot more reasons to do that kind of thing.

AM: If one of the MER rovers found a rock that seemed to contain evidence of martian biology, would NASA want go back to that spot and bring it home?

AK: You bet. Depending on what we find in Meridiani – not to prejudice what we find – it may make it either a very high-priority site for NASA to return with more sophisticated equipment and be a very top priority site for sample return; or we may write it off.

That’s the whole reason for this sort of incremental work. I actually like the whole architecture of NASA’s plan to go one step at a time, do each step carefully, and in step two build on what you learned in step one. It makes sense.

AM: I realize I’m asking you to speculate, here, but what do you think are the odds that Mars was once a living world?

AK: I really don’t know. But everything we’ve learned in the last few years suggests to me that water may have been episodic rather than persistent on Mars. And that lowers the probability for biology.

If water is present on the Martian surface for 100 years every 10 million years, that’s not very interesting for biology. If it’s present for 10 million years, that’s very interesting.

It is certainly not a given that we will find that Mars was a biological planet. Half of my brain keeps trying to throw out a percentage, and I know it’s such a meaningless thing to do – I think I’m just going to not do it.

But I can tell you that one of the best chances we’re going to get for a number of years to address that question is right here in the iron deposits of Meridiani.

Original Source: Astrobiology Magazine

Closeup Look at Martian Soil

Image credit: NASA/JPL
This magnified look at the martian soil near the Mars Exploration Rover Opportunity’s landing site, Meridiani Planum, shows coarse grains sprinkled over a fine layer of sand. The image was captured by the rover’s microscopic imager on the 10th day, or sol, of its mission and roughly approximates the color a human eye would see. Scientists are intrigued by the perfectly round pebbles, which most likely were formed by one of two geologic processes. The first, accretion, is the same mechanism by which pearls take shape in oysters: concentric layers of material build up around a “seed.” The seed, in this case, may be either waterborne particles or volcanic ash. In the second process, droplets of material are sprayed into the air, by either volcanic eruptions or asteroid impacts. The examined patch of soil is 3 centimeters (1.2 inches) across. The large, circular pebble in the lower left corner is approximately 3 millimeters (.12 inches) across, or about the size of a sunflower seed. This color composite was obtained by merging images acquired with the orange-tinted dust cover in both its open and closed positions. The blue tint at the lower right corner is a tag used by scientists to indicate that the dust cover is closed.

Original Source: NASA/JPL News Release

Clouds of Hydrogen Swarm Around Andromeda

Image credit: NRAO
A team of astronomers using the National Science Foundation’s Robert C. Byrd Green Bank Telescope (GBT) has made the first conclusive detection of what appear to be the leftover building blocks of galaxy formation — neutral hydrogen clouds — swarming around the Andromeda Galaxy, located in the Andromeda constellation, the nearest large spiral galaxy to the Milky Way.

This discovery may help scientists understand the structure and evolution of the Milky Way and all spiral galaxies. It also may help explain why certain young stars in mature galaxies are surprisingly bereft of the heavy elements that their contemporaries contain.

“Giant galaxies, like Andromeda and our own Milky Way, are thought to form through repeated mergers with smaller galaxies and through the accretion of vast numbers of even lower mass ‘clouds’ — dark objects that lack stars and even are too small to call galaxies,” said David A. Thilker of the Johns Hopkins University in Baltimore, Maryland. “Theoretical studies predict that this process of galactic growth continues today, but astronomers have been unable to detect the expected low mass ‘building blocks’ falling into nearby galaxies, until now.”

Thilker’s research is published in the Astrophysical Journal Letters. Other contributors include: Robert Braun of the Netherlands Foundation for Research in Astronomy; Rene A.M. Walterbos of New Mexico State University; Edvige Corbelli of the Osservatorio Astrofisico di Arcetri in Italy; Felix J. Lockman and Ronald Maddalena of the National Radio Astronomy Observatory (NRAO) in Green Bank, West Virginia; and Edward Murphy of the University of Virginia.

The Milky Way and Andromeda were formed many billions of years ago in a cosmic neighborhood brimming with galactic raw materials — among which hydrogen, helium, and cold dark matter were primary constituents. By now, most of this raw material has probably been gobbled up by the two galaxies, but astronomers suspect that some primitive clouds are still floating free.

Previous studies have revealed a number of clouds of neutral atomic hydrogen that are near the Milky Way but not part of its disk. These were initially referred to as high-velocity clouds (HVCs) when they were first discovered because they appeared to move at velocities difficult to reconcile with Galactic rotation.

Scientists were uncertain if HVCs comprised building blocks of the Milky Way that had so far escaped capture, or if they traced gas accelerated to unexpected velocities by energetic processes (multiple supernovae) within the Milky Way. The discovery of similar clouds bound to the Andromeda Galaxy strengthens the case that at least some of these HVCs are indeed galactic building blocks.

Astronomers are able to use radio telescopes to detect the characteristic 21-centimeter radiation emitted naturally by neutral atomic hydrogen. The great difficulty in analyzing these low-mass galactic building blocks has been that their natural radio emission is extremely faint. Even those nearest to us, clouds orbiting our Galaxy, are hard to study because of serious distance uncertainties. “We know the Milky Way HVCs are relatively nearby, but precisely how close is maddeningly tough to determine,” said Thilker.

Past attempts to find missing satellites around external galaxies at well-known distances have been unsuccessful because of the need for a very sensitive instrument capable of producing high-fidelity images, even in the vicinity of a bright source such as the Andromeda Galaxy.

One might consider this task similar to visually distinguishing a candle placed adjacent to a spotlight. The novel design of the recently commissioned GBT met these challenges brilliantly, and gave astronomers their first look at the cluttered neighborhood around Andromeda.

The Andromeda Galaxy was targeted because it is the nearest massive spiral galaxy. “In some sense, the rich get richer, even in space,” said Thilker. “All else being equal, one would expect to find more primordial clouds in the vicinity of a large spiral galaxy than near a small dwarf galaxy, for instance. This makes Andromeda a good place to look, especially considering its relative proximity — a mere 2.5 million light-years from Earth.”

What the GBT was able to pin down was a population of 20 discrete neutral hydrogen clouds, together with an extended filamentary component, which, the astronomers believe, are both associated with Andromeda. These objects, seemingly under the gravitational influence of Andromeda’s halo, are thought to be the gaseous clouds of the “missing” (perhaps dark-matter dominated) satellites and their merger remnants. They were found within 163,000 light-years of Andromeda.

Favored cosmological models have predicted the existence of these satellites, and their discovery could account for some of the missing “cold dark matter” in the Universe. Also, confirmation that these low-mass objects are ubiquitous around larger galaxies could help solve the mystery of why certain young stars, known as G-dwarf stars, are chemically similar to ones that evolved billions of years ago.

As galaxies age, they develop greater concentrations of heavy elements formed by the nuclear reactions in the cores of stars and in the cataclysmic explosions of supernovae. These explosions spew heavy elements out into the galaxy, which then become planets and get taken up in the next generation of stars.

Spectral and photometric analysis of young stars in the Milky Way and other galaxies, however, show that there are a certain number of young stars that are surprisingly bereft of heavy elements, making them resemble stars that should have formed in the early stages of galactic evolution.

“One way to account for this strange anomaly is to have a fresh source of raw galactic material from which to form new stars,” said Murphy. “Since high-velocity clouds may be the leftover building blocks of galaxy formation, they contain nearly pristine concentrations of hydrogen, mostly free from the heavy metals that seed older galaxies.” Their merger into large galaxies, therefore, could explain how fresh material is available for the formation of G-dwarf stars.

The Andromeda Galaxy, also known as M31, is one of only a few galaxies that are visible from Earth with the unaided eye, and is seen as a faint smudge in the constellation Andromeda. When viewed through a modest telescope, Andromeda also reveals that it has two prominent satellite dwarf galaxies, known as M32 and M110. These dwarfs, along with the clouds studied by Thilker and collaborators, are doomed to eventually merge with Andromeda. The Milky Way, M33, and the Andromeda Galaxy plus about 40 dwarf companions, comprise what is known as the “Local Group.”

Today, Andromeda is perhaps the most studied galaxy other than the Milky Way. In fact, many of the things we know about the nature of galaxies like the Milky Way were learned by studying Andromeda, since the overall features of our own galaxy are disguised by our internal vantage point. “In this case, Andromeda is a good analogue for the Milky Way,” said Murphy. “It clarifies the picture. Living inside the Milky Way is like trying to determine what your house looks like from the inside, without stepping outdoors. However, if you look at neighbors’ houses, you can get a feeling for what your own home might look like.”

The GBT is the world’s largest fully steerable radio telescope.

The National Radio Astronomy Observatory is a facility of the National Science Foundation, operated under cooperative agreement by Associated Universities, Inc.

Original Source: NRAO News Release

Satellites Could Help Predict Landslides

Image credit: ESA
As winter rains come, thousands of square kilometres of territory across Europe’s heart face a looming threat: steep slopes and waterlogged soils combine to trigger landslides.

A build-up of groundwater within a slope increases its weight and decreases its cohesiveness, weakening the slope’s ability to resist the remorseless pull of gravity. The heavy earth flows downward. For all in the path of a landslide the results are devastating, and frequently lethal.

“In Italy, landslides have claimed an average of 54 victims per year during the last half century,” says Nicola Casagli of Italy’s National Group for Hydro-geological Disaster Prevention (GNDCI),a research network working with Italy’s Civil Protection Department.

“The extreme rainfall of our climate, our mountainous geography and recent uncontrolled urbanisation of unstable land makes us one of the countries most affected by landslide hazards. The total cost of direct damage done by Italian landslides is estimated at between one and two thousand million Euro per year.”

Very gradual ground shifts are known to precede more major landslides. Often these are on a scale of millimetres ? too slight to even be noticed by local observers, but enough to be detected via satellite using a powerful technique called radar interferometry.

It involves mathematically combining multiple radar images of the same site – acquired using instruments such as the Synthetic Aperture Radar (SAR) aboard ESA’s ERS spacecraft – in such a way that tiny changes in the landscape occurring between images are highlighted.

This technique is the basis of a new project called Service for Landslide Monitoring (SLAM), enabling landslide susceptibility mapping across parts of Italy and Switzerland, two of the European countries most under threat. GNDCI is one of three national-level users working with SLAM, along with Italy’s Ministry of the Environment and Switzerland’s Federal Office for Water and Geology (FOWG).

“Surface movements assessed over wide areas are one of the best indicators of landslide activity, and can be employed for risk forecasting,” added Casagli. “Extremely slow movements usually occur for several weeks or months before a sudden collapse.”

Trial services are being provided across Italy’s Arno river basin as well as a section of the Campania region. In Switzerland the service covers the eastern Valais and Berne cantons.

“Our interest is to have a tool evaluate landslides and mass displacements all across the Swiss Alps,” explains Hugo Raetzo of FOWG. “About 8% of Swiss territory is vulnerable to landslides, making up thousands of square kilometres. The annual landslide frequency varies with the weather ? heavy rainfall can potentially re-accelerate existing landslides.”

Three different service products are available: a large-scale Landslide Motion Survey identifying areas affected by landslides across an entire river basin, a reduced-scale Landslide Displacement Monitoring measuring ground deformation over particular sites of interest, and Landslide Susceptibility Mapping which merges the previous data products with thematic maps of land use, slope, geomorphology and other relevant parameters to provide geological hazard maps.

More than a decade’s worth of ERS data archives are being exploited to derive SLAM products. These products disclose new and essential information to the institutions charged with landslide risk and hazard management. Benefits from the service include the identification and characterisation of displacements both known and previously unknown and the verification of remedial interventions performed in the past to stabilise particular landslides.

The SLAM service is being formally implemented in February and will run until the end of this year. It is entirely funded as part of ESA’s Data User Programme and is carried out by an international consortium led by Planetek Italia with five other partners: Tele-Rilevamento Europa, Gamma Remote Sensing, Spacebel, Geotest and Florence University.

Original Source: ESA News Release

Columbia Astronauts Get Mountains on Mars

Image credit: NASA
NASA Administrator Sean O’Keefe today announced the martian hills, located east of the Spirit Mars Exploration Rover’s landing site, would be dedicated to the Space Shuttle Columbia STS-107 crew.

“These seven hills on Mars are named for those seven brave souls, the final crew of the Space Shuttle Columbia. The Columbia crew faced the challenge of space and made the supreme sacrifice in the name of exploration,” Administrator O’Keefe said.

The Shuttle Columbia was commanded by Rick Husband and piloted by William McCool. The mission specialists were Michael Anderson, Kalpana Chawla, David Brown, Laurel Clark; and the payload specialist was Israeli astronaut Ilan Ramon. On February 1, 2003, the Columbia and its crew were lost over the western United States during re-entry into Earth’s atmosphere.

The 28th and final flight of Columbia was a 16-day mission dedicated to research in physical, life and space sciences. The Columbia crew successfully conducted approximately 80 separate experiments during their mission.

NASA will submit the names of the Mars features to the International Astronomical Union for official designation. The organization serves as the internationally recognized authority for assigning designations to celestial bodies and their surface features.

An image taken by the Mars Global Surveyor Mars Orbiter Camera of the Columbia Memorial Station and Columbia Hills is available on the Internet at:

For information about NASA and the Mars mission on the Internet, visit:

The Jet Propulsion Laboratory, a division of the California Institute of Technology, Pasadena, manages the Mars Exploration Rover project for NASA’s Office of Space Science, Washington, D.C. Additional information about the project is available on the Internet at:

Rosetta Launch Date Approaching

Image credit: ESA
The countdown to Rosetta?s rendezvous in space began on 1 March 1997. At the end of February 2004, seven years and not a few headaches later, the European Space Agency (ESA) probe will at last be setting off on its journey to meet 67P/Comet Churyumov-Gerasimenko.

The long-planned get-together will not however take place until the middle of 2014. A few months after arriving at the comet, Rosetta will release a small lander onto its surface. Then, for almost two years it will investigate Churyumov-Gerasimenko from close up.

Dr Gerhard Schwehm, lead scientist for the Rosetta project, explains that, ?With this mission we will be breaking new ground – this will be the first protracted cometary encounter.? The trip to the meeting place in space will certainly be a long one, located as it is some 4.5 astronomical units from the Sun, which translates into something like 675 million kilometres. Rosetta will be on the road for ten years, during which time it will clock up in excess of five billion kilometres.

Launch in February 2004
Rosetta will be waved off on 26 February when it lifts off from the space centre in Kourou, French Guiana, aboard an Ariane 5 launcher. Shortly after the spacecraft?s release, its solar panels will be deployed and turned towards the Sun to build up the necessary power reserves. Its various systems and experiments will be gradually brought into operation and tested. Just three months into the mission the first active phase will be over, followed by final testing of the experiments in October 2004. Rosetta will then spend the following years flying a lonely path to the comet, passing by the Earth, Mars, the Earth and the Earth again.

There is no alternative to this detour, for even Ariane 5, the most powerful launcher on the market today, lacks the power to hurl the probe on a direct route to the comet. To get the required momentum, it will rely on swing-by man?uvres, using the gravitation pull of Mars (in 2007) and the Earth (three times, in 2005, 2007 and 2008) to pick up speed.

Asteroids for company
A change is as good as a rest, and a meeting with at least one asteroid should help break the monotony for Rosetta. The spacecraft will come close to an asteroid at the end of 2008. Asteroids are, it will be remembered, rocky bodies, some as large as mountains, some even larger, that orbit the Sun in much the same way as planets.

?These ?brief encounters? are a scientific opportunity and also a chance to test Rosetta?s instrument payload,? says Gerhard Schwehm. But asteroid exploration also serves an entirely practical purpose: ?The more we find out about them, the better the prospect of being able one day to avert a possible collision.? Following a period of low-activity cruising, the probe?s course will be adjusted one last time in May 2011. From July 2011, a further two-and-a-half years’ radio silence will be observed, and Rosetta, left entirely to its own resources, will fly close to the Jupiter orbit.

Link-up in 2014
Finally, in January 2014, the probe will be reactivated and will, by October 2014, be only a few kilometres distant from Churyumov-Gerasimenko. This is where the dream of so many scientists becomes reality. Having deposited its precious lander cargo on the comet?s surface, Rosetta will continue to orbit Churyumov-Gerasimenko and together they will spend the next seventeen months flying towards the Sun.

Rosetta was built by an international consortium led by Astrium. The lander probe was developed in Cologne under the aegis of the DLR, Germany?s space agency, with contributions from ESA and research centres in Austria, Finland, France, Hungary, Ireland, Italy and Great Britain.

The comet explorer carries ten scientific instruments. Their job is to draw out the secrets of the comet?s chemical and physical composition and reveal its magnetic and electrical properties. Using a specially designed camera, the lander will take pictures in the macro and micro ranges and send all the data thus acquired back to Earth, via Rosetta.

?This will be our first ever chance to be there, at first hand, so to speak, as a comet comes to life,? Schwehm goes on to explain. When Churyumov-Gerasimenko gets to within about 500 million kilometres of the Sun, the frozen gases that envelop it will evaporate and a trail of dust will be blown back over hundreds of thousands of kilometres. When illuminated by the Sun, this characteristic comet tail then becomes visible from Earth. In the course of the mission, the processes at work within the cometary nucleus will be studied and measured more precisely than has ever before been possible, for earlier probes simply flew past their targets.

?As we will be accompanying Churyumov-Gerasimenko for two years, until the comet reaches its closest point to the Sun and travels away from it, we can at long last hope to acquire new knowledge about comets. We are confident we will come a step nearer to understanding the origins and formation of our solar system and the emergence of life on Earth.?

More information on the Rosetta launch can be found on:

More on ESA Science Programme at:

Original Source: ESA News Release

Twin Rovers Examining at the Same Time

Image credit: NASA/JPL
Each of NASA’s two Mars Exploration Rovers is using its versatile robotic arm for positioning tools at selected targets on the red planet.

Also, a newly completed 360-degree color panorama from Opportunity shows a trail of bounce marks coming down the inner slope of the small crater where the spacecraft came to rest when it landed on Mars nine days ago.

Opportunity extended its arm early today for the first time since pre-launch testing. “This was a great confirmation for the team,” said Joe Melko of NASA’s Jet Propulsion Laboratory, Pasadena, Calif. Melko is mechanical systems engineer for the arm, which is also called the instrument deployment device.

Mission controllers at JPL are telling Opportunity to use two of the instruments on the arm overnight tonight to examine a patch of soil in front of the rover. A microscope on the arm will reveal structures as thin as a human hair and a Moessbauer Spectrometer will collect information to identify minerals in the soil, according to plans. Tomorrow, the rover will be told to turn the turret at the end of the arm in order to examine the same patch of soil with another instrument, the alpha particle X-ray spectrometer, which reveals the chemical elements in a target.

Spirit is now in good working order after more than a week of computer-memory problems. It is brushing dust off of a rock today with the rock abrasion tool on its robotic arm. After the brushing, Spirit will use the microscope and two spectrometers on the arm to examine the rock.

“We’re moving forward with our science on the rock Adirondack,” said JPL’s Jennifer Trosper, Spirit mission manager. Reformatting of Spirit’s flash memory was postponed from today to tomorrow. The reformatting is a precautionary measure against recurrence of the problem that prevented Spirit from doing much science last week.

Later in the week, Spirit will grind the surface off of a sample area on Adirondack with the rock abrasion tool to inspect the rock’s interior. After observations of Adirondack are completed, the rover will begin rolling again. “We are already strategizing how to drive far and fast,” Trosper said.

Observations by each rover’s panoramic camera help scientists choose where to drive and what to examine with the instruments on each rover’s arm. Dr. Jeff Johnson, a rover science team member from the U.S. Geological Survey’s Astrogeology Team, Flagstaff, Ariz., said that 14 filters available on each rover’s panoramic camera allow the instrument to provide much more information for identifying different types of rocks than can be gleaned from color images such as the new panoramic view.

“By looking at the brightness values in each of these wavelengths, we can start to get an idea of the things we’re interested in, especially to unravel the geological history of these landing sites,” Johnson said.

The main task for both rovers in coming weeks and months is to find clues in rocks and soil about past environmental conditions, particularly about whether the landing areas were ever watery and possibly suitable for sustaining life.

Each martian day, or “sol” lasts about 40 minutes longer than an Earth day. Spirit begins its 31st sol on Mars at 1:23 a.m. Tuesday, Pacific Standard Time. Opportunity begins its 11th sol on Mars at 1:44 p.m. Tuesday, PST. The two rovers are halfway around Mars from each other.

JPL, a division of the California Institute of Technology in Pasadena, manages the Mars Exploration Rover project for NASA’s Office of Space Science, Washington, D.C. Images and additional information about the project are available from JPL at and from Cornell University, Ithaca, N.Y., at

Original Source: NASA/JPL News Release

Spirit is Fully Recovered

Image credit: NASA/JPL
NASA’s Mars Exploration Rover Spirit is healthy again, the result of recovery work by mission engineers since the robot developed computer-memory and communications problems 10 days ago.

“We have confirmed that Spirit is booting up normally. Tomorrow we’ll be doing some preventive maintenance,” Dr. Mark Adler, mission manager at NASA’s Jet Propulsion Laboratory, Pasadena, Calif., said Sunday morning.

Spirit’s twin, Opportunity, which drove off its lander platform early Saturday, will be commanded tonight to reach out with its robot arm early Monday, said JPL’s Matt Wallace, mission manager. Opportunity will examine the soil in front of it over the next few days with a microscope and with a pair of spectrometer instruments for determining what elements and minerals are present.

For Spirit, part of the cure has been deleting thousands of files from the rover’s flash memory — a type of rewritable electronic memory that retains information even when power is off. Many of the deleted files were left over from the seven- month flight from Florida to Mars. Onboard software was having difficulty managing the flash memory, triggering Spirit’s computer to reset itself about once an hour.

Two days after the problem arose, engineers began using a temporary workaround of sending commands every day to put Spirit into an operations mode that avoided use of flash memory. Now, however, the computer is stable even when operating in the normal mode, which uses the flash memory.

“To be safe, we want to reformat the flash and start again with a clean slate,” Adler said. That reformatting is planned for Monday. It will erase everything stored in the flash file system and install a clean version of the flight software.

Today, Spirit is being told to transmit priority data remaining in the flash memory. The information includes data from atmospheric observations made Jan. 16 in coordination with downward-looking observations by the European Space Agency’s Mars Express orbiter. Also today, Spirit will make new observations coordinated with another Mars Express overflight and will run a check of the rover’s miniature thermal emission spectrometer.

Spirit will resume examination of a rock nicknamed Adirondack later this week and possibly move on to a lighter-colored rock by week’s end.

Each martian day, or “sol” lasts about 40 minutes longer than an Earth day. Spirit begins its 30th sol on Mars at 12:44 a.m. Monday, Pacific Standard Time. Opportunity begins its 10th sol on Mars at 1:05 p.m. Monday, PST. The two rovers are halfway around Mars from each other.

The main task for both Spirit and Opportunity in coming weeks and months is to find geological clues about past environmental conditions at their landing sites, particularly about whether the areas were ever watery and possibly suitable for sustaining life.

JPL, a division of the California Institute of Technology in Pasadena, manages the Mars Exploration Rover project for NASA’s Office of Space Science, Washington, D.C. Images and additional information about the project are available from JPL at and from Cornell University, Ithaca, N.Y., at

Original Source: NASA/JPL News Release