Microbial Life on the Moon?

Shackelton Crater (and Earth) as seen by Kaguya. Credit: JAXA

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One astrobiologist claims the deep, dark craters on the Moon might contain traces of early life from meteorites blasted off the Earth by asteroids billions of years ago. Joop Houtkooper, from the University of Giessen in Germany says studying these craters could reveal clues about the origin and evolution of life on Earth or even contain remnants of life from other planets in the Solar System, such as Mars. Houtkooper is also one of the few scientists who insist that the experiments done by the Viking Mars Landers in the 1970’s actually did reveal microbial life in the Martian soil, and earlier this year, Houtkooper predicted microbes could be detected by NASA’s Phoenix lander. So, could this new claim about microbes on the Moon be just the latest in a long series of contentious claims, or is Houtkooper onto something?

Houtkooper said the best place for finding evidence of life is on the moon is within the Shackleton Crater at the Moon’s south pole. Houtkooper presented his ideas at the recent 2008 European Planetary Science Congress in Germany. However, this was before results were released from the Japanese Kaguya lunar orbiter, which peered into Shackleton Crater and found no appreciable evidence of water ice. So, while ice on the moon hasn’t been ruled out completely, right now, the evidence isn’t there.

But Houtkooper said the evidence could come in the form of organic molecules, fossil remains, dead organisms, or even organisms in a dormant state that could be revived, such as bacterial spores. He said it is even possible that microbes could have survived for a short while after impact. Although there is no atmosphere to support life today, a temporary, thin atmosphere could have formed shortly after an impact event, as water and gases from the space rock vaporized, Houtkooper claimed.

The permanently shaded craters would be at almost a constant deep freeze temperature of -248ºC, ideal for freezing water and gases such as nitrogen, carbon dioxide or methane, and preserving traces of life undisturbed by sunlight and solar winds.

Other astrobiologists say the theory is possible, but would be a long shot.

“The microbial system on Earth extends to a depth of several kilometers into the crust, and so rocks blasted off the Earth by asteroid impacts could well have contained microbes,” said astrobiologist Malcolm Walter from the University of New South Wales in Sydney.

“I’d be very conservative about this idea,” said Lewis Dartnell, an astrobiologist at University College London (UCL) in the United Kingdom. “If, say, a comet landed right in the middle of a crater, then it’s possible”.

While Houtkooper agreed the idea is controversial, he maintains that there’s a good chance that remains of life could be found – and the latest mission to the Moon could provide the proof. India’s Chandrayaan-1 space probe launched in October will be specifically looking for ice deposits at the lunar poles.

“The long-existing knowledge about the Moon’s rotation axis implies that there are places in eternal shadow at the Moon’s poles,” Houtkooper said. “That means exceptionally low temperatures at, and some depth below, the surface there.”

Source: Cosmos Magazine

The Cosmic Web – NGC 2070 by Joseph Brimacombe

The Cosmic Web - NGC 2070 by Joseph Brimacombe

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Just one glance at this incredible visage is enough to make you do a double take. This intricate net of nebular mists is known as 30 Doradus, or even more commonly as the “Tarantula”, but no space spider created this web. No, sir. What spun out these gossamer strands of HII silk is one of the largest and most active star forming regions known to our local galaxy group…

When Nicolas Louis de Lacaille first saw it in 1751 through his half-inch spyglass, he knew it was something different. He wrote down that it was nebular in nature, without stars and said; “It resembles the nucleus of a small comet.” Too bad he didn’t realize what he was really looking at, for Lacaille was a huge fan of all things science. What he couldn’t see with his primitive telescope is there really is a cluster of stars at the heart of this web… A very compact cluster stars known as R136a. And in its midst? Twelve stars… twelve very massive and luminous stars almost exclusively of spectral type O3. Even at a distance of 180,000 light years these stars light up this nebula so brightly that if it were as close to Earth as the Orion Nebula, it would cast shadows on the night.

So what else lay hidden in the 1000 light year expanse of the cosmic web? Look beyond what you can see in visible light and think like a spider… Try infra-red. With the eyes of the Spitzer Space Telescope aimed towards NGC 2070, scientists could penetrate the dust clouds throughout the Tarantula to reveal previously hidden sites of star formation. Within the luminescent nebula, holes began to appear. These voids are created by highly energetic winds spewing out from the massive stars in the central star cluster. Like the intricate designs woven by the spider, the structures at the edges of these voids are particularly interesting. Dense pillars of gas and dust, sculpted by the stellar radiation, will be the birthplace of future generations of stars!

But like the spider web… It’s a place of death, too.

In 1987 one of the closest supernova events ever to occur near Earth happened in the outskirts of the Tarantula Nebula. The light from the supernova reached Earth on February 23, 1987 and not.since 1604 had humankind been witness to such an event. Even though we were witnessing something that occurred 168,000 years in the past, those X-ray and radio emission were still just as bright as the day the highly energetic electrons and particles spewed into the interstellar medium upon the explosive death of the progenitor star. Oh, there is skeletons in the web, too. Older and weaker supernovae remnants are scattered about, their signatures as faint as the imprint of a fallen leaf that has long blown away. This “Cosmic Web” is home to many supergiant stars. At any moment, a snapshot of any dense region of supergiant stars will show a mixture of newborn stars and supernovae, the signature of stars who those that have lived fast and died young.

Many thanks to AORAIA member, Joe Brimacombe for allowing me to swipe his wonderful image and tell a story.

Where In The Universe Challenge #28

Here’s your image for this week’s “Where In The Universe” challenge. Take a look and see if you can name where in the Universe this image is from. Give yourself extra points if you can name the spacecraft responsible for the image. The new way we’re doing this challenge is that we’ll provide the image today, but won’t reveal the answer until tomorrow. This gives you a chance to mull over the image and provide your answer/guess in the comment section — if you dare. Check back tomorrow on this same post (reminder: no new post tomorrow — come back to this one) to see how you did!

UPDATE (11/6): The answer has now been posted below. If you haven’t made your guess yet, no peeking before you do!!


I have to say, I am impressed with the knowledge of you UT readers! Great job! Yes, it is Tycho’s Supernova Remnant, taken by the Chandra spacecraft. This is a bubble of hot gaseous supernova debris (green and red) inside a more rapidly moving shell of extremely high-energy electrons (blue). These features were created as the supersonic expansion of the debris into interstellar gas produced two shock waves – one that moves outward and accelerates particles to high energies, and another that moves backward and heats the stellar debris. The Chandra X-ray Observatory, which was launched and deployed by Space Shuttle Columbia on July 23, 1999, took this image in 2005.

Learn more about the image here.

And I’m sorry about the delay in posting the answer.

NASA News Too Depressing for a Headline

OK, I give up. I’ve sat here for about a half an hour trying to come up with a headline for this news piece. Actually, there are three different news items I’m combining into one article. One is fairly good news, the other two are very depressing.

First the good news: Today, the first major flight hardware of the Ares I-X rocket arrived in Florida to begin preparation for the inaugural test flight of NASA’s next-generation launch system. But amid this tangible event of moving toward the future comes bad financial news about the Constellation program. Congressional investigators have concluded that the Constellation program is likely to cost $7 billion more than budgeted if it is going to be ready to fly by its target date of March 2015. Without extra money, it could be delayed by 18 months or more.

At the same time another report concludes that NASA would need an extra $2 billion a year to keep its shuttle fleet flying beyond 2010, a measure which would shorten the gap where NASA wouldn’t have a human rated vehicle available for access to space. But doing so would hamper plans to convert a launch pad and other facilities for moon missions, likely delaying Constellation even more.

More money for either Constellation or the shuttle program is just not in NASA’s budget, and shifting money around from other programs “would be disastrous,” NASA shuttle program manager John Shannon said. “What we’re trying to do is find a path that continues to keep Americans flying on American vehicles, but does not mortgage the future of manned space flight,” he said. “We really have to step back and think very hard about what we want the future to look like, and make sure that we’re not going to make it something that is not achievable.”

I need ideas for a headline for this article. Readers — comments?

Both Republican presidential candidate John McCain and Democratic presidential candidate Barack Obama have said they would increase NASA’s budget by $2 billion to minimize the gap between shuttle retirement and the first piloted flights of Ares 1 rockets and Orion crew capsules. (This is being written before the election results are in.) But even that won’t be enough to solve all of the problems.

The Congressional Budget Office report listed several of problems facing the Ares I rocket and the Orion capsule, which NASA hopes will return astronauts to the moon by 2020. Among them are difficulties in developing an engine for Ares and a heat shield for Orion. “NASA has identified several problems associated with the Ares I that could delay successful development of the vehicle,” according to the 18-page report. Read the report here.

We’ve discussed all the issues previously on Universe Today, including intense shaking on liftoff, and concerns that Ares could crash into the launch gantry.

NASA officials said they were studying the report. But agency managers insist the program is on track.

At a news conference NASA held last week to counter reports of Constellation’s problems, Steve Cook, Ares project manager said, “The Ares I rocket is a sound design that not only meets the high safety standards required for a manned spacecraft, it is within budget, on schedule, and meets its performance requirements with margin.”

So what’s the real story? I’m not certain anymore. I desperately want to believe that the media (is that me, too?) overblowing the problems and NASA isn’t just looking through rose colored glasses. But the bad news keeps coming from all fronts.

NASA’s options other than the Ares appear limited.

One proposed option would extend the current space shuttle flight schedule through 2012, using the giant external fuel tanks and other hardware NASA has already planned to build. A second option calls for NASA to build more fuel tanks and hardware to keep flying three shuttle missions per year until 2015.

The CBO report also cautioned that the cost of more shuttle flights could only hurt Constellation under NASA’s limited budget.

Even by throwing more money at Constellation, the investigators also don’t think that NASA could speed up Constellation’s development, at least in the near term. They said NASA told them that “additional funding can no longer significantly change” the March 2015 target date of a first launch.

Even so, the Orlando Sentinel reports that NASA is looking at radical changes in the program to see if it can speed up development.

According to former astronaut Eileen Collins, currently a member of the NASA Advisory Council, one option under consideration would eliminate features needed to go to the moon and turn it a simple craft that could ferry crew and cargo to the space station. That would mean further delays for the real reason for Constellation: returning to the moon.

I thought we had some good news about Constellation last week. But this seems depressing. Too depressing for a headline.

Sources: NASA, Orlando Sentinel, Florida Today

5 Years At Mars: The Best of Mars Express

Water ice in a North Pole crater. Credit: ESA/DLR/FU Berlin (G. Neukum).

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In December, the Mars Express spacecraft will celebrate the fifth anniversary of its arrival at Mars. In observation of this milestone the German Aerospace Center DLR has put together a collection of some of the best images from the High-Resolution Stereo Camera (HRSC), the main camera on board the spacecraft. The stunning, high resolution images this instrument has produced of Mars’ surface are nothing short of jaw dropping, and they have provided new perspectives and new discoveries about our neighboring planet. One of the iconic images from Mars Express is the image above of water ice inside a crater near Mars North Pole.

And here’s more from The Best of Mars Express:

Echus Chasma mosaic.  Credits: ESA/DLR/ FU Berlin (G. Neukum)
Echus Chasma mosaic. Credits: ESA/DLR/ FU Berlin (G. Neukum)

My personal favorite is the image above of Echus Chasma, located in the Lunae Planum high plateau, north of Valles Marineris the ‘Grand Canyon’ of Mars. It doesn’t take much imagination to consider the possibility that once, gigantic water falls may have plunged over these 4,000 meter high cliffs on to the valley floor. See more of Echus Chasma here.

Here’a another of my favorites, this perspective color view of Coprates Chasma and the “Grabenkette” (a chain of depressions or rifts in Mars’ surface) Coprates Catena in an eastern section of Valles Marineris.
Coprates Chasma and the "Grabenkette" Coprates Catena in an eastern section of Valles Marineris. Credit: ESA/DLR/FU Berlin (G. Neukum).

The ability of the HRSC to provide “perspective” views — images that are not just straight down camera shots — are what sets the Mars Express mission apart from all the other orbiting spacecraft. When seen in full resolution (please, go download the biggie image here) these 3-D perspective views, are mind blowing!

In March of this year, Ian wrote about these high resolution and 3-D images from Hebes Chasma, one of the deepest canyons on Mars, so see more images there, along with links to additional images and information.

Hebes Chasma Credit: ESA/DLR/FU Berlin (G. Neukum).
Hebes Chasma Credit: ESA/DLR/FU Berlin (G. Neukum).

The HRSC is imaging the entire planet in full color, 3-D and with a resolution of about 10 meters. Selected areas will be imaged at two-meter resolution. One of the camera’s greatest strengths is he unprecedented pointing accuracy achieved by combining images at the two different resolutions. Another is its ability for 3-D imaging which reveals the topography of Mars in full color.

Mars North Pole.  Credit: ESA/DLR FU Berlin (G. Neukum)
Mars North Pole. Credit: ESA/DLR FU Berlin (G. Neukum)

Here’s another look at Mars north arctic region, with water ice visible in Chasma Boreale.

Below is a view of Aureum Chaos, located in the eastern part of Valles Marineris. This “chaotic” landscape is dominated by randomly oriented, large-scale mesas and knobs that are heavily eroded. These mesas range from a few kilometres to tens of kilometers wide.

Perspective colour view of Aureum Chaos, northerly direction.   Credit: ESA/DLR/FU Berlin (G. Neukum).
Perspective colour view of Aureum Chaos, northerly direction. Credit: ESA/DLR/FU Berlin (G. Neukum).

For a little more history on Mars Express, the spacecraft was launched on June 2, 2003 from Baikonur Cosmodrome on a Soyuz-Fregat rocket. The goal of Mars Express is to search for water and the possibility of Martian life. Mars Express is a European Space Agency (ESA) mission to the Red Planet involving a consortium of countries (primarily France, Germany, Great Britain, Ireland, Italy, Japan, the Netherlands, Norway, Russia, Sweden, Spain, and the United States). The mission consisted of the orbiter and the Beagle lander, which unfortunately crash landed on Christmas Day 2003. Mars Express is currently in its second mission extension, which goes until May 2009.
Phobos from Mars Express.  Credit: ESA/DLR/FU Berlin (G. Neukum).
Phobos from Mars Express. Credit: ESA/DLR/FU Berlin (G. Neukum).

And finally, Mars Express not only takes images the surface of the Red Planet, but also of Mars’ moon Phobos. On July 23 of this year, the spacecraft flew only 93 kilometers from Mars’ moon Phobos, and took the most detailed images ever of the small, irregular moon. Read more about the flyby here.

That’s just a taste of all the wonderful images taken in the last five years by Mars Express. Check out more images at the DLR site.

Source: DLR

Ion Shield for Interplanetary Spaceships Now a Reality

Bubble chamber image of charged particles being deflected by a magnetic field (CERN)

[/caption]British scientists invent “mini-magnetosphere” to protect astronauts during solar storms.

Space travel during a solar storm just became a little less risky. UK scientists working at Rutherford Appleton Laboratory near Oxford and the universities of York and Strathclyde have tested a “mini-magnetosphere” enveloping a model spacecraft in the lab. It turns out that their prototype offers almost total protection against high energy solar particles. By mimicking the natural protective environment of the Earth, the researchers have scaled the protective magnetic bubble down into an energy efficient, yet powerful deflector shield.

This astounding achievement is a big step toward protecting sensitive electronics and the delicate human body against the radioactive effects of manned missions between the planets. It may sound like science fiction, but future astronauts may well shout the order to “RAISE SHIELDS!” if the Sun flares up during a 36 million mile journey to Mars…

A mission to Mars will benefit from a mini-magnetosphere (NASA)
A mission to Mars will benefit from a mini-magnetosphere (NASA)
On writing “Scientists Designing ‘Ion Shield’ To Protect Astronauts From Solar Wind” way back in January, I was a little dubious as to whether the preliminary results could be replicated on a full-scale spaceship. At the time, Dr Ruth Bamford (the lead researcher from Rutherford Appleton) had created a mini version of a magnetic shield that acted as a “bubble” in a stream of ions. As ions were charged, they could be deflected by a magnetic field, so the field acts as a barrier to deflect the paths of these ions around the void encapsulated by the magnetic field. All that had to be done was to scale the idea up a notch or two and then place a spaceship in the middle of the protected void. Solved!

Not so fast. The biggest drawback I could see back in January was the large amount of energy that would be required to power the system. After all, to generate a stable, spaceship-sized mini-magnetosphere would need a vast quantity of electricity (and be very bulky), or it would need to be highly efficient (and compact). As this is space travel we’re talking about, the scientists would need to look into the latter. The mini-magnetosphere would need to be a highly efficient device.

The USS Enterprise has many uses for its deflector shields, including repelling the Borg (Paramount Pictures)
The USS Enterprise has many uses for its deflector shields, including repelling the Borg (Paramount Pictures)
Eleven months later and it looks like the British team have found their answer. In results just published in the journal Plasma Physics and Controlled Fusion, they have devised a system no bigger than a large desk that uses the same energy as an electric kettle. Two mini-magnetospheres will be contained within two mini satellites located outside the spaceship. Should there be an increase in solar wind flux, or an approaching cloud of energetic particles from a flare and/or coronal mass ejection (CME), the magnetospheres can be switched on and the solar ions are deflected away from the spacecraft.

These initial experiments have shown promise and that it may be possible to shield astronauts from deadly space weather,” Dr Bamford said. After all, the effects of radiation poisoning can be devastating.

Prof. Bob Bingham, a theoretical physicist at the University of Strathclyde, gives a graphic account as to why this technology is important:

Solar storms or winds are one of the greatest dangers of deep space travel. If you got hit by one not only would it take out the electronics of a ship but the astronauts would soon take on the appearance of an overcooked pizza. It would be a bit like being near the Hiroshima blast. Your skin would blister, hair and teeth fall out and before long your internal organs would fail. It is not a very nice way to go. This system creates a Magnetic Field Bubble that would deflect the dangerous radiation away from the spacecraft.” – Prof. Bob Bingham

Bingham added that the team was currently patenting the technology and hopes to have a working full size prototype within five years. So we might have to wait some time until we see some pictures of the system in action

Source: Telegraph (UK)

Forget the LHC, the Aging Tevatron May Have Uncovered Some New Physics

The Collider Detector at Fermilab may have found some unexpected particles (Fermilab)

[/caption]If you thought any quantum discoveries would have to wait until the Large Hadron Collider (LHC) is switched back on in 2009, you’d be wrong. Just because the LHC represents the next stage in particle accelerator evolution does not mean the world’s established and long-running accelerator facilities have already closed shop and left town. It would appear that the Tevatron particle accelerator at Fermilab in Batavia, Illinois, has discovered…

something.

Scientists at the Tevatron are reluctant to hail new results from the Collider Detector at Fermilab (CDF) as a “new discovery” as they simply do not know what their results suggest. During collisions between protons and anti-protons, the CDF was monitoring the decay of bottom quarks and bottom anti-quarks into muons. However, CDF scientists uncovered something strange. Too many muons were being generated by the collisions, and muons were popping into existence outside the beam pipe

The Tevatron was opened in 1983 and is currently the most powerful particle accelerator in the world. It is the only collider that can accelerate protons and anti-protons to 1 TeV energies, but it will be surpassed by the LHC when it finally goes into operation sometime early next year. Once the LHC goes online, the sub-atomic flame will be passed to the European accelerator and the Tevatron will be prepared for decommissioning some time in 2010. But before this powerful facility closes down, it will continue probing matter for a little while yet.

In recent proton collision experiments, scientists using the CDF started seeing something they couldn’t explain with our current understanding of modern physics.

The particle collisions occur inside the 1.5 cm-wide “beam pipe” that collimate the relativistic particle beams and focus them to a point for the collision to occur. After the collision, the resulting spray of particles are detected by the surrounding layers of electronics. However the CDF team detected too many muons being generated after the collision. Plus, muons were being generated inexplicably outside the beam pipe with no tracks detected in the innermost layers of CDF detectors.

CDF spokesperson Jacobo Konigsberg, is keen to emphasise that more investigations need to be done before an explanation can be arrived at. “We haven’t ruled out a mundane explanation for this, and I want to make that very clear,” he said.

However, theorists aren’t so reserved and are very excited about what this could mean to the Standard Model of sub-atomic particles. If the detection of these excess muons does prove to be correct, the “unknown” particle has a lifetime of 20 picoseconds and has the ability to travel 1 cm, through the side of the beam pipe, and then decay into muons.

Dan Hooper, another Fermilab scientist, points out that if this really is a previously unknown particle, it would be a huge discovery. “A centimetre is a long way for most kinds of particles to make it before decaying,” says . “It’s too early to say much about this. That being said, if it turns out that a new ‘long-lived’ particle exists, it would be a very big deal.”

Neal Weiner of New York University agrees with Hooper. “If this is right, it is just incredibly exciting,” he says. “It would be an indication of physics perhaps even more interesting than we have been guessing beforehand.”

Particle accelerators have a long history of producing unexpected results, perhaps this could be an indicator of a particle that has previously been overlooked, or more interestingly, not predicted. Naturally, scientists are quick to postulate that dark matter might be behind all this.

Weiner, with colleague Nima Arkani-Hamed, have formulated a model that predicts the existence of dark matter particles in the Universe. In their theory, dark matter particles interact among themselves via force-carrying particles of a mass of approximately 1 GeV. The CDF muons generated outside the beam pipe have been calculated to be produced by an “unknown” decaying parent particle with a mass of approximately 1 GeV.

The comparison is striking, but Weiner is quick to point out that more work is needed before the CDF results can be linked with dark matter. “We are trying to figure that out,” he said. “But I would be excited by the CDF data regardless.”

Perhaps we don’t have to wait for the LHC, some new physics may be uncovered before the brand new CERN accelerator is even repaired…

Source: New Scientist

Can Cassini be Used to Detect Life on Enceladus?

Artist impression of the surface of Enceladus and the source of the plumes (BBC/Karl Kofoed)

[/caption]Having just returned the most detailed images yet of Saturn’s 500km-wide moon Enceladus, it is little wonder scientists are excited about this mysterious natural satellite. However, in new research recently published, the results aren’t related to the recent “skeet shot” Cassini carried out above the moon’s south pole (although there is some common ground). The paper’s origins started out in July 2005 when Enceladus’ plume of gas (containing organic compounds) was discovered fizzing from the moon’s surface, inside the “tiger stripes” just imaged by Cassini.

In some computer models, this plume is attributed to a sub-surface ocean. This possibility has led scientists to speculate that it might be an ideal environment for basic forms of life to thrive. What’s more, although the Cassini spacecraft isn’t equipped to directly search for life, it may be able to detect the signature of life

The four long fissures straddle the south pole of Enceladus and run for more than 100 kilometres – the circular grid marks 60° South (NASA)
Point of interest: The four long fissures straddle the south pole of Enceladus and run for more than 100 kilometres – the circular grid marks 60° South (NASA)
This new research published in the journal Astrobiology and led by Christopher McKay at NASA’s Ames Research Center in Moffett Field, suggests that the Cassini probe may have already collected data that could be analysed in the search for extraterrestrial life. By sifting through the data collected by the Saturn spacecraft after it passed though the plume of gas and ice particles emitted from Enceladus’ south pole, organic chemicals, such as methane, have been detected.

As Nancy wrote earlier today in relation to the search for life on Mars, methane is a key by-product from biological processes on Earth. It seems that Enceladus has a whole cocktail of the key components for life blasting into space.

If you think about what you need for life, you need water, energy, organic material, and you need nitrogen, and they’re all coming out of the plume,” McKay said. “Here is a little world that seems to have it all.”

So what could be producing this possible biological signature? It seems possible that micro-organisms known as methanogens (as the name suggests, they produce methane as a gaseous by-product to their biological cycles) could be a possible explanation, but there must be the correct ratio of organic compounds (in favour of methane) present in the plume for this to be the case.

Life's smoking gun? The plume above Enceladus (NASA)
Life's smoking gun? The plume above Enceladus (NASA)
McKay’s team argues that for the organic compounds found in Enceladus’ plume to be of biological origin, there should be a much higher concentration of methane than any heavier organic compound (i.e. non-methane hydrocarbons). McKay’s paper suggests that the non-methane hydrocarbon to methane ratio needs to be lower than 0.001 for the methane to favour a biological origin.

This method was recently used on hydrothermal vents at the bottom of the Atlantic ocean. A higher ratio of non-methane hydrocarbons were measured, indicating the gases emitted from the vents were non-biological in origin. This research suggests that Cassini’s Ion and Neutral Mass Spectrometer (INMS) can be used in a similar way to see if the organic compounds detected in the Enceladus plume can be attributed to biological processes.

However, previous fly-bys of the plume suggest it is very comet-like (and therefore an ancient source of organic compounds), so more data needs to be collected and better models need to be devised.

This research is very encouraging for the future exploration of the Solar System’s gas giant moons, and it is hoped that more sensitive equipment can be put into Saturn orbit in the future to possibly refine the preliminary results from Cassini. Whether the organic compounds in Enceladus’ south polar plume can be attributed to biological processes, or not, will probably have to wait a while yet…

Source: New Scientist

Rover Sand Traps Provide Clues on Mars Climate

Opportunity's self portrait while stuck in the sand in 2005. Credit: NASA/JP

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If you watched the “Five Years on Mars” documentary on the National Geographic channel about the Mars Exploration Rovers, you probably saw how both rovers have gotten stuck in some of the small sand dunes on Mars surface. These dune fields on Mars are a bit of a mystery to planetary geologists, and in fact, there is nothing like them on Earth. The fields of rippled sand on Mars, called Transverse Aeolian Ridges (TARs), are found over large areas across Mars. The dunes themselves are smaller than the gigantic dunes also found on Mars, but the fields are bigger than any sand ripple fields found on Earth. TARs hold clues to past and present climate processes, and since they can be death traps for rovers, scientists want to know more about these unusual features.

TARS are formed by the wind. If you frequently peruse the website for the HiRISE Camera on the Mars Reconnaissance Orbiter, you’ll see the word “aeolian” quite often in science themes and descriptions. Aeolian refers to any phenomena involving air movement.

TARS in the northern lowlands on Mars, as seen by HiRISE.  Credit: NASA/JPL/U of AZ
TARS in the northern lowlands on Mars, as seen by HiRISE. Credit: NASA/JPL/U of AZ

The ridges assume many shapes, such as simple ripples, forked ripples, snake-like sinuous waves, barchan-like (crescent-shaped) forms or complex, overlapping networks.

In 2005, the Opportunity rover got stuck in a small dune, called Purgatory Dune for six weeks with its wheels firmly mired in what planetary geologists believe was a small TAR. After the rover was finally freed, from images the rover took of the surrounding area, mission scientists noticed they were surrounded by dunes. (See this link for movies of the rover wheels turning in the sand.) They had to carefully drive around all the dunes, which slowed the progress down considerably. So it’s important to know where TARs are located to avoid landing among them on future rover missions.

One of the people studying TARs is Matt Balme, a research scientist with the the Planetary Science Institute. Balme and his colleagues have conducted a pole-to-pole planet survey of more than 10,000 images taken by the Mars Orbiter Camera, which was (is) on board the Mars Global Surveyor spacecraft.

Here’s what they found about TARs:

-They are more common in the southern hemisphere than in the northern.

-They are found in an equatorial belt between 30 degrees north and 30 degrees south latitude.

-They exist in two distinct environments: near layered terrain or adjacent to Large Dark Dunes (LLDs). Those adjacent to dunes have formed recently, while those near layered terrain are millions of years old.

-They are abundant in the Meridiani Planum region and in southern-latitude craters.

The Opportunity rover’s TAR encounter provided additional data, showing that at least that TAR was composed of an outer layer of granule-sized material ranging from about 2mm to 5 mm in diameter, Balme said. Beneath this was a mixed mass of fine and coarse particles.

Opportunity looks back at Purgatory Dune after escape.  See the other dunes in the surrounding area.  Credit: NASA/JPL
Opportunity looks back at Purgatory Dune after escape. See the other dunes in the surrounding area. Credit: NASA/JPL

TARs need two things to form, Balme explained: a supply of sediment and strong winds. The sediment requirement helps explain why they’re found near dunes and layered terrain and why they’re confined to a central belt around the planet, Balme said.

“My theory is that the very young TARs are found near the Large Dark Dunes, which are also very young, because the sand blowing off the dunes provides the energy needed to form TARs,” Balme said. “Meanwhile you have areas near layered landforms that used to have active sediment transport, but no longer. This shows a dynamic environment that has changed, and we might be able to use TARs as paleo markers to help decipher ancient climates.”

Current Martian circulation models don’t provide much evidence that wind patterns and atmospheric densities on Mars were significantly different in the past than from what they are today. “But I think the geology we are seeing suggests that there might have been different patterns and densities,” Balme said. “The observations we’re getting now from Mars Global Surveyor and the HiRISE camera are giving us really good data to drive the models.”

Although Blame and his team have discovered much about TARs, they still don’t know what materials compose the various TAR fields or why they’re seeing these large features on Mars but not on Earth.

“Over the next couple of years we should be seeing many more images from HiRISE that can give us more information, for example, about the heights versus spacing and whether TARs have more in common with dunes or the ripple fields found on Earth,” Balme said. “And they could provide insights into present and past climate patterns as we learn more about them and use that data to help drive general circulation models.”

Source: Planetary Science Institute

US Space Station Crew’s Orbital Presidential Vote

NASA astronaut, Michael Fincke (Expedition 18 commander) will vote from orbit (NASA)

[/caption]Astronauts realise that there are some things they will miss out on. Whilst living on the International Space Station (ISS) for months at a time they may miss out on their child’s first words, they may forget to record the new season of Heroes, they may also miss out on a terrestrial celebration of their birthday.

While many of these things can upsetting or frustrating, say if you’re in space when a life-changing event or historical moment for your whole country is about to occur? This is exactly what is going to happen for the two US astronauts currently looking down on their nation from the orbiting outpost. Tomorrow is Presidential Election Day, so Michael Fincke and Gregory Chamitoff are going to exercise their rights as American citizens (that only four astronauts have been able to do previously) to vote in their next leader…

Fincke and Chamitoff will be able to vote in tomorrow’s US election using a Texas law that was passed in 1997. The eleven year-old law extends the right that every ground-based adult American citizen takes for granted to the US astronauts carrying out their duties on the space station.

So I’m going to exercise my privilege as a citizen and actually vote from space on Election Day,” the ISS Expedition 18 Commander Michael Fincke said before he left Earth. “I think the candidates this year are exciting in and of themselves. But hopefully we get people to realize what a privilege it is, and they exercise and get a chance to vote.” Fincke was launched on October 12th with cosmonaut Yuri Lonchakov and space tourist Richard Garriott on the Soyuz TMA-13 flight.

The 1997 Texas bill has allowed four astronauts to vote in the southern US state. Astronaut David Wolf was the first space-based ballot to be cast in the ’97 Houston election from the Russian Space Station Mir. Then Leroy Chiao (2004 ISS Expedition 10 commander) was able to vote in the last presidential election. In 2006 and 2007, astronauts Michael Lopez-Alegria and Clayton Anderson were also able to cast their votes during separate space station missions.

This year, both orbiting astronauts are urging American citizens to get to their local polling places, as regardless of who is being voted for, the right to vote is a privilege. “Voting is the most important statement Americans can make in fulfilling a cherished right to select its leaders,” Fincke said in a patriotic NASA TV video with Chamitoff. “So this Election Day, take time to go to the polls and vote. If we can do it, so can you.”

It all sounds great, but how do astronauts actually vote in space?

The Texas bill allows astronauts to cast an absentee ballot from space with the help of the County Clerk of Harris and Brazoria counties (containing Houston). A secure electronic ballot is then sent to the ISS via mission control from the Clerk’s Office. Separately, an email is sent to the astronauts on board the space station with login information to the secure ballot. Once completed in orbit, the secure ballot is sent back to Mission Control and then forwarded to the Clerk’s Office.

I was thankful for everyone making it possible for me to vote from space,” Leroy Chiao said. “I think it was an important symbolic gesture. Also, it was important to me personally.” Chiao added that making the space vote possible also encouraged ordinary US citizens to make the short trek down to their local polling station.

Source: MSNBC