Posted on by Fraser Cain

Air From Moonrocks

A focusing lens to produce oxygen and slug from a vacuum moondust filled chamber. Image credit: NASA. Click to enlarge
When astronauts return to the Moon, to explore and eventually build a moon base, they’re going to need oxygen… and lots of it. Fortunately lunar soil – or regolith – is almost half oxygen. NASA researchers are using a technique called vacuum pyrolysis, where the regolith is heated until it releases oxygen. Light from the Sun was focused by a lens to heat lunar soil to 2,500 degrees C. As much as 20% of the soil was converted to free oxygen, and the leftover slag could be used for bricks, radiation shielding or pavement.

An early, persistent problem noted by Apollo astronauts on the Moon was dust. It got everywhere, including into their lungs. Oddly enough, that may be where future Moon explorers get their next breath of air: The moon’s dusty layer of soil is nearly half oxygen.

The trick is extracting it.

“All you have to do is vaporize the stuff,” says Eric Cardiff of NASA’s Goddard Space Flight Center. He leads one of several teams developing ways to provide astronauts oxygen they’ll need on the Moon and Mars. (See the Vision for Space Exploration.)

Lunar soil is rich in oxides. The most common is silicon dioxide (SiO2), “like beach sand,” says Cardiff. Also plentiful are oxides of calcium (CaO), iron (FeO) and magnesium (MgO). Add up all the O’s: 43% of the mass of lunar soil is oxygen.

Cardiff is working on a technique that heats lunar soils until they release oxygen. “It’s a simple aspect of chemistry,” he explains. “Any material crumbles into atoms if made hot enough.” The technique is called vacuum pyrolysis–pyro means “fire”, lysis means “to separate.”

“A number of factors make pyrolysis more attractive than other techniques,” Cardiff explains. “It requires no raw materials to be brought from Earth, and you don’t have to prospect for a particular mineral.” Simply scoop up what’s on the ground and apply the heat.

In a proof of principle, Cardiff and his team used a lens to focus sunlight into a tiny vacuum chamber and heated 10 grams of simulated lunar soil to about 2,500 degrees C. Test samples included ilmenite and Minnesota Lunar Simulant, or MLS-1a. Ilmenite is an iron/titanium ore that Earth and the Moon have in common. MLS-1a is made from billion-year-old basalt found on the north shore of Lake Superior and mixed with glass particles that simulate the composition of the lunar soil. Actual lunar soil is too highly prized for such research now.

In their tests, “as much as 20 percent of the simulated soil was converted to free oxygen,” Cardiff estimates.

What’s leftover is “slag,” a low-oxygen, highly metallic, often glassy material. Cardiff is working with colleagues at NASA’s Langley Research Center to figure out how to shape slag into useful products like radiation shielding, bricks, spare parts, or even pavement.

The next step: increase efficiency. “In May, we’re going to run tests at lower temperatures, with harder vacuums.” In a hard vacuum, he explains, oxygen can be extracted with less power. Cardiff’s first test was at 1/1,000 Torr. That is 760,000 times thinner than sea level pressure on Earth (760 Torr). At 1 millionth of a Torr — another thousand times thinner — “the temperatures required are significantly reduced.”

Cardiff is not alone in this quest. A team led by Mark Berggren of Pioneer Astronautics in Lakewood, CO, is working on a system that harvests oxygen by exposing lunar soil to carbon monoxide. In one demonstration they extracted 15 kg of oxygen from 100 kg of lunar simulant–an efficiency comparable to Cardiff’s pyrolysis technique: more.

D.L. Grimmett of Pratt & Whitney Rocketdyne in Canoga Park, CA, is working on magma electrolysis. He melts MLS-1 at about 1,400 deg. C, so it is like magma from a volcano, and uses an electric current to free the oxygen: more.

Finally, NASA and the Florida Space Research Institute, through NASA’s Centennial Challenge, are sponsoring MoonROx, the Moon Regolith Oxygen competition. A $250,000 prize goes to the team that can extract 5 kg of breathable oxygen from JSC-1 lunar simulant in just 8 hours.

The competition closes June 1, 2008, but the challenge of living on other planets will last for generations.

Got any hot ideas?

Original Source: NASA News Release

Posted on by Fraser Cain

Milky Way is Consuming Many Galaxies

The Field of Streams. Image credit: Vasily Belokurov/SDSS-II. Click to enlarge
The Milky Way is continuing to consume entire galaxies, and the evidence is right there in the night sky. After analyzing data from the Sloan Digital Sky Survey, astronomers have found many streams of stars – all that remains from these gobbled up galaxies. As a satellite galaxy merges with the Milky Way, it’s slowly torn apart as it sinks into the galactic halo. Streams of stars are unraveled like a ball of yarn, and these continue to orbit the Milky Way, distinct from the orbital movements of the rest of the stars in our galaxy.

A new map of stars in the Milky Way Galaxy, constructed with data from the Sloan Digital Sky Survey (SDSS-II), reveals a night sky criss-crossed with streams of stars, left behind by satellite galaxies and star clusters spiraling to their deaths.

Analyzing five years of data spanning nearly one-quarter of the sky, Cambridge University (UK) researchers Vasily Belokurov and Daniel Zucker created a dramatic new image of the outer Milky Way, using stellar colors eliminating the redder, nearby stars that would otherwise swamp the view of background structures. They found so many trails of stars in their high contrast image that they named the area the “Field of Streams.”

Satellite galaxies orbiting the Milky Way are literally ripped apart by the tidal forces of our galaxy. As these satellites sink in gravitational quicksand, their stars are torn from them in giant streams that trace their orbital paths — just like meteor streams lie along the paths of defunct comets in the Solar system.

Dominating the Field of Streams image is the enormous, arching stream of the Sagittarius dwarf galaxy. The Sagittarius dwarf was discovered more than a decade ago and other researchers have previously mapped its long tidal stream in other regions of the sky.

But the new SDSS-II data had a remarkable surprise in store.

“The stream appears forked,” said Belokurov. “We are seeing different wraps superimposed on the sky, as the stream goes around the galaxy two or three times.”

Because of the multiple wraps, the observations provide strong new constraints on the dark matter halo of the Milky Way, according to Mike Fellhauer of Cambridge University. “The leading theories of dark matter predict that the Galaxy’s halo should be flattened, like a rugby football. But our simulations only match the forked Sagittarius stream if the inner halo is round, like a soccer ball.”

In addition to the Sagittarius arches, the Field shows faint trails of stars torn from globular clusters, and other rings, trails, and lumps that appear to be the remains of disrupted dwarf galaxies. “There are more streams here than in a river delta,” commented Zucker.

Prominent among these is the Monoceros stream, discovered previously by SDSS-II scientists Heidi Jo Newberg of Rensselaer Polytechnic Institute and Brian Yanny of the Fermi National Accelerator Laboratory. The multiple rings of stars are all that remain from a dwarf satellite that was absorbed by the Milky Way long ago.

Crossing the Field is an enigmatic, new stream of stars extending over 70 degrees on the sky, whose original source remains unknown.

“Some of these ‘murdered’ galaxies have been named,” explained SDSS-II team member Wyn Evans of Cambridge, “but this galactic corpse hasn’t been identified yet. We’re looking for it right now.”

These new discoveries add weight to a picture in which galaxies like the Milky Way are built up from the merging and accretion of smaller galaxies.

“We’ve known about merging for some time,” said Yanny, “but the Field of Streams gives us a striking demonstration of multiple merger events going on the Milky Way galaxy right now. This is happening all over the Universe, as big galaxies grow by tearing up smaller ones into streams.”

These streams also provide new tests of the nature of dark matter itself, according to theorist James Bullock of University of California at Irvine; Bullock was not part of the SDSS team.

“The fact that we can see a ‘Field of Streams’ like this suggests that dark matter particles are very ‘cold’, or slow moving. If the dark matter was made up of ‘warm,’ fast moving particles, we wouldn’t expect these thin streams to hang around long enough for us to find them.”

Original Source: RAS News Release

Posted on by Fraser Cain

Two Milky Way Companion Galaxies Found

An artist’s impression of the Milky way galaxy. Image credit: NASA. Click to enlarge
Astronomers have turned up two new companion galaxies to the Milky Way by looking through images in the Sloan Digital Sky Survey. The first is about 640,000 light years away in the constellation Canes Venatici – the most remote satellite galaxy ever discovered. The second is smaller and dimmer, and located in the constellation Bootes. It has a squashed structure because it’s being distorted by the Milky Way’s gravitational tides.

The Sloan Digital Sky Survey (SDSS-II) announced today (May 8) the discoveries of two new, very faint companion galaxies to the Milky Way.

The first was found in the direction of the constellation Canes Venatici (the Hunting Dog) by SDSS-II researcher Daniel Zucker at Cambridge University (UK). His colleague Vasily Belokurov discovered the second in the constellation Bootes (the Herdsman).

“I was poring over the survey’s map of distant stars in the Northern Galactic sky – what we call a Field of Streams — and noticed an overdensity in Canes Venatici,” Zucker explained. “Looking further, it proved to be a previously unknown dwarf galaxy. It’s about 640,000 light years (200 kiloparsecs) from the Sun. This makes it one of the most remote of the Milky Way’s companion galaxies.”

Zucker emailed Belokurov with the news, and, just as discoveries often build upon one another, Belokurov excitedly emailed back a few hours later with the discovery of a new, even fainter dwarf galaxy. The new galaxy in Bootes, which Belokurov called ‘Boo,’ shows a distorted structure that suggests it is being disrupted by the Milky Way’s gravitational tides. “Something really bashed Boo about,” said Belokurov.

Although the dwarf galaxies are in our own cosmic backyard, they are hard to discover because they are so dim. In fact, the new galaxy in Bootes is the faintest galaxy so far discovered, with a total luminosity of only about 100,000 Suns. But because of its distance (640,000 light years) it appears almost invisible to most telescopes. The previous dimness record holder was discovered last year in Ursa Major using SDSS-II data.

New galactic neighbors are exciting in their own right, but the stakes in searches for ultra-faint dwarfs are especially high because of a long-standing conflict between theory and observations. The leading theory of galaxy formation predicts that hundreds of clumps of “cold dark matter” should be orbiting the Milky Way, each one massive enough in principle to host a visible dwarf galaxy. But only about ten dwarf companions have been found to date.

One possibility is that the galaxies in the smaller dark matter clumps are too faint to have appeared in previous searches, but might be detectable in deep surveys like SDSS-II.

“It’s like panning for gold. Our view of the sky is enormous, and we’re looking for very small clumps of stars,” explained Cambridge University astronomer Wyn Evans, a member of the SDSS-II research team. Added collaborator Mark Wilkinson: “Finding and studying these small galaxies is really important. From their structure and their motions, we can learn about the properties of dark matter, as well as measure the mass and the gravity field of the Milky Way”.

The new discoveries are part of the SEGUE project (Sloan Extension for Galactic Understanding and Exploration), one of the three component surveys of SDSS-II. SEGUE will probe the structure and stellar make-up of the Milky Way Galaxy in unprecedented detail.

“I’m confident there are more dwarf galaxies out there and SEGUE will find them,” said Heidi Newberg of Rensselaer Polytechnic Institute, co-chair of SEGUE.

Original Source: RAS News Release

Posted on by Fraser Cain

What’s Up This Week – May 8 – May 14, 2006

What's Up 2006

Download our free “What’s Up 2006” ebook, with entries like this for every day of the year.

Fra Mauro. Image credit: Fra Mauro. Click to enlarge.
Greetings, fellow SkyWatchers! “There’s a bad Moon on the rise”… But that won’t keep us from viewing historic lunar areas such as the captivating Fra Mauro and catching bright clusters and double stars! Come along and join us a we take a look at what can be seen this week, because…

Here’s what’s up!

Monday, May 8, 2006 – A little more than 35 years ago, the Apollo 13 crew was on a mission to land in the Fra Mauro highlands. Although a near-disaster kept the crew from completing the mission, Apollo 14 carried out the plan less than a year later. Tonight we will be able to see this landing area on the lunar surface. Along the terminator to the south, you will see a dark expanse known as Mare Nubium. On its northern shore and near the terminator’s center, you will see an inlet of small shallow craters. The brightest of these small rings is crater Parry with Fra Mauro appearing larger and shallower to its north. Power up! Fra Mauro has a long fissure running between its north and south borders. At the northern crater edge you will see the ruins of an ancient impact. Appearing as an X, it definitely marks the spot of this successful lunar landing.

Tonight let’s use binoculars to hunt down a large open cluster – Melotte 111 – northwest of Arcturus. Like other visible clusters such as the Hyades, Pleiades and Praesepe, this Coma Berenices star cluster has a place in history. Known as the “Queen’s Hair,” it was first noted by Ptolemy. In more recent times, R.J. Trumpler identified 37 stars in Melotte 111 that share common movement. This discovery revealed the Coma Berenices cluster as a true group and not just a random collection.

Satellite observatories, like ESA’s Hipparcos, show us the members of Mel 111 are located around 288 light-years distant, making it one of the closest clusters in the heavens. Of the 37 stars identified by Trumpler, the brightest is 4.35 magnitude Gamma and the faintest members range to magnitude 10.5. Of the 400 stars gathered in this region, only about 129 are not true members of the group.

Tuesday, May 9 – Today in 1962, the first Earth-based laser was aimed at crater Albategnius. While the terminator has moved well beyond its position, you can still pick it out of the jumbled landscape. Look centrally on the lunar surface for the small, heart-shaped, grey area known as Sinus Medii. Just south of it lie a pair of prominent craters, Ptlomaeus to the west and Albategnius to the east.

The Moon will also offer many features such as the fully disclosed Tycho, the incomparable Copernicus and the fascinating Bullialdus, but tonight we’ll be looking for “The Great Wall.” Start by drawing a mental line from Tycho to Copernicus, then extend that line by two-thirds the distance north. Here you will discover what looks like huge wall on the lunar surface. At 48 kilometers high and 161 kilometers long, that would be a great wall! It is nothing more than the western portion or the Juras Mountains surrounding the lovely Sinus Iridum, but it’s definitely a rather striking feature and well worth the time to look in both binoculars and telescopes. Klare nacht!

Ready for more? How about another unexpected “open” cluster? Then look at Ursa Major. The primary stars – Merak, Phecda, Megrez, Mizar, and Alioth – have their own designation. Known as Collinder 285, it was first recognized as a cluster by R.A. Proctor in 1869. The Ursa Major “Moving Cluster” is headed south and east toward a spot in Sagittarius (RA 20:24 and Dec -37). The center of Collinder 285 is located 75 light-years away and its most distant bright member is outlying Alpha Coronae Borealis. The stars in this group are very similar to those in the Hyades – giving a cluster age of roughly 750 million years. Motion studies of over 100 stars throughout the sky (including Sirius, Alpha Ophiuchi, Delta Leonis, and Beta Aurigae) all show a similar “drift” across the heavens at a speed of almost 50 kilometers per second. That’s faster than the average speed of Mercury orbiting the Sun!

Wednesday, May 10 – Tonight bright Spica will join the Moon – making a very close appearance for some – and an occultation for others! Be sure to check IOTA for details. The most prominent lunar feature will be the ancient and graceful Gassendi. Its bright ring stands on the north shore of Mare Humorum – an area about the size of the state of Arkansas. At 113 kilometers in diameter and 2012 meters deep, you will see a triple mountain peak in its center and the south wall eroded by lava flows. Gassendi offers numerous fine details to telescopic observers on its ridge and rille covered floor.

When you have finished your lunar observations, let’s revisit a fascinating double star and try a simple experiment. Center your scope on Cor Caroli and watch as the “Heart of Charles” drifts west. The warm yellow primary is a magnetic spectrum variable and the pale blue secondary makes watching this 120 light-year distant pair pure pleasure. Now wait two and a half minutes as widely separated double Struve 1702 comes into view. Now that’s finding faint double stars made easy!

Thursday, May 11 – Tonight’s lunar observations will be a challenging study worthy of larger scopes. Start by identifying previous study craters, Hansteen and Billy. Due west of Hansteen you will find a small crater known as Sirsalis near the terminator. It will appear as a small, dark ellipse with a bright west wall along with its twin, Sirsalis B. The feature you will be looking for is the Sirsalis Rille – the longest presently known. Stretching northeast of Sirsalis and extending 459 kilometers south to the bright rays of Byrgius, this major “crack” in the lunar surface shows several branchings – like a long dry river bed.

Tonight let’s go from one navigational extreme to another as viewers in the northern hemisphere try their hand at Polaris. As guide star for the north, Polaris is also a wonderful double with an easily resolved, faint blue companion. But what about the south? Viewers in the southern hemisphere can never see Polaris – is there a matching star for the south? The answer is yes. Sigma Octantis. But at magnitude 5, it doesn’t make a very good unaided eye guide.

Ancient navigators found better success with the constellation Crux – better known as the “Southern Cross” – to guide them. Two bright stars of the Southern Cross, Gacrux and Acrux, are oriented north-south and point across the pole to brilliant Archenar. Splitting the distance between Gacrux and Archenar puts you within two degrees of the rather desolate south pole of the sky. Southern hemisphere observers wishing to see a double star comparable to Polaris in appearance should choose Lambda Centauri. The difference in magnitude between components and separation are about the same.

Friday, May 12 – The Moon and Jupiter rise tonight shortly before the Sun sets. Despite lunar surface brightness, we can do some exploring. Start by identifying the grey oval of Grimaldi central on the western terminator. Just north of Grimaldi is Hevelius. It appears as a bright oval, similar to Grimaldi, but contains an off-center mountain peak. Hevelius’ north wall is broken by well defined Cavalerius, a narrow, bright ellipse with thin, black border to the east. 100 kilometers west of Cavalerius on the edge of Oceanus Procellarum are the remains of the very first successful lunar landing. It was here on February 3, 1966 that the Soviet probe Luna 9 touched down. The man-sized craft sent back panoramic television images revealing an uneven, jagged surface covered with dust. So good were the probe’s images, that scientists were able to discern small depressions and protrusions only millimeters in size.

While we’re out, let’s take a look at bright Spica – Alpha Virginis. Located 262 light-years away, 1.0 magnitude Spica glows with the combined light of four unresolved stars and has a visual luminosity 2100 times that of the Sun. As a rotating ellipsoidal variable, the four stars cause complex changes in luminosity by distorting the shape of the brightest components.

The dominant star – Spica A – has a mass 11 times that of the Sun and fluctuates in physical size as it varies in brightness. The primary star is at maximum when smallest, giving it the highest photospheric surface temperature. Spica B has a mass of 7 suns. As a spectral type B, these two components produce more light in ultraviolet due to exceedingly high surface temperatures. Spica has two distant telescopic companions – magnitude 12 to the north-northeast, and magnitude 10.5 to the east-northeast.

Saturday, May 13 – Tonight is Full Moon. By May in most areas, flowers are everywhere, so it’s not hard to imagine how this came to be known as the “Full Flower Moon.” Since northern hemisphere Earth is re-awakening after the winter season, the agricultural cycle has begun and this is also known as the “Full Corn Planting Moon.” Another name? The “Milk Moon” due to the increased productivity from cows grazing on the rapidly greening pastures. No matter what you call it, the Moon still rises majestically upward from the eastern horizon!

Just because we have a full Moon doesn’t mean we can’t have any fun. Tonight let’s explore the star in the middle of the handle of the “Big Dipper.” Its name is Mizar, but if you have exceptional eyes you may also see its companion Alcor as well! The ancient Arabs used this star as an “eye test” for warriors – if you could see both stars, you were given a horse. The names Mizar and Alcor literally translate to “the horse and rider.” If it’s not clear to you, even the slightest optical aid will separate the two, but a treat is in store for telescope users. Mizar itself is a double star. It was the very first to be discovered and photographed. In the eyepiece, Alcor appears to the east of Mizar A and B, but look for a faint star in between. It has the very impressive name of Sidus Ludovicianum and was once believed to be a planet.

Sunday, May 14 – With just a little time to spare tonight before lunacy, let’s take a look at the fine double star – Epsilon Bootes. At magnitude 2.7, Izar is easily located a fist width north-northeast of brilliant Arcturus. A “test double” for small scopes, the real limiting factor to resolving this disparate pair is the stability of the night sky. Look for the blue 5.1 magnitude companion 2.6 arc seconds north-northwest of the yellow-orange 2.7 magnitude primary.

May all your journeys be at light speed… ~Tammy Plotner with Jeff Barbour.

Posted on by Fraser Cain

Astrophoto: Omega Centauri by Bernd Flach-Wilken and Volker Wendel

Omega Centauri by Bernd Flach-Wilken and Volker Wendel
For thousands of years, we saw ourselves as the focal point of the Universe and the center of all things. Then, in the early 16th century, Copernicus revealed that this was not the case; humanity’s home was a huge globe spinning once every 24 hours circling the distant Sun on an annual basis. Over the next 400 years, this idea begrudgingly gained acceptance. But it was not until early in the last century, when Harlow Shapley measured the distance to several globular clusters like the one in this picture, that humanity next understood we were located far from the Milky Way’s center, then believed to be the center of the Universe, and therefore even less special in the grand scheme of things.

The Milky Way is surrounded by swarms of similarly aged stars held together by the mutual gravitational attraction of their individual constituents. These clumps of Suns are known as Globular Clusters and our galaxy has about two hundred of them orbiting its massive central region. About nine years after Shapley used globular clusters to determined we were not the center of the Milky Way Universe, Edwin Hubble proved that the Universe is filled with a hundred billion galaxies of which the Milky Way is but one example. His discovery was the latest demotion that mankind has suffered and around many of these distant island universes, swarms of globular clusters have also been observed hovering above their centers. Thus, the dazzling beauty of globular clusters has played a significant role in recent history by helping us understand our true place in the vastness of the Cosmos.

Of all the globular clusters associated with the Milky Way galaxy, none are larger or more luminous than Omega Centauri, located 15,000 light years away toward the constellation of Centaurus. This ball of light is estimated to contain about 10 million stars and is so large that it takes light 150 years to travel from a star on one side to a star on the other. In the local group of galaxies, only one other globular cluster, part of the Andromeda Galaxy, is larger. Under dark skies, Omega Centaurus can be seen with the naked eye as a fuzzy star and it is often mistaken for a new comet.

This incredibly sharp picture was taken under the very dark skies of rural Namibia, in southern Africa, by two astrophotographers who live in Germany named Bernd Flach-Wilken and Volker Wendel. Taken through a 16-inch f/8 Hypergraph telescope and a 3 mega-pixel camera, the core of Omega Centaurus is clearly resolved into individual points of light. There are many yellow-white stars that are smaller than our Sun, numerous yellow-orange Red Giants and more than a few hot blue straggler stars clearly visible. 15 5-minute exposures were combined digitally to create this stunning image from the astronomer’s summer 2004 visit.

Do you have photos you’d like to share? Post them to the Universe Today astrophotography forum or email them, and we might feature one in Universe Today.

Written by R. Jay GaBany

Posted on by Fraser Cain

Crater Hopmann by SMART-1

ESA’s SMART-1 spacecraft captured this photograph of Crater Hopmann, located on the Moon. Only a quarter of the full crater is visible in this photograph, and it contains several other smaller craters inside of it. The small crater chains are created when secondary debris is blasted off the surface of the Moon, and then falls back in an arc of molten droplets. This area isn’t visible from the Earth because it’s on the far side of the Moon – only spacecraft have ever seen it.

This image, taken by the advanced Moon Imaging Experiment (AMIE) on board ESA’s SMART-1 spacecraft, shows one quarter of crater Hopmann – an impact structure about 88 kilometres in diameter.

AMIE obtained this image on 25 January 2006 from a distance of about 840 kilometres from the surface, with a ground resolution of 76 metres per pixel.

The imaged area, not visible from Earth because it is located on the far side of the Moon, is positioned at latitude of 51.7 degrees South and longitude 159.2 degrees East. It covers a square of about 39 kilometres per side.

The crater (centred at 50.8 degrees South, 160.3 degrees East) is situated on the edge of the giant South Pole-Aitken basin SPA, the largest impact crater in the solar system with a diameter of 2500 kilometres and a depth of 13 kilometres. The SPA basin shows distinctive chemical composition with unusual mineralogy types, and possible exposure of rocks from the lower crust or the upper mantle.

The hills on the lower left side are the crater wall of Hopmann. This crater is very old – many small craters can be seen on its flat floor, the largest one showing an interesting double-ringed structure. The outer rim has been also eroded by later impacts.

The small crater chains to the left of Hopmann can be interpreted as series of so-called ‘secondary craters’, created by the impact of the material ejected from a nearby large impact. This ejected material flies away in molten state, and fall in large ‘droplets’. When these impact on the surface, they form typical crater chains as those visible in this image.

The crater is named after Josef Hopmann (1890-1975), an astronomer that worked in Bonn, Leipzig and as Director of the Vienna Observatory.

Original Source: ESA Portal

Posted on by Fraser Cain

Nitrogen Would Indicate Extraterrestrial Life

Martian atmosphere has a very low nitrogen content. Image credit: NASA. Click to enlarge
When searching for life, most researchers have been hunting the Solar System for signs of liquid water; past and present. But geobiologists from the University of Southern California think that more effort should be spent looking for evidence of nitrogen. Since nitrogen isn’t a major component in rocks and minerals but an essential component of life, any concentration of this element would strongly indicate life’s fingerprint. They hope that next generation spacecraft will have advanced nitrogen sampling capabilities.

The great search for extraterrestrial life has focused on water at the expense of a crucial element, say USC geobiologists.

Writing in the Perspectives section of the May 5 issue of Science, four USC researchers propose searching for organic nitrogen as a direct indicator of the presence of life. Nitrogen is essential to the chemistry of living organisms.

Even if NASA were to find water on Mars, its presence only would indicate the possibility of life, said Kenneth Nealson, Wrigley Professor of earth sciences in USC College.

“It’s hard to imagine life without water, but it’s easy to imagine water without life,” Nealson said.

The discovery of nitrogen on the Red Planet would be a different story.

“If you found nitrogen in abundance on Mars, you would get extremely excited because it shouldn’t be there,” Nealson said.

The reason has to do with the difference between nitrogen and carbon, the other indispensable organic element.

Unlike carbon, nitrogen is not a major component of rocks and minerals. This means that any substantial organic nitrogen deposits found in the soil of Mars, or of another planet, likely would have resulted from biological activity.

Dimming the hopes of life-on-Mars believers is the makeup of the planet’s atmosphere. The abundant nitrogen in Earth’s atmosphere is constantly replenished through biological activity. Without the ongoing contribution of living systems, the atmosphere slowly would lose its nitrogen.

The extremely low nitrogen content in the Martian atmosphere suggests that biological nitrogen production is close to zero.

However, the authors write, it is possible that life existed on Mars at some hypothetical time when nitrogen filled the atmosphere.

Co-author Douglas Capone, Wrigley Professor of environmental biology in USC College, said NASA should establish a nitrogen detection program alongside its water-seeking effort. He noted that next-generation spacecraft will have advanced sampling capabilities.

“What we’re suggesting here is basically drilling down into geological strata, which they’re going to be doing for water anyway,” Capone said.

“The real smoking gun would be organic nitrogen.”

Said Nealson: “If your goal is to search for life, it would be wise to include nitrogen.”

In their acknowledgments, the authors thanked the students of the Spring 2004 Geobiology & Astrobiology course at USC, with whom Nealson and Capone began their discussion on how to search for life outside earth.

“That’s really what stimulated this [paper],” Nealson said.

The authors also thanked NASA, the U.S. Department of Energy and the National Science Foundation for their financial support.

Along with Nealson and Capone, USC graduate student Beverly Flood and former USC research professor Radu Popa (now a professor of biology at Portland State University) contributed to the Perspectives paper.

Original Source: USC News Release

Posted on by Fraser Cain

Titan’s Sandy Oceans

Titan’s sand dunes. Image credit: NASA/JPL. Click to enlarge
When they first noticed the dark equatorial regions on Titan, researchers thought they could be looking at oceans of liquid methane. But new radar images taken by NASA’s Cassini spacecraft has provided the answer: sand dunes. The images show enormous dunes that run parallel to each other for hundreds of kilometers. Saturn’s powerful gravity causes gentle winds on Titan, possibly transporting sand from across the moon and depositing it around the equator.

Until a couple of years ago, scientists thought the dark equatorial regions of Titan might be liquid oceans.

New radar evidence shows they are seas — but seas of sand dunes like those in the Arabian or Namibian Deserts, a University of Arizona member of the Cassini radar team and colleagues report in Science (May 5).

Radar images taken when the Cassini spacecraft flew by Titan last October show dunes 330 feet (100 meters) high that run parallel to each other for hundreds of miles at Titan’s equator. One dune field runs more than 930 miles (1500 km) long, said Ralph Lorenz of UA’s Lunar and Planetary Laboratory.

“It’s bizarre,” Lorenz said. “These images from a moon of Saturn look just like radar images of Namibia or Arabia. Titan’s atmosphere is thicker than Earth’s, its gravity is lower, its sand is certainly different — everything is different except for the physical process that forms the dunes and resulting landscape.”

Ten years ago, scientists believed that Saturn’s moon Titan is too far from the sun to have solar-driven surface winds powerful enough to sculpt sand dunes. They also theorized that the dark regions at Titan’s equator might be liquid ethane oceans that would trap sand.

But researchers have since learned that Saturn’s powerful gravity creates significant tides in Titan’s atmosphere. Saturn’s tidal effect on Titan is roughly 400 times greater than our moon’s tidal pull on Earth.

As first seen in circulation models a couple of years ago, Lorenz said, “Tides apparently dominate the near-surface winds because they’re so strong throughout the atmosphere, top to bottom. Solar-driven winds are strong only high up.”

The dunes seen by Cassini radar are a particular linear or longitudinal type that is characteristic of dunes formed by winds blowing from different directions. The tides cause wind to change direction as they drive winds toward the equator, Lorenz said.

And when the tidal wind combines with Titan’s west-to-east zonal wind, as the radar images show, it creates dunes aligned nearly west-east except near mountains that influence local wind direction.

“When we saw these dunes in radar it started to make sense,” he said. “If you look at the dunes, you see tidal winds might be blowing sand around the moon several times and working it into dunes at the equator. It’s possible that tidal winds are carrying dark sediments from higher latitudes to the equator, forming Titan’s dark belt.”

The researchers’ model of Titan suggests tides can create surface winds that reach about one mile per hour (a half-meter per second). “Even though this is a very gentle wind, this is enough to blow grains along the ground in Titan’s thick atmosphere and low gravity,” Lorenz said. Titan’s sand is a little coarser but less dense than typical sand on Earth or Mars. “These grains might resemble coffee grounds.”

The variable tidal wind combines with Titan’s west-to-east zonal wind to create surface winds that average about one mile per hour (a half meter per second). Average wind speed is a bit deceptive, because sand dunes wouldn’t form on Earth or Mars at their average wind speeds.

Whether the grains are made of organic solids, water ice, or a mixture of both is a mystery. Cassini’s Visual and Infrared Mapping Spectrometer, led by UA’s Robert Brown, may get results on sand dune composition.

How the sand formed is another peculiar story.

Sand may have formed when liquid methane rain eroded particles from ice bedrock. Researchers previously thought that it doesn’t rain enough on Titan to erode much bedrock, but they thought in terms of average rainfall.

Observations and models of Titan show that clouds and rain are rare. That means that individual storms could be large and still yield a low average rainfall, Lorenz explained.

When the UA-led Descent Imager/Spectral Radiometer (DISR) team produced images taken during the Huygens probe landing on Titan in January 2005, the world saw gullies, streambeds and canyons in the landscape. These same features on Titan have been seen with radar.

These features show that when it does rain on Titan, it rains in very energetic events, just as it does in the Arizona desert, Lorenz said.

Energetic rain that triggers flash floods may be a mechanism for making sand, he added.

Alternatively, the sand may come from organic solids produced by photochemical reactions in Titan’s atmosphere.

“It’s exciting that the radar, which is mainly to study the surface of Titan, is telling us so much about how winds on Titan work,” Lorenz said. “This will be important information for when we return to Titan in the future, perhaps with a balloon.”

An international group of scientists are co-authors on the Science article, “The Sand Seas of Titan: Cassini Observations of Longitudinal Dunes.” They are from the Jet Propulsion Laboratory, California Institute of Technology, U.S. Geological Survey – Flagstaff, Planetary Science Institute, Wheeling Jesuit College, Proxemy Research of Bowie, Md., Stanford University, Goddard Institute for Space Studies, Observatoire de Paris, International Research School of Planetary Sciences, Universita’ d’Annunzio, Facolt di Ingegneria, Universit La Sapienza, Politecnico di Bari and Agenzia Spaziale Italiana. Jani Radebaugh and Jonathan Lunine of UA’s Lunar and Planetary Laboratory are among the co-authors.

The Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency and the Italian Space Agency. The Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, manages the mission for NASA’s Science Mission Directorate, Washington. The Cassini orbiter was designed, developed and assembled at JPL.

Original Source: UA News Release

Posted on by Fraser Cain

New Technique for Finding Organic Molecules in Meteorites

Tiny particles of meteorites with portions of nitrogen and hydrogen. Image credit: Henner Busemann. Click to enlarge
When the Solar System first formed billions of years ago, organic molecules – the building blocks of life – were churned into the mix that went on to create the planets. Scientists from the Carnegie Institution have developed a technique to find these tiny organic particles hidden inside meteorites. These meteorites have survived since the formation of the Solar System, so it allows scientists to track the distribution of organic material and the processes they went through as the planets formed.

Like an interplanetary spaceship carrying passengers, meteorites have long been suspected of ferrying relatively young ingredients of life to our planet. Using new techniques, scientists at the Carnegie Institution’s Department of Terrestrial Magnetism have discovered that meteorites can carry other, much older passengers as well-primitive, organic particles that originated billions of years ago either in interstellar space, or in the outer reaches of the solar system as it was beginning to coalesce from gas and dust. The study shows that the parent bodies of meteorites-the large objects from the asteroid belt-contain primitive organic matter similar to that found in interplanetary dust particles that might come from comets. The finding provides clues about how organic matter was distributed and processed in the solar system during this long-gone era. The work is published in the May 5, 2006, issue of Science.

“Atoms of different elements come in different forms, or isotopes, and the relative proportions of these depend on the environmental conditions in which their carriers formed, such as the heat encountered, chemical reactions with other elements, and so forth,” explained lead author Henner Busemann. “In this study we looked at the relative amounts of different isotopes of hydrogen (H) and nitrogen (N) associated with tiny particles of insoluble organic matter to determine the processes that produced the most pristine type of meteorites known. The insoluble material is very hard to break down chemically and survives even very harsh acid treatments.”

The researchers used a microscopic imaging technique to analyze the isotopic composition of insoluble organic matter from six carbonaceous chondrite meteorites-the oldest type known. The relative proportion of isotopes of nitrogen and hydrogen associated with the insoluble organic matter act as “fingerprints” and can reveal how and when the carbon was formed. The isotope of nitrogen that is most often found in nature is 14N; its heavier sibling is 15N. Differing amounts of 15N, in addition to a heavier form of hydrogen called deuterium, (D), allow researchers to tell if a particle is relatively unaltered from the time when the solar system was first forming.

“The tell-tale signs are lots of deuterium and 15N chemically bonded to carbon,” commented co-author Larry Nittler. “We have known for some time, for instance, that interplanetary dust particles (IDP), collected from high-flying airplanes in the upper atmosphere, contain huge excesses of these isotopes, probably indicating vestiges of organic material that formed in the interstellar medium. The IDPs have other characteristics indicating that they originated on bodies-perhaps comets-that have undergone less severe processing than the asteroids from which meteorites originate.”

The scientists found that some meteorite samples, when examined at the same tiny scales as interplanetary dust particles, actually have similar or even higher abundances of 15N and D than those reported for IDPs. “It’s amazing that pristine organic molecules associated with these isotopes were able to survive the harsh and tumultuous conditions present in the inner solar system when the meteorites that contain them came together,” reflected co-author Conel Alexander. “It means that the parent bodies-the comets and asteroids-of these seemingly different types of extraterrestrial material are more similar in origin than previously believed.”

“Before, we could only explore minute samples from IDPs. Our discovery now allows us to extract large amounts of this material from meteorites, which are large and contain several percent of carbon, instead of from IDPs, which are on the order of a million million times less massive. This advancement has opened up an entirely new window on studying this elusive period of time,” concluded Busemann.

Original Source: Carnegie Institution

Posted on by Fraser Cain

Hubble Pictures of Red Spot Jr.

Jupiter’s junior red spot. Image credit: NASA/ESA. Click to enlarge
The Hubble Space Telescope has snapped a picture of “Red Spot Jr.”, the newly forming storm on Jupiter. This new spot is half the size of Jupiter’s Great Red Spot, and formed after three white storms merged together. But when viewed in near-infrared wavelengths, the spot is as prominent as the Great Red Spot, so this is a big storm too. Scientists think that Jupiter might be in the midst of a global climate change, warming up a few degrees in some latitudes.

NASA’s Hubble Space Telescope is giving astronomers their most detailed view yet of a second red spot emerging on Jupiter. For the first time in history, astronomers have witnessed the birth of a new red spot on the giant planet, which is located half a billion miles away. The storm is roughly one-half the diameter of its bigger and legendary cousin, the Great Red Spot. Researchers suggest that the new spot may be related to a possible major climate change in Jupiter’s atmosphere.

Dubbed by some astronomers as “Red Spot Jr.,” the new spot has been followed by amateur and professional astronomers for the past few months. But Hubble’s new images provide a level of detail comparable to that achieved by NASA’s Voyager 1 and 2 spacecraft as they flew by Jupiter a quarter-century ago.

Before it mysteriously changed to the same color as the Great Red Spot, the smaller spot was known as the White Oval BA. It formed after three white oval-shaped storms merged during 1998 to 2000. At least one or two of the progenitor white ovals can be traced back to 90 years ago, but they may have been present earlier. A third spot appeared in 1939. (The Great Red Spot has been visible for the past 400 years, ever since earthbound observers had telescopes to see it).

When viewed at near-infrared wavelengths (specifically 892 nanometers – a methane gas absorption band) Red Spot Jr. is about as prominent in Jupiter’s cloudy atmosphere as the Great Red Spot. This may mean that the storm rises miles above the top of the main cloud deck on Jupiter just as its larger cousin is thought to do. Some astronomers think the red hue could be produced as the spots dredge up material from deeper in Jupiter’s atmosphere, which is then chemically altered by the Sun’s ultraviolet light.

Researchers think the Hubble images may provide evidence that Jupiter is in the midst of a global climate change that will alter its average temperature at some latitudes by as much as 10 degrees Fahrenheit. The transfer of heat from the equator to the planet’s south pole is predicted to nearly shut off at 34 degrees southern latitude, the latitude where the second red spot is forming. The effects of the shut-off were predicted by Philip Marcus of the University of California, Berkeley (UCB) to become apparent approximately seven years after the White Oval collisions in 1998 to 2000.

Two teams of astronomers were given discretionary time on Hubble to observe the new red spot.

Original Source: HubbleSite News Release