Thursday, May 27, 2010

Lost bugs Found Again in South Dakota

I was frustrated. I had been searching for years for the so-called "lost ladybugs," but hadn't found any.

It was 2008, and only a few had been found by anyone in the last three decades, although they were once common in many areas, especially crop fields such as wheat and alfalfa.

There are actually hundreds of kinds of ladybugs, but three in particular--the two-spotted, nine-spotted, and transverse ladybugs--seemed to have vanished from the landscape of eastern South Dakota.

Research scientists publish findings from their observations and experiments. So, I began to question myself. "How can I, as a scientist, publish my findings of 'no findings'?" I wondered if maybe my methods and approach were wrong.

I had been working from three hunches about the fate of lost ladybugs. First, maybe the once-common lost ladybugs would recover in abundance on their own, as some populations of insects have rebounded after prolonged periods of sparseness. There was added hope for this since populations of the soybean aphid had recently exploded in soybean fields of the north-central United States, providing a new prey source for ladybugs. Nonetheless, after years of sampling soybean and other crops, I had not found the lost ladybugs.

A second possibility was that lost ladybugs had moved from crop fields to habitats such as prairies, tree belts or weedy patches. At about the time native ladybugs were lost from crop fields, two kinds of ladybugs imported from Eurasia--the seven-spotted and multicolored Asian ladybugs--had become plentiful in fields over much of North America. The apparent aggressiveness of these newly established ladybugs may have forced some of the native ladybugs into non-crop habitat in order to minimize competition. However, despite searching various habitats, I was still unable to detect lost ladybugs.

I then followed up on a notion that the ladybugs may have only been lost locally, and that I could find them by simply surveying a few hundred miles from my workstation. This led me and colleagues to venture into southeastern North Dakota, Iowa and Minnesota, but sampling again failed to yield any lost ladybugs. More importantly, based on similar surveys by scientists in other regions, there was also increasing alarm that lost ladybugs had become extremely rare throughout eastern North America.

However, a glimmer of hope arose after Robert Kieckhefer, a retired U.S. Department of Agriculter (USDA) entomologist, found two-spotted ladybugs in western South Dakota. This finding sparked a hunch that lost ladybugs might fare better in more arid western North America. So, I called Michael Catangui, an entomologist at South Dakota State University who heads up the National Science Foundation- (NSF) sponsored Lost Ladybug Project with me in South Dakota. Buoyed by Kieckhefer's recent finds, we headed to western South Dakota with sweepnets and other gear to sample for lost ladybugs.

We arrived in the Badlands of western South Dakota on a typical June day--sunny, fairly hot and breezy. We sampled roadside vegetation and various patches of grasses and forbs within and around Badlands National Park, finding various ladybugs but not lost ladybugs.

At sunset while sampling roadside vegetation near the southern unit of the park, Mike called excitedly to me from about 10 yards away. "Hey, Louis. Come see what I have," referring to the nine-spotted lady beetle he had just found on a curlycup gumweed plant.

"Okay," I replied, "but maybe you should first see what I found," as I carefully teased a nine-spotted lady beetle from gumweed into a container and headed toward Mike.

We fondly remember our simultaneous discoveries. "We had searched for lost ladybugs all day, and been stumped. Then, as daylight was fading, each of us independently found a nine-spotted lady beetle. Remarkable!" Catangui recalls.

Soon afterward, John Losey, entomologist in charge of the Lost Ladybug Project at Cornell University in Ithaca, N.Y., joined the hunt for lost ladybugs in western South Dakota. John and I found transverse and two-spotted ladybugs at several spots there. That same summer, colleagues conducting grasshopper surveys in western South Dakota found more nine-spotted ladybugs, and I found both transverse and nine-spotted ladybugs during a survey of sites in western Nebraska.

The presence of lost ladybugs in western South Dakota and western Nebraska fits a pattern in which most recent finds have occurred in western states. Many of these recent finds were submitted as digital images by citizen scientists to the Lost Ladybug Project website run by Losey and colleagues at Cornell. Our recruitment of citizen scientists to the project was paying off. Now, both they and entomologists on the project were finding lost ladybugs. And my self-doubt had faded as I realized lost ladybugs actually were hard to detect in the east, but could be found in western states.

These findings raise questions as to why lost ladybugs are more easily found in western than eastern parts of North America, and why their populations have declined in general. Entomologists on the Lost Ladybug Project are now avidly seeking answers through field and laboratory experiments.

Atlantis and the STS-132 landed Safely in Florida

With Commander Ken Ham and Pilot Tony Antonelli at the controls, space shuttle Atlantis descended to its final planned landing at Kennedy Space Center, Fla. The STS-132 crew concluded its successful mission to the International Space Station when the shuttle touched down at 8:48 a.m. EDT.

The crew began its mission May 14 and arrived at the station May 16.

Using the station’s robotic arm, Mission Specialists Piers Sellers and Garrett Reisman added Rassvet, the Russian Mini-Research Module 1, to the station. The new module will host a variety of biotechnology and biological science experiments and fluid physics and educational research.

During three spacewalks Reisman, along with Mission Specialists Mike Good and Steve Bowen, added a backup high-data-rate antenna to the station and a tool platform to Dextre, the robot-like special purpose dexterous manipulator. They removed and replaced six 375-pound batteries on the station’s P6 truss segment.

STS-132 is the 132nd shuttle mission and the 34th mission to visit the space station. The next mission, STS-133, is slated to launch in September.

"It was smooth as silk," STS-132 Commander Ken Ham said of Atlantis' entry and landing. "We were clearly riding in the middle of a fireball, and it was spectacular. The windows, all of them, were bright, brilliant orange. One of the neatest things was when we flew right into orbital sunrise."

This was the final scheduled flight for Atlantis, which has logged more than 120 million miles during its 25 years of service. The orbiter will go through standard prelaunch preparations as the "launch-on-need" vehicle for Endeavour's STS-134 mission. That flight currently is targeted for November.

"Atlantis treated us very well. She was just an incredible ship," Mission Specialist Michael Good said, citing the precision of the deorbit burn as an example of Atlantis' performance. "The engines had it trimmed out to within .01 of what the burn was supposed to be."

The all-veteran astronaut crew will head home to Houston on Thursday. The public is invited to attend the welcome ceremony for the crew Thursday at 4 p.m. CDT at Ellington Field's NASA Hangar 276.

"We're thrilled, because we accomplished the mission that was put in front of us," Ham said. He explained that in addition to the technical objectives of the 12-day mission, the astronauts also wanted to enjoy themselves and share their enthusiasm of spaceflight with the world.

Tuesday, May 25, 2010

Mystery Behind normal Earthquake Faults Solved

Cristiano and the rocks arrived at Penn State in October to begin the lab-friction experiments. We wanted to see if the fault rocks were weak enough to explain why low-angle, normal faults are active in that region. I had done similar studies on fault rocks before, so we started with the standard approach, which is to crush the rock samples and construct layers of rock powder that we could shear (abrade).

But Cristiano was insistent that we also measure the properties of the intact rock, by shearing it in the orientation it existed in within the fault zone. Andre Niemeijer, who was then a post-doc in my lab, and Igor Faoro, an Italian graduate student, had been working to develop methods for cutting fragile samples, so we started testing ideas about how we could create a sample that was roughly 5 centimeters (cm) by 5 cm by 1.0 cm and which had the fault zone fabric parallel to the main sample faces.

Luckily, we had quite a bit of sample, because the first several attempts failed. Then, Igor had a revelation and set up a makeshift sculpting studio by duct-taping a Shopvac hose to the leveling jig that held the sample and using a Dremel tool to sculpt the blocks.

When we began to run experiments, we noticed a problem right away. The rock powders had typical coefficients of friction (~ 0.6), but the solid wafers of rock--that Andre and Igor were by now experts at sculpting--produced much lower values. We were perplexed because we had made the powders and wafers from exactly the same fault rock samples, so the material properties should have been identical.

It's not uncommon to find experiment-to-experiment variability in friction due to heterogeneities in the rocks, but differences this large were unheard of. Even though all the samples were labeled in the field and packed in labeled containers, I thought we must have mixed them up. So, we made more powders and wafers and started again.

The result was the same, and now we were perplexed. The wafers were not perfectly homogeneous, but there was nothing visible to explain such large differences in steady-state sliding friction. After we reproduced this curious result three times, on different pieces from the same fault zone unit, I decided to take the wafers, after shearing, and powder them. That way we'd be sure that the bulk chemistry was the same in both cases.

We took each of the wafers and crushed them, and then made layers with the powders. To our surprise, the new powders had friction values of ~ 0.6! It wasn't until we made thin sections and started to think about the thin- (less than 10 millionths of a meter) but-very-abundant seams of clays that we realized these fabric elements in the rock were acting in concert to produce a form of lubrication.

The role of fabric in rock deformation at high temperature had been well known for many years, but as a community, geophysicists working on faults in the brittle field had not considered that they could be so important as a possible mechanism for fault weakening.

The Heart and Soul nebulae

The Heart and Soul nebulae are seen in this infrared mosaic from NASA's Wide-field Infrared Survey Explorer, or WISE. The image covers an area of the sky over ten times as wide as the full moon and eight times as high (5.5 x 3.9 degrees) in the constellation Cassiopeia.

Located about 6,000 light-years from Earth, the Heart and Soul nebulae form a vast star-forming complex that makes up part of the Perseus spiral arm of our Milky Way galaxy. The nebula to the left is the Heart, designated IC 1805 and named after its resemblance to a human heart. To the right is the Soul nebula, also known as the Embryo nebula, IC 1848 or W5. The Perseus arm lies further from the center of the Milky Way than the arm that contains our sun. The Heart and Soul nebulae stretch out nearly 580 light-years across, covering a small portion of the diameter of the Milky Way, which is roughly 100,000 light-years across.

The two nebulae are both massive star-making factories, marked by giant bubbles that were blown into surrounding dust by radiation and winds from the stars. WISE's infrared vision allows it to see into the cooler and dustier crevices of clouds like these, where gas and dust are just beginning to collect into new stars. These stars are less than a few million of years old -- youngsters in comparison to stars like the sun, which is nearly 5 billion years old.

Also visible near the bottom of this image are two galaxies, Maffei 1 and Maffei 2. Both galaxies contain billions of stars and, at about 10 million light-years away, are well outside our Milky Way yet relatively close compared to most galaxies. Maffei 1 is the bluish elliptical object and Maffei 2 is the spiral galaxy.

All four infrared detectors aboard WISE were used to make this image. Color is representational: blue and cyan represent infrared light at wavelengths of 3.4 and 4.6 microns, which is dominated by light from stars. Green and red represent light at 12 and 22 microns, which is mostly light from warm dust.

Friday, May 21, 2010

Atlantis Crew Performs Final Spacewalk

Mission Specialists Michael Good and Garrett Reisman began the third and final spacewalk of the STS-132 mission at 6:27 a.m. EDT.

The spacewalkers first task was the installation of an ammonia jumper on the port 4 and 5 truss. They are finishing the last of the battery replacement work, swapping the remaining two batteries and installing a battery that was left in a temporary stow position from the last spacewalk.

The final planned task is the retrieval of a Power and Data Grapple Fixture (PDGF) from the orbiter’s payload bay to bring inside the station at the end of the spacewalk. The PDGF will be installed to the Zarya module’s exterior on a spacewalk later this summer.

Pilot Tony Antonelli and Mission Specialist Steve Bowen will assist from inside the complex throughout the spacewalk. Mission Specialist Piers Sellers and Expedition 23 Flight Engineer Tracy Caldwell Dyson will provide robotics support. STS-132 Commander Ken Ham will oversee the activities and assist with orbiter activities and transfer work.

Wednesday, May 19, 2010

NASA's Mars Rovers Set's Record

NASA's Mars Exploration Rover Project will pass a historic Martian longevity record on Thursday, May 20. The Opportunity rover will surpass the duration record set by NASA's Viking 1 Lander of six years and 116 days operating on the surface of Mars. The effects of favorable weather on the red planet could also help the rovers generate more power.

Opportunity's twin rover, Spirit, began working on Mars three weeks before Opportunity. However, Spirit has been out of communication since March 22. If it awakens from hibernation and resumes communication, that rover will attain the Martian surface longevity record.

Spirit's hibernation was anticipated, based on energy forecasts, as the amount of sunshine hitting the robot's solar panels declined during autumn on Mars' southern hemisphere. Unfortunately, mobility problems prevented rover operators from positioning Spirit with a favorable tilt toward the north, as during the first three winters it experienced. The rovers' fourth winter solstice, the day of the Martian year with the least sunshine at their locations, was Wednesday, May 12.

"Opportunity, and likely Spirit, surpassing the Viking Lander 1 longevity record is truly remarkable, considering these rovers were designed for only a 90-day mission on the surface of Mars," Callas said. "Passing the solstice means we're over the hump for the cold, dark, winter season."

Unless dust interferes, which is unlikely in the coming months, the solar panels on both rovers should gradually generate more electricity. Operators hope that Spirit will recharge its batteries enough to awaken from hibernation, start communicating and resume science tasks.

Unlike recent operations, Opportunity will not have to rest to regain energy between driving days. The gradual increase in available sunshine will eventually improve the rate of Opportunity's progress across a vast plain toward its long-term destination, the Endeavour Crater.

This month, some of Opportunity's drives have been planned to end at an energy-favorable tilt on the northern face of small Martian plain surface ripples. The positioning sacrifices some distance to regain energy sooner for the next drive. Opportunity's cameras can see a portion of the rim of Endeavour on the horizon, approximately eight miles away, across the plain's ripples of windblown sand.

"The ripples look like waves on the ocean, like we're out in the middle of the ocean with land on the horizon, our destination," said Steve Squyres of Cornell University in Ithaca, N.Y. Squyres is the principal investigator for Opportunity and Spirit. "Even though we know we might never get there, Endeavour is the goal that drives our exploration."

The team chose Endeavour as a destination in mid-2008, after Opportunity finished two years examining the smaller Victoria Crater. Since then, the goal became even more alluring when orbital observations found clay minerals exposed at Endeavour. Clay minerals have been found extensively on Mars from orbit, but have not been examined on the surface.

"Those minerals form under wet conditions more neutral than the wet, acidic environment that formed the sulfates we've found with Opportunity," said Squyres. "The clay minerals at Endeavour speak to a time when the chemistry was much friendlier to life than the environments that formed the minerals Opportunity has seen so far. We want to get there to learn their context. Was there flowing water? Were there steam vents? Hot springs? We want to find out."

Launched in 1975, Project Viking consisted of two orbiters, each carrying a stationary lander. Viking Lander 1 was the first successful mission to the surface of Mars, touching down on July 20, 1976. It operated until Nov. 13, 1982, more than two years longer than its twin lander or either of the Viking orbiters.

The record for longest working lifetime by a spacecraft at Mars belongs to a later orbiter: NASA's Mars Global Surveyor operated for more than 9 years after arriving in 1997. NASA's Mars Odyssey, in orbit since in 2001, has been working at Mars longer than any other current mission and is on track to take the Mars longevity record late this year. Science discoveries by the Mars Exploration Rover have included Opportunity finding the first mineralogical evidence that Mars had liquid water and Spirit finding evidence for hot springs or steam vents and a past environment of explosive volcanism.

A Daring Spacewalk

Anchored to a Canadarm2 mobile foot restraint, astronaut Garrett Reisman continued his work during the first of three planned spacewalks for the STS-132 mission. During the seven-hour, 25-minute spacewalk, Reisman and NASA astronaut Steve Bowen installed a second antenna for high-speed Ku-band transmissions and added a spare parts platform to Dextre, a two-armed extension for the station’s robotic arm.

Monday, May 17, 2010

Atlantis Back Flip

The Expedition 23 crew snapped this imageof the underside of Atlantis' crew cabin, during a survey of the approaching space shuttle prior to docking with the International Space Station.

Friday, May 14, 2010

Good Bacteria Eat Bad Greenhouse Gas

A small rectangular window on the front of the fermenter shows bubbling liquid inside. If it is clear, then that means it is only solution. If it is foggy, then bacteria have been added. Today, the liquid looks milky grey. It fizzes and froths as the correct amounts of air and methane are added, growing and feeding the bacteria inside.

This solution is more than just bacterial soup; it could hold the answers to some of the world's most complex problems, including how to mitigate global warming and how to clean up toxic waste in the environment.

At first, that doesn't seem possible. How could a simple, one-celled organism do something that advanced technology struggles to do?

Amy Rosenzweig, a professor of biochemistry, molecular biology, cell biology and chemistry at Northwestern University, explains that this type of bacteria uses copper from the environment to metabolize methane, turning it into methanol for food.

Not only does this mean the bacteria leech heavy metals from the soil, but they also consume a potent greenhouse gas--solving two environmental issues in one molecular gulp.

"The process is very basic science," said Rosenzweig, whose work is funded by a National Science Foundation (NSF) grant from the American Reinvestment and Recovery Act (ARRA) (MCB-0842366). "But it has potential for a lot of real life applications."

Some people suggest venting methane emissions through filters of these bacteria to scrub the methane out of the atmosphere. Others suggest feeding leftover methane from natural gas reserves to the bacteria so they can convert the gas into methanol--instead of exercising the typical solution of burning it. Then, the methanol could be stored and later used for fuel. The bacteria could also be used to dispose of copper and other heavy metals where levels are unnaturally high, preventing illness in humans.

But, before these real-world applications are explored, it's important to understand the physiological processes of how the bacterial cells work.

"There are always problems with stability," explained Rama Balasubramanian, a postdoctoral fellow in Rosenzweig's lab. "Any biological molecule is going to die over time. If we understand how it works, then we can design something more stable that will last for years."

For Rosenzweig's group, this involves better understanding how these bacteria are able to acquire copper from environmental mineral resources. Previous work suggests that the bacteria secrete a molecule called methanobactin, which binds tightly to copper ions to deliver them back to the cell.

"Something outside the cell would have to recognize the molecule, grab it, and push it back inside," she said. "We're trying to discover what cellular machinery makes this happen."

The process is explored by closely watching the bacteria in action. Members of Rosenzweig's lab spend their days growing bacteria in a 15-liter fermenter that's calibrated with an optimal flow of air and methane. The bacteria are starved of copper to force them to secrete methanobactin into the extracellular solution.

The researchers place the medium into a centrifuge and spin it at 7,000 times the force of gravity until the cells fall to the bottom, allowing methanobactin in the solution to be isolated. After a couple purification steps, the molecule is ready to be studied.

"We don't know if all methane-consuming bacteria make methanobactins and secrete them to get copper," Rosenzweig said. "And if they do, is the process different in different species? You could imagine that every type of bacteria might make something slightly different to help them compete for copper."

The particular strain of bacteria that Rosenzweig studies was originally isolated in the hot baths in Bath, England, so the bacteria prefer high temperatures. But she emphasizes that methane-metabolizing bacteria, known as methanotrophs, are found everywhere.

Although Rosenzweig's grant covers three more years of research, Balasubramanian feels optimistic that a breakthrough will happen sooner.

"If our experiments continue to run correctly, then we may be just a year or two away from understanding how this molecule works," he said. "It will take much longer for the applications, but knowing how the molecule enters the cell is step number one."

Thursday, May 13, 2010

Humans Have a Lot to Learn From Bonobos, Scientists Say

Primatologist Brian Hare wishes more people could discover what bonobos can teach us about human nature. "I really think they are the smartest ape in the world," he said. "We have a lot to learn from them."

Bonobos are genetically close to humans, yet most people know very little about them. Through his ongoing research, Hare hopes to change that.

"Bonobos really are our less familiar cousins that we have kept at arm's length," Hare said. "The general public is so unfamiliar with them that even many reporters who have interviewed me have written in their stories that they are bonobo 'monkeys,' not realizing they are apes--like us. So it is great when the bonobos can have some attention."

Bonobos are often confused with chimpanzees, but actually are quite different. In looks, bonobos are smaller, with black faces, pink lips and long black hair, neatly parted in the middle. Chimps have low, loud voices, while bonobos' voices are high-pitched.

More significantly, chimps make war, males take charge, and chimps can be quite violent, even to the extent of killing one another. Bonobos, on the other hand, are governed by females, they use sexual activity to maintain a peaceful collective temperament, and scientists have not observed any instances of bonobos killing one another.

Hare, assistant professor of evolutionary anthropology at Duke University, spends several months of the year in the Democratic Republic of Congo, where he studies bonobos. He focuses on their behavior, specifically on how they solve problems and interact with other bonobos.

Recently, he and his colleagues found that bonobos are natural sharers. The researchers' work, published in a recent Current Biology and funded by the National Science Foundation (NSF) and the European Research Council, described how bonobos enjoy sharing food with other bonobos, and never outgrow their willingness to do so--unlike chimpanzees, who become more selfish when they reach adulthood.

In one experiment, the animals in an enclosure were allowed to keep an entire food pile for themselves or open a one-way door that would allow another bonobo to enter the room to eat with them. Invariably, they opened the door.

"What we found is that the bonobos voluntarily chose to open the door for their neighbor so they could share the food," Hare said.

Another set of experiments, at the Tchimpounga Sanctuary in Congo, compared chimpanzees to bonobos. The young chimps were quite similar to young bonobos in their willingness to share food, but researchers discovered that the chimps became less willing to share as they grew older. Bonobos, on the other hand, continued to share like juveniles, even after reaching adulthood, the scientists said.

"It seems like some of these adult differences might actually derive from developmental differences," said Victoria Wobber, a Harvard graduate student who collaborates with Hare. "Evolution has been acting on the development of their cognition."

Hare and his mentor, Richard Wrangham at Harvard, believe bonobos act this way because they always have enjoyed an abundant environment. They typically live south of the Congo River, where there is plenty of food, and where they don't have to compete with gorillas--as chimpanzees must--or with each other.

However, bonobos have human enemies, specifically hunters engaged in the illegal international trade in bush meat. Conservationists are working to rescue bonobos who have been orphaned by these activities, sheltering them in sanctuaries, where they are protected for as long as they live.

"Unfortunately, bonobos are not immune to the bullets of hunters and often fall prey," Hare said. "Their meat is sold in big cities in Congo, but bush meat traders try to sell infants that survive their mothers' deaths as pets. Here in Congo, it is illegal to buy and sell bonobos, so when an infant is discovered in the market, or in the possession of a wildlife trafficker, they are confiscated."

The animals live in a sanctuary called Lola ya Bonobo, located in Les Petites Chutes de la Lukaya, just outside of Kinshasa. "Lola ya Bonobo" means "paradise for bonobos" in Lingala, the main language of Kinshasa.

Lola ya Bonobo cares for more than 60 bonobo orphans. The facility is run by a staff of conservation and welfare experts who "do an amazing job quickly rehabilitating the infant bonobos, so that they quickly recover from the trauma of their capture, and live a very normal and happy life with other bonobos here at the sanctuary," Hare said, adding: "They have a huge 75 acre forest they play in each day."

Many of these rescued bonobos serve as Hare's research subjects. At the sanctuary, Hare and his fellow researchers use experimental techniques to test the bonobos and observe their behavior. "Essentially, we design fun games that the bonobos can play and enjoy, but at the same time, (the games) can reveal how they solve problems," he said. "The study published in Current Biology is a great example of how experiments are important to understand the psychology of animals."

After the games, "we let the bonobos back out into their giant outdoor enclosures so they can play with all the other bonobos in the primary tropical forest they live in during the day," Hare added. "Basically, they stay inside for an hour or so, and get a lot of yummy food, and they go back outside."

Born and raised in Atlanta, Hare, 34, was always interested in animals and biology, so a career studying animal behavior, "comes kind of naturally," he said. He went to Emory University, where, among other things, he studied chimpanzees.

"However, I'd always wanted to study bonobos and compare them to chimpanzees," he said. "I did my Ph.D. work at Harvard with Richard Wrangham, who encouraged me to start working in African sanctuaries, like Lola ya Bonobo. This is exciting because our research dollars go to organizations in ape habitat countries working on welfare and conservation efforts."

Hare's wife, Vanessa Woods, is a research scientist in biological anthropology and anatomy at Duke. She is expecting their first child in August, and has written a book about the bonobos, Congo and their research on bonobos, entitled Bonobo Handshake, scheduled to be released in June by Gotham/Penguin. "I do think it could be a great reference if people want to learn more about bonobos," Hare said. "She detailed a lot of the story about our research--maybe too much detail in some places--a good place to look for embarrassing stories."

Lola ya Bonobo is the largest bonobo captive facility in the world that supports research, Hare said, which enables scientists "to do a number of comparisons between chimpanzees and bonobos that would otherwise be impossible."

Hare is especially pleased that one of his research colleagues, Suzy Kwetuenda, based at Lola ya Bonobo, is the first Congolese student ever to study the psychology of bonobos.

"Hopefully, she will be the first of many students studying bonobos' behavior and psychology," added Hare, "and that will get average Congolese citizens excited about saving the bonobo, which is only found in their country."

Wednesday, May 12, 2010

Chandra X-ray Discovery Points to Location of Missing Matter

Using observations with NASA's Chandra X-ray Observatory and ESA's XMM-Newton, astronomers have announced a robust detection of a vast reservoir of intergalactic gas about 400 million light years from Earth. This discovery is the strongest evidence yet that the "missing matter" in the nearby Universe is located in an enormous web of hot, diffuse gas.

This missing matter -- which is different from dark matter -- is composed of baryons, the particles, such as protons and electrons, that are found on the Earth, in stars, gas, galaxies, and so on. A variety of measurements of distant gas clouds and galaxies have provided a good estimate of the amount of this "normal matter" present when the universe was only a few billion years old. However, an inventory of the much older, nearby universe has turned up only about half as much normal matter, an embarrassingly large shortfall.

The mystery then is where does this missing matter reside in the nearby universe? This latest work supports predictions that it is mostly found in a web of hot, diffuse gas known as the Warm-Hot Intergalactic Medium (WHIM). Scientists think the WHIM is material left over after the formation of galaxies, which was later enriched by elements blown out of galaxies.

"Evidence for the WHIM is really difficult to find because this stuff is so diffuse and easy to see right through," said Taotao Fang of the University of California at Irvine and lead author of the latest study. "This differs from many areas of astronomy where we struggle to see through obscuring material."

To look for the WHIM, the researchers examined X-ray observations of a rapidly growing supermassive black hole known as an active galactic nucleus, or AGN. This AGN, which is about two billion light years away, generates immense amounts of X-ray light as it pulls matter inwards.

Lying along the line of sight to this AGN, at a distance of about 400 million light years, is the so-called Sculptor Wall. This "wall", which is a large diffuse structure stretching across tens of millions of light years, contains thousands of galaxies and potentially a significant reservoir of the WHIM if the theoretical simulations are correct. The WHIM in the wall should absorb some of the X-rays from the AGN as they make their journey across intergalactic space to Earth.

Using new data from Chandra and previous observations with both Chandra and XMM-Newton, absorption of X-rays by oxygen atoms in the WHIM has clearly been detected by Fang and his colleagues. The characteristics of the absorption are consistent with the distance of the Sculptor Wall as well as the predicted temperature and density of the WHIM.

This result gives scientists confidence that the WHIM will also be found in other large-scale structures.

Several previous claimed detections of the hot component of the WHIM have been controversial because the detections had been made with only one X-ray telescope and the statistical significance of many of the results had been questioned.

"Having good detections of the WHIM with two different telescopes is really a big deal," said co-author David Buote, also from the University of California at Irvine. "This gives us a lot of confidence that we have truly found this missing matter."

In addition to having corroborating data from both Chandra and XMM- Newton, the new study also removes another uncertainty from previous claims. Because the distance of the Sculptor Wall is already known, the statistical significance of the absorption detection is greatly enhanced over previous "blind" searches. These earlier searches attempted to find the WHIM by observing bright AGN at random directions on the sky, in the hope that their line of sight intersects a previously undiscovered large-scale structure.

Confirmed detections of the WHIM have been made difficult because of its extremely low density. Using observations and simulations, scientists calculate the WHIM has a density equivalent to only 6 protons per cubic meter. For comparison, the interstellar medium -- the very diffuse gas in between stars in our galaxy -- typically has about a million hydrogen atoms per cubic meter.

"Evidence for the WHIM has even been much harder to find than evidence for dark matter, which is invisible and can only be detected indirectly," said Fang.

There have been important detections of possible WHIM in the nearby Universe with relatively low temperatures of about 100,000 degrees using ultraviolet observations and relatively high temperature WHIM of about 10 million degrees using observations of X-ray emission in galaxy clusters. However, these are expected to account for only a relatively small fraction of the WHIM. The X-ray absorption studies reported here probe temperatures of about a million degrees where most of the WHIM is predicted to be found.

Monday, May 10, 2010

NASA Extreme Environment Mission Operations (NEEMO) 14 Mission

On May 10, two astronauts, a veteran undersea engineer and an experienced scientist will embark on the 14th NASA Extreme Environment Mission Operations (NEEMO) undersea analog mission.

The crew will conduct a series of extravehicular activities (EVAs), simulating activities that astronauts would be likely to perform during missions in space.

Using near-scale mockup vehicles, EVA teams will conduct off-loading, retrieval and survival missions, including the transfer of an incapacitated astronaut from the ocean floor to the deck of the lander.

While inside the Aquarius laboratory, the crew will perform life sciences experiments focused on human behavior, performance and physiology.

The mission also includes a study of autonomous crew work. This will include periods of time when there is limited communication between the crew and the mission control center, much like what could happen during missions to the moon or Mars.

Sunday, May 09, 2010

Ash and Steam Continues to flutter from Icelandic Volcano

Ash and steam continued billowing from Eyjafjallajökull Volcano in early May 2010. The Advanced Land Imager (ALI) on NASA’s Earth Observing-1 (EO-1) satellite captured this natural-color image on May 2, 2010.

The volcano’s summit is near the left edge of this image, capped by a dark plume. The plume is dull gray-brown, indicating that its principal visible component is volcanic ash. Ash from the plume blows toward the east-southeast, passing over a charcoal-colored ash field on the land surface. Just to the north of Eyjafjallajökull’s summit are white puffs of steam, likely from surface lava flows vaporizing snow and glacial ice.

On May 4, 2010, the Icelandic Meteorological Office warned that Eyjafjallajökull showed no signs of ending its eruptive activity in the near future. The Met Office reported that ash from the volcano had reached a height of 5.8 to 6.0 kilometers (19,000 to 20,000 feet) above sea level, and had spread 65 to 80 kilometers (40 to 50 miles) east-southeast of the volcano, where it impeded visibility for local residents. The Met Office also reported that lava continued flowing down a steep hill north of the crater.

Thursday, May 06, 2010

Pad Abort 1 Test launched Successfully

Justify FullNASA's Pad Abort 1 flight test, a launch of the abort system designed for the Orion crew vehicle, lifted off at 9 a.m. EDT Thursday at the U.S. Army's White Sands Missile Range (WSMR) near Las Cruces, N.M. The flight lasted about 135 seconds from launch until the crew module touchdown about a mile north of the launch pad.

The flight was the first fully-integrated test of this launch abort system design. The information gathered from the test will help refine design and analysis for future launch abort systems, resulting in safer and more reliable crew escape capability during rocket launch emergencies.

The test involved three motors. An abort motor produced a momentary half-million pounds of thrust to propel the crew module away from the pad. It burned for approximately six seconds, with the highest impulse in the first 2.5 seconds. The crew module reached a speed of approximately 445 mph in the first three seconds, with a maximum velocity of 539 mph, in its upward trajectory to about 1.2 miles high.

The attitude control motor fired simultaneously with the abort motor and steered the vehicle using eight thrusters producing up to 7,000 pounds of thrust. It provided adjustable thrust to keep the crew module on a controlled flight path and reorient the vehicle as the abort system burned out.

The jettison motor, the only motor of the three that would be used in all nominal rocket launches, pulled the entire launch abort system away from the crew module and cleared the way for parachute deployment and landing. After explosive bolts fired and the jettison motor separated the system from the crew module, the recovery parachute system deployed. The parachutes guided the crew module to touchdown at 16.2 mph (24 feet per second), about one mile from the launch pad.

The Orion Project has begun the process of recovering all of the test articles from the WSMR and will be evaluating all of the data over the coming weeks.

Wednesday, May 05, 2010

Permafrost - Climate's Ticking Time Bomb

Jacobson, a professor of earth and planetary sciences at Northwestern University, extracts soil and water samples in search of clues to one of global warming's biggest ticking time bombs: the melting of permafrost.

Permafrost, or frozen ground, covers approximately 20 to 25 percent of the land-surface area in the northern hemisphere, and is estimated to contain up to 1,600 gigatons of carbon, primarily in the form of organic matter. (One gigaton is equivalent to 1 billion tons.)

By comparison, the atmosphere now contains around 850 gigatons of the element as carbon dioxide.

"Permafrost historically has served as a carbon sink, largely isolating carbon from participating in the carbon cycle," says Jacobson, whose research is funded by the National Science Foundation (NSF) and the David and Lucile Packard Foundation. "However, global warming could transform the Arctic into a new carbon source by accelerating the rate of permafrost melting. This undoubtedly would have a dramatic effect on the global carbon cycle."

Jacobson says the key concern is that permafrost carbon will oxidize to carbon dioxide as melting accelerates, causing a positive feedback to global warming. A vicious cycle is created as a warmer climate facilitates more carbon release, which in turn favors more warming.

So Jacobson and his colleagues collect river water and soil samples near NSF's Toolik Long-Term Ecological Research station, approximately 250 kilometers (km)--155 miles--north of the Arctic Circle. The Dalton Highway--built as a supply road to support the Trans-Alaska Pipeline System--provides the only access to the site.

"Planning constitutes a large part of our day--looking at maps, figuring out where to go and how to get there," he laughs. "Fieldwork is typically fraught with vehicle problems, poor roads and bad weather. One thing you can always count on is that every expedition is exciting."

While a logical first step for modeling global warming is quantifying carbon flow, unresolved complexities surrounding the Arctic carbon cycle make it difficult to create models for that element.

Jacobson and his team take a complementary approach by analyzing naturally occurring isotopes of other elements, such as calcium and strontium, which track permafrost melting and therefore provide insight into carbon release.

Initial data show that rivers and permafrost have distinctly different calcium and strontium isotope compositions.

When permafrost thaws during the summer and melts into rivers, the rivers show calcium and strontium isotope compositions that approach those for permafrost. Jacobson hypothesizes that in a warmer world, the permafrost signature in rivers will be more pronounced for longer periods of time.

Changes in the isotope composition of rivers can relate to changes in the release of carbon. So the calcium and strontium isotope composition of Arctic rivers can track the impact of warming on permafrost stability and carbon dioxide release.

"The ultimate goal is to establish a baseline to which future changes can be compared," Jacobson says. "Several years from now, we can compare real changes to model predictions and improve our understanding of how the system works."

The sampling season lasts for only a short time when permafrost thaws in the spring until it refreezes in the fall. Although he visited Alaska in May and will return in October, Jacobson has a team of colleagues and students who will conduct fieldwork throughout the season and again next year. Samples are shipped from the field to Jacobson's laboratory in Evanston, Ill., where he analyzes them in the off-season.

He received NSF funding in 2007 to acquire a multi-collector thermal ionization mass spectrometer for measuring isotopes of calcium, strontium and other elements. Northwestern currently is building a state-of-the-art "metal free" clean laboratory that will house the instrument and support Jacobson's research.

Tuesday, May 04, 2010

Pad Abort 1 (PA-1) is ready for launch on May 6

With hundreds of tests and verifications officially complete, members of the Flight Test Readiness Review board unanimously agreed that Pad Abort 1 (PA-1) is ready for launch May 6 at White Sands Missile Range, N.M.

Often in a readiness review prior to any launch, there are open items that need to be closed before a mission gets the “go-ahead.” If there is an issue with hardware or software, the launch date could be delayed until it is fixed. However, on April 22, the PA-1 team concluded that all flight and support hardware and software are flight ready, launch facilities and range assets are in place and that the flight test team is prepared to execute PA-1 efficiently, effectively, and safely.

PA-1 is the first fully integrated flight test of the launch abort system being developed for the Orion crew exploration vehicle. The test is part of an ongoing mission to develop safer vehicles for human spaceflight applications.

The only question mark for the launch is the weather with the major constraint being wind. The flight test team will monitor the weather closely on test day, leading up to the targeted 9 a.m. EDT launch.

› Orion Pad Abort 1 Countdown and Flight Profile

Check out the pre-game show for the Pad Abort-1 Flight Test. NASA EDGE Live@Pad Abort-1 Flight test will webcast between 8-9 a.m. EDT from the White Sands Missile Range.

Monday, May 03, 2010

Preparations for Next Shuttle Mission

Less than two weeks remain until space shuttle Atlantis' liftoff on its STS-132 mission, targeted for May 14 at 2:20 p.m. EDT. At NASA's Kennedy Space Center in Florida, technicians will attach the orbital midbody unit to Atlantis. Additionally, the spacewalk suits to be worn by Atlantis' astronauts during the mission will be checked out before they're stowed for flight.

The six STS-132 astronauts are at their home base, NASA's Johnson Space Center in Houston. They'll go through medical exams and a final prelaunch crew news conference with reporters today.

NASA managers will hold a news conference Wednesday, May 5, at Kennedy after the Flight Readiness Review meeting to discuss space shuttle Atlantis' upcoming mission.

NASA is planning to make some changes to the target launch dates for the last two scheduled space shuttle flights. Scientists with the Alpha Magnetic Spectrometer, or AMS, program recently decided to change out the current magnet in the particle physics experiment module that will be attached to the International Space Station to a longer lasting one. This will take advantage of NASA's plan to extend station operations until at least 2020.

Because of the magnet change, space shuttle Endeavour's STS-134 mission, which will carry the AMS experiment to the station and was targeted to launch July 29, now is expected to launch no earlier than mid-November 2010. An exact target launch date hasn't yet been determined.

The AMS is designed to help study the formation of the universe and search for evidence of dark matter and antimatter by measuring cosmic rays.

Space shuttle Discovery's STS-133 mission currently remains targeted for its Sept. 16 launch date, but managers will continue to assess its readiness for flight and make changes as appropriate.

NASA Keeping Eye on the Gulf Oil Spill

NASA's Terra and Aqua satellites are helping the National Oceanic and Atmospheric Administration (NOAA) keep tabs on the extent of the recent Gulf oil spill with satellite images from time to time. NOAA is the lead agency on oil spills and uses airplane fly-overs to assess oil spill extent.

A semisubmersible drilling platform called the Deepwater Horizon located about 50 miles southeast of the Mississippi Delta experienced a fire and explosion at approximately 11 p.m. CDT on April 20. Subsequently, oil began spilling out into the Gulf of Mexico and efforts to contain the spill continue today. NASA's Terra and Aqua satellite imagery has captured the spill in between cloudy days.

NOAA used data from the Moderate Imaging Spectroradiometer or MODIS instrument from the Terra satellite on April 26, 27 and 29 to capture the extent of the oil spill, which measured 600-square-miles. The MODIS instrument flies aboard both the Terra and Aqua satellites.

In the satellite image from April 27 at 12:05 p.m. CDT the MODIS image showed that the oil slick was continuing to emanate from the spill location. Individual slicks lay just north of 29 degrees and zero minutes north, where they have been noted in the days before. Oil had spread further east and the edge of the slick passed 87 degrees and 30 minutes west compared to the MODIS image taken on April 26. The April 26 satellite image came from NASA's Aqua satellite.

On April 29, the MODIS image on the Terra satellite captured a natural-color image of the oil slick just off the Louisiana coast. The oil slick appeared as dull gray interlocking comma shapes, one opaque and the other nearly transparent. The northwestern tip of the oil slick almost touches the Mississippi Delta.

Deepwater Horizon had more than120 crew aboard and contained an estimated to 17,000 barrels of oil (700,000 gallons) of number two fuel oil or marine diesel fuel.

Today, April 30, NOAA declared the Deepwater Horizon incident "a Spill of National Significance (SONS)." A SONS is defined as, "a spill that, due to its severity, size, location, actual or potential impact on the public health and welfare or the environment, or the necessary response effort, is so complex that it requires extraordinary coordination of federal, state, local, and responsible party resources to contain and clean up the discharge" and allows greater federal involvement. NOAA's estimated release rate of oil spilling into the Gulf is estimated at 5,000 barrels (210,000 gallons) per day based on surface observations and reports of a newly discovered leak in the damaged piping on the sea floor.

NOAA reported on April 29 that dispersants are still being aggressively applied to the oil spill and over 100,000 gallons have been applied. NOAA's test burn late yesterday was successful and approximately 100 barrels of oil were burned in about 45 minutes. NOAA is flying planes over the area and using NASA satellite imagery from the Terra and Aqua satellites to monitor the spill.