Posted on by Fraser Cain

Five Years of Universe Today

In case you weren’t counting, today marks the fifth anniversary of Universe Today. That’s right, I started this space web rag on March 22, 1999 as a hobby; an excuse for me to learn more about web publishing and online marketing. Little did I realize I’d still be working on it five years later. 🙂 I never dreamed I’d have more than a few hundred subscribers, but there are now 21,000 of you signed up to get the email edition.

Since I began Universe Today, I’ve moved servers seven times, had two children, lost two hard drives, published 805 newsletters, worked at three different jobs, and served up about 200 million “hits”. There have been a few dry spells, too, when I didn’t have the time or enthusiasm to work on the website – the last year’s been a blast though. If you want to take a look back at the history of the website, here’s a handy link through the Wayback Machine. I know, I know, it started out pretty ugly.

So, I just wanted to take a moment and thank everyone for your enthusiastic support, engaging conversation in the forum, and gentle feedback at my tpyos. I’d also like to thank my sponsors (especially Countdown Creations, who’s been a big contributor right from the beginning).

Here’s to many, many more years.

Fraser Cain
Publisher
Universe Today

Posted on by Fraser Cain

A New Look at McNeil’s Nebula

Image credit: Gemini
A timely discovery by American amateur astronomer Jay McNeil, followed immediately by observations at the Gemini Observatory, has provided a rare glimpse into the slow, yet violent birth of a star about 1,500 light-years away. The resulting findings reveal some of the strongest stellar winds ever detected around an embryonic Sun-like star.

McNeil?s find was completely serendipitous. He was surveying the sky in January from his backyard in rural Kentucky and taking electronic images through his 3-inch (8-centimeter) telescope. When he examined his work, he noticed a small glowing smudge of light in the constellation of Orion that wasn?t there before. ?I knew this part of the sky very well and I couldn?t believe what I was seeing,? said McNeil. Astronomers were alerted almost immediately, via the Internet, and quickly realized that he had come across something special.

?It is extremely rare that we have an opportunity to study an important event like this, where a newly born star erupts and sheds light on its otherwise dark stellar nursery,? said Gemini astronomer Dr. Colin Aspin. Dr. Aspin and Dr. Bo Reipurth, (of the University of Hawaii?s Institute for Astronomy), published the first paper on this object, now known as McNeil?s Nebula. Their work, based on observations using the Frederick C. Gillett Gemini North Telescope on Mauna Kea, is in press for Astrophysical Journal Letters.

?McNeil?s Nebula is allowing us to add another important piece to the puzzle of the long, protracted birth of a star,? said Reipurth. ?It has been more than thirty years since anything similar has been seen, so for the first time, we have an opportunity to study such an event with modern instrumentation like that available at Gemini.?

Detailed images and spectra of the stellar newborn, taken using the Gemini Near-Infrared Imager and Multi-Object Spectrograph, demonstrate that the star has brightened considerably. It is blasting gas away from itself at speeds of more than 600 kilometers per second (over 2000 times faster than a typical commercial airplane). The observations indicate the eruption was triggered by complex interactions in a rotating disk of gas and dust around the star. For reasons that are still not fully understood, the inner part of the disk begins to heat up, causing the gases to glow. At the same time, some gas funnels along magnetic field lines onto the surface of the star, creating very bright hot spots and causing the star to grow. The eruption also cleared out some of the dust and gas surrounding the young star, allowing light to escape and illuminate a cone-shaped cavity carved out by previous eruptions into the gas.

The birth of a star takes several tens of thousands of years and these observations are but a brief snapshot of the process. Although this is very a rapid schedule on astronomical time scales, Reipurth explained that it?s impossibly slow compared to a human lifetime. ?We astronomers therefore have no choice but to compare various objects where each one is in a different state of development,? he said. ?This is very similar to the imaginary situation of an alien landing on Earth with only half an hour to understand the full life cycle of humans. By looking at people of various ages and using some logic, this alien could piece together our growth from infant to old age. This is how we are beginning to understand the birth and youth of stars. Rare events like the one McNeil discovered help to fill in the blanks in our understanding of stellar origins.?

This outburst may not be the first time the star has flared during its long tumultuous birth. Following McNeil?s discovery, an inspection of archival plates revealed that a similar event took place in 1966, when the star flared and faded again into its enshrouding gas. ?We know so little about these kind of eruptions that we cannot even say whether the star will continue to flare or will rapidly fade from view again,? said Aspin. ?We were extremely fortunate that Mr. McNeil discovered this when he did. In an event like this, the earlier we can observe it, the better our chances are of understanding what is going on.?

Fortunately for Aspin and Reipurth, McNeil discovered this in the early winter while the Orion region is still high in the night-time sky. It was also fortunate that McNeil was so familiar with this part of the sky that he noticed right away that something had changed. This combination of circumstances enabled the astronomers to prepare an observation run on Gemini very quickly. ?Our window for observing this object is closing rapidly but it will become visible again later this year,? said Aspin. ?By then this eruption could be over.?

A striking color image from Gemini reveals fine details in McNeil?s Nebula. The star and its bright disk shine like a lighthouse through the cavity of gas and dust. The Gemini image and an artist?s conception of how the escaping gas and hotspots on a young star might have caused this event can be found here.

The Gemini Observatory is an international collaboration that has built two identical 8-meter telescopes. The Frederick C. Gillett Gemini Telescope is located on Mauna Kea, Hawai`i (Gemini North) and the Gemini South telescope is located on Cerro Pach?n in central Chile (Gemini South), and hence provide full coverage of both hemispheres of the sky. Both telescopes incorporate new technologies that allow large, relatively thin mirrors under active control to collect and focus both optical and infrared radiation from space.

The Gemini Observatory provides the astronomical communities in each partner country with state-of-the-art astronomical facilities that allocate observing time in proportion to each country’s contribution. In addition to financial support, each country also contributes significant scientific and technical resources. The national research agencies that form the Gemini partnership include: the US National Science Foundation (NSF), the UK Particle Physics and Astronomy Research Council (PPARC), the Canadian National Research Council (NRC), the Chilean Comisi?n Nacional de Investigaci?n Cientifica y Tecnol?gica (CONICYT), the Australian Research Council (ARC), the Argentinean Consejo Nacional de Investigaciones Cient?ficas y T?cnicas (CONICET) and the Brazilian Conselho Nacional de Desenvolvimento Cient?fico e Tecnol?gico (CNPq). The Observatory is managed by the Association of Universities for Research in Astronomy, Inc. (AURA) under a cooperative agreement with the NSF. The NSF also serves as the executive agency for the international partnership.

The Institute for Astronomy at the University of Hawaii conducts research into galaxies, cosmology, stars, planets, and the sun. Its faculty and staff are also involved in astronomy education, deep space missions, and in the development and management of the observatories on Haleakala and Mauna Kea. Refer to http://www.ifa.hawaii.edu/ for more information about the Institute.

Original Source: Gemini Observatory News Release

Posted on by Fraser Cain

Saturn With Cassini’s Blue Filter

Image credit: NASA/JPL
Bands and spots in Saturn’s atmosphere, including a dark band south of the equator with a scalloped border, are visible in this image from the Cassini-Huygens spacecraft.

The narrow-angle camera took the image in blue light on Feb. 29, 2004. The distance to Saturn was 59.9 million kilometers (37.2 million miles). The image scale is 359 kilometers (223 miles) per pixel.

Three of Saturn’s moons are seen in the image: Enceladus (499 kilometers, or 310 miles across) at left; Mimas (398 kilometers, or 247 miles across) left of Saturn’s south pole; and Rhea (1,528 kilometers, or 949 miles across) at lower right. The imaging team enhanced the brightness of the moons to aid visibility.

The BL1 broadband spectral filter (centered at 451 nanometers) allows Cassini to “see” light in a part of the spectrum visible as the color blue to human eyes. Scientist can combine images made with this filter with those taken with red and green filters to create full-color composites.

In this image, everything on the planet is a cloud, and the contrast between bright and dark features is determined by the different blue-light absorbing properties of the particles that comprise the clouds. White regions contain material reflecting in the blue; dark regions contain material absorbing in the blue. This reflecting/absorbing behavior is controlled by the composition of the cloud’s colored material, which is still a mystery — one which may be answered by Cassini. The differing concentrations of this material across the planet are responsible for its banded appearance in the visible region of the electromagnetic spectrum.

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 Cassini-Huygens mission for NASA’s Office of Space Science, Washington, D.C. The imaging team is based at the Space Science Institute, Boulder, Colo.

For more information about the Cassini-Huygens mission visit, http://saturn.jpl.nasa.gov and the Cassini imaging team home page, http://ciclops.org .

Original Source: CICLOPS News Release

Posted on by Fraser Cain

Does Io Look Like an Early Earth?

Image credit: NASA/JPL
Investigations into lava lakes on the surface of Io, the intensely volcanic moon that orbits Jupiter, may provide clues to what Earth looked like in its earliest phases, according to researchers at the University at Buffalo and NASA’s Jet Propulsion Laboratory.

“When I look at the data, it becomes startlingly suggestive to me that this may be a window onto the primitive history of Earth,” said Tracy K. P. Gregg, Ph.D., assistant professor of geology in the UB College of Arts and Sciences.

“When we look at Io, we may be seeing what Earth looked like when it was in its earliest stages, akin to what a newborn baby looks like in the first few seconds following birth,” she added.

Gregg and Rosaly M. Lopes, Ph.D., research scientist at JPL, gave a presentation about Io’s volcano, Loki, on Tuesday (March 16, 2004) at the Lunar and Planetary Science Conference in Houston.

Scientists have been interested in Loki, considered the most powerful volcano in the solar system, because of debate over whether or not it is an active lava lake, where molten lava is in constant contact with a large reservoir of magma stored in the planet’s crust.

Using models developed to investigate temperature changes on active lava lakes on Earth, Gregg and Lopes have concluded that Loki behaves quite differently from terrestrial lava lakes.

Gregg suggests that Loki and other lava lakes on Io might be more similar volcanologically to fast-spreading mid-ocean ridges on Earth, like the Southern East Pacific Rise.

According to Gregg, plate tectonics on Earth make these features long — as in thousands of kilometers — and narrow — as in less than 10 kilometers wide. Io, on the other hand, has no plate tectonics and a similar release of heat and magma would be circular, like Loki.

“These lava lakes could be an Ionian version of mid-ocean ridges,” functioning the way these ridges do on Earth, spilling huge amounts of lava on its surface, thus generating new crust, she said.

During the most intense periods of its eruption cycle, Gregg said, Loki churns out about 1,000 square meters of lava — about the size of a soccer field — per second.

“All planets start out hot and spend their ‘lifetimes’ trying to get cold,” explained Gregg.

This effort by planets to “chill,” she explained, is an attempt to attain a similar temperature to that of outer space, which is 4 Kelvin, or minus 269 degrees Celsius.

On Earth, she explained, the shifting of the planet’s tectonic plates, which focus the eruption of volcanoes at their boundaries, function to cool down the planet’s surface.

Io never developed plate tectonics because it is stuck in an incessant orbit between Jupiter and Europa, another of the Jovian planet’s moons.

“Io just never grew up,” she said, “since it’s continually being pushed around by Jupiter and Europa.”

But, she added, Earth only developed plate tectonics after it had been in existence for perhaps 200 to 500 million years.

Gregg and Lopes analyzed data obtained by the Galileo spacecraft, which orbited Jupiter for 14 years, finally disintegrating in Jupiter’s atmosphere last fall.

The University at Buffalo is a premier research-intensive public university, the largest and most comprehensive campus in the State University of New York.

Original Source: University at Buffalo News Release

Posted on by Fraser Cain

Five Visible Planets Starting Tonight

Image credit: NASA/JPL
Like a busy urban family, planets rarely get together all at once. Later this month, however, the five so-called naked-eye planets – Mercury, Venus, Mars, Jupiter and Saturn – will reunite in the night sky, giving spectators a unique chance to see Earth’s closest companions in one easy sitting.

The gathering will be visible every night for an hour after sunset, beginning around March 22 and lasting about two weeks. While other opportunities to catch a five-planet rendezvous will take place in the next few years, both at dawn and dusk, this one is not to be missed.

“This particular planetary grouping will quite possibly offer the best nighttime views until 2036,” says Dr. Myles Standish, an astronomer at NASA’s Jet Propulsion Laboratory, Pasadena, Calif.

For early risers, there will be another chance to see all five naked-eye planets together just before sunrise in December of this year and early January 2005.

Since ancient times, the naked-eye planets have intrigued and inspired onlookers all over the world. But only sporadically, usually every few years or so, do their orbits take them to the same side of the Sun. When this happens, the planets stretch across the morning or evening skies depending on which side of the Sun they reside. More rare are planetary alignments in which the five planets assemble in a very small corner of the sky.

“Every so often the five visible planets will collect on one side of the Sun,” says Standish. “Only when conditions are right, will they all be clearly visible at either dusk or dawn.”

The Details
To catch the planetary get-together, you’ll need a good view of the sky, free of buildings and bright city lights (you should still be able to see the planets through urban light pollution). The show begins around March 22 and lasts through early April, when Mercury fades from sight. The finest views will take place during the last 8 to 10 days of March.

Begin by looking to the western horizon each evening just after sunset. Seated in a row up and across the sky will be Mercury, Venus, Mars and Saturn. Saturn will lie almost directly overhead. Following the line of the planets, Jupiter will be close to the eastern horizon. Together, the planets will span about 135 degrees. About an hour after dusk, Mercury will dip below the western horizon.

The Moon will also be attending the festivities, mingling through the planets in an orderly fashion. On March 22, it will take a seat next to Mercury, and then climbing up the night sky, it will end its tour on April 1 right above mighty Jupiter, the largest planet in our solar system. As the Moon slides from planet to planet, it will grow in size from a slender crescent to a nearly full circle of white.

Note that Venus is currently brighter than usual because of where it lies in relation to Earth and the Sun.

The Moon and planets will appear to follow nearly the same path through the stars. This is because their orbits around the Sun occupy planes that are close to that of Earth’s orbit. The plane Earth moves in is called the ecliptic.

If for some reason you miss the “Fab Five,” another set of orbiting bodies will soon make a grand debut. In April and May of this year, two naked-eye comets, C/2001 Q4 and C/2002 T7, will grace the twilight skies. To spot the cosmic balls of dust and ice look to the west at dusk or dawn. A pair of binoculars will help to initially locate the comets because they may be slightly washed out by the Sun. On May 12 to 16 look out for a mini-reunion with the naked-eye planets, when comet C/2001 Q4 lines up with Venus, Mars, Saturn and Jupiter.

Original Source: NASA/JPL News Release

Posted on by Fraser Cain

50th GPS Satellite Launched

Image credit: Boeing
The 50th satellite launched for the U.S. Air Force Global Positioning System (GPS), GPS IIR-11, was delivered to space today by a Boeing [NYSE: BA] Delta II rocket.

The three-stage configuration Delta II launch vehicle lifted off from Space Launch Complex 17B at Cape Canaveral Air Force Station, Fla., at 12:53 p.m. EST.

GPS IIR-11 was successfully deployed to a transfer orbit following a 68-minute flight, where it will join the 24-satellite system.

?Today?s launch is a significant milestone for the Boeing Delta team,? said Will Trafton, vice president and general manager, Boeing Expendable Launch Systems. ?Our team?s commitment to mission assurance has played a critical role in the success of the GPS program and the services it provides to the U.S. military as well as civilian users around the world.?

Boeing Delta II rockets have launched all of the Block II GPS satellites making up the current operating constellation.

The successful deployment to space of GPS satellites aboard Delta II rockets has enabled the U.S. military to utilize GPS to assist aircraft, ships, land vehicles and ground personnel using handheld devices.

GPS also provides directional guidance for the freefall flight of the Boeing-built Joint Direct Attack Munition (JDAM) smart weapon system, which has successfully been used in the war on terrorism.

GPS provides military and civilian users three-dimensional position location data in longitude, latitude and elevation as well as precise time and velocity.

The Air Force Space Command administers the GPS program, which is operated by the 50th Space Wing at Schriever Air Force Base, Colo.

The next mission for the Delta team is the launch of Gravity Probe B for NASA aboard a Delta II, scheduled for launch in April from Vandenberg Air Force Base, Calif.

A unit of The Boeing Company, Integrated Defense Systems is one of the world?s largest space and defense businesses. Headquartered in St. Louis, Boeing Integrated Defense Systems is a $27 billion business. It provides systems solutions to its global military, government and commercial customers. It is a leading provider of intelligence, surveillance and reconnaissance; the world?s largest military aircraft manufacturer; the world?s largest satellite manufacturer and a leading provider of space-based communications; the primary systems integrator for U.S. missile defense; NASA?s largest contractor; and a global leader in launch services.

Original Source: Boeing News Release

Posted on by Fraser Cain

Paul Allen Funds Next Stage of SETI Project

Image credit: SETI Institute
Investor and philanthropist Paul G. Allen has committed $13.5 million to support the construction of the first and second phases of the Allen Telescope Array (the ATA-32 and ATA-206), the world’s newest multiple use radio telescope array. The ATA will eventually consist of 350 ? 6.1-meter dishes (ATA-350), when construction is completed late in the decade. The announcement was made today by Thomas Pierson, chief executive officer for the SETI Institute, a leading astrobiology institution with the mission of exploring the origin, nature and prevalence of life in the universe. The ATA is a partnership between the SETI Institute and the Radio Astronomy Laboratory of the University of California, Berkeley (RAL).

Today’s announcement follows the successful completion of a three-year research and development phase which was originally funded by an $11.5 million gift from the Allen Foundation. The R & D proved that one of the primary advantages of the array design ? its scalability ? makes it possible for the ATA to conduct scientific investigations as soon as the first 32 dishes are installed.

Pierson also announced that the ATA-32 is scheduled to begin conducting scientific investigations by the end of 2004, significantly earlier than the 350 element array can be completed.

The ATA will be a general-purpose radio telescope that will provide fundamentally new measurements and insights into the density of the very early universe, the formation of stars, the magnetic fields in the interstellar medium, and a host of other applications of deep interest to astronomers. At the same time, this 21 st Century radio telescope will also have the capability to search for possible signals from technologically advanced civilizations elsewhere in the galaxy.

“I am very excited to be supporting one of the world’s most visionary efforts to seek basic answers to some of the fundamental question about our universe and what other civilizations may exist elsewhere,” said Paul G. Allen, primary funder of the ATA. “I am a big proponent of leveraging revolutionary technology and design and applying it to important problems in science. The developments taking place with this new instrument will not only enables us to realize a lot of bang for our research and development buck, but it will also change the landscape of how telescopes will be built in the future. An instrument of this magnitude, which will result in the expansion of our understanding of how the universe was formed, and how it has evolved, and our place therein, is the reason I am the primary supporter of its development, design and construction.”

Allen’s $13.5 million funding, structured as a challenge grant, will allow construction and operation of the first phase of 32-dishes by the end of the year. It will also support construction of the second phase of 174 additional dishes (the ATA-206), which is contingent upon fulfilling the Foundations’ challenge grant, in response to which the Institute will raise $16 million in additional support.

?It is especially thrilling to see the Allen Telescope Array approach its first significant milestone,? said SETI Institute CEO Tom Pierson. ?We are grateful for the additional support from the Allen Foundation that is making this new facility ? and further discovery ? possible. Mr. Allen and his Foundation have set the bar high. Mr. Allen’s support of this worthwhile project, when matched by other supporters of radio astronomy and SETI, will quickly bring this project to fruition.?

The ATA is the result of a multi-faceted private-public partnership between the SETI Institute and the RAL. It differs in practice, appearance, and cost from traditional radio telescopes currently in use. When completed, the ATA-350 will be among the world’s largest and fastest observing instruments.

Rather than a single enormous dish or several large dishes, the ATA will be constructed using hundreds of specially produced small dishes. The telescope will incorporate innovative technologies and modern, miniaturized electronics in concert with increasingly affordable computer processing. These new technologies, combined with the ability to conduct continuous observations, will increase SETI search speed by 300 times over previous efforts and simultaneously allow astronomers to conduct complex radio astronomy projects requiring long-term observations. And the instrument will achieve these goals at one-fifth the cost of traditional radio telescopes of comparable collecting area and complexity.

In its first phase, the ATA-32 will have more antennas than any of the world’s other centimeter-wavelength radio telescopes. The individual antennas will be linked by fiber optics. The fiber, power, and air distribution systems will be installed in ten-antenna ?nodes,? an efficient way to maintain the cool operating temperature required by the equipment.

The ATA-32 will observe in the direction of the galactic anti-center to detect primordial deuterium, study dark matter in nearby dwarf galaxies, generate maps of polyatomic molecules in molecular clouds, and conduct a SETI survey of the inner galaxy.

?I am eager to begin observing on the ATA,? commented Dr. Jill C. Tarter, ATA project leader and Director of the Center for SETI Research at the Institute. ?Conducting observations 24/7 is a dream come true for any astronomer, and it is particularly exciting for the Institute’s astronomers, who have been constrained by limited time on other large centimeter wavelength telescopes. Finally, our tools are becoming commensurate with the size of our task.?

Scientists believe that radio waves, such as those commonly produced by a variety of technologies on Earth and traveling at light-speed through interstellar space, may offer the easiest way to detect evidence of a technologically sophisticated civilization elsewhere in the galaxy. With sufficient collecting area, it is possible to detect signals from a distant technology that are no more powerful than those produced on Earth today.
Dr. Leo Blitz, professor of astronomy and director of the Radio Astronomy Laboratory at UC Berkley said, “The ATA will revolutionize radio astronomy, making it possible to provide answers to the two biggest questions in astronomy: How did we get here? Are we alone?” Blitz went on to say, “The ATA’s ability to make radio images over large swaths of sky, to make measurements over an unprecedented range of radio wavelengths, and its ability to do several kinds of observations at once, provide a power and flexibility that will allow astronomers to address whole areas of astronomy that are currently inaccessible. Because of the telescope’s unique capabilities, I expect that we’ll discover things we don’t even know are out there.”

Construction of the ATA is underway at the Hat Creek Observatory, 290 miles northeast of San Francisco on a site operated by the RAL. The Hat Creek Observatory is located in an area that is ?radio quiet,’ thereby reducing the level of interfering signals from man-made sources.

Original Source: SETI Institute News Release

Posted on by Fraser Cain

Rover Sees a UFO?

Image credit: NASA/JPL
Observing the sky with the green filter of it panoramic camera, the Mars Exploration Rover Spirit came across a surprise: a streak across the sky. The streak, seen in the middle of this mosaic of images taken by the navigation and panoramic cameras, was probably the brightest object in the sky at the time. Scientists theorize that the mystery line could be either a meteorite or one of seven out-of-commission spacecraft still orbiting Mars. Because the object appeared to move 4 degrees of an arc in 15 seconds it is probably not the Russian probes Mars 2, Mars 3, Mars 5, or Phobos 2; or the American probes Mariner 9 or Viking 1. That leaves Viking 2, which has a polar orbit that would fit with the north-south orientation of the streak. In addition, only Viking 1 and 2 were left in orbits that could produce motion as fast as that seen by Spirit. Said Mark Lemmon, a rover team member from Texas A&M University, Texas, “Is this the first image of a meteor on Mars, or an image of a spacecraft sent from another world during the dawn of our robotic space exploration program? We may never know, but we are still looking for clues.”

Original Source: NASA/JPL

Posted on by Fraser Cain

New Research Helps Explain Dust Bowl Drought

Image credit: NOAA
NASA scientists have an explanation for one of the worst climatic events in the history of the United States, the “Dust Bowl” drought, which devastated the Great Plains and all but dried up an already depressed American economy in the 1930’s.

Siegfried Schubert of NASA’s Goddard Space Flight Center, Greenbelt, Md., and colleagues used a computer model developed with modern-era satellite data to look at the climate over the past 100 years. The study found cooler than normal tropical Pacific Ocean surface temperatures combined with warmer tropical Atlantic Ocean temperatures to create conditions in the atmosphere that turned America’s breadbasket into a dust bowl from 1931 to 1939. The team’s data is in this week’s Science magazine.

These changes in sea surface temperatures created shifts in the large-scale weather patterns and low level winds that reduced the normal supply of moisture from the Gulf of Mexico and inhibited rainfall throughout the Great Plains.

“The 1930s drought was the major climatic event in the nation’s history,” Schubert said. “Just beginning to understand what occurred is really critical to understanding future droughts and the links to global climate change issues we’re experiencing today,” he said.

By discovering the causes behind U.S. droughts, especially severe episodes like the Plains’ dry spell, scientists may recognize and possibly foresee future patterns that could create similar conditions. For example, La Ni?as are marked by cooler than normal tropical Pacific Ocean surface water temperatures, which impact weather globally, and also create dry conditions over the Great Plains.

The researchers used NASA’s Seasonal-to-Interannual Prediction Project (NSIPP) atmospheric general circulation model and agency computational facilities to conduct the research. The NSIPP model was developed using NASA satellite observations, including; Clouds and the Earth’s Radiant Energy System radiation measurements; and the Global Precipitation Climatology Project precipitation data.

The model showed cooler than normal tropical Pacific Ocean temperatures and warmer than normal tropical Atlantic Ocean temperatures contributed to a weakened low-level jet stream and changed its course. The jet stream, a ribbon of fast moving air near the Earth’s surface, normally flows westward over the Gulf of Mexico and then turns northward pulling up moisture and dumping rain onto the Great Plains. As the low level jet stream weakened, it traveled farther south than normal. The Great Plains dried up and dust storms formed.

The research shed light on how tropical sea surface temperatures can have a remote response and control over weather and climate. It also confirmed droughts can become localized based on soil moisture levels, especially during summer. When rain is scarce and soil dries, there is less evaporation, which leads to even less precipitation, creating a feedback process that reinforces lack of rainfall.

The study also shed light on droughts throughout the 20th century. Analysis of other major U.S. droughts of the 1900s suggests a cool tropical Pacific was a common factor. Schubert said simulating major events like the 1930s drought provides an excellent test for computer models. While the study finds no indication of a similar Great Plains drought in the near future, it is vital to continue studies relating to climate change. NASA’s current and planned suite of satellite sensors is uniquely poised to answer related climate questions.

Original Source: NASA News Release

Posted on by Fraser Cain

Minerals in Martian Spherules Point to Water

Image credit: NASA/JPL
A major ingredient in small mineral spheres analyzed by NASA’s Mars Exploration Rover Opportunity furthers understanding of past water at Opportunity’s landing site and points to a way of determining whether the vast plains surrounding the site also have a wet history.

The spherules, fancifully called blueberries although they are only the size of BBs and more gray than blue, lie embedded in outcrop rocks and scattered over some areas of soil inside the small crater where Opportunity has been working since it landed nearly two months ago.

Individual spherules are too small to analyze with the composition-reading tools on the rover. In the past week, those tools were used to examine a group of berries that had accumulated close together in a slight depression atop a rock called “Berry Bowl.” The rover’s Moessbauer spectrometer, which identifies iron-bearing minerals, found a big difference between the batch of spherules and a “berry-free” area of the underlying rock.

“This is the fingerprint of hematite, so we conclude that the major iron-bearing mineral in the berries is hematite,” said Daniel Rodionov, a rover science team collaborator from the University of Mainz, Germany. On Earth, hematite with the crystalline grain size indicated in the spherules usually forms in a wet environment.

Scientists had previously deduced that the martian spherules are concretions that grew inside water-soaked deposits. Evidence such as interlocking spherules and random distribution within rocks weighs against alternate possibilities for their origin. Discovering hematite in the rocks strengthens this conclusion. It also adds information that the water in the rocks when the spherules were forming carried iron, said Dr. Andrew Knoll, a science team member from Harvard University, Cambridge, Mass.

“The question is whether this will be part of a still larger story,” Knoll said at a press briefing today at NASA’s Jet Propulsion Laboratory, Pasadena, Calif. Spherules below the outcrop in the crater apparently weathered out of the outcrop, but Opportunity has also observed plentiful spherules and concentrations of hematite above the outcrop, perhaps weathered out of a higher layer of once-wet deposits. The surrounding plains bear exposed hematite identified from orbit in an area the size of Oklahoma — the main reason this Meridiani Planum region of Mars was selected as Opportunity’s landing site.

“Perhaps the whole floor of Meridiani Planum has a residual layer of blueberries,” Knoll suggested. “If that’s true, one might guess that a much larger volume of outcrop once existed and was stripped away by erosion through time.”

Opportunity will spend a few more days in its small crater completing a survey of soil sites there, said Bethany Ehlmann, a science team collaborator from Washington University, St. Louis. One goal of the survey is to assess distribution of the spherules farther from the outcrop. After that, Opportunity will drive out of its crater and head for a much larger crater with a thicker outcrop about 750 meters (half a mile) away.

Halfway around Mars, NASA’s other Mars Exploration Rover, Spirit, has been exploring the rim of the crater nicknamed “Bonneville,” which it reached last week. A new color panorama shows “a spectacular view of drift materials on the floor” and other features, said Dr. John Grant, science team member from the National Air and Space Museum in Washington. Controllers used Spirit’s wheels to scuff away the crusted surface of a wind drift on the rim for comparison with drift material inside the crater.

A faint feature at the horizon of the new panorama is the wall of Gusev Crater, about 80 kilometers (50 miles) away, said JPL’s Dr. Albert Haldemann, deputy project scientist. The wall rises about 2.5 kilometers (1.6 miles) above Spirit’s current location roughly in the middle of Gusev Crater. It had not been seen in earlier Spirit images because of dust, but the air has been clearing and visibility improving, Haldemann said.

Controllers have decided not to send Spirit into Bonneville crater. “We didn’t see anything compelling enough to take the risk to go down in there,” said JPL’s Dr. Mark Adler, mission manager. Instead, after a few more days exploring the rim, Spirit will head toward hills to the east informally named “Columbia Hills,” which might have exposures of layers from below or above the region’s current surface.

The main task for both rovers is to explore the areas around their landing sites for evidence in rocks and soils about whether those areas ever had environments that were watery and possibly suitable for sustaining life. JPL, a division of the California Institute of Technology in Pasadena, manages the Mars Exploration Rover project for NASA’s Office of Space Science, Washington, D.C. Images and additional information about the project are available from JPL at http://marsrovers.jpl.nasa.gov and from Cornell University, Ithaca, N.Y., at http://athena.cornell.edu.

Original Source: NASA/JPL News Release