Cassini Detects Hint of Fresh Air at Dione

NASA’s Cassini spacecraft has “sniffed” molecular oxygen ions around Saturn’s icy moon Dione for the first time, confirming the presence of a very tenuous atmosphere. The oxygen ions are quite sparse – one for every 0.67 cubic inches of space (one for every 11 cubic centimeters of space) or about 2,550 per cubic foot (90,000 per cubic meter) – show that Dione has an extremely thin neutral atmosphere.

At the Dione surface, this atmosphere would only be as dense as Earth’s atmosphere 300 miles (480 kilometers) above the surface. The detection of this faint atmosphere, known as an exosphere, is described in a recent issue of the journal Geophysical Research Letters.

“We now know that Dione, in addition to Saturn’s rings and the moon Rhea, is a source of oxygen molecules,” said Robert Tokar, a Cassini team member based at Los Alamos National Laboratory, Los Alamos, N.M., and the lead author of the paper. “This shows that molecular oxygen is actually common in the Saturn system and reinforces that it can come from a process that doesn’t involve life.”

Dione’s oxygen appears to derive from either solar photons or energetic particles from space bombarding the moon’s water ice surface and liberating oxygen molecules, Tokar said. But scientists will be looking for other processes, including geological ones, that could also explain the oxygen.

“Scientists weren’t even sure Dione would be big enough to hang on to an exosphere, but this new research shows that Dione is even more interesting than we previously thought,” said Amanda Hendrix, Cassini deputy project scientist at NASA’s Jet Propulsion Laboratory, Pasadena, Calif., who was not directly involved in the study. “Scientists are now digging through Cassini data on Dione to look at this moon in more detail.”

Several solid solar system bodies – including Earth, Venus, Mars and Saturn’s largest moon Titan – have atmospheres. But they tend to be typically much denser than what has been found around Dione. However, Cassini scientists did detect a thin exosphere around Saturn’s moon Rhea in 2010, very similar to Dione. The density of oxygen at the surfaces of Dione and Rhea is around 5 trillion times less dense than that at Earth’s surface.

Tokar said scientists suspected molecular oxygen would exist at Dione because NASA’s Hubble Space Telescope detected ozone. But they didn’t know for sure until Cassini was able to measure ionized molecular oxygen on its second flyby of Dione on April 7, 2010 with the Cassini plasma spectrometer. On that flyby, the spacecraft flew within about 313 miles (503 kilometers) of the moon’s surface.

Cassini scientists are also analyzing data from Cassini’s ion and neutral mass spectrometer from a very close flyby on Dec. 12, 2011. The ion and neutral mass spectrometer made the detection of Rhea’s thin atmosphere, so scientists will be able to compare Cassini data from the two moons and see if there are other molecules in Dione’s exosphere.

The Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency, and the Italian Space Agency. NASA’s Jet Propulsion Laboratory, Pasadena, Calif., a division of the California Institute of Technology in Pasadena, manages the mission for NASA’s Science Mission Directorate, Washington, D.C. The Cassini orbiter was designed, developed and assembled at JPL. The Cassini plasma spectrometer team and the ion and neutral mass spectrometer team are based at Southwest Research Institute, San Antonio.

For more information about the Cassini mission, visit: http://www.nasa.gov/cassini andhttp://saturn.jpl.nasa.gov .

Image Credit: NASA/JPL/Space Science Institute

Source: JPL/NASA

Dark Matter Core Defies Explanation in NASA Hubble Image

Astronomers using data from NASA’s Hubble Telescope have observed what appears to be a clump of dark matter left behind from a wreck between massive clusters of galaxies. The result could challenge current theories about dark matter that predict galaxies should be anchored to the invisible substance even during the shock of a collision.

Abell 520 is a gigantic merger of galaxy clusters located 2.4 billion light-years away. Dark matter is not visible, although its presence and distribution is found indirectly through its effects. Dark matter can act like a magnifying glass, bending and distorting light from galaxies and clusters behind it. Astronomers can use this effect, called gravitational lensing, to infer the presence of dark matter in massive galaxy clusters.

This technique revealed the dark matter in Abell 520 had collected into a “dark core,” containing far fewer galaxies than would be expected if the dark matter and galaxies were anchored together. Most of the galaxies apparently have sailed far away from the collision.

“This result is a puzzle,” said astronomer James Jee of the University of California in Davis, lead author of paper about the results available online in The Astrophysical Journal. “Dark matter is not behaving as predicted, and it’s not obviously clear what is going on. It is difficult to explain this Hubble observation with the current theories of galaxy formation and dark matter.”

Initial detections of dark matter in the cluster, made in 2007, were so unusual that astronomers shrugged them off as unreal, because of poor data. New results from NASA’s Hubble Space Telescope confirm that dark matter and galaxies separated in Abell 520.

One way to study the overall properties of dark matter is by analyzing collisions between galaxy clusters, the largest structures in the universe. When galaxy clusters crash, astronomers expect galaxies to tag along with the dark matter, like a dog on a leash. Clouds of hot, X-ray emitting intergalactic gas, however, plow into one another, slow down, and lag behind the impact.

That theory was supported by visible-light and X-ray observations of a colossal collision between two galaxy clusters called the Bullet Cluster. The galactic grouping has become an example of how dark matter should behave.

Studies of Abell 520 showed that dark matter’s behavior may not be so simple. Using the original observations, astronomers found the system’s core was rich in dark matter and hot gas, but contained no luminous galaxies, which normally would be seen in the same location as the dark matter. NASA’s Chandra X-ray Observatory was used to detect the hot gas. Astronomers used the Canada-France-Hawaii Telescope and Subaru Telescope atop Mauna Kea to infer the location of dark matter by measuring the gravitationally lensed light from more distant background galaxies.

The astronomers then turned to the Hubble’s Wide Field Planetary Camera 2, which can detect subtle distortions in the images of background galaxies and use this information to map dark matter. To astronomers’ surprise, the Hubble observations helped confirm the 2007 findings.

“We know of maybe six examples of high-speed galaxy cluster collisions where the dark matter has been mapped,” Jee said. “But the Bullet Cluster and Abell 520 are the two that show the clearest evidence of recent mergers, and they are inconsistent with each other. No single theory explains the different behavior of dark matter in those two collisions. We need more examples.”

The team proposed numerous explanations for the findings, but each is unsettling for astronomers. In one scenario, which would have staggering implications, some dark matter may be what astronomers call “sticky.” Like two snowballs smashing together, normal matter slams together during a collision and slows down. However, dark matter blobs are thought to pass through each other during an encounter without slowing down. This scenario proposes that some dark matter interacts with itself and stays behind during an encounter.

Another possible explanation for the discrepancy is that Abell 520 has resulted from a more complicated interaction than the Bullet Cluster encounter. Abell 520 may have formed from a collision between three galaxy clusters, instead of just two colliding systems in the case of the Bullet Cluster.

A third possibility is that the core contained many galaxies, but they were too dim to be seen, even by Hubble. Those galaxies would have to have formed dramatically fewer stars than other normal galaxies. Armed with the Hubble data, the group will try to create a computer simulation to reconstruct the collision and see if it yields some answers to dark matter’s weird behavior.

The Hubble Space Telescope is a project of international cooperation between NASA and the European Space Agency. NASA’s Goddard Space Flight Center in Greenbelt, Md., manages the telescope. The Space Telescope Science Institute (STScI) in Baltimore, Md., conducts Hubble science operations. STScI is operated by the Association of Universities for Research in Astronomy, Inc., in Washington, D.C.

For more information about Hubble visit: http://www.nasa.gov/hubble

Image Credit: NASAESA, CFHT, CXO, M.J. Jee (University of California, Davis), and A. Mahdavi (San Francisco State University)

Source: NASA

Meet I Zw 18: A Dwarf Galaxy

The Center of Astrophysics of the University of Porto recently came up with an analysis that seriously calls into question the current model of galactic formation. Polychronis Papaderos represented the CAUP, and with his Swedish colleague Göran Östlin, Papderos examined data from the Hubble Space Telescope to better understand the I Zw 18 dwarf galaxy. That particular object has received a lot of attention, and it is one of the few places where star-forming activity can be readily observed.

I Zw 18 region. (Credit: Image courtesy of Centro de Astrofísica da

For a long time, astrophysicists have simply assumed that stars were emitting light from gas structures. These structures occupied the same region as the stars that were emitting the light. The research suggests that galaxies that undergo active starbursts don’t follow this rule. Instead, nebula gases might actually be emitting around half of the total light in question. Since star mass is often calculated from the galaxy’s total luminosity, the idea that nebular emissions account for so much light means that many of these calculations could be totally off. One could also surmise that since I Zw 18 is young, the galaxy is acting the way many objects did shortly after the Big Bang. Many of the stars there have been around for less than 1 billion years. It will be interesting to watch this galaxy in the years ahead.

Reference:

Papaderos, P., & Östlin, G. (2012). I Zw 18 as morphological paradigm for rapidly assembling high-galaxies Astronomy & Astrophysics, 537 DOI: 10.1051/0004-6361/201117551

Izotov, Y., Chaffee, F., Foltz, C., Thuan, T., Green, R., Papaderos, P., Fricke, K., & Guseva, N. (2001). A Spectroscopic Study of Component C and the Extended Emission around I Zw 18 The Astrophysical Journal, 560 (1), 222-235 DOI: 10.1086/322494

Image Credit: Hubble

ResearchBlogging.org

Vernier Launches LabQuest 2 for STEM Education

STEM students in more than 130 countries have deepened their knowledge of scientific practices using sensors and Vernier’s data-collection interface, the LabQuest. Now, that technology is even more powerful. Vernier Software & Technology‘s new LabQuest 2 features faster computing, a large high-resolution screen, wireless data sharing, and five built-in sensors, including GPS. LabQuest 2 is compatible with all Vernier probes, which includes more than 70 different sensors used in experiments to study physics, chemistry, biology, and a variety of other STEM topics.

“LabQuest 2 is part of what we call the Connected Science System, which we designed to expand possibilities for science educators,” said David Vernier, co-founder of Vernier Software & Technology and a former physics teacher. “As educators look to the future for data-collection technology that can be used with a variety of tablet devices, smart phones, and other mobile technology, LabQuest 2 offers teachers the greatest versatility.”

Used as a standalone device, or as a data-collection interface for computers with Vernier’s Logger Prosoftware, LabQuest 2 offers a 12.8 cm, high-resolution touch screen, real-time data collection, powerful analysis tools, and on-board curriculum. Its built-in GPS, 3-axis accelerometer, ambient temperature, light, and microphone sensors broaden data-collection opportunities while offering schools increased value. LabQuest 2’s software features quick response to touch, curve fits, and modeling, and the interface can collect data at a rate of up to 100,000 samples per second.

New to LabQuest 2 is the Connected Science System, a networked collection of technology that supports hands-on, collaborative learning with individualized accountability. Using the built-in Wi-Fi capability, students can share data from LabQuest 2 to any device with a web browser, including iPads®, iPhones®, and Android™ devices. Students can also send data from LabQuest 2 to any email address, and they can connect LabQuest 2 to a computer with a projector to view and control the device in a presentation format.

LabQuest 2 comes with a rechargeable battery, USB cable, power adapter, CD containing Logger Lite software, stylus, and stylus tether.

Pricing and Availability
LabQuest 2 replaces Vernier’s award-winning original LabQuest. It will be available for purchase in April 2012 for $329. To learn more about LabQuest 2, visit www.vernier.com/labquest2.

Image Credit: 1) The Hacktory

Source: Vernier Software & Technology

Young Stars Flicker Amidst Clouds of Gas and Dust

Astronomers have spotted young stars in the Orion nebula changing right before their eyes, thanks to the European Space Agency‘s Herschel Space Observatory and NASA’s Spitzer Space Telescope. The colorful specks — developing stars strung across the image — are rapidly heating up and cooling down, speaking to the turbulent, rough-and-tumble process of reaching full stellar adulthood.

The rainbow of colors represents different wavelengths of infrared light captured by both Spitzer and Herschel. Spitzer is designed to see shorter infrared wavelengths than Herschel. By combining their observations, astronomers get a more complete picture of star formation. NASA’s Jet Propulsion Laboratory in Pasadena, Calif., manages the Spitzer mission for NASA, and also plays an important role in the European Space Agency-led Herschel mission.

In the portion of the Orion nebula pictured, the telescopes’ infrared vision reveals a host of embryonic stars hidden in gas and dust clouds. These stars are at the very earliest stages of evolution.

A star forms as a clump of this gas and dust collapses, creating a warm glob of material fed by an encircling disk. In several hundred thousand years, some of the forming stars will accrete enough material to trigger nuclear fusion at their cores, and then blaze into stardom.

Herschel mapped this region of the sky once a week for six weeks in the late winter and spring of 2011. To monitor for activity in protostars, Herschel’s Photodetector Array Camera and Spectrometer probed long infrared wavelengths of light that trace cold dust particles, while Spitzer gauged the warmer dust emitting shorter infrared wavelengths. In this data, astronomers noticed that several of the young stars varied in their brightness by more than 20 percent over just a few weeks. As this twinkling comes from cool material emitting infrared light, the material must be far from the hot center of the young star, likely in the outer disk or surrounding gas envelope. At that distance, it should take years or centuries for material to spiral closer in to the growing starlet, rather than mere weeks.

A couple of scenarios under investigation could account for this short span. One possibility is that lumpy filaments of gas funnel from the outer to the central regions of the star, temporarily warming the object as the clumps hit its inner disk. Or, it could be that material occasionally piles up at the inner edge of the disk and casts a shadow on the outer disk.

“Herschel’s exquisite sensitivity opens up new possibilities for astronomers to study star formation, and we are very excited to have witnessed short-term variability in Orion protostars,” said Nicolas Billot, an astronomer at the Institut de Radioastronomie Millimétrique (IRAM) in Grenada, Spain who is preparing a paper on the findings along with his colleagues. “Follow-up observations with Herschel will help us identify the physical processes responsible for the variability.”

Herschel is a European Space Agency cornerstone mission, with science instruments provided by consortia of European institutes and with important participation by NASA. NASA’s Herschel Project Office is based at JPL. JPL contributed mission-enabling technology for two of Herschel’s three science instruments. The NASA Herschel Science Center, part of the Infrared Processing and Analysis Center at the California Institute of Technology in Pasadena, supports the United States astronomical community. Caltech manages JPL for NASA.

More information is online at http://www.herschel.caltech.edu , http://www.nasa.gov/herschel andhttp://www.esa.int/SPECIALS/Herschel .

Image Credit: JPL
Source: JPL/NASA

Let’s Explore Gamma-ray Bursts

Astronomers remain fascinated by gamma-ray bursts. These bursts of energy appear to be among the most powerful explosions in the universe today. They occur about once a day and are divided into two categories. The first category is called long gamma-ray bursts and last from two seconds to about thirty seconds. They have a clearly defined burst of energy followed by an afterglow which can be clearly seen. The second type is short gamma-ray bursts. These bursts last under two seconds and most last a few milliseconds.

When gamma-ray bursts were first detected in 1969, scientists believed the intense flashes of energy may have originated from distant alien civilizations. We now know that gamma-ray bursts result from the cores of massive stars collapsing at the end of their lives. These stars are known as supernovas and, if the star has enough mass, they turn into black holes. As the gas descends into the center of the black hole, some of it escapes as gamma-rays and is shot out from the dying star’s poles at nearly the speed of light.

Although gamma-ray bursts only last from a few seconds to a few minutes and are not visible to human eyes, they emit the same amount of energy the Milky Way produces in 100 years and are brighter than all other sources of gamma-rays, including neighboring stars and our Sun. Scientist have observed gamma-ray bursts from 13.14 billion light-years away, making them the most powerful forms of energy in the universe, secondary only to the big bang.

Gamma-ray bursts produce large amounts of gas that evelopes the entire surrounding area. Because new stars form from the gas clouds left behind by larger stars that have undergone the supernova process, gamma ray bursts are often found in these “stellar nurseries.” Scientists now use gamma-ray bursts to locate areas of new star formation and study the life cycle of stars.

Astronomers also believe that long gamma-ray bursts are caused by the collapse of a Wolf-Rayet star. When the star collapses, a black hole is formed within the star. Then, as the star further collapses, matter escapes from the star. It is this matter that astronomers are seeing.

These long gamma-ray bursts come from all directions within the universe. Astronomers believe that most of them originate at the very edge of where the most powerful telescopes can see and beyond. NASA and other space agencies have satellites that are studying the bursts. When they detect one, they send a signal to several points on Earth. Telescopes can then be pointed in the right direction.

Image Credit: 1) Artist’s conception of a gamma-ray burst by NASA/SkyWorks Digital

Reference:

Woosley, S., & Bloom, J. (2006). The Supernova–Gamma-Ray Burst Connection Annual Review of Astronomy and Astrophysics, 44 (1), 507-556 DOI: 10.1146/annurev.astro.43.072103.150558

Extreme Gamma-ray Burst – NASA Science. (2009, February 20). NASA Science. Retrieved February 24, 2012, from http://science.nasa.gov/science-news/science-at-nasa/2009/20feb_extremegrb/

Gamma-Ray Burst Physics. (n.d.). Astronomy and Astrophysics. Retrieved February 24, 2012, from http://www2.astro.psu.edu/users/nnp/grbphys.html

NASA – National Aeronautics and Space Administration. (2009, November 02). NASA. Retrieved February 24, 2012, from http://www.nasa.gov/mission_pages/GLAST/news/star_factories.html

NASA – National Aeronautics and Space Administration. (2011, May 27). NASA. Retrieved February 24, 2012, from http://www.nasa.gov/mission_pages/swift/bursts/swift-20110527.html

ResearchBlogging.org

Using Pinterest to Teach Science

First, let me say I’m not some “Pinterest Guru” or anything like that. I only recently joined this growing network and have stumbled through trying to figure out what the hell it’s all about. In the short time I’ve been on the site however, I’ve learned that it’s a phenomenal way to share astronomy concepts (within limits – more on this below) while spreading the greatness of science (or any subject really) to others! And this can be applied to virtually any branch of science or subject for that matter. Best of all, it’s fast, free (except for your time), and is an exceptional way to reach students and engage with them in a new way. Read More →

Where Are The Darkest Skies in the World?

Have you ever wondered where the best place in the world is to see the night sky? The International Dark Sky Association has the answer for you. They have designated five places in the world as gold tier international dark sky parks.

In order to qualify for this award, the land must be publically owned, open to the public at least part of the night and meet strict rules in the surrounding area to protect the quality of the night sky from light pollution. While many have tried for this honor, only five in the world have achieved this level of success.

The largest gold tier International Dark Sky Park in the United States is Big Bend National Park in west Texas with 803,000 acres. The park has also been declared as having the darkest skies in the lower 48 states, due to strict light ordinances in the few neighboring communities. Big Bend National Park was not a Dark Sky Park until February, 2012.

Other gold tier dark sky parks in the United States include Cherry Springs in Pennsylvania, Clayton Lake State Park in New Mexico, and National Bridges Natural Monument in Utah. Each of these parks has an active program to help families enjoy the night sky. The only international gold tier dark sky park is Galloway Forest Park located in Scotland.

Now you know where to go for unparalleled star gazing goodness.

Happy universe hunting!

Image Credit: David Hardy

Reference:

http://www.darksky.org/IDSParks

SETI Live to Crowdsource Search for Extraterrestrials

As part of the TED Prize Wish made by renowned astronomer Jill Tarter, the TED Prize today launches SETI Live (setilive.org): a site where – for the first time – the public can view data being collected by radio telescopes and collectively help search for intelligent life on other planets. Read More →

Science Foundation Arizona Launches Arizona STEM Network

Science Foundation Arizona (SFAz), a nonprofit public-private partnership that serves as a catalyst for revitalizing Arizona and strengthening its economic future, joined with partners today to announce the launch of the Arizona STEM Network. The STEM Network is a first-of-its-kind strategic effort to help transform Arizona’s educational system for Science, Technology, Engineering and Mathematics.

A five-year plan being led by SFAz will leverage effective education practices and teaching advances including the state-adopted, internationally benchmarked Common Core Standards. The Arizona STEM Network is a unified approach that will provide educators, the business community and donors with a centralized infrastructure, tools, resources and the framework needed to measure performance and achieve collective impact in Arizona classrooms. The plan’s driving force is to help Arizona children be successful in school, careers and life.

Since 2008, the Freeport-McMoRan Copper & Gold Foundation has been the leading financial supporter, providing a total of $2.2 million for the establishment of SFAz’s STEM initiative, as well as the collaboration of work leading up to the launch of the new Arizona STEM Network and plan for implementation. Freeport-McMoRan Copper & Gold Foundation today announced a new three-year commitment beginning in 2012, totaling $2.1 million for operational funding that will allow SFAz to roll out its plan for the Arizona STEM Network. The plan focuses on four strategic areas:

  • Integrate STEM learning into Arizona schools and districts
  • Develop and deploy a predictive analytics system to measure impacts
  • Strengthen teacher effectiveness in STEM teaching
  • Create opportunities for the private business sector to meaningfully engage with schools

The development of the Arizona STEM Network began after Arizona Governor Jan Brewer, along with philanthropic and private sector leaders, tapped SFAz to spearhead the initiative in September 2010. Over a 14 month period, SFAz leaders logged more than 10,000 miles throughout Arizona and met with more than 1,500 individuals from the education, business and government sectors in all 15 counties and the Navajo Nation, as well as the Arizona Department of Education and the State Board of Education to determine statewide needs. Using the feedback gathered, SFAz created the Arizona STEM Network plan.

“Arizona must develop a globally competitive educational system and STEM disciplines will lead the way,” said Darcy Renfro, vice president of education and coordinator of the Arizona STEM Network at SFAz. “The Network will link existing STEM assets in Arizona, build on best practices and foster innovative teaching approaches for school districts to help students improve in these areas.”

Gov. Brewer, Freeport-McMoRan Copper & Gold Foundation and Helios Education Foundation provided major funding for the development of the Arizona STEM Network plan and were joined by Intel, JPMorgan Chase Foundation and Research Corporation for Science Advancement.

“We believe that the private sector must play an active role in developing the next generation to keep our businesses competitive and our economy vibrant,” said Tracy Bame, president of Freeport-McMoRan Copper & Gold Foundation. “A first-rate education that encompasses the STEM disciplines is a foundational step to provide students with the skills and knowledge they need to succeed.

Arizona is one of 12 states in the U.S., with developing or existing STEM Networks, that are leading the charge to implement a proactive approach to STEM teaching which provides interactive coursework in classrooms to prepare students for successful careers in the 21st century. STEM education is an interdisciplinary approach to learning that provides project-based and relevant experiences for students.

“Helios Education Foundation’s investment in the Arizona STEM Network’s plan to transform K-12 education is really an investment in the future of our state,” said the Foundation’s Executive Vice President and Chief Operating Officer Barbara Ryan. “STEM education is the linchpin that will better prepare our students academically and ultimately increase the number of high school graduates ready to succeed in postsecondary education.”

The Arizona STEM Network will be led and coordinated by SFAz staff with a structured system of information management tools, processes and technical assistance. The Network is in place and will be rolled out in phases, with initial pilot sites to be announced by late 2012. SFAz is currently securing additional long-term operational and program funding from other corporate partners to further support the Arizona STEM Network.

“The vision for a statewide, strategic commitment to STEM education is coming to fruition,” said Gov. Brewer. “The Arizona STEM Network will help build a common agenda for STEM education that will lead our teachers and students forward.”

About Science Foundation Arizona
Science Foundation Arizona (SFAz) is a 501(c)(3) non-profit organization initiated in 2006 by the Greater Phoenix Leadership Inc., Southern Arizona Leadership Council and the Flagstaff Forty in conjunction with the executive and legislative branches of state government. SFAz serves as a catalyst for high-wage, knowledge-based jobs and economic diversity through administration and strict oversight of research, development and education grants to public education and other non-profit research performing institutions. For more information, visit www.sfaz.org.

Source: Science Foundation Arizona