NASA Pinning Down Where ‘Here’ is Better Than Ever

Before our Global Positioning System (GPS) navigation devices can tell us where we are, the satellites that make up the GPS need to know exactly where they are. For that, they rely on a network of sites that serve as “you are here” signs planted throughout the world. The catch is, the sites don’t sit still because they’re on a planet that isn’t at rest, yet modern measurements require more and more accuracy in pinpointing where “here” is.

To meet this need, NASA is helping to lead an international effort to upgrade the four systems that supply this crucial location information. NASA’s Jet Propulsion Laboratory, Pasadena, Calif., in partnership with NASA’s Goddard Space Flight Center in Greenbelt, Md., where the next generation of laser ranging and radio interferometry systems is being developed and built, is bringing all four systems together in a state-of-the-art ground station. This demonstration station and merger of technique processing, known as the Space Geodesy Project, will serve as an example of what is required to measure Earth’s properties to keep up with the ever-changing, yet subtle, movements in land as it rises and sinks along with shifts in the balances of the atmosphere and ocean. All of these movements tweak Earth’s shape, its orientation in space and its center of mass — the point deep inside the planet that everything rotates around. The changes show up in Earth’s gravity field and literally slow down or speed up the planet’s rotation.

“NASA and its sister agencies around the world are making major investments in new stations or upgrading existing stations to provide a network that will benefit the global community for years to come,” says John LaBrecque, Earth Surface and Interior Program Officer at NASA Headquarters.

GPS won’t be the only beneficiary of the improvements. All observations of Earth from space — whether it’s to measure how far earthquakes shift the land, map the world’s ice sheets, watch the global mean sea level creep up or monitor the devastating reach of droughts and floods — depend on the International Terrestrial Reference Frame, which is determined by data from this network of designated sites.

 

For more information, visit: http://www.nasa.gov/topics/technology/features/here-pin-down.html.

Image Credit: Artist’s concept of a quasar (bright area with rays) embedded in the center of a galaxy. Credit: NASA/JPL-Caltech/T. Pyle (SSC)

Source: JPL

Claudius Ptolemy- Great Astronomer or Plagiarist?

Many amateur astronomers today may not even recognize the name of Claudius Ptolemy, but the field of astronomy owes this man’s work a huge thank you. That is… according to some scholars. Others, however, think he was nothing more than a common thief.

His work, Almagest, is the oldest surviving star chart. In his 13 volume work Ptolemy puts forward a mathematical model to fit his observational data that was much more sophisticated than any known at that time. Almagest still holds the record for the longest used scientific text ever. Almagest was considered so important that the text was translated into Arabic 500 years after it was written. The translated book was found in the great libraries of Cordova and Toledo, Spain. Many consider Claudius Ptolemy one of the greatest astronomers of history.Ptolemy’s theory saw the earth as the center of the universe. All of calculations of how the planets moved were based on this fact. Read More →

The Extraterrestrial Debate Rages On

Sigh…another day, another research paper trying to convince the world that we are alone in the universe…

I came across a post last night on The Daily Galaxy discussing a paper that was published last summer by David Spiegel with Princeton University and Edwin Turner with the University of Tokyo entitled, Bayesian analysis of the astrobiological implications of life’s early emergence on Earth.

PDF Download HERE.

Jeez, where to begin? Read More →

Chandra Discovers the Fastest Wind From a Stellar-Mass Black Hole

Making use of NASA’s Chandra X-ray Observatory, astronomers recently announced that they have recorded the quickest wind ever recorded coming off of a stellar-mass black hole. This discovery has important implications for how exactly these type of black holes work.

This record-breaking wind was found to be moving at about 20 million mph, which is about three percent of the speed of light. This is about ten times as fast as astronomers have ever witnessed coming off of a stellar-mass black hole.

Stellar-mass black holes, such as this one, become formed when large stars reach their end and collapse. They have an approximate mass of five to ten times that of our sun. The stellar-mass black hole that produced these particular winds was IGR J17091-3624. These winds are the equivalent of a cosmic category five hurricane, which took astronomers by surprise to see such powerful winds coming from a stellar-mass black hole such as this one. This black hole is relatively small compared to some of the other black holes astronomers have discovered, yet it has produced winds that far exceed that of the larger black holes.

Unlike winds found on Earth, the winds found in the black hole blow in various directions rather then in a single direction. This would send you on quite a ride!

Image Credit: NASA/CXC/M.Weiss

Reference: http://astronomy.com/News-Observing/News/2012/02/Chandra finds fastest wind from stellar-mass black hole.aspx

Changing Faces of Titan

A set of recent papers, many of which draw on data from NASA’s Cassini spacecraft, reveal new details in the emerging picture of how Saturn’s moon Titan shifts with the seasons and even throughout the day. The papers, published in the journal Planetary and Space Science in a special issue titled “Titan through Time”, show how this largest moon of Saturn is a cousin – though a very peculiar cousin – of Earth.

“As a whole, these papers give us some new pieces in the jigsaw puzzle that is Titan,” said Conor Nixon, a Cassini team scientist at the NASA Goddard Space Flight Center, Greenbelt, Md., who co-edited the special issue with Ralph Lorenz, a Cassini team scientist based at the Johns Hopkins University Applied Physics Laboratory, Laurel, Md. “They show us in detail how Titan’s atmosphere and surface behave like Earth’s – with clouds, rainfall, river valleys and lakes. They show us that the seasons change, too, on Titan, although in unexpected ways.”

This series of false-color images obtained by NASA

A paper led by Stephane Le Mouelic, a Cassini team associate at the French National Center for Scientific Research (CNRS) at the University of Nantes, highlights the kind of seasonal changes that occur at Titan with a set of the best looks yet at the vast north polar cloud.

A newly published selection of images – made from data collected by Cassini’s visual and infrared mapping spectrometer over five years – shows how the cloud thinned out and retreated as winter turned to spring in the northern hemisphere.

Cassini first detected the cloud, which scientists think is composed of ethane, shortly after its arrival in the Saturn system in 2004. The first really good opportunity for the spectrometer to observe the half-lit north pole occurred on December 2006. At that time, the cloud appeared to cover the north pole completely down to about 55 degrees north latitude.  But in the 2009 images, the cloud cover had so many gaps it unveiled to Cassini’s view the hydrocarbon sea known as Kraken Mare and surrounding lakes.

“Snapshot by snapshot, these images give Cassini scientists concrete evidence that Titan’s atmosphere changes with the seasons,” said Le Mouelic. “We can’t wait to see more of the surface, in particular in the northern land of lakes and seas.”

In data gathered by Cassini’s composite infrared mapping spectrometer to analyze temperatures on Titan’s surface, not only did scientists see seasonal change on Titan, but they also saw day-to-night surface temperature changes for the first time. The paper, led by Valeria Cottini, a Cassini associate based at Goddard, used data collected at a wavelength that penetrated through Titan’s thick haze to see the moon’s surface. Like Earth, the surface temperature of Titan, which is usually in the chilly mid-90 kelvins (around minus 288 degrees Fahrenheit), was significantly warmer in the late afternoon than around dawn.

“While the temperature difference – 1.5 kelvins – is smaller than what we’re used to on Earth, the finding still shows that Titan’s surface behaves in ways familiar to us earthlings,” Cottini said. “We now see how the long Titan day (about 16 Earth days) reveals itself through the clouds.”

A third paper by Dominic Fortes, an outside researcher based at University College London, England, addresses the long-standing mystery of the structure of Titan’s interior and its relationship to the strikingly Earth-like range of geologic features seen on the surface. Fortes constructed an array of models of Titan’s interior and compared these with newly acquired data from Cassini’s radio science experiment.

The work shows the moon’s interior is partly or possibly even fully differentiated. This means that the core is denser than outer parts of the moon, although less dense than expected. This may be because the core still contains a large amount of ice or because the rocks have reacted with water to form low-density minerals.

Earth and other terrestrial planets are fully differentiated and have a dense iron core. Fortes’ model, however, rules out a metallic core inside Titan and agrees with Cassini magnetometer data that suggests a relatively cool and wet rocky interior. The new model also highlights the difficulty in explaining the presence of important gases in Titan’s atmosphere, such as methane and argon-40, since they do not appear to be able to escape from the core.

The Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency and the Italian Space Agency. NASA’s Jet Propulsion Laboratory manages the mission for NASA’s Science Mission Directorate, Washington, D.C. The visual and infrared mapping spectrometer team is based at the University of Arizona, Tucson. The composite infrared spectrometer team is based at NASA’s Goddard Space Flight Center in Greenbelt, Md., where the instrument was built. The radio science subsystem has been jointly developed by NASA and the Italian Space Agency.

Source: JPL/NASA

Reference:

Rodriguez S, Le Mouélic S, Rannou P, Tobie G, Baines KH, Barnes JW, Griffith CA, Hirtzig M, Pitman KM, Sotin C, Brown RH, Buratti BJ, Clark RN, & Nicholson PD (2009). Global circulation as the main source of cloud activity on Titan. Nature, 459 (7247), 678-82 PMID: 19494910

Fortes, D. (2008). Uncovering Titan’s secrets Nature Geoscience, 1 (7), 415-416 DOI: 10.1038/ngeo238

Fortes, A., & Grindrod, P. (2006). Modelling of possible mud volcanism on Titan Icarus, 182 (2), 550-558 DOI: 10.1016/j.icarus.2005.11.013

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AFCEA Increases Scholarships for Future STEM Teachers

AFCEA International and the AFCEA Educational Foundation are expanding the Science, Technology, Engineering and Math (STEM) Teacher Scholarship Program for the second year in a row to help address the growing shortage of young Americans educated in STEM subjects.  AFCEA’s investment is a long-term solution to develop more skilled and motivated teachers of STEM subjects who will inspire and prepare students to desire and be successful in STEM fields.

For the current school year, AFCEA is offering 60 scholarships of $5,000 each, up from 50 scholarships awarded last year.  AFCEA also will provide grants of $1,000 each year for three years to these scholarship winners when they begin teaching.

According to the U.S. Department of Labor, 15 of the 20 fastest-growing professions will require high proficiency in science or mathematics. However, the outlook for meeting those requirements seems bleak. The National Center for Educational Statistics projects that only 6 in 100 of today’s ninth graders in the U.S. are currently expected to pursue a STEM degree in college.

“The latest studies show that America is continuing to fall behind – even while other nations multiply their investments in science, math and technical education,” said Fred Rainbow, Vice President for Education, AFCEA International. “Nothing less than the future of our country is at stake.  Our capabilities in math, science, engineering and other technical fields drive innovation, exports, jobs, quality of life, and ultimately our economic and national security.”

Kent Schneider, AFCEA’s President and CEO, amplifies: “As a long-time supporter of STEM education through teaching tool grants and other programs, AFCEA started its STEM Teacher Scholarship program in 2010. In just three years, the program has grown from 35 to 60 scholarships thanks to financial support from Booz Allen Hamilton, Terremark Worldwide, Inc., AFCEA International, along with funding from AFCEA’s chapters.”

Support for the AFCEA Educational Foundation also has enabled it to award $1,000 Teaching Tools grants to those graduates who benefited from the first year of STEM scholarships in 2010 and now are actively engaged in teaching.  These grants can be used for information technology hardware and software, other classroom tools, field trips, STEM-focused clubs and other activities.

Interested candidates, teachers and mentors can find more information and apply online for a scholarship at http://stem.afcea.org. The application deadline is April 1, 2012.  Regular updates on the program are available through Twitter (@afcea_ed) or Facebook (http://www.facebook.com/#!/AFCEA.Scholarships).

About AFCEA International and the AFCEA Educational Foundation
AFCEA International, established in 1946, is a non-profit membership association serving the military, government, industry, and academia as an ethical forum for advancing professional knowledge and relationships in the fields of communications, IT, intelligence, and global security. For more information, visit www.afcea.org.

The AFCEA Educational Foundation works closely with the chapters, raises funds, and provides leadership, guidance, and rewards to help motivate more students to become scientists and engineers. The Foundation is an independent 501(c)(3) organization dedicated to providing educational incentives, opportunities, and assistance for students and teachers in the science, technology, engineering, and mathematics disciplines (broadly known as STEM). In 2011 the AFCEA Educational Foundation and AFCEA chapters awarded more than $1.5M in scholarships and grants. The AFCEA Educational Foundation has been granting scholarships and grants to college students in STEM disciplines for 30 years.

Source: AFCEA International

Image Credit: STEM Conference

NASA’s Spitzer Finds Solid Buckyballs in Space

Astronomers using data from NASA’s Spitzer Space Telescope have, for the first time, discovered buckyballs in a solid form in space. Prior to this discovery, the microscopic carbon spheres had been found only in gas form.

Formally named buckminsterfullerene, buckyballs are named after their resemblance to the late architectBuckminster Fuller’s geodesic domes. They are made up of 60 carbon molecules arranged into a hollow sphere, like a soccer ball. Their unusual structure makes them ideal candidates for electrical and chemical applications on Earth, including superconducting materials, medicines, water purification and armor.

In the latest discovery, scientists using Spitzer detected tiny specks of matter, or particles, consisting of stacked buckyballs. They found them around a pair of stars called “XX Ophiuchi,” 6,500 light-years from Earth.

Image credit: NASA/JPL-Caltech/University of Western Ontario

“These buckyballs are stacked together to form a solid, like oranges in a crate,” said Nye Evans of Keele University in England, lead author of a paper appearing in the Monthly Notices of the Royal Astronomical Society. “The particles we detected are miniscule, far smaller than the width of a hair, but each one would contain stacks of millions of buckyballs.”

Buckyballs were detected definitively in space for the first time by Spitzer in 2010. Spitzer later identified the molecules in a host of different cosmic environments. It even found them in staggering quantities, the equivalent in mass to 15 Earth moons, in a nearby galaxy called the Small Magellanic Cloud.

In all of those cases, the molecules were in the form of gas. The recent discovery of buckyballs particles means that large quantities of these molecules must be present in some stellar environments in order to link up and form solid particles. The research team was able to identify the solid form of buckyballs in the Spitzer data because they emit light in a unique way that differs from the gaseous form.

“This exciting result suggests that buckyballs are even more widespread in space than the earlier Spitzer results showed,” said Mike Werner, project scientist for Spitzer at NASA’s Jet Propulsion Laboratory inPasadena, Calif. “They may be an important form of carbon, an essential building block for life, throughout the cosmos.”

Buckyballs have been found on Earth in various forms. They form as a gas from burning candles and exist as solids in certain types of rock, such as the mineral shungite found in Russia, and fulgurite, a glassy rock from Colorado that forms when lightning strikes the ground. In a test tube, the solids take on the form of dark, brown “goo.”

“The window Spitzer provides into the infrared universe has revealed beautiful structure on a cosmic scale,” said Bill Danchi, Spitzer program scientist at NASA Headquarters in Washington. “In yet another surprise discovery from the mission, we’re lucky enough to see elegant structure at one of the smallest scales, teaching us about the internal architecture of existence.”

NASA’s Jet Propulsion Laboratory (JPL) in Pasadena, Calif., manages the Spitzer Space Telescope mission for NASA’s Science Mission Directorate in Washington. Science operations are conducted at the Spitzer Science Center at the California Institute of Technology in Pasadena. Caltech manages JPL for NASA.

Image credit: NASA/JPL-Caltech

For information about previous Spitzer discoveries of buckyballs, visit:

http://www.nasa.gov/mission_pages/spitzer/news/spitzer20100722.html

and

http://www.nasa.gov/mission_pages/spitzer/news/spitzer20101027.html

For more information about Spitzer, visit:

http://www.nasa.gov/spitzer

Source: NASA

Unidentified Future Objects?

The current model of physics, far from outlawing time travel, stipulates that it could be theoretically possible in a variety of different ways. It was Albert Einstein who first discovered the curious phenomenon of time dilation, in which time progresses more slowly at extremely high velocities. Since then, many scientists have injected their input into the debate. One of the most respected of these is Cambridge Professor Stephen Hawking, who once stated that: “If time travel were possible, we’d already be inundated by tourists from the future.” Perhaps Hawking is more right than he even realized when he made the comment. Read More →

Let’s Explore the Phases of Matter: Sublimation and Deposition

Image Credit: European Space Agency/David Hardy

The Basic Phases
Science recognizes four states of matter that we can find in every day life. These include solid, liquid, gas and plasma. Other states (I’ve written about a few of them here) such as Bose-Einstein, supercritical fluid, and degenerate gas occur in extreme conditions, but I’m focusing primarily on phases today. It is important to remember that matter remains the same substance regardless of which state it is in. For example, water is still water, regardless of whether it is ice or in a cloud. What makes the difference is the amount of energy in the matter. The more energy the atoms in the matter have, the further apart the atoms become. Thus, solids are denser than liquids, liquids are denser than gases and so on. The energy that excites atoms typically is heat. The phase change puzzle doesn’t include only energy, however. It also includes pressure. The higher the pressure, the harder it is for matter to expand in response to the extra energy present, so phase changes become more difficult as pressure increases.

Sublimation
Although matter usually goes through phase changes gradually as heat energy is added or taken away, in some situations, there is enough energy present that matter can go directly from the solid state to the gaseous state. This is called sublimation. Sublimation occurs most easily when pressure is low because the atoms have less resistance when trying to expand.

Deposition
Deposition is perhaps the lesser-known cousin of sublimation. It occurs when matter skips from the gaseous state directly to the solid state. This requires energy to be lost quickly. A good example of this is frost. Deposition occurs most easily when pressure is high because the pressure makes it easier for atoms to come closer together to form a solid.

What Does This Have to Do with Astronomy?

Glad you asked!

Comets like the comet Hyakutake are an excellent example of sublimation at work. Comets consist mostly of what I think of as dirty ice and dust. If you live in an area where it snows, you’ve likely seen how snow and ice on roads turns dark as it’s mixed with dirt. Hence, dirty ice. Anyhow, as comets approach the Sun, the radiated heat warms and sublimates the large mass of ice found in the comet. As a result, gas is released in the form of a temporary atmosphere or cloud around the comet known as a coma. Because comets have virtually no gravity, this temporary atmosphere is unsustained by the comet. As a result, the coma is flung away from the comet and results in the streaming tail that you see behind comets as they soar through space. So this is a great example of sublimation occurring in our universe.

Examples of sublimation can also be found on many planets and moons in our solar system as well. Many of these masses have little or extremely low pressure atmospheres resulting in ice buildup on their surfaces. When the ice is heated, sublimation occurs if the pressure is low enough. We see this occurring frequently on Mars during the Martian summer season. The planet has polar ice caps that sublimate into the atmosphere during the Martian summer season at its’ poles.

Reference:

Heiselberg, H. (2000). Phases of dense matter in neutron stars Physics Reports, 328 (5-6), 237-327 DOI: 10.1016/S0370-1573(99)00110-6

Image Credit: European Space Agency/David Hardy

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Building Blocks of Early Earth – Collision that Created Moon

Unexpected new findings by a University of Maryland team of geochemists show that some portions of the Earth’s mantle (the rocky layer between Earth’s metallic core and crust) formed when the planet was much smaller than it is now, and that some of this early-formed mantle survived Earth’s turbulent formation, including a collision with another planet-sized body that many scientists believe led to the creation of the Moon.

“It is believed that Earth grew to its current size by collisions of bodies of increasing size, over what may have been as much as tens of millions of years, yet our results suggest that some portions of the Earth formed within 10 to 20 million years of the creation of the Solar System and that parts of the planet created during this early stage of construction remained distinct within the mantle until at least 2.8 billion years ago.” says UMD Professor of Geology Richard Walker, who led the research team.

Prior to this finding, scientific consensus held that the internal heat of the early Earth, in part generated by a massive impact between the proto-Earth and a planetoid approximately half its size (i.e., the size of Mars), would have led to vigorous mixing and perhaps even complete melting of the Earth. This, in turn, would have homogenized the early mantle, making it unlikely that any vestiges of the earliest-period of Earth history could be preserved and identified in volcanic rocks that erupted onto the surface more than one and a half billion years after Earth formed.

However, the Maryland team examined volcanic rocks that flourished in the first half of Earth’s history, called komatiites, and found that these have a different type of composition than what they, or anyone, would have, expected. Their findings were just published in the journalScience: “182W Evidence for Long-Term Preservation of Early Mantle Differentiation Products,” by Mathieu TouboulIgor S. Puchtel, and Richard J. Walker, University of Maryland. Their laboratory and work are supported by funding from the National Science Foundation and NASA.

An Isotopic Signature

“We have discovered 2.8 billion year old volcanic rocks from Russia that have a combination of isotopes of the chemical element tungsten that is different from the combination seen in most rocks — different even from the tungsten filaments in incandescent light bulbs,” says the first author, Touboul, a research associate in the University of Maryland’s Department of Geology. “We believe we have detected the isotopic signature of one of the earliest-formed portions of the Earth, a building block that may have been created when the Earth was half of its current mass.”

As with many other chemical elements, tungsten consists of different isotopes. All isotopes of an element are characterized by having the same number of electrons and protons but different numbers of neutrons. Therefore, isotopes of an element are characterized by identical chemical properties, but different mass and nuclear properties. Through radioactive decay, some unstable (radioactive) isotopes spontaneously transform from one element into another at a specific, but constant, rate. As a result, scientists can use certain radioactive isotopes to determine the age of certain processes that happen within the Earth, as well as for dating rocks.

For the Maryland team the tungsten isotope182-tungsten (one of the five isotopes of tungsten) is of special interest because it can be produced by the radioactive decay of an unstable isotope of the element hafnium, 182-hafnium.

According to the UMD team, the radioactive isotope 182-hafnium was present at the time our Solar System formed, but is no longer present on Earth today. Indeed, decay of 182-hafnium into 182-tungsten is so rapid (~9 million year half-life) that variations in the abundance of 182-tungsten relative to other isotopes of tungsten can only be due to processes that occurred very early in the history of our Solar System, they say.

The Maryland geochemists found that the 2.8 billion year old Russian komatiites from Kostomuksha have more of the tungsten isotope 182-W than normal. “This difference in isotopic composition requires that the early Earth formed and separated into its current metallic core, silicate mantle, and perhaps crust, well within the first 60 million years after the beginning of our 4.57-billion-year-old Solar System,” says Touboul.

“In itself this is not new,” he says, “but what is new and surprising is that a portion of the growing Earth developed the unusual chemical characteristics that could lead to the enrichment in 182-tungsten; that this portion survived the cataclysmic impact that created our moon; and that it remained distinct from the rest of the mantle until internal heat melted the mantle and transported some of this material to the surface 2.8 billion years ago, allowing us to sample it today.”

Higher Precision Yields New Findings, Insights

The UMD team explained that they were able to conduct this research because they have developed new techniques that allow the isotopic composition of tungsten to be measured with unprecedented precision. “We do this by chemically separating and purifying the tungsten from the rocks we study. We then use an instrument termed a mass spectrometer to measure the isotopic composition of the tungsten”

According to the researchers their new findings have far reaching implications for understanding how Earth formed; how it differentiated into a metallic core, rocky mantle and crust; and the dynamics of change within the mantle.

“These findings indicate that the Earth’s mantle has never been completely melted and homogenized, and that convective mixing of the mantle, even while Earth was growing, was evidently very sluggish,” says Walker. “Many questions remain. The rocks we studied are 2.8 billion years old. We don’t know whether the portion of the Earth with this unusual isotopic composition or signature can be found in much younger rocks. We plan to analyze some modern volcanic rocks in the near future to assess this.”

Source: University of Maryland