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Space News Update — January 11, 2013 —

Contents

In the News

Story 1: Life Possible on Extrasolar Moons

Story 2: NASA, ESA Telescopes Find Evidence for Asteroid Belt Around Vega

Story 3: Spacetime: A Smoother Brew Than We Knew

Departments

The Night Sky

ISS Sighting Opportunities

Space Calendar

NASA-TV Highlights

Food for Thought

Space Image of the Week

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1. Life Possible on Extrasolar Moons

In their search for habitable worlds, astronomers have started to consider exomoons, or those likely orbiting planets outside the solar system. In a new study, a pair of researchers has found that exomoons are just as likely to support life as exoplanets.

The research, conducted by Rene Heller of Germany's Leibniz Institute for Astrophysics Potsdam and Rory Barnes of the University of Washington and the NASA Astrobiology Institute, will appear in the January issue of Astrobiology.

About 850 extrasolar planets -- planets outside the solar system -- are known, and most of them are sterile gas giants, similar to Jupiter. Only a few have a solid surface and orbit their host stars in the habitable zone, the circumstellar belt at the right distance to potentially allow liquid surface water and a benign environment.

Heller and Barnes tackled the theoretical question whether such planets could host habitable moons. No such exomoons have yet been discovered but there's no reason to assume they don't exist.

The climatic conditions expected on extrasolar moons will likely differ from those on extrasolar planets because moons are typically tidally locked to their planet. Thus, similar to the Earth's moon, one hemisphere permanently faces the planet. Beyond that moons have two sources of light -- that from the star and the planet they orbit -- and are subject to eclipses that could significantly alter their climates, reducing stellar illumination. "An observer standing on the surface of such an exomoon would experience day and night in a totally different way than we do on Earth." explained Heller. "For instance stellar eclipses could lead to sudden total darkness at noon."

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Heller and Barnes also identified tidal heating as a criterion for exomoon habitability. This additional energy source is triggered by a moon's distance to its host planet; the closer the moon, the stronger tidal heating. Moons that orbit their planet too closely will undergo strong tidal heating and thus a catastrophic runaway greenhouse effect that would boil away surface water and leave them forever uninhabitable.

They also devised a theoretical model to estimate the minimum distance a moon could be from its host planet and still allow habitability, which they call the "habitable edge." This concept will allow future astronomers to evaluate the habitability of extrasolar moons. "There is a habitable zone for exomoons, it's just a little different than the habitable zone for exoplanets," Barnes said.

The exquisite photometric precision of NASA's Kepler space telescope now makes the detection of a Mars- to Earth-size extrasolar moon possible, indeed imminent. Launched in 2009, the telescope enabled scientists to reveal thousands of new extrasolar planet candidates. Since 2012 the first dedicated "Hunt for Exomoons with Kepler" is under way.

Heller and Barnes' paper, "Exomoon Habitability Constrained by Illumination and Tidal Heating," will be published in the January issue of the journal Astrobiology.

Source: Spaceref.com Return to Contents

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2. NASA, ESA Telescopes Find Evidence for Asteroid Belt Around Vega

Astronomers have discovered what appears to be a large asteroid belt around the star Vega, the second brightest star in northern night skies. The scientists used data from NASA's Spitzer Space Telescope and the European Space Agency's Herschel Space Observatory, in which NASA plays an important role.

The discovery of an asteroid belt-like band of debris around Vega makes the star similar to another observed star called Fomalhaut. The data are consistent with both stars having inner, warm belts and outer, cool belts separated by a gap. This architecture is similar to the asteroid and Kuiper belts in our own solar system.

What is maintaining the gap between the warm and cool belts around Vega and Fomalhaut? The results strongly suggest the answer is multiple planets. Our solar system's asteroid belt, which lies between Mars and Jupiter, is maintained by the gravity of the terrestrial planets and the giant planets, and the outer Kuiper belt is sculpted by the giant planets.

"Our findings echo recent results showing multiple-planet systems are common beyond our sun," said Kate Su, an astronomer at the Steward Observatory at the University of Arizona, Tucson. Su presented the results Tuesday at the American Astronomical Society meeting in Long Beach, Calif., and is lead author of a paper on the findings accepted for publication in the Astrophysical Journal.

Vega and Fomalhaut are similar in other ways. Both are about twice the mass of our sun and burn a hotter, bluer color in visible light. Both stars are relatively nearby, at about 25 light-years away. The stars are thought to be around 400 million years old, but Vega could be closer to its 600 millionth birthday. Fomalhaut has a single candidate planet orbiting it, Fomalhaut b, which orbits at the inner edge of its cometary belt.

The Herschel and Spitzer telescopes detected infrared light emitted by warm and cold dust in discrete bands around Vega and Fomalhaut, discovering the new asteroid belt around Vega and confirming the existence of the other belts around both stars. Comets and the collisions of rocky chunks replenish the dust in these bands. The inner belts in these systems cannot be seen in visible light because the glare of their stars outshines them.

Both the inner and outer belts contain far more material than our own asteroid and Kuiper belts. The reason is twofold: the star systems are far younger than our own, which has had hundreds of millions more years to clean

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house, and the systems likely formed from an initially more massive cloud of gas and dust than our solar system.

The gap between the inner and outer debris belts for Vega and Fomalhaut also proportionally corresponds to the distance between our sun's asteroid and Kuiper belts. This distance works out to a ratio of about 1:10, with the outer belt 10 times farther from its host star than the inner belt. As for the large gap between the two belts, it is likely there are several undetected planets, Jupiter-size or smaller, creating a dust-free zone between the two belts. A good comparison star system is HR 8799, which has four known planets that sweep up the space between two similar disks of debris.

"Overall, the large gap between the warm and the cold belts is a signpost that points to multiple planets likely orbiting around Vega and Fomalhaut," said Su.

If unseen planets do, in fact, orbit Vega and Fomalhaut, these bodies will not likely stay hidden.

"Upcoming new facilities such as NASA's James Webb Space Telescope should be able to find the planets," said paper co-author Karl Stapelfeldt, chief of the Exoplanets and Stellar Astrophysics Laboratory at NASA's Goddard Space Flight Center in Greenbelt, Md.

NASA's Jet Propulsion Laboratory, Pasadena, Calif., manages the Spitzer Space Telescope mission for NASA's Science Mission Directorate, Washington. Science operations are conducted at the Spitzer Science Center at the California Institute of Technology in Pasadena. Data are archived at the Infrared Science Archive housed at the Infrared Processing and Analysis Center at Caltech. Caltech manages JPL for NASA. For more information about Spitzer, visit: http://spitzer.caltech.edu and http://www.nasa.gov/spitzer .

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, which 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 Caltech, supports the United States astronomical community. More information is online at: http://www.herschel.caltech.edu , http://www.nasa.gov/herschel, and http://www.esa.int/SPECIALS/Herschel/index.html.

You can follow JPL News on Facebook at: http://www.facebook.com/nasajpl and on Twitter at: http://www.twitter.com/nasajpl .

Source: NASA Return to Contents

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3. Spacetime: A Smoother Brew Than We Knew

Spacetime may be less like foamy quantum beer and more like smooth Einsteinian whiskey, according to research led by physicist Robert Nemiroff of Michigan Technological University being presented today at the 221st American Astronomical Society meeting in Long Beach, Calif.

Or so an intergalactic photo finish would suggest.

Nemiroff and his team reached this heady conclusion after studying the tracings of three photons of differing wavelengths recorded by NASA's Fermi Gamma-ray Space Telescope in May 2009.

The photons originated about 7 billion light-years away from Earth from a gamma-ray burst and arrived at the orbiting telescope a mere millisecond apart.

"Gamma-ray bursts can tell us some very interesting things about the universe," Nemiroff says. In this case, those three photons recorded by the Fermi telescope may be validating Albert Einstein's view of smooth spacetime into the realm of quantum mechanics. In other words, spacetime may not be not as foamy as some scientists think.

In his General Theory of Relativity, Einstein described space and time as smooth, deforming only under the weight of matter and energy. But according to some theories of quantum gravity, which deal with matter and energy at the smallest scale, spacetime is made up of a froth of particles and possibly even black holes that pop in and out of existence over infinitesimally small moments at the so-called Planck-length scale, which is less than a trillionth of a trillionth the diameter of a hydrogen atom.

The "bubbles" in this foam -- should they exist -- are so small as to be almost undetectable. However, scientists have theorized that photons from gamma-ray bursts should be able to track down the bubbles' signature.

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Here's why. The wavelengths of gamma-ray burst photons are some of the shortest distances known to science -- so short they should interact with the even smaller bubbles of quantum foam. And if they interact, the photons should be dispersed -- scattered -- on their trek through frothy spacetime.

In particular, they should disperse in different ways if their wavelengths differ, as in the case of Nemiroff's three photons. Imagine a Ping Pong ball, a bowling ball, and a softball taking alternate paths down a gravely hillside.

Furthermore, few things can delay gamma-ray photons like these, so they might travel for unimaginably long distances unimpeded. You wouldn't notice the scattering over short distances, but across 7 billion light-years, the quantum foam might knock the light around enough to notice. And three photons from the same gamma-ray burst might not have crashed through the Fermi telescope in a dead heat.

Bolstered by the evidence garnered from the three photons, Nemiroff's analysis supports earlier indications but takes them clearly below the Planck length: "If foaminess exists at all, we think it must be at a scale far smaller than the Planck length, indicating that other physics might be involved," he says.

"There is a possibility of a statistical fluke, or that spacetime foam interacts with light differently than we imagined," Nemiroff said.

"If future gamma-ray bursts confirm this, we will have learned something very fundamental about our universe," says Bradley E. Schaefer, professor of physics and astronomy at Louisiana State University.

For now, at least, this looks like another win for Einstein. Perhaps it calls for a toast.

Source: Spaceref.com

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The Night Sky

Friday, January 11

• In early evening at this time of year, the Great Square of Pegasus balances on one corner high in the west. The vast Andromeda-Pegasus constellation complex runs all the way from near the zenith (Andromeda's foot) down through the Great Square (Pegasus's body) to low in the west (Pegasus's nose). Saturday, January 12 • As twilight turns to night, look low in the northwest for Vega. To its upper left, by two or three fists at arm's length, shines Deneb. Deneb is the head of the big Northern Cross, which is now swinging down and soon will stand nearly upright on the northwest horizon (as seen from mid-northern latitudes).

Sunday, January 13

• In twilight this evening, look below the waxing crescent Moon in the west to see if you can still spot faint little Mars, as shown here. Mars has been hanging in there in twilight ever since August (!) but is now gradually creeping lower week by week.

Monday, January 14

• Before moonlight returns in force to wash out low-surface-brightness telescopic objects, try tonight for the Bubble and Pac-Man Nebulae in Cassiopeia using Ken Hewitt-White's "Hot Gas in Cass" article with finder chart and photos in the January Sky & Telescope, page 65. Source:

Sky & Telescope Return to Contents

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ISS Sighting Opportunities For Denver:

SATELLITE LOCAL DURATION MAX ELEV APPROACH DEPARTURE

DATE/TIME (MIN) (DEG) (DEG-DIR) (DEG-DIR) ISS Sat Jan 12/05:57 AM 5 86 23 above SW 11 above NE

ISS Sun Jan 13/05:09 AM 2 33 33 above E 11 above ENE

ISS Sun Jan 13/06:43 AM 5 24 11 above W 10 above NNE

ISS Mon Jan 14/05:55 AM 3 37 37 above NW 11 above NE

Sighting information for other cities can be found at NASA’s Satellite Sighting Information NASA-TV Highlights (all times Eastern Daylight Time) No special programming

Watch NASA TV on the Net by going to the NASA website.

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Space Calendar

• Jan 11 - [Jan 07] Asteroid 2013 AB4 Near-Earth Flyby (0.017 AU) • Jan 11 - Asteroid 163800 Richardnorton Closest Approach To Earth (1.418 AU) • Jan 11 - Asteroid 1777 Gehrels Closest Approach To Earth (1.593 AU) • Jan 11 - Asteroid 11947 Kimclijsters Closest Approach To Earth (2.794 AU) • Jan 12 - Asteroid 6336 Dodo Closest Approach To Earth (1.492 AU) • Jan 12 - Asteroid 214476 Stephencolbert Closest Approach To Earth (2.393 AU) • Jan 13 - Asteroid 5891 Gehrig Closest Approach To Earth (1.286 AU) • Jan 13 - Asteroid 12490 Leiden Closest Approach To Earth (2.269 AU) • Jan 14 - Asteroid 13188 Okinawa Closest Approach To Earth (1.191 AU) • Jan 14 - Asteroid 1913 Sekanina Closest Approach To Earth (1.842 AU) • Jan 14 - Kuiper Belt Object 20000 Varuna At Opposition (42.669 AU) • Jan 14 - 5th Anniversary (2008), MESSENGER, 1st Mercury Flyby

Artist’s impression of MESSENGER at Mercury

Source: JPL Space Calendar

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Food for Thought

The Self-Assembling Particles That Come From InSPACE e

Shape-shifting malleable, gelatinous forms are orbiting the Earth at this very moment -- assembling and disassembling, growing as they are bombarded by magnetic pulses. These forms will take shape as astronauts run experiments involving smart fluids aboard the International Space Station.

While they may change shape, the forms are not things of science fiction. They are the things of fundamental science.

The purpose of the Investigating the Structures of Paramagnetic Aggregates from Colloidal Emulsions-3, or InSPACE-3, study is to gather fundamental data about Magnetorheological, or MR fluids. These fluids are a type of smart fluid that tends to self-assemble into shapes. When they are exposed to a magnetic field, they can quickly transition into a nearly solid-like state. When the magnetic field is removed, they return to a liquid state.

"Initially the particles in the fluid form long, thin chains," said Eric Furst, InSPACE-3 principal investigator, University of Delaware, Newark, Del. "The magnetic dipoles induced in the particles cause these singular chains to grow parallel to the applied field. Over time the chains parallel to each other interact and bond together. These 'bundles' of chains become more like columns when the magnetic field is toggled on and off. And these columns grow in diameter with time exposed to a pulsed magnetic field."

This self-directed "bundling" was never before observed until it was seen in an earlier space station investigation, InSPACE-2, which ended in 2009. The results of InSPACE-2 were highlighted in a September 2012 article titled "Multi-scale Kinetics of a Field-directed Phase Transition" published in the Proceedings of the National Academy of Sciences.

"Earlier InSPACE investigations looked at MR fluids composed of spherical, or round, particles," said Bob Green, InSPACE-3 project scientist, NASA's Glenn Research Center, Cleveland, Ohio. "InSPACE-3 is focused on oval or ellipsoid-shaped particles. The expectation is that these shapes will pack differently and form column-like structures differently than in previous experiments. The particles in InSPACE-3 are made of a polystyrene material embedded with tiny nano-sized iron oxide particles."

Iron oxide is chemically similar to rust. In fact, when the fluid is mixed, it has a brownish rust-type hue. Astronauts, under the direction of the project team, are currently running a series of experiments on this rust-colored mixture and will continue to do so for the next few months.

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"We have six vials of which three are primary and three are backups," said Nang Pham, InSPACE-3 project manager at Glenn. "We'll run 12 tests on each of the three vials of different sized ellipsoid-shaped particles for a total of 36 test runs."

A test run could be changing the frequency of the magnetic pulse, altering the magnetic field strength, or using different particle sizes. The first InSPACE-3 test was Oct. 5. Plans are to complete the test runs in early 2013.

For the investigation, astronauts apply a magnetic field of a certain strength, which is pulsed from a low frequency of around 0.66 hertz up to 20 hertz. The pulse is on for a very short time and then is turned off. Scientists are looking for formation of structures that are at a lower energy state. Typically in an MR fluid application, a constant field is applied and the particles form a gel-like structure. They don't pack very well, so the particles have no definite form. They are like a cloud or hot glass that can form into almost any shape.

In a pulsed field, the on-off magnetic field forces the particles to assemble, disassemble, assemble, disassemble and so on. This on-and-off action occurs in millisecond pulses over the approximately two hours of the experiment. In this pulsed field, the particles organize into a more tightly packed structure. Scientists can then measure and plot the column growth over time.

"The idea is to understand the fundamental science around this directed self-assembly in the hopes of better defining new methods of manufacturing materials composed of small colloidal or nanoparticle building blocks," Furst said.

New manufacturing models resulting from InSPACE-2 and -3 studies could be used to improve or develop active mechanical systems such as new brake systems, seat suspensions, stress transducers, robotics, rovers, airplane landing gears and vibration damping systems.

Coupled with the work of InSPACE-2, the InSPACE-3 investigation into fundamental science could advance these systems and improve how we ride, drive and fly. Thanks to these space station investigations, the fluids that come from space may one day further improve your daily commute, whether on the highway or off the road.

Source: NASA Return to Contents

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Space Image of the Week

Sizzling Remains of a Dead Star Explanation: This new view of the historical supernova remnant Cassiopeia A, located 11,000 light-years away, was taken by NASA's Nuclear Spectroscopic Telescope Array, or NuSTAR. Blue indicates the highest energy X-ray light, where NuSTAR has made the first resolved image ever of this source. Red and green show the lower end of NuSTAR's energy range, which overlaps with NASA's high-resolution Chandra X-ray Observatory. Light from the stellar explosion that created Cassiopeia A is thought to have reached Earth about 300 years ago, after traveling 11,000 years to get here. While the star is long dead, its remains are still bursting with action. The outer blue ring is where the shock wave from the supernova blast is slamming into surrounding material, whipping particles up to within a fraction of a percent of the speed of light. NuSTAR observations should help solve the riddle of how these particles are accelerated to such high energies X-ray light with energies between 10 and 20 kiloelectron volts are blue; X-rays of 8 to 10 kiloelectron volts are green; and X-rays of 4.5 to 5.5 kiloelectron volts are red. The starry background picture is from the Digitized Sky Survey. Image Credit: NASA/JPL-Caltech/DSS Source: NASA NuSTAR Return to Contents