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Space News Update — March 18, 2014 —

Contents

In the News

Story 1:

Surf’s Up on Titan! Cassini May Have Spotted Waves in Titan’s Seas

Story 2:

Amazon Inhales More Carbon than It Emits, NASA Finds

Story 3:

First Microlensing Detection of a Planet Circling a Brown Dwarf Candidate

Departments

The Night Sky

ISS Sighting Opportunities

NASA-TV Highlights

Space Calendar

Food for Thought

Space Image of the Week

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1.0 Surf’s Up on Titan! Cassini May Have Spotted Waves in Titan’s Seas

It’s no surprise that Titan’s north polar region is covered with vast lakes and seas of liquid methane — these have been imaged many times by Cassini during its ten years in orbit around Saturn. What is surprising though is just how incredibly smooth the surfaces of these lakes have been found to be. One would think that such large expanses of surface liquid — some of Titan’s seas are as big the Great Lakes — would exhibit at least a little surface action on a world with an atmosphere as dense as Titan’s. But repeated radar imaging has shown their surfaces to be “as smooth as the paint on a car.” Over the past several years scientists have puzzled over this anomaly but now they may have truly seen the light — that is, reflected light from what could actually be waves on Titan! Using data acquired during flybys of Titan in 2012 and 2013, planetary scientist Jason Barnes from the University of Idaho and a team of researchers from several other institutions including JPL, Cornell, and MIT, have identified what might be waves in the surface of Punga Mare, one of Titan’s biggest lakes. For a sense of scale, Lake Victoria, the largest lake in Africa, could fit lengthwise across Titan’s 380-km (236-mile) -wide Punga Mare. Variations in specular highlights in four pixels observed in the surface of Punga Mare by Cassini’s VIMS (Visible and Infrared Mapping Spectrometer) have been interpreted by the team as being the result of waves — or, perhaps more accurately, ripples, seeing as that they are estimated to be a mere 2 centimeters in height. Still, based on what’s been observed thus far on Titan, that’s downright choppy. If the Cassini observations interpreted by Barnes et al. are indicative of waves in Punga Mare, they could also explain previous specular variations seen in other bodies of liquid, like the smaller Kivu Lacus. Then again, wave action isn’t the only possible answer. Similar varied specular highlights could also be caused by a wet surface — like a methane mud flat. Further observations will be needed to rule out other possibilities and obtain a more accurate “surf forecast” for Titan. The findings were presented by Jason Barnes at the 45th Lunar and Planetary Science Conference in Houston on March 17, 2014. Read the team’s abstract here, and read more in this article by Alexandra Witze on Nature News.

Source: Universe Today Return to Contents

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2. Amazon Inhales More Carbon than It Emits, NASA Finds

A new NASA-led study seven years in the making has confirmed that natural forests in the Amazon remove more carbon dioxide from the atmosphere than they emit, therefore reducing global warming. This finding resolves a long-standing debate about a key component of the overall carbon balance of the Amazon basin. The Amazon's carbon balance is a matter of life and death: living trees take carbon dioxide out of the air as they grow, and dead trees put the greenhouse gas back into the air as they decompose. The new study, published in Nature Communications on March 18, is the first to measure tree deaths caused by natural processes throughout the Amazon forest, even in remote areas where no data have been collected at ground level. Fernando Espírito-Santo of NASA's Jet Propulsion Laboratory, Pasadena, Calif., lead author of the study, created new techniques to analyze satellite and other data. He found that each year, dead Amazonian trees emit an estimated 1.9 billion tons (1.7 billion metric tons) of carbon to the atmosphere. To compare this with Amazon carbon absorption, the researchers used censuses of forest growth and different modeling scenarios that accounted for uncertainties. In every scenario, carbon absorption by living trees outweighed emissions from the dead ones, indicating that the prevailing effect in natural forests of the Amazon is absorption.

Until now, scientists had only been able to estimate the Amazon's carbon balance from limited observations in small forest areas called plots. On these plots, the forest removes more carbon than it emits, but the scientific community has been vigorously debating how well the plots represent all the natural processes in the huge Amazon region. That debate began with the discovery in the 1990s that large areas of the forest can be killed off by intense storms in events called blowdowns. Espírito-Santo said that the idea for the study arose from a 2006 workshop where scientists from several nations came together to identify NASA satellite instruments that might help them better understand the carbon cycle of the Amazon. In the years since then, he worked with 21 coauthors in five nations to measure the carbon impacts of tree deaths in the Amazon from all natural causes -- from large-area blowdowns to single trees that died of old age. He used airborne lidar data, satellite images, and a 10-year set of plot measurements collected by the University of Leeds, England, under the leadership of Emanuel Gloor and Oliver Phillips. He estimates that he himself spent a year-and-a-half doing fieldwork in the Amazon. "It was a difficult and audacious study, and only Espírito-Santo's dedication made it possible," said Michael Keller, a research scientist at the U.S. Forest Service and co-author of the study. Correlating satellite and airborne-instrument data with ground observations, Espírito-Santo and his colleagues devised methods to identify dead trees in different types of remotely sensed images. For example, fallen trees create a gap in the forest canopy that can be measured by lidar on research aircraft, and dead wood changes

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the colors in a satellite optical image. The researchers then scaled up their techniques so they could be applied to satellite and airborne data for parts of the Amazon with no corresponding ground data.

"We found that large natural disturbances -- the sort not captured by plots -- have only a tiny effect on carbon cycling throughout the Amazon," said Sassan Saatchi of JPL, also a co-author. Each year, about two percent of the entire Amazon forest dies of natural causes. The researchers found that only about 0.1 percent of those deaths are caused by blowdowns. This study looked only at natural processes in Amazonia, not at the results of human activities such as logging and deforestation, which vary widely and rapidly with changing political and social conditions. The other institutions participating in the study are the University of New Hampshire, Durham; the Universities of Leeds and Nottingham, U.K.; Oxford University, U.K.; James Cook University, Cairns, Australia; U.S. Forest Service International Institute of Tropical Forestry, Puerto Rico; EMBRAPA Satellite Monitoring Center, Campinas, Brazil; National Institute for Research in Amazonia, Manaus, Brazil; EMBRAPA Eastern Amazonia, Santarém, Brazil; National Institute for Space Research (INPE), São José dos Campos, Brazil; the Missouri Botanical Garden, Oxapampa, Peru; and the Carnegie Institute for Science, Stanford, Calif. NASA monitors Earth's vital signs from land, air and space with a fleet of satellites and ambitious airborne and ground-based observation campaigns. NASA develops new ways to observe and study Earth's interconnected natural systems with long-term data records and computer analysis tools to better see how our planet is changing. The agency shares this unique knowledge with the global community and works with institutions in the United States and around the world that contribute to understanding and protecting our home planet.

NASA JPL Return to Contents

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3. First Microlensing Detection of a Planet Circling a Brown Dwarf Candidate

When astronomers detect new exoplanets they typically do so using one of two techniques. First, there’s the famous transit technique, which looks for slight dips in light as a planet passes in front of its host star, and second is the radial velocity technique, which senses the motion of a star due to the gravitational pull of its planet. But then there is gravitational microlensing, the chance magnification of the light from a distant star by the mass of a foreground star and its planets due to the distortion in the fabric of spacetime.

While this technique sounds almost improbable, it is so accurate that every detection skips nominating planets as candidates and immediately verifies them as bona-fide worlds. But without follow-up observations, the microlensing technique struggles with characterizing the incredibly faint host star. Now, a team of international astronomers led by PhD candidate Jennifer Yee from Ohio State University has detected the first microlensing signature, lovingly called MOA-2013-BLG-220Lb, that looks like a confirmed planet orbiting a candidate brown dwarf — an object so faint because it isn’t massive enough to kick-off nuclear fusion in its core. Matter — no matter how great or small — curves the fabric of spacetime. It can ultimately acts like a lens by curving the background light around it and therefore magnifying the background source. In microlensing, the intervening matter is simply a faint star or perhaps a planetary system. “As the ‘lens system’ passes in front of a distant, background star, the magnification of that background star changes as a function of time,” Yee told Universe Today. “By measuring the changing magnification of the background star, we can learn about the lensing star and perhaps whether or not it has a planet.” In a planetary system, the light from the background star will be magnified when the foreground star passes in front of it. If there is a cirlcing planet, there will be an additional cusp in brightness (to a lesser extent but still a tell-tale detection nonetheless). At the moment the planetary system transits in front of the background star (and for many years after) we can’t separate the two objects. While the light of the background star may be greatly magnified, its image is distorted because its light merges with the planetary system. So the microlensing signature cannot tell astronomers anything about the lens system’s star. “It’s out of the ordinary,” Andrew Gould, Yee’s PhD advisor and coauthor on the paper, told Universe Today. “In other techniques people have definitely detected a star and they’re struggling to detect the planet. But microlensing is just the opposite. We detect the planet very clearly, but we can’t detect the host star.” However, the microlensing signature does give away the lens system’s proper motion — the apparent change in distance over time — as it passes in front of the background star. MOA-2013-BLG-220Lb’s proper motion is extremely high, clocking in at 12.5 milliarcseconds (a distance on the sky that is 2400 times smaller than the size of the full moon) per year. This is roughly three times higher than average. A high proper motion may be caused by an object that is very close by and is moving slowly or a very distant object moving rapidly. As most stars tend not to move at high speeds, the team assumes the object is relatively close, placing it at a distance of 6,000 light-years. With a distance fixed, the team is also able to assume a mass for the object. It weighs in below the hydrogen-burning limit and is therefore considered the best brown dwarf candidate microlensing has detected. “The double-edged sword of microlensing is that no light from the lens star is required,” Yee told Universe Today. “On the one hand, microlensing can find planets around dark or faint objects like brown dwarfs. The flip side is that it’s very difficult to characterize the lens star if its light is not detected.” Astronomers will have to wait until 2021 to take a second look at the lens system. This time frame is how long we expect it to take before the candidate brown dwarf separates appreciably on the sky from the background star. Once it has done so astronomers will be able to verify whether or not the candidate is truly a brown dwarf.

Universe Today Return to Contents

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The Night Sky

Tuesday, March 18

after they rise in the east late tonight and on into dawn on the morning of the 19th. Wednesday, March 19

Asteroid to occult Regulus. For skywatchers in the New York City region and certain areas northward, the faint asteroid 163 Erigone (eh-RIG-uh-nee) will black out 1st-magnitude Regulus for up to 14 seconds a little after 2 a.m. EDT Thursday morning. This is the best asteroid occultation ever predicted to cross such a heavily populated area. And, anywhere from the Carolinas to Nova Scotia to Manitoba, it's also worth watching to see if Regulus might be occulted by a yet-unknown satellite of Erigone!

The International Occultation Timing Association is working up a big public observing campaign. See our article Regulus Occultation: Asteroid to Black Out a Bright Star, and IOTA's big public how-to site at occultations.org/Regulus2014.

Thursday, March 20

in the Southern Hemisphere, at the equinox: 12:57 p.m. Eastern Daylight Time (16:57 UT). This is when the Sun crosses the equator heading north for the year.

or midnight tonight with Saturn shining near it. They reach their highest station in the south before the beginning of dawn. Although they look paired, Saturn is 3,600 times farther away in the background.

Friday, March 21 mond" — bright Jupiter

on top, bright Sirius on the bottom, and Procyon and Betelgeuse forming the left and right corners —

persists well into spring. It stands straight up in the south around dusk, then tips westward as the evening advances.

Saturday, March 22

is standing on its handle in the northeast. As evening grows late the Dipper climbs higher and starts tipping to the left.

Source: Sky 2& Telescope Return to Contents

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ISS Sighting Opportunities For Denver:

Date Visible Max Height Appears Disappears Tue Mar 18, 5:23 AM 2 min 32° 32 above N 11 above NE

Wed Mar 19, 4:35 AM < 1 min 16° 16 above NE 13 above NE

Wed Mar 19, 6:08 AM 4 min 14° 10 above NW 10 above NNE

Thu Mar 20, 5:21 AM 2 min 18° 18 above NNW 11 above NNE

Fri Mar 21, 4:33 AM < 1 min 12° 12 above NNE 11 above NNE

Fri Mar 21, 6:08 AM 2 min 11° 10 above NNW 10 above NNE

Sat Mar 22, 5:19 AM 2 min 13° 12 above NNW 10 above NNE

Sighting information for other cities can be found at NASA’s Satellite Sighting Information

NASA-TV Highlights (all times Eastern Daylight Time)

March 18, Tuesday

5 p.m. - Replay of ISS Expedition 40/41 Crew News Conference - HQ (All Channels)

March 19, Wednesday

2 p.m. - Video File of the ISS Expedition 39/40 Crew Activities in Baikonur, Kazakhstan - JSC via Baikonur,

Kazakhstan (All Channels)

March 20, Thursday

7 - 8 a.m. - Live Interviews with Expedition 38 Flight Engineer Michael Hopkins of NASA - JSC (All

Channels)

March 21, Friday

2 p.m. - Video File of the ISS Expedition 39/40 Crew Activities in Baikonur, Kazakhstan - JSC via Baikonur,

Kazakhstan (All Channels) Watch NASA TV online by going to the NASA website. Return to Contents

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Space Calendar Mar 18 - Comet 169P/NEAT Closest Approach To Earth (1.121 AU) Mar 18 - Comet 244P/Scotti Closest Approach To Earth (3.782 AU) Mar 18 - Comet P/2008 O2 (McNaught) At Opposition (4.176 AU) Mar 18 - Comet C/2013 G7 (McNaught) Perihelion (4.677 AU)

Mar 18 - [Mar 13] Asteroid 2014 EY24 Near-Earth Flyby (0.022 AU) Mar 18 - Asteroid 2013 WT44 Near-Earth Flyby (0.033 AU)

Mar 18 - [Mar 11] Asteroid 2014 EO12 Near-Earth Flyby (0.049 AU) Mar 18 - Asteroid 2005 FN Near-Earth Flyby (0.081 AU) Mar 18 - Asteroid 172996 Stooke Closest Approach To Earth (1.883 AU) Mar 18 - Asteroid 10168 Stony Ridge Closest Approach To Earth (1.929 AU) Mar 18 - Asteroid 54522 Menaechmus Closest Approach To Earth (2.100 AU)

Mar 19 - [Mar 15] Comet C/2014 E2 (Jacques) At Opposition (1.116 AU) Mar 19 - Comet C/2013 Y2 (PANSTARRS) Closest Approach To Earth (1.557 AU) Mar 19 - Comet C/2012 K6 (McNaught) At Opposition (3.462 AU) Mar 19 - Asteroid 770 Bali Closest Approach To Earth (1.348 AU) Mar 19 - Asteroid 8990 Compassion Closest Approach To Earth (1.889 AU) Mar 19 - Asteroid 132524 APL Closest Approach To Earth (2.075 AU) Mar 19 - 135th Anniversary (1879), Tenham Meteorite Shower in Australia Mar 20 - Cassini, Orbital Trim Maneuver #375 (OTM-375) Mar 20 - Vernal Equinox, 16:57 UT Mar 20 - Comet P/2014 D2 (Catalina-PANSTARRS) Closest Approach To Earth (2.597 AU) Mar 20 - Comet C/2013 C2 (Tenagra) Closest Approach To Earth (8.415 AU) Mar 20 - Asteroid 163 Erigone Occults HIP 49669 (1.3 Magnitude Star) Mar 20 - Asteroid 4798 Mercator Closest Approach To Earth (1.140 AU) Mar 20 - Asteroid 5035 Swift Closest Approach To Earth (1.500 AU) Mar 20 - Asteroid 6216 San Jose Closest Approach To Earth (1.890 AU) Mar 20 - Asteroid 4352 Kyoto Closest Approach To Earth (2.026 AU) Mar 20 - Dwarf Planet 136472 Makemake At Opposition (51.482 AU) Mar 21 - Astra 5B/ Amazonas 4A/ Ariane 5 Launch Mar 21 - Moon Occults Saturn Mar 21 - Comet 124P/Mrkos Closest Approach To Earth (0.679 AU) Mar 21 - Comet 57P/du Toit-Neujmin-Delporte At Opposition (2.582 AU) Mar 21 - Asteroid 2014 DW110 Near-Earth Flyby (0.065 AU) Mar 21 - Asteroid 51829 Williemccool Closest Approach To Earth (1.194 AU) Mar 21 - Asteroid 2187 La Silla Closest Approach To Earth (1.854 AU) Mar 21 - Asteroid 76272 De Jong Closest Approach To Earth (1.917 AU) Mar 21 - Asteroid 4446 Carolyn Closest Approach To Earth (3.534 AU) Mar 22 - Mercury Passes 1.25 Degrees From Neptune Mar 22 - Venus At Its Greatest Western Elongation (47 Degrees) Mar 22 - Comet C/2014 C3 (NEOWISE) Closest Approach To Earth (1.064 AU) Mar 22 - Comet P/2008 J2 (Beshore) At Opposition (1.579 AU) Mar 22 - Comet 135P/Shoemaker-Levy At Opposition (1.960 AU) Mar 22 - Comet 114P/Wiseman-Skiff Closest Approach To Earth (2.228 AU) Mar 22 - Asteroid 21 Lutetia At Opposition (11.0 Magnitude) Mar 22 - Asteroid 17023 Abbott Closest Approach To Earth (1.291 AU) Mar 22 - Asteroid 214476 Stephencolbert Closest Approach To Earth (2.283 AU)

Source: JPL Space Calendar Return to Contents

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Food for Though

Astronomers discover echoes from expansion after Big Bang

Astronomers announced on Monday that they had discovered what many consider the holy grail of their field:

ripples in the fabric of space-time that are echoes of the massive expansion of the universe that took place just

after the Big Bang. Predicted by Albert Einstein nearly a century ago, the discovery of the ripples, called

gravitational waves, would be a crowning achievement in one of the greatest triumphs of the human intellect: an

understanding of how the universe began and evolved into the cornucopia of galaxies and stars, nebulae and

vast stretches of nearly empty space that constitute the known universe. "This detection is cosmology's missing

link," Marc Kamionkowski, a physicist of Johns Hopkins University and one of the researchers on the

collaboration that made the finding, told reporters on Monday at a press conference at the Harvard-Smithsonian

Center for Astrophysics in Cambridge, Massachusetts. Gravitational waves are feeble, primordial undulations

that propagate across the cosmos at the speed of light. Astronomers have sought them for decades because they

are the missing evidence for two theories. One is Einstein's general theory of relativity, first published in 1915,

which launched the modern era of research into the origins and evolution of the cosmos. The general theory

explains gravity as the deformation of space by massive bodies. Einstein posited that space is like a flimsy

blanket, with embedded stars and planets causing it to curve rather than remain flat. Those curvatures of space

are not stationary, Einstein said. Instead, they propagate like water in a lake or seismic waves in Earth's crust

and so are "gravitational waves" that "alternately squeeze space in one direction and stretch it in the other

direction," Jamie Bock, a physicist at the California Institute of Technology in Pasadena and one of the lead

scientists on the collaboration, told Reuters.

The other, much more recent theory that predicted gravitational waves is called cosmic inflation. Developed in

the 1980s, it starts with the well-accepted idea that the universe began in a Big Bang, an explosion of space-

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time, 13.8 billion years ago. An instant later, according to the theory, the infant cosmos expanded

exponentially, inflating in size by 100 trillion times. That made the cosmos remarkably uniform across vast

expanses of space and also super-sized tiny fluctuations in gravity, producing gravitational waves. Although

the theory of cosmic inflation received a great deal of experimental support, the failure to find the gravitational

waves it predicted caused many cosmologists to hold off endorsing it. That may change after the announcement

on Monday. "These results are not only a smoking gun for inflation, they also tell us when inflation took place

and how powerful the process was," Harvard University physicist Avi Loeb said in a statement. The strength of

the gravitational waves' signal is tied to how powerfully the universe expanded during the brief era of inflation.

The measurements announced by the astronomers on Monday are nearly twice as large as cosmologists

predicted for gravitational waves, suggesting a great deal more could be learned about how inflation worked.

The gravitational waves were detected by a radio telescope called BICEP2 (Background Imaging of Cosmic

Extragalactic Polarization). The instrument, which scans the sky from the South Pole, examines what is called

the cosmic microwave background, the extremely weak radiation that pervades the universe. Its discovery in

1964 by astronomers at Bell Labs in New Jersey was hailed as the best evidence to date that the universe began

in an immensely hot explosion. The microwave background radiation, which has been bathing the universe

since 380,000 years after the Big Bang, is a mere 3 degrees above absolute zero, having cooled to near non-

existence from the immeasurably hot plasma that was the universe in the first fractions of a second of its

existence. The background radiation is not precisely uniform. And like light, the relic radiation is polarized as

the result of interacting with electrons and atoms in space. Computer models predicted a particular curl pattern

in the background radiation that would match what would be expected with the universe's inflation after the Big

Bang. "It's mind-boggling to go looking for something like this and actually find it," Clem Pryke, a physicist at

the University of Minnesota and another lead scientist on the collaboration, told reporters. "Theorists are forever

sending the experimentalists on wild goose-chase missions. When we first saw hints of a signal we totally didn't

believe it." It will be up to other teams of scientists, working with an array of Earth-based, balloon-launched

and space telescopes, to verify the findings. "This is the smoking gun for inflation," Kamionkowski said. But

even if the results hold up, "we've learned only that inflation has sent us a telegram, encoded on gravitational

waves and transcribed on the cosmic microwave background sky." It will be essential, he added, "to follow

through with more detailed and precise measurements to infer fully what this telegram is telling us."

QUANTUM HINTS - The detection of gravitational waves may help physicists realize a dream of Einstein's

that he died before achieving: unifying all the forces of nature. Three of the four forces have been unified,

which means that physicists have shown that they are facets of the same basic force. But the fourth, Einstein's

beloved gravity, remains the odd man out: it seems to be a property of space rather than a consequence of

subatomic, or quantum, particles as the other forces are. The three quantum-based forces are electromagnetism,

the weak nuclear force (responsible for radioactivity) and the strong nuclear force (which glues together the

protons and neutrons in atomic nuclei). Because cosmic inflation was powered by quantum effects, with the

universe springing from a volume smaller than a subatomic particle, primordial gravitational waves were also

created by quantum processes, cosmologists believe. If so, then by scrutinizing the gravitational waves that

pervade today's cosmos, scientists might finally show that all four forces of nature arise from a single uber-

force, achieving Einstein's dream.

Reuters Return to Contents

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Space Image of the Week

Warped Sky: Star Trails over Arches National Park

Image Credit & Copyright: Vincent Brady

Explanation: What's happened to the sky? A time warp, of sorts, and a digital space warp too. The time warp occurs because this image captured in a single frame a two and a half hour exposure of the night sky. As a result, prominent star trails are visible. The space warp occurs because the picture is actually a full 360 degree panorama, horizontally compressed to fit your browser. As the Earth rotated, stars appeared to circle both the North Celestial Pole, on the left, and the South Celestial Pole, just below the horizon on the right. The above panorama over Arches National Park in Utah, USA, was captured two weeks ago during early morning hours. While the eye-catching texture of ancient layered sandstone covers the image foreground, twenty-meter tall Delicate Arch is visible on the far right, and the distant arch of our Milky Way Galaxy is visible near the image center.

Source: NASA APOD Return to Contents