Showing posts from 2012

NASA Spacecraft Finds New Evidence for Water Ice on Mercury

Source:   NASA RELEASE 12-411  Excerpt: NASA's MErcury Surface, Space ENvironment, GEochemistry, and Ranging (MESSENGER) spacecraft… has provided compelling support for the long-held hypothesis the planet harbors abundant water ice … within its permanently shadowed polar craters. …"The new data indicate the water ice in Mercury's polar regions, if spread over an area the size of Washington, D.C., would be more than 2 miles thick," said David Lawrence, a MESSENGER participating scientist …. Given its proximity to the sun, Mercury would seem to be an unlikely place to find ice. However, the tilt of Mercury's rotational axis is less than 1 degree, and as a result, there are pockets at the planet's poles that never see sunlight. …MESSENGER's neutron spectrometer provides a measure of average hydrogen concentrations within Mercury's radar-bright regions. Water ice concentrations are derived from the hydrogen measurements….

The Origin of the Moon

Source:  Alex  N. Halliday,  Science: Vol. 338 no. 6110 pp. 1040-1041 DOI: 10.1126/science.1229954 Excerpt: Any successful model of lunar origin has to explain the Moon’s angular momentum and its slightly lower density (than Earth). …The Moon formed relatively late given its size … more than 30 million years after the start of the solar system, whereas most objects this size are predicted to have formed in the first few hundred thousand years. The oldest rocks appear to have formed from a magma ocean, implying an intensely energetic fiery start…. The oxygen isotopic composition of the Moon is identical to that of Earth to within 5 parts per million, whereas that of nearly all asteroidal and planetary objects are different…. The Giant Impact Theory is the … widely accepted current explanation for the Moon’s late, molten start as a low-density object that now contributes most of the angular momentum in the Earth-Moon system. … an Earth when it was about 85 to 90% formed and anothe

Out There: Discovery Rekindles Wish for a Journey to the Stars

Source:  Dennis Overbye, New York Times Excerpt:  The discovery last week of an Earth-like planet circling Alpha Centauri B "set off an epidemic of daydreaming among the astronomical and sci-fi set," including Sara Seager, an MIT astronomer, who repeated a call made last year by Berkeley astronomer Geoff Marcy that "we should drop everything and send a probe there.” "But if astronomers have learned anything over the last few years from devices like the Kepler satellite, it is that small planets come in packs. There is plenty of room in the system for more planets, habitable ones." Read the full article:

NASA's Infrared Observatory Measures Expansion of Universe

Source:  NASA 12-343   Excerpt:  …Astronomers using NASA's Spitzer Space Telescope have announced the most precise measurement yet of …the rate at which our universe is stretching apart. …It … brings the uncertainty down to 3 percent, a giant leap in accuracy for cosmological measurements.   … "Just over a decade ago, using the words 'precision' and 'cosmology' in the same sentence was not possible, and the size and age of the universe was not known to better than a factor of two," said Freedman. "Now we are talking about accuracies of a few percent." …

Sizing up a new measuring ruler for the solar system

Source:  Jacob Aron, NewScientist Excerpt:  At … the IAU in Beijing, China, members unanimously voted to redefine the astronomical unit, or AU, which has long served as the fundamental unit of distance between objects in the solar system. … the official definition of the AU is now exactly 149,597,870,700 metres, and the unit should be written "au". Historically, calculating the astronomical unit was based on the average distance between Earth and the sun, or 149,597,870,691 metres. An amendment in 1976 complicated things by also tying the unit to the sun's mass. Although the recent decision doesn't alter the value by much, it simplifies things and should improve the accuracy of distance measurements over time..

Hubble discovers a fifth moon orbiting Pluto

Source:  NASA,  Goddard Space Flight Center, ScienceDaily                Excerpt: … discovery of another moon orbiting the icy dwarf planet Pluto … estimated to be irregular in shape and 6 to 15 miles across … in a 58,000-mile-diameter circular orbit around Pluto…. The discovery increases the number of known moons orbiting Pluto to five. The Pluto team is intrigued that such a small planet can have such a complex collection of satellites. …"The discovery of so many small moons indirectly tells us that there must be lots of small particles lurking unseen in the Pluto system," said Harold Weaver of the Johns Hopkins University Applied Physics Laboratory….

NASA'S Cassini Finds Probable Subsurface Ocean on Saturn Moon

Source:  Jia-Rui C. Cook,  NASA News RELEASE: 12-218    Excerpt: Data from NASA's Cassini spacecraft have revealed Saturn's moon Titan likely harbors a layer of liquid water under its ice shell. …"Cassini's detection of large tides on Titan leads to the almost inescapable conclusion that there is a hidden ocean at depth," said Luciano Iess, … Cassini team member at the Sapienza University of Rome, Italy. "The search for water is an important goal in solar system exploration, and now we've spotted another place where it is abundant."

NASA Spacecraft Reveals Ice Content in Moon Crater

Source:   Nancy Neal-Jones / Bill Steigerwald,    NASA Release 12-208  Excerpt: NASA's Lunar Reconnaissance Orbiter (LRO) spacecraft has returned data that indicate ice may make up as much as 22 percent of the surface material in a crater located on the moon's south pole. ….

NASA Dawn Spacecraft Reveals Secrets of Large Asteroid

Source:   NASA RELEASE: 12-153 Excerpt: NASA's Dawn spacecraft has provided researchers with the first orbital analysis of the giant asteroid Vesta, yielding new insights into its creation and relation to the terrestrial planets and Earth's moon. Vesta now has been revealed as a special fossil of the early solar system … Vesta more closely resembles a small planet or Earth's moon than another asteroid. …Scientists now see Vesta as a layered, planetary building block with an iron core - the only one known to survive the earliest days of the solar system. The asteroid's geologic complexity can be attributed to a process that separated the asteroid into a crust, mantle and iron core with a radius of approximately 68 miles (110 kilometers) about 4.56 billion years ago. The terrestrial planets and Earth's moon formed in a similar way. …Data also confirm a distinct group of meteorites found on Earth did, as theorized, originate from Vesta.  ...These objects account

Apollo Lunar Surface Journal

Source:   Eric M. Jones and Ken Glover, NASA Excerpt: …the actual recording of events which took place during the Apollo Program flights. The twelve astronauts who landed and explored the Earth's closest neighbor were the only human beings ever to observe firsthand the surface of a body in our universe other than the Earth. … their personal comments and interpretations made during their exploration of the Moon are rare national treasures.….

NASA Dawn Spacecraft Reveals Secrets of Giant Asteroid Vesta

Source:   NASA  RELEASE: 12-134   Excerpt: ...Findings from NASA's Dawn spacecraft reveal new details about the giant asteroid Vesta, including its varied surface composition, sharp temperature changes and clues to its internal structure. … Many of the materials seen by Dawn are composed of iron- and magnesium-rich minerals, which often are found in Earth's volcanic rocks. Images also reveal smooth pond-like deposits, which might have formed as fine dust created during impacts settled into low regions.  …Dawn obtained the highest-resolution surface temperature maps of any asteroid visited by a spacecraft. Data reveal temperatures can vary from as warm as -10 degrees Fahrenheit (-23 degrees Celsius) in the sunniest spots to as cold as -150 degrees Fahrenheit (-100 degrees Celsius) in the shadows….

NASA Scientists Find History of Asteroid Impacts in Earth Rocks

Source:  NASA RELEASE : 12-135   Excerpt: … Research by NASA and international scientists concludes giant asteroids, similar or larger than the one believed to have killed the dinosaurs, hit Earth billions of years ago with more frequency than previously thought. To cause the dinosaur extinction, the killer asteroid that impacted Earth 65 million years ago would have been almost 6 miles (10 kilometers) in diameter. By studying ancient rocks in Australia and using computer models, researchers estimate that approximately 70 asteroids the same size or larger impacted Earth 1.8 to 3.8 billion years ago. During the same period, approximately four similarly-sized objects hit the moon…. :

Hunting for the Great Galactic Internet

Source:    Anil Ananthaswamy,  Slate/The New Scientist Excerpt: Interview with veteran astronomer, Geoffrey Marcy, who is turning his attention to the search for extraterrestrial intelligence. As the new chair of Search for Extra-Terrestrial Intelligence, Geoffrey Marcy has started looking for alien civilizations….

Evidence Against Moon as Meteoroid’s Offspring

Source:   Sindyan N. Bhanoo, The New York Times Excerpt: Astronomers have long theorized that the Moon was formed when an object the size of Mars slammed into Earth, sending a huge mass of rock into orbit around it. “According to the prevailing model prediction, approximately half of the Moon-forming material should come from the Mars-size impactor,” said Junjun Zhang, an isotope geochemist at the University of Chicago and the study’s first author. But samples of isotopic titanium from the Moon and from Earth now suggest that material from Earth is predominant on the Moon, researchers report in the journal Nature Geoscience. …She and her colleagues used lunar samples gathered by the Apollo missions in the 1960s and ’70s. They compared the isotopic titanium ratio in these samples to that of samples from Earth. The researchers also found that meteorites have a much wider range of isotopic titanium. “That also tells us that the impactor that hit the Earth was very unlikely to have

Many Billions of Rocky Planets in the Habitable Zones around Red Dwarfs in the Milky Way

Source:   European Southern Observatory (ESO)  Excerpt: A new result from ESO’s HARPS planet finder shows that rocky planets not much bigger than Earth are very common in the habitable zones around faint red stars. The international team estimates that there are tens of billions of such planets in the Milky Way galaxy alone, and probably about one hundred in the Sun’s immediate neighbourhood. … red dwarf stars…are faint and cool compared to the Sun, but very common and long-lived, and therefore account for 80% of all the stars in the Milky Way. "… about 40% of all red dwarf stars have a super-Earth orbiting in the habitable zone where liquid water can exist on the surface of the planet,” says Xavier Bonfils …. “Because red dwarfs are so common — there are about 160 billion of them in the Milky Way — this leads us to the astonishing result that there are tens of billions of these planets in our galaxy alone.” The HARPS team surveyed a carefully chosen sample of 102 red dwarf

Is It Snowing Microbes on Enceladus?

Source:   Dauna Coulter, NASA Science News  An article relevant to GSS A Changing Cosmos chapter 7. Excerpt: …In a series of tantalizingly close flybys to the moon, named "Enceladus," NASA's Cassini spacecraft has revealed watery jets erupting from what may be a vast underground sea. These jets, which spew through cracks in the moon's icy shell, could lead back to a habitable zone that is uniquely accessible in all the solar system. …says Carolyn Porco …"Cassini has flown several times now through this spray and has tasted it. And we have found that aside from water and organic material, there is salt in the icy particles. The salinity is the same as that of Earth's oceans." …She believes the small moon, with its sub-surface liquid sea, organics, and an energy source, may host the same type of life we find in similar environments on Earth. …But what makes Enceladus special is that its habitable zone offers itself up for easy access. "It's

Dawn Sees New Surface Features on Giant Asteroid

Source:   NASA Dawn Mission NASA's Dawn spacecraft has revealed unexpected details on the surface of the giant asteroid Vesta. Vesta is the only asteroid in the so-called main belt between Mars and Jupiter visible to the naked eye from Earth. Carbon-rich asteroids may have hit Vesta at speeds low enough to produce some of the smaller deposits without blasting away the surface. Higher-speed asteroids also could have hit Vesta's surface and melted the volcanic basaltic crust, darkening existing surface material. That melted conglomeration appears in the walls and floors of impact craters, on hills and ridges, and underneath brighter, more recent material called ejecta, which is material thrown out from a space rock impact.

The Sky in Infrared

Source:  Bryan Mendez, NASA WISE mission  Excerpt: Today NASA and the Wide-field Survey Explorer (WISE) Team have released the full-sky infrared observations of the sky. As part of this release, a down-sampled but very high resolution spherical image map of the infrared sky has been rendered from this dataset and is available for use! The image includes 3.4 (blue), 12 (green), and 22 micron (red) bands and has been cleaned to remove frame edge artifacts and the irregular traces of zodiacal emission. It is 19,000 x 9,500 pixels, which is ideal for all full-dome projection systems. You can find the image at the WISE website (along with an annotated version that highlights the locations of many objects of interest that have been released as images):    Note that this image aligns with other full-sky infrared images that have been available for some time at:  

Scale of the Universe

Source:  Huang, Middle Schoolers Scale of universe animation put together by two ninth grade students.  Comments by each object.  Incredible.

NASA Mars Orbiter Catches Twister in Action

Source:    High Resolution Imaging Science Experiment (HiRISE), NASA  NASA - High Resolution Imaging Science Experiment (HiRISE) camera on NASA's Mars Reconnaissance Orbiter. See image of an afternoon whirlwind on Mars lofting a twisting column of dust more than half a mile (800 meters) high and casting a shadow on the Martian ground. Image location:

GRAIL MoonKAM (Moon Knowledge Acquired)

Source:  Middle School Students, The New York Times Led by Dr. Sally Ride, America's first woman in space, and her team at Sally Ride Science in collaboration with undergraduate students at the University of California San Diego, enables fifth- to eighth-grade students to select target areas on the lunar surface and send requests to the GRAIL MoonKAM Mission Operations Center (MOC). Photos of the target areas are sent back by the GRAIL satellites and made available in the Images section of the MoonKAM website. Students use the images to study craters, highlands, and maria while also learning about future landing sites.  

Up All Night on NASA's Flying Telescope

Source:  Lauren Sommer, NASA The new SOFIA observatory [Stratospheric Observatory for Infrared Astronomy] isn't your average NASA project. Engineers took a 30-year old 747 airplane, cut a hole in the side and installed a 17-ton telescope. Most telescopes are either on the ground or somewhere in orbit, but SOFIA falls somewhere in the middle, flying around at about 40,000 feet.

NASA Spacecraft Reveals Recent Geological Activity on the Moon

Source:   NASA RELEASE: 12-055 Excerpt: WASHINGTON -- New images from NASA's Lunar Reconnaissance Orbiter (LRO) spacecraft show the moon's crust is being stretched, forming minute valleys in a few small areas on the lunar surface. Scientists propose this geologic activity occurred less than 50 million years ago, which is considered recent compared to the moon's age of more than 4.5 billion years. …"We think the moon is in a general state of global contraction because of cooling of a still hot interior," said Thomas Watters of the Center for Earth and Planetary Studies at the Smithsonian's National Air and Space Museum in Washington, …"This pulling apart tells us the moon is still active," said Richard Vondrak, LRO Project Scientist at NASA's Goddard Space Flight Center in Greenbelt, Md.

Impact Calculator

Source:  Purdue University  An online interative that allows the user to input projectile diameter, density, angle of impact, velocity, type of target.

On this date in 1610, Galileo wrote a letter..

Source:  Garrison Keillor, Writer's Almanac Excerpt: On this date in 1610, Galileo wrote a letter describing his discovery of three of Jupiter's moons. He had recently made some improvements to his telescope, and he discovered them in December. As he continued to observe them over the next few months, a fourth celestial body appeared, and he realized that they were actually orbiting the giant planet.

Astronomers describe new class of planetary system

Source:   NSF   Press Release 12-007   Excerpt: Research [published in the January 12 issue of the journal Nature] presented today at the annual meeting of the American Astronomical Society indicates that circumbinary planetary systems--planets that orbit two stars--are not rare, rather that millions may exist in the Milky Way alone. At a press conference today, William Welsh of San Diego State University described Kepler 34b and Kepler 35b, the newest additions to this new class of planetary systems.  "The eclipses of the stars allow us to measure the properties of the stars with exquisite precision," said Welsh, "which in turn allows us to measure the planet properties."