Follow Friday & Weekly Stumbles For 2011-06-10

This week I recommend to follow @NASATweetup for interesting tweets about space and info about upcoming NASA Tweetups. For more Twitter follow suggestions see our astronomy list @TheAstroBlog/astronomy

Weekly Stumbles:

Moons like Earth’s could be more common than we thought
About one in 10 rocky planets around stars like our Sun may host a moon proportionally as large as Earth’s, researchers say. Our Moon is disproportionately large – more than a quarter of Earth’s diameter – a situation once thought to be rare. Using computer simulations of planet formation, researchers have now shown that the grand impacts that resulted in our Moon may in fact be common. The result may also help identify other planets that are hospitable to life.

Has Fermi glimpsed dark matter?
New results from NASA’s Fermi Gamma-Ray Space Telescope appear to confirm a larger-than-expected rate of high-energy positrons reaching the Earth from outer space. This anomaly in the cosmic-ray flux was first observed by the Italian-led PAMELA spacecraft in 2008 and suggests the existence of annihilating dark-matter particles. Physicists believe that about 80% of the mass in the universe is in the form of a mysterious substance known as dark matter.

A new rocket for science
The recent announcement by SpaceX that it will field and launch its Falcon Heavy launch vehiclein 2013has been heralded as an important and welcome development in many quarters. Reasons cited for this positive reception include heavy-lift applications for defense, satellite communications and human space exploration. But the Falcon Heavy also offers tremendous benefits to science, and that has not been as well recognized. It doesn’t take a rocket scientist to understand that broad use of the Falcon Heavy by NASA’s Science Mission Directorate could translate to large and much-needed cost savings.

Dark Energy Is Driving Universe Apart: NASA’s Galaxy Evolution Explorer Finds Dark Energy Repulsive
A five-year survey of 200,000 galaxies, stretching back seven billion years in cosmic time, has led to one of the best independent confirmations that dark energy is driving our universe apart at accelerating speeds. The survey used data from NASA’s space-based Galaxy Evolution Explorer and the Anglo-Australian Telescope on Siding Spring Mountain in Australia. The findings offer new support for the favored theory of how dark energy works – as a constant force, uniformly affecting the universe and propelling its runaway expansion.

Collective assurance vs. independence in national space policies
Earlier this year, after the fanfare and applause by many for the new US Space Policy and National Security Space Strategy, the European Union released their long awaited space strategy. Despite numerous articles, commentaries, and international discussions about the merits and failings of American space policies released in 2006 and 2010, there is very little commentary on the EU’s new priority statement on space. This article outlines some views about this policy that national leaders could consider as the United States implements its policy that has been described by the Pentagon Space Policy office as “collective assurance.”

Radio Telescopes Capture Best-Ever Snapshot of Black Hole Jets
An international team, including NASA-funded researchers, using radio telescopes located throughout the Southern Hemisphere has produced the most detailed image of particle jets erupting from a supermassive black hole in a nearby galaxy. “These jets arise as infalling matter approaches the black hole, but we don’t yet know the details of how they form and maintain themselves,” said Cornelia Mueller, the study’s lead author and a doctoral student at the University of Erlangen-Nuremberg in Germany.

Is the Rocky Alien Planet Gliese 581d Really Habitable?
A rocky alien planet called Gliese 581d may be the first known world beyond Earth capable of supporting life as we know it, a new study suggests. Astronomers performing a new atmospheric-modeling study have found that the planet likely lies in the “habitable zone” of its host star — that just-right range of distances that allow liquid water to exist. The alien world could be Earth-like in key ways, harboring oceans, clouds and rainfall, according to the research. This conclusion is consistent with several other recent modeling studies. But it does not definitively establish that life-sustaining water flows across the planet’s surface.

The Strangest Alien Planets
This artist’s concept of Kepler-10b shows the smallest known exoplanet, announced in January 2011. The largest exoplanet ever discovered is also one of the strangest and theoretically should not even exist, scientists say. Dubbed TrES-4, the planet is about 1.7 times the size of Jupiter and belongs to a small subclass of so-called puffy planets that have extremely low densities. The planet is located about 1,400 light years away from Earth and zips around its parent star in only three and a half days.

Transition to commercial services for LEO transportation
This paper was conceived during a series of discussions between Mike Lounge and I, beginning in the spring of 2010. The impetus for these was our mutual concern about Congressional and NASA reaction to the shift in policy announced on February 1 of that year. Essentially, the new NASA policy targeted an alternative procurement mechanism for getting cargo and then crew back and forth to low Earth orbit (LEO). “Commercial Transportation Services” (CTS) to space was something both of us had advocated for years—Mike much longer than I—and we wanted to see it succeed.

A transorbital railroad to Mars
One of the biggest challenges for the effective exploration and exploitation of space has been the high cost of space access. Over the last several decades governments and companies alike have made numerous attempts to lower the cost of reaching orbit, from the Space Shuttle program to various proposed commercial launchers, with little success. At the same time, efforts to move ahead with human exploration of Mars — widely regarded as the long-term goal for human spaceflight — have been stymied in part by the perceived need to develop a heavy-lift launch vehicle similar in capacity to the Saturn V to carry out such missions.

NASA’s Two Lunar-Bound Spacecraft, Vacuum-Packed
NASA’s two Gravity Recovery And Interior Laboratory (Grail) spacecraft have completed all assembly and testing prior to shipment to Florida. As seen in the photo, taken April 29, technicians installed lifting brackets prior to hoisting the 200-kilogram Grail-A spacecraft out of a vacuum chamber at Lockheed Martin Space Systems, Denver. Along with its twin Grail-B, the Grail-A spacecraft underwent an 11-day-long test that simulated many of the flight activities they will perform during the mission, all while being exposed to the vacuum and extreme hot and cold that simulate space.

Carrying Humans Into Deep Space: NASA Announces Key Decision for Next Deep Space Transportation System
NASA has reached an important milestone for the next U.S. transportation system that will carry humans into deep space. NASA Administrator Charles Bolden announced May 25, 2011 that the system will be based on designs originally planned for the Orion Crew Exploration Vehicle. Those plans now will be used to develop a new spacecraft known as the Multi-Purpose Crew Vehicle (MPCV). “We are committed to human exploration beyond low-Earth orbit and look forward to developing the next generation of systems to take us there,” Bolden said.

Brilliant but Solitary Superstar Discovered in Nearby Galaxy
An international team of astronomers has used ESO’s Very Large Telescope to carefully study the star VFTS 682 in the Large Magellanic Cloud, a small neighbouring galaxy to the Milky Way. By analysing the star’s light, using the FLAMES instrument on the VLT, they have found that it is about 150 times the mass of the Sun. Stars like these have so far only been found in the crowded centres of star clusters, but VFTS 682 lies on its own. “We were very surprised to find such a massive star on its own, and not in a rich star cluster,” notes Joachim Bestenlehner, the lead author of the new study and a student at Armagh Observatory in Northern Ireland. “Its origin is mysterious.”

The disappearing shuttle
A space shuttle launch is one of the most amazing experiences one can witness, one that attracts hundreds of thousands of people even at 8:30 on a Monday morning. There’s the brilliant, almost blinding glow of the exhaust of the SRBs, the roar that first reaches the observer well after liftoff, and a plume that arcs high into the sky as the shuttle ascends to orbit. Or, at least until it goes through a cloudbank. As shuttle launches go, last Monday’s launch of the shuttle Endeavour on mission STS-134 was a little disappointing, at least visually. About 20 seconds after liftoff Endeavour passed through a layer of low clouds directly over the Kennedy Space Center (KSC).

Nearby Supernova Factory Ramps Up
A local supernova factory has recently started production, according to a wealth of new data from NASA’s Chandra X-ray Observatory on the Carina Nebula. This discovery may help astronomers better understand how some of the Galaxy’s heaviest and youngest stars race through their lives and release newly-forged elements into their surroundings. Located in the Sagittarius-Carina arm of the Milky Way a mere 7,500 light years from Earth, the Carina Nebula has long been a favorite target for astronomers using telescopes tuned to a wide range of wavelengths.

How to Learn a Star’s True Age
For many movie stars, their age is a well-kept secret. In space, the same is true of the actual stars. Like our Sun, most stars look almost the same for most of their lives. So how can we tell if a star is one billion or 10 billion years old? Astronomers may have found a solution – measuring the star’s spin. “A star’s rotation slows down steadily with time, like a top spinning on a table, and can be used as a clock to determine its age,” says astronomer Soren Meibom of the Harvard-Smithsonian Center for Astrophysics.

Just Four Percent of Galaxies Have Neighbors Like the Milky Way
How unique is the Milky Way? To find out, a group of researchers led by Stanford University astrophysicist Risa Wechsler compared the Milky Way to similar galaxies and found that just four percent are like the galaxy Earth calls home. “We are interested in how the Milky Way fits into the broader context of the universe,” said Wechsler. “This research helps us understand whether our galaxy is typical or not, and may provide clues to its formation history.” The research team compared the Milky Way to similar galaxies in terms of luminosity – a measure of how much light is emitted – and distance to other bright galaxies.

Kepler’s Astounding Haul of Multiple-Planet Systems
NASA’s Kepler spacecraft is proving itself to be a prolific planet hunter. Within just the first four months of data, astronomers have found evidence for more than 1,200 planetary candidates. Of those, 408 reside in systems containing two or more planets, and most of those look very different than our solar system. In particular, the Kepler systems with multiple planets are much flatter than our solar system. They have to be for Kepler to spot them. Kepler watches for a planet to cross in front of its star, blocking a tiny fraction of the star’s light. By measuring how much the star dims during such a transit, astronomers can calculate the planet’s size, and by observing the time between successive events they can derive the orbital period – how long it takes the planet to revolve around its star.

Black Holes Spin Faster and Faster
Two UK astronomers have found that the giant black holes in the centre of galaxies are on average spinning faster than at any time in the history of the Universe. Dr Alejo Martinez-Sansigre of the University of Portsmouth and Prof. Steve Rawlings of the University of Oxford made the new discovery by using radio, optical and X-ray data. They publish their findings in the journal Monthly Notices of the Royal Astronomical Society. There is strong evidence that every galaxy has a black hole in its centre. These black holes have masses of between a million and a billion Suns and so are referred to as ‘supermassive’.

NASA’s WISE Mission Offers a Taste of Galaxies to Come
An assorted mix of colorful galaxies is being released by NASA’s Wide-field Infrared Survey Explorer mission, or WISE. The nine galaxies are a taste of what’s to come. The mission plans to release similar images for the 1,000 largest galaxies that appear in our sky, and possibly more. “Galaxies come in all sorts of delicious flavors,” said Tom Jarrett, a WISE team member at the Infrared Processing and Analysis Center, California Institute of Technology, in Pasadena, who studies our Milky Way’s neighboring galaxies. “Our first sample shows what WISE is capable of. We can produce spectacular high-resolution images of the largest galaxies.”

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