Word has just come in that TripAdvisor has acquired Jetsetter, Gilt's private community for exclusive travel deals.Source: http://feedproxy.google.com/~r/Techcrunch/~3/4-laBBOdB_c/
jenelle evans jenelle evans mlb 12 the show sabu franchise tag lesotho a wrinkle in time
Prime Minister Margaret Thatcher of the United Kingdom, left, makes remarks after visiting United States President Ronald Reagan, right, at the White House in Washington, D.C. on Friday, July 17, 1987. Thatcher died from a stroke at 87 on Monday, April 8, 2013. Credit: Howard L. Sachs - CNP Photo by: Howard L. Sachs/picture-alliance/dpa/AP Images
Prime Minister Margaret Thatcher of the United Kingdom, left, makes remarks after visiting United States President Ronald Reagan, right, at the White House in Washington, D.C. on Friday, July 17, 1987. Thatcher died from a stroke at 87 on Monday, April 8, 2013. Credit: Howard L. Sachs - CNP Photo by: Howard L. Sachs/picture-alliance/dpa/AP Images
Believers hailed its reduced tax rates and deregulation as springboards for economic miracles under the leadership of President Ronald Reagan and British Prime Minister Margaret Thatcher. Critics dismissed the very same ideas as so much trickle-down hocus-pocus and voodoo.
It's been most of three decades since debate over "supply-side" economic policies was at the center of U.S. politics. But for the moment, talk of conservative economic ideas that were as central to the story of the 1980s as Michael Jackson's moonwalk and the first MacIntosh personal computer is back. Why? A pair of its leading proponents have returned to the headlines.
Memories of economic days gone by were rekindled last week when David Stockman, Reagan's budget director, unleashed a scathing attack on years of decision-making by U.S. leaders, including his former boss. It continued this week, when Thatcher's death on Monday prompted recollections ? some fond, others not so much ? of how the Iron Lady imposed her will on a long-stagnant British economy.
The confluence of events got economists waxing about what the past means for today, although there's disagreement on how much supply-side's ideas have been abandoned in the U.S. or are just awaiting their moment of return. In the meantime, there was Arthur Laffer, the U.S. economist often called the father of supply-side, back on television three times Monday, recalling a warm friendship with Thatcher that highlighted a time when prevailing wisdom on taxes, deficits, and the roles of government and individuals was very different.
"We're back in the time machine," said Yoram Bauman, a Seattle economist who makes a living doing stand-up comedy about the dismal science ? and who has long opened with a joke or two about supply-side to test the depth and endurance of his audience's knowledge.
Supply-side economists argued that reducing taxes through lower rates would encourage work, saving and investment. Early supply-side theory promised that the reduced tax rates could pay for themselves by raising tax revenues. Under Reagan, the government lowered tax rates and reduced government regulation as the Federal Reserve worked to rein in inflation. The administration's focus on lowering tax rates for the wealthy, labeled "trickle-down economics," reflected the belief that these gains would encourage the rich to spend and invest more to create jobs for others.
Now that theory ? and Bauman's comic material, for that matter ? may have found its moment, but it's not clear how long it will last.
It began last week when Stockman wrote a lengthy opinion piece in The New York Times, followed by interviews, to build awareness of his new book, "The Great Deformation: The Corruption of Capitalism in America." He used the forum to go after everyone from Richard Nixon to Federal Reserve Chairman Ben Bernanke, Presidents Barack Obama and George W. Bush for decades of decisions that he said have left government bloated and swimming in deficits and the economy on a fault line.
Along the way, Stockman also lambasted Reagan ? whom many Republicans embrace as an economic hero ? for the "destruction of fiscal rectitude" inherent in running up big deficits. The criticism by Stockman, who resigned from the administration in 1985 over disagreement with those policies, was labeled as a rant by some economists. But there was little doubt that, if only briefly, it revived memories of the economics of the 1980s ? and pointed out how much the landscape has changed.
"I think to the extent that anyone is thinking about supply-side anymore it's nostalgically. It's not with an expectation that it's going to make a comeback," said Ed Yardeni, president and chief investment strategist for Yardeni Research
"In many ways, Stockman's book is just a scathing indictment of how the supply-side revolution has been taken apart by a counter-revolution, by the promoters of big government," he said.
With Washington focused on gun control, immigration reform and other issues, attention to the economics debate as embodied by Stockman might not have lasted. But Thatcher's death Monday unearthed memories of the economic malaise that saddled both Britain and the U.S. through the early 1980s. It was characterized by high inflation, weak financial markets, multiple recessions and, in Britain's case, the sense of "an economy that was producing goods that nobody wanted to buy," said Brian Domitrovic, author of "Econoclasts: The Rebels Who Sparked the Supply-Side Revolution and Restored American Prosperity."
In obituaries and recollections, observers recalled how Thatcher cut back on regulation, cut taxes and reduced government's role in enterprise, to recast the British economy. In doing so, she adopted some tenets of the economic gospel preached by Laffer. According to Washington legend, he had introduced the basics of supply-side to Nixon-era officials Dick Cheney and Donald Rumsfeld during a 1974 lunch at a restaurant not far from the White House by drawing, on a cocktail napkin, a curve showing the tradeoff between tax rates and revenue.
To Domitrovic, the revived debate over old economic ideas is a sign that people have not forgotten the crises of the 1970s or the way the Reagan and Thatcher administrations wrestled with them.
"When these great names come up, there is a sense of impressiveness and a kind of awesomeness," said Domitrovic, chair of the history department at Sam Houston State University.
Laffer, who runs an economic consultancy in Nashville, said there are still many believers in supply-side ideas, which he maintains are just as applicable to the huge deficits and economic sluggishness of today as back then.
"I don't think it's Thatcher's death that brought it back or Stockman's resurrection," Laffer said. "I mean, do you think the economy is doing well?"
Even now, the legacy of 1980s economics is quite vibrant, he said. Despite Obama's quest to raise taxes on the wealthy, no one in Washington would consider returning to the policies inherited by Reagan, who lowered the top tax rate from 50 percent to 28 percent, Laffer said. And in states like Kansas and Wisconsin, many governors, most of them Republicans, are working to cut taxes and reduce the size of government, he said.
Others, though, say memories of 1980s economic ideas have largely faded. Their prediction: Even the current turn in the spotlight will be brief.
Bauman, the economic comedian who billed a 2008 series of performances as his "Supply Side Tour," points out how much times have changed. Stumbling on such old economic policies now, Bauman says, is like rummaging through a pantry and finding a bag of chocolate chips with an expiration date from long, long ago and realizing that something once delicious might now be better to leave out of the recipe.
On stage, he introduces himself as a supply-side economist who does standup and lets the jokes trickle down, a line that wins knowing chuckles. But during frequent performances on college campuses, he notices that a joke about the Laffer Curve often brings groans or simply blank stares.
To get the joke about the economics of the 1980s, Bauman said, it helps to have been there.
___
EDITOR'S NOTE ? AP National Writer Adam Geller can be reached at features (at) ap.org. Follow him on Twitter at http://twitter.com/AdGeller
Associated Pressfrank ocean Justin Timberlake Grammys adam levine mumford and sons prince jessica biel Lena Dunham
PHL @ UPR Arecibo
An artist's conception shows Alpha Centauri Bb, the nearest known exoplanet. Will it end up being called "Amara," or "Tiber," or plain old Alpha Centauri Bb?
By Alan Boyle, Science Editor, NBC News
Zeb Gray thought naming an exoplanet after his girlfriend would be the perfect tribute to "the eternal love that we share for each other"?? and whether or not the name sticks, the decision arguably changed his life. On Friday, Gray asked Amara Somers to marry him, and she said yes.
Did the fact that Gray proposed the name "Amara" for the planet now known as Alpha Centauri Bb have anything to do with the way his more personal proposal was received? "I think it weighed on her decision," Gray, a 25-year-old security guard from Carson City, Nev., told NBC News.
The planet-naming gap
Amara is currently the top vote-getter in Uwingu's online contest to give Alpha Centauri Bb, the closest-known exoplanet, a more mellifluous name. Traditionally, the International Astronomical Union has had the job of naming celestial bodies ??but for now,?the IAU has held off on setting up an exoplanet-naming system. Instead, astronomers refer to alien worlds using a combination of the star's name (for example, Alpha Centauri B) and a lower-case letter (which is where that second "b" comes from).
Uwingu, a space-themed entertainment venture, has stepped into the gap with a system that lets users suggest planet names for $4.99, and cast ballots for 99 cents a vote. Half of the proceeds will go to support space science and education projects.
The contest to rename Alpha Centauri Bb runs until April 15, and although the resulting name won't have any official standing with the IAU, Gray would love to see Amara win. "I'm glad to see it has a decent lead, but that could go away pretty quickly," Gray said.
Uwingu
Zeb Gray pays tribute to his fiancee, Amara Somers, with an online card as well as an exoplanet name suggestion.
It helps that Amara is also the name of a magical world featured in Graham Edwards' "Stone" science-fiction trilogy. In Edwards' books, Amara is also known as Stone. It's structured like a spiraling stone wall, and inhabited by hundreds of civilizations.
There's another contender with a strong science-fiction connection, and a high-profile backer to boot. The name "Tiber" is favored by Apollo 11 moonwalker Buzz Aldrin, who's the co-author of a 1977 sci-fi novel titled "Encounter With Tiber."?The Tiberians hail from a planet in the Alpha Centauri, and that's one of Aldrin's selling points.
"Don't forget to vote for TIBER in the contest to replace the name for Alpha Centauri Bb," Aldrin told his nearly 800,000 followers in a Twitter update last week. As of this writing, Tiber is No. 17 on the charts with 35 votes ? ranking below Amara as well as Heinlein, Pele, Sagan, Asimov and Ron Paul.
Wooed by a moon
Gray, who met Somers at the state agency where they both work four months ago, isn't the first guy to impress a woman by naming a celestial body after her. When Naval Observatory astronomer James Christy discovered Pluto's biggest moon in 1978, he proposed naming it "Charon"?? not only because Charon was the ferryman of the dead in Greek mythology, but also because the name paid tribute to his wife, Charlene.
("Char" was Christy's pet nickname for his wife. In her honor, the name is often pronounced "Shar-on" rather than "Care-on, " which is the pronunciation associated with the Greek ferryman. That's one of the many fun facts you'll find in my book, "The Case for Pluto.")
Is it really worth all this fuss to give Alpha Centauri Bb a better name? Astronomer Xavier Dumusque, the lead author of the paper that announced the exoplanet's discovery last year, thinks so.
"I would definitively endorse the name for public outreach and lectures," Dumusque told NBC News in an email. "In astronomy, we have some chance to be able to make people dream, by showing a wonderful picture, by discovering new worlds. If someone is interested in astronomy, he should not face troubles to understand all the nomenclature. Therefore, giving memorable names for planets is one way to get more people interested in our wonderful research."
Do you agree? What names would you suggest? Check out the Uwingu list, and feel free to leave your suggestions as comments below.
More about the celestial name game:
Alan Boyle is NBCNews.com's science editor. Connect with the Cosmic Log community by "liking" the log's?Facebook page, following?@b0yle on Twitter?and adding the?Cosmic Log page?to your Google+ presence. To keep up with Cosmic Log as well as NBCNews.com's other stories about science and space, sign up for the Tech & Science newsletter, delivered to your email in-box every weekday.
Don Grady ann curry euro 2012 Colorado Springs Nora Ephron mario balotelli mario balotelli
By Thomas Ferraro
WASHINGTON (Reuters) - The fate of one of President Barack Obama's key gun-control proposals appeared on Monday night to be in the hands of two senators: one Democrat, the other Republican, both of them longtime opponents of restrictions on guns.
Democratic Senator Joe Manchin of West Virginia and Republican Senator Pat Toomey of Pennsylvania are seeking a compromise on expanding background checks for prospective gun buyers. The proposal appears to be Obama's best hope for meaningful gun-control legislation in the wake of the December massacre of 20 children and six adults at a school in Connecticut, where the president spoke Monday evening to a crowd that included some victims' families.
If Manchin and Toomey can't strike a deal, Obama's calls to require nearly all gun buyers to submit to background checks for criminal records and mental health problems likely will fail, Senate aides said on Monday.
Another centerpiece of Obama's efforts, a renewal of a ban on the sale of military-style assault weapons, appears unlikely to be approved, said Senate Majority Leader Harry Reid, a Nevada Democrat. A proposed 10-bullet limit on ammunition magazines also appears to be in trouble, he has said.
Obama, who has called the day of the Newtown massacre the worst of his presidency, made a strong appeal on Monday for action in Congress.
But at this point, Senate aides said, there seems to be strong, bipartisan support for only two of Obama's proposals: a crackdown on gun trafficking and improvements to security at schools.
The talks between Manchin and Toomey - both allies of the National Rifle Association, the nation's largest gun-rights group - symbolize why the background checks proposal is not a sure thing in Congress, even though polls have indicated that it is backed by 80 to 90 percent of Americans.
Toomey is pushing for expanded background checks even as 13 conservative Republican senators are threatening a filibuster to delay votes on any gun-control bills.
And Manchin represents how Democrats' move in recent years to embrace candidates who strongly support gun rights is complicating the Democratic president's push for gun restrictions.
Manchin is among eight Senate Democrats rated as friendly to gun rights by the NRA to have joined the chamber since 2006.
That was when the Democratic officials - fed up with losing congressional races to Republicans in rural and conservative states such as Montana, Virginia, North Carolina, Alaska and West Virginia - stepped up its recruiting of pro-gun candidates.
The strategy worked.
Democrats won control of the U.S. Senate and House of Representatives in 2006 and increased their majorities in 2008, when Obama captured the White House.
The House fell back to Republicans in 2010, but not before conservative Democrats such as Manchin helped Obama get his healthcare overhaul through Congress.
But now, those conservative Democrats have become speed bumps for several of Obama's gun-control proposals - particularly his call to ban assault weapons, which both sides see as unlikely to pass even the Senate, where Democrats control 55 of the 100 seats.
On expanding background checks, "Manchin is upbeat about their chances of success," said one Senate aide, who offered an assessment of her own: "50-50."
SEEING A 'SLIPPERY SLOPE'
Reid, who schedules floor votes in the Senate, had planned to begin consideration of gun legislation this week. But that timetable could be pushed to next week to give Manchin and Toomey more time to negotiate, or if Republicans try to delay action, aides said.
Even the gun trafficking plan, which would make it a federal crime for someone banned from having a firearm to buy one, could face problems. The NRA is seeking to revise it in a way that critics say would make it difficult to enforce.
Obama's call to ban rapid-firing assault weapons - a pet cause of Senator Dianne Feinstein, a California Democrat - has gone nowhere in part because even those in Feinstein's party are not solidly behind it.
Several Democrats who have joined the Senate since 2006 have said they could not vote for Feinstein's plan.
They include Manchin, Mark Begich of Alaska and Jon Tester of Montana, a gun-rights Democrat and farmer who won a Senate seat in 2006 by unseating a three-term Republican.
Tester said he sees an assault weapons ban as "a slippery slope" that could lead to other restrictions on gun ownership. He said he favors stepping up efforts to keep guns out of the hands of criminals and the mentally ill.
"That would be the smart thing to do," Tester said.
Begich, another Democrat rated as a friend on Capitol Hill by the NRA, ousted a six-term Republican when he was elected in 2008. Begich is a co-sponsor of a bipartisan bill to clarify when a person loses the right to possess a firearm based on mental illness.
Critics of the bill, which is backed by the NRA, say the measure could make firearms more accessible to the mentally ill.
Manchin, elected to the Senate in 2010, has been trying for months to find a way to expand background checks while addressing gun-rights' advocates concerns that such checks could be used to create registries of gun owners. Gun rights advocates say the government could use such registries to confiscate weapons.
"I think everyone wants to do something that is right and responsible," Manchin said. "I really do."
A POLITICAL CALCULATION
Few Democrats regret the party's decision to recruit gun-rights candidates in recent years.
If senators such as Tester and Begich had not won their seats, many Democrats figure, the seats would be held by pro-gun Republicans - and many of Obama's legislative accomplishments, including the healthcare overhaul and new regulations on Wall Street, would not have happened.
"The profile of the guy who can win in these states is the profile of a guy who is pro-gun," said Jennifer Duffy, who tracks Senate races for the nonpartisan Cook Political Report.
Larry Sabato, who tracks congressional races as head of University of Virginia's Center for Politics, said that in 2006, "Democrats made a practical decision ... to win rather, than to be (ideologically) pure."
Sabato said he now sees some Republicans similarly bending their stances on some issues to try to appeal to more voters, such as easing their opposition to gay marriage and tax increases.
(Editing by David Lindsey and Lisa Shumaker)
Source: http://news.yahoo.com/two-senators-key-obamas-push-broader-checks-gun-003114309.html
jersey shore Pasquale Rotella Michael Clark Duncan michael jackson courtney stodden Ncaa Football Scores Plaquemines Parish
Many people were surprised by Halle Berry's pregnancy -- including the actress herself!
deron williams jarhead montrose marshawn lynch earthquake bay area clear channel drexel
LOS ANGELES (AP) ? A top executive with the owner of the Fox broadcast network on Monday threatened to convert the network to a pay-TV-only channel if Internet startup Aereo Inc. continues to "steal" Fox's over-the-air signal and sell it to consumers without paying for rights.
Anyone with an antenna can pick up a TV station's signals for free. But cable and satellite companies typically pay stations and networks for the right to distribute their programming to subscribers. Industrywide, those retransmission fees add up to billions of dollars every year.
Last week, that business was shaken after a federal appeals court issued a preliminary ruling siding with Aereo, which contends that it doesn't have to pay those fees because it relies on thousands of tiny antennas.
News Corp. Chief Operating Officer Chase Carey said that not being paid by Aereo jeopardizes the economics of broadcast TV, which relies on both retransmission fees and advertising.
"This is not an ideal path we look to pursue, but we can't sit idly by and let an entity steal our signal," Carey said at the annual gathering of broadcasters, called NAB Show, in Las Vegas. "If we can't do a fair deal, we could take the whole network to a subscription model."
If realized, Carey's proposal would amount to a sea change in how Fox does business. Currently, Fox sends its signal to TV stations across the country, including 27 that it owns directly. Those stations relay Fox programming such as "Glee" and "Family Guy" for free over the airwaves in local markets and add their own local news and other programming. While most people get Fox through a pay TV provider anyway, millions of other Americans rely on the free signal coming over their own antennas.
Carey didn't explain how TV stations would be affected if Fox shut off the signals it sent to broadcasters and went straight to a pay TV model. Later, the company said in a statement that any change would occur "in collaboration with both our content partners and affiliates."
Aereo takes broadcast signals for free from the air with thousands of little antennas, recodes them for Internet use and feeds that to subscribers' computers, tablets and smartphones. Plans start at $8 a month, which is much cheaper than a cable package, though the service is mostly limited to broadcast channels.
Last week, the 2nd U.S. Circuit Court of Appeals in New York said that Aereo could continue its service despite a legal challenge by broadcast networks Fox, ABC, NBC and CBS.
In a split ruling, the court accepted Aereo's position that having individual antennas meant that Aereo wasn't retransmitting signals. Rather, the appeals court said that Aereo enabled its subscribers to do what they already could on their own with their own antenna and video recorder.
In a separate case, broadcasters are suing a different Internet company called Aereokiller LLC. It also takes broadcast signals using mini antennas and transmits them to paying customers. That case is now before the 9th U.S. Circuit Court of Appeals in San Francisco.
Gordon Smith, president of the National Association of Broadcasters, was interviewing Carey onstage when he made the comments. Smith said he hopes that the courts will eventually rule against Aereo and force it to get in line with other pay TV operators.
"We think in the end, we'll be on the right side of the law and we will never get to the 'what-if' scenarios," Smith said.
Smith said he hopes that a different ruling at the 9th Circuit will prompt the U.S. Supreme Court to take over the matter.
Ultimately, Congress could step in and update a cable law governing retransmission fees. It was passed in 1992, before the world even had a commercial Web browser let alone viable Internet video technology.
Aereo, backed by billionaire Barry Diller, was limited to New York City when it debuted early last year, but has since expanded to the New York City suburbs, including parts of New Jersey and Connecticut. It plans to expand to Boston, Chicago, Philadelphia, Washington and 18 other U.S. markets this spring.
Aereo Chief Executive Chet Kanojia said the legal OK for Aereo's service is now the "law of the land" with or without Fox.
"We believe that broadcasting in this country, irrespective of Fox, is a very powerful, fundamental presence," he said. If Fox exits the space, "we think somebody will be there to take advantage of that great idea of reaching this mass audience."
Analyst Todd Juenger of Bernstein Research speculated in a research note in January on what would make broadcast networks transition to a pay TV model.
Such a system would result in the loss of local news programs, broadcast personalities and advertising. But a pay TV system could be better for network owners such as Fox if services like Aereo were to thrive, because doing so would cut off technology that siphons away customers from pay TV operators, he wrote.
News Corp.'s stock rose 77 cents, or 2.5 percent, to close Monday at $31.41.
Associated Pressfacebook ipo mike kelley puxatony phil josh harvey clemons college football recruiting rankings ground hog day 2012 aaron carter
Apr. 8, 2013 ? Neutron stars have been called the zombies of the cosmos. They shine even though they're technically dead, occasionally feeding on neighboring stars if they venture too close. Interestingly, these unusual objects, born when a massive star extinguishes its fuel and collapses under its own gravity, also may help future space travelers navigate to Mars and other distant destinations.
NASA recently selected a new mission called the Neutron-star Interior Composition Explorer (NICER) to not only reveal the physics that make neutron stars the densest objects in nature, but also to demonstrate a groundbreaking navigation technology that could revolutionize the agency's ability to travel to the far reaches of the solar system and beyond.
The multi-purpose mission, also known as NICER/SEXTANT (Station Explorer for X-ray Timing and Navigation Technology), consists of 56 X-ray telescopes in a compact bundle, their associated silicon detectors, and a number of other advanced technologies. Both NASA's Science Mission Directorate's Explorers Program and the Space Technology Mission Directorate's Game Changing Program are contributing to the mission's development.
"It's rare that you have an opportunity to fly a cross-cutting experiment," said Principal Investigator Keith Gendreau, a scientist at NASA's Goddard Space Flight Center in Greenbelt, Md., who is leading NICER/SEXTANT's development. "The time is right for this experiment. This is one that we can do now."
In addition to NASA Goddard scientists and engineers, the mission team includes the Massachusetts Institute of Technology and commercial partners, who are providing spaceflight hardware. The Naval Research Laboratory and universities across the United States, as well as in Canada and Mexico, are providing science expertise.
Space Station Bound
Slightly larger than a typical college dormitory refrigerator, NICER/SEXTANT will be deployed on the International Space Station (ISS) in 2017. It will fly as an external attached payload on one of the ISS ExPRESS Logistics Carriers, unpressurized platforms used for experiments and storage.
The X-ray instrument's primary objective is to learn more about the interior composition of neutron stars, the remnants of massive stars that, after exhausting their nuclear fuel, exploded and collapsed into super-dense spheres about the size of New York City. Their intense gravity crushes an astonishing amount of matter -- often more than 1.4 times the content of the sun or at least 460,000 Earths -- into these city-sized balls, creating the densest objects known in the universe. Just one teaspoonful of neutron star matter would weigh a billion tons on Earth.
"A neutron star is right at the threshold of matter as it can exist -- if it were compressed any further, it would collapse completely in on itself and become a black hole," said Zaven Arzoumanian, a NASA Goddard scientist serving as the deputy principal investigator on the mission. "We have no way of creating or studying this matter in any laboratory. There are many theories about what it is and how it behaves, but the only way to test our models and understand what happens to matter under such incredible pressures is to study neutron stars," he added. "The closest we come to simulating these conditions is in particle accelerators that smash atoms together at almost the speed of light. However, these collisions are not an exact substitute -- they only last a split second, and they generate temperatures that are much higher than what's inside neutron stars."
Although the nuclear-fusion fires that sustained their parent stars are extinguished, neutron stars still shine with heat left over from their explosive formation, and from radiation generated by their magnetic fields that became intensely concentrated as the core collapsed.
Although neutron stars emit radiation across the spectrum, observing in the X-ray band offers the greatest insights into their structure, the ultimate stability of their pulses as precise clock "ticks," and the high-energy, dynamic phenomena that they host, including starquakes, thermonuclear explosions, and the most powerful magnetic fields known in the universe.
NICER's 56 telescopes will collect X-rays generated from its tremendously strong magnetic field and from hotspots located at the stars' two magnetic poles. At these locations, the intense magnetic field emerges from the surface. Particles trapped in the magnetic field rain down and generate X-rays when they strike the surface. As the hotspots rotate into and out of our line of sight, we perceive a rise and fall in X-ray brightness.
This subgroup of pulsating neutron stars, called pulsars, rotate rapidly, emitting from their magnetic poles powerful beams of light that sweep around as the star spins, much like a lighthouse. At Earth, these beams are seen as flashes of light, blinking on and off at intervals from seconds down to milliseconds.
Because of their predictable pulsations -- especially millisecond pulsars, which are the target of the navigation demonstration -- "they are extremely reliable celestial clocks" and can provide high-precision timing just like the atomic clock signals supplied through the 26-satellite, military-operated Global Positioning System (GPS), an Earth-centric system that weakens the farther one travels out beyond Earth orbit and into the solar system, Arzoumanian said. "Pulsars, on the other hand, are accessible in virtually every conceivable flight regime, from low-Earth orbit to interplanetary to deepest space," Gendreau added.
As a result, NICER/SEXTANT also will demonstrate the viability of pulsar-based navigation. "The hardware needed for neutron star science is identical to that needed for pulsar-based navigation," Gendreau said. "In fact, the mission's two goals share many of the same targets and the same operational concept. The differences are on the back end in terms of how the data will be used."
To demonstrate the navigation technology's viability, the NICER/SEXTANT payload will use its telescopes to detect X-ray photons within these powerful beams of light to estimate the arrival times of the pulses. With these measurements, the system will use specially developed algorithms to stitch together an on-board navigation solution.
If an interplanetary mission were equipped with such a navigational device, it would be able to calculate its location autonomously, independent of NASA's Deep Space Network (DSN), Gendreau said. DSN, considered the most sensitive telecommunications system in the world, allows NASA to continuously observe and communicate with interplanetary spacecraft. However, like GPS, the system is Earth-centric. DSN-supplied navigational solutions also degrade the farther one travels out into the solar system. Furthermore, missions must share time on the network, Gendreau said.
"We're excited about NICER/SEXTANT's possibilities," Gendreau added. "The experiment meets critical science objectives and is a stepping-stone for technology applications that meet a variety of NASA needs. It's rare that you get an opportunity to do a cross-cutting experiment like this."
Related Links:
Share this story on Facebook, Twitter, and Google:
Other social bookmarking and sharing tools:
Story Source:
The above story is reprinted from materials provided by NASA.
Note: Materials may be edited for content and length. For further information, please contact the source cited above.
Note: If no author is given, the source is cited instead.
Disclaimer: Views expressed in this article do not necessarily reflect those of ScienceDaily or its staff.
Source: http://feeds.sciencedaily.com/~r/sciencedaily/space_time/astronomy/~3/SL-GcAeiWQ8/130408035333.htm
bill cosby us open bill nye Hurricane Isaac 2012 Snooki Baby terrell owens terrell owens
