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Next ISS crew lifts off
A Russian Soyuz spacecraft safely launched from Baikonur Cosmodrome Friday night with the International Space Station's twelfth resident crew and a paying tourist aboard.

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Discovery crew's movies
The seven astronauts of space shuttle Discovery's return to flight mission recently gathered for a public celebration of their mission. They narrated an entertaining movie of highlights and personal footage taken during the mission.

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GPS satellite launched
The Boeing Delta 2 rocket roars off Cape Canaveral's launch pad 17A carrying the first modernized Global Positioning System satellite for the U.S. Air Force.

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Back to the Moon!
NASA unveils the agency's blueprint for building the future spacecraft and launch vehicles needed for mankind's return to the lunar surface in the next decade.

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Distant space explosion
Astronomers announce the detection by NASA's Swift satellite of the most distant explosion yet, a gamma-ray burst from the edge of the visible universe, during this media teleconference held Monday, September 12. (54min 01sec file)

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Hill-climbing Mars rover
The Mars Exploration Rover Spirit has reached the summit of Husband Hill, returning a spectacular panorama from the hilltop in the vast Gusev Crater. Scientists held a news conference Sept. 1 to reveal the panorama and give an update on the twin rover mission.

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Planes track Discovery
To gain a new perspective on space shuttle Discovery's ascent and gather additional imagery for the return to flight mission, NASA dispatched a pair of high-flying WB-57 aircraft equipped with sharp video cameras in their noses.

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Rocket booster cams
When space shuttle Discovery launched its two solid-fuel booster rockets were equipped with video cameras, providing dazzling footage of separation from the external fuel tank, their free fall and splashdown in the sea.

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Discovery ferried home
Mounted atop a modified Boeing 747, space shuttle Discovery was ferried across the country from Edwards Air Force Base, California, to Kennedy Space Center, Florida.

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Shuttle tank returned
Shuttle fuel tank ET-119 is loaded onto a barge at Kennedy Space Center for the trip back to Lockheed Martin's Michoud Assembly Facility in New Orleans. The tank will be used in the investigation to determine why foam peeled away from Discovery's tank on STS-114 in July.

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Delta 4 launch delayed
Launch of the GOES-N weather observatory aboard a Boeing Delta 4 rocket is postponed at Cape Canaveral, Florida.

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Mars probe leaves Earth
The Mars Reconnaissance Orbiter lifts off aboard a Lockheed Martin Atlas 5 rocket from Cape Canaveral's Complex 41.

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Holy Grail of black hole astronomy is within grasp
HARVARD-SMITHSONIAN CENTER FOR ASTROPHYSICS NEWS RELEASE
Posted: October 3, 2005

Common wisdom holds that we can never see a black hole because nothing can escape it - not even light. Fortunately, black holes aren't completely black. As gas is pulled into a black hole by its strong gravitational force, the gas heats up and radiates. That radiation can be used to illuminate the black hole and paint its profile.

Within a few years, astronomers believe they will be able to peer close to the horizon of the black hole at the center of the Milky Way. Already, they have spotted light from "hot spots" just outside the black hole. While current technology is not quite ready for the final plunge, Harvard theorists Avery Broderick and Avi Loeb (Harvard-Smithsonian Center for Astrophysics) already have modeled what observers will see when they look into the maw of this monster.

"It will be really remarkable when observers can see all the way to the edge of the Milky Way's central black hole - a hole 10 million miles in diameter that's more than 25,000 light-years away," said Broderick.

All it will take is a cross-continental array of submillimeter telescopes to effectively create a single telescope as large as the Earth. This process, known as interferometry, has already been used to study longer wavelength radio emissions from outer space. By studying shorter wavelength submillimeter emissions, astronomers could get a high-resolution view of the region just outside the black hole.

"The Holy Grail of black hole astronomy is within our grasp," said Broderick. "We could see the shadow that the black hole casts on surrounding material, and determine the size and spin of the black hole itself."

Infrared observations using existing and near-future interferometric instruments also offer the possibility of imaging the core of our Galaxy in incredible detail, with resolutions better than one milli-arcsecond.

"Submillimeter and infrared observations are complementary," said Smithsonian astronomer Lincoln Greenhill of the Center. "We need to use both to tackle the problem of getting high-resolution observations. It's the only way to get a complete picture of the Galactic center."

The black hole at the center of the Milky Way is the best target for interferometric observations because it spans the largest area in the sky of any known black hole. Nevertheless, its angular size of tens of micro-arcseconds poses a major challenge to observers, requiring resolution 10,000 times better than the Hubble Space Telescope provides in visible light.

"When astronomers achieve it, that first image of the black hole's shadow and inner accretion disk will enter textbooks, and will test our current notions on gravity in the regime where spacetime is strongly curved," said Loeb.

"Ultimately, we want to test Einstein's general theory of relativity in the strong field limit - within a strong gravitational field like that of a black hole," said Broderick.

In preparation for that observational leap, Broderick and Loeb created a computer program to simulate the view. Emissions from the Galaxy's central black hole are known to fluctuate, probably due to clumps of material being swallowed. The researchers modeled those clumps of hot gas and predicted the up-close appearance. They also summed the total light from the "hot spots" to simulate low-resolution observations possible with current technology.

New observational results are starting to come out and already are proving consistent with Broderick and Loeb's prediction.

"Observations to date only span a limited time interval," said Loeb. "With routine monitoring, astronomers will be able to collect many examples of flares and start deriving the characteristics of the black hole itself."

Headquartered in Cambridge, Mass., the Harvard-Smithsonian Center for Astrophysics (CfA) is a joint collaboration between the Smithsonian Astrophysical Observatory and the Harvard College Observatory. CfA scientists, organized into six research divisions, study the origin, evolution and ultimate fate of the universe.