Cemenk Cantique

Hundreds of massive black holes left over from the early universe may wander the Milky Way, according to new calculations.

These rogue black holes are thought to have originally lurked at the centers of tiny, low-mass galaxies. Over billions of years, those dwarf galaxies smashed together to form full-sized galaxies like the Milky Way.

The idea of such wandering black holes has been suggested before, but a new computer simulation calculated that hundreds of them should be left over, and predicted that they might now be shrouded by small star clusters.

“These black holes are relics of the Milky Way’s past,” said researcher Avi Loeb of the Harvard-Smithsonian Center for Astrophysics. “You could say that we are archaeologists studying those relics to learn about our galaxy’s history and the formation history of black holes in the early universe.”

It appears that Earth is safe. The closest rogue black hole should reside thousands of light-years away.

Astronomers are eager to locate them for the clues they will provide about the formation of the Milky Way, since they are thought to date from the universe’s galaxy-building days.

Back then, whenever two young galaxies with central black holes collided, their black holes would merge to form a single black hole. In the chaos of the merger, the black hole could be flung out toward the edges of the galaxy, the new computer model shows.

It predicts that hundreds of such black holes would still be around today in the outer reaches of the Milky Way, each containing the mass of 1,000 to 100,000 suns. They would be difficult to spot on their own, though, because a black hole is not visible. They can be detected, however, when matter they’re about to swallow is superheated as it accelerates inward.

Another telltale sign could mark a rogue black hole: a surrounding cluster of stars yanked from the dwarf galaxy when the black hole escaped. Only the stars closest to the black hole would be tugged along, so the cluster would be very compact.

These clusters are so small that each looks like a single star from far away. Thus, astronomers will have to use tricks to distinguish them, such as separating the light from the clusters into its component colors to discover the individual stars hiding inside.

“The surrounding star cluster acts much like a lighthouse that pinpoints a dangerous reef,” said Harvard-Smithsonian Center for Astrophysics’ Ryan O’Leary, who co-wrote the paper. “Without the shining stars to guide our way, the black holes would be all but impossible to find.”

The number of rogue black holes in our galaxy depends on how many of the early galaxy building blocks contained black holes at their cores, and how those proto-galaxies merged to form the Milky Way. Finding and studying them would provide new clues about the history of our galaxy.

Locating the star cluster signposts may turn out to be relatively straightforward.

“Until now, astronomers were not searching for such a population of highly compact star clusters in the Milky Way’s halo,” Loeb said. “Now that we know what to expect, we can examine existing sky surveys for this new class of objects.”

The research will be detailed in an upcoming issue of the journal Monthly Notices of the Royal Astronomical Society.

by space.com

By Tariq Malik

NASA on Friday began the first wave of layoffs that will ultimately eliminate 900 jobs by September as the space agency resumes plans to retire its space shuttle fleet next year.

The space agency issued 160 layoff notices today for manufacturing jobs that are no longer required to support the last eight missions slated to launch between now and the December 2010 deadline to mothball NASA’s three aging space shuttles.

“This is the first significant loss of manufacturing capability,” John Shannon, NASA’s shuttle program manager, told reporters late Thursday.

The layoffs are primarily focused in Utah and New Orleans, where contractors build the twin solid rocket boosters and 15-story external tanks that help boost NASA shuttles into space. They came one day after the expiration of a temporary hold enacted by Congress to delay the shuttle program shutdown until April 30 so President Barack Obama’s administration had time to weigh in.

Now that the deadline has passed, NASA will resume shutting down shuttle manufacturing operations that are no longer needed for the remaining flights. NASA plans to launch the space shuttle Atlantis on May 11 to perform one final service call on the Hubble Space Telescope. Seven other missions are scheduled to complete construction of the International Space Station.

Last month, President Obama released a budget outline that could allow one extra flight to the space station to deliver a billion-dollar experiment – the Alpha Magnetic Spectrometer – but only if the mission would fit within NASA’s 2010 retirement plan.

“I love the shuttle. I have spent my career working on the shuttle,” Shannon said. “At some time you have to decide that what the shuttle was meant to do has been done. And I would say that it has.”
The space shuttle is the only reusable spacecraft capable of launching astronauts on space service calls like the Hubble repair mission or carrying massive construction pieces to the International Space Station.

Not all of the 900 eliminated shuttle positions are layoffs, Shannon said. Some include attrition as employees leave the workforce, while others include reassignment to other projects, such as NASA’s Constellation program that is building its space shuttle successor.

NASA will shift the funding saved from the shuttle’s retirement over to the development of that new spaceship – the Orion Crew Exploration Vehicle – which is expected to make its operational debut no earlier than March 2015.

Orion is a capsule-based spacecraft that builds on the legacy of NASA’s Apollo-era vehicles. The new vehicle will be launched on a shuttle-derived Ares I rocket to ferry new crews to the International Space Station. It is also slated to return astronauts to the moon by 2020.

Orion was initially slated to come in two versions: a six-seater for space station crew flights, and a four-seater for moon missions. NASA confirmed this week that it is focusing on the four-person Orion for now, which should save time, money and keep the spacecraft on track for a 2015 target.

by space.com

The first astronauts to walk on the moon in the 1960s and 1970s were inundated by sticky lunar dust that clung to their spacesuits whenever they ventured outside. Now, four decades later, a self-funded study by an Australian physicist has found a link between the dust’s stickiness and the angle of the sun at the time of each moonwalk.

The new research, which drew on the personal files and paper charts of physicist Brian O’Brien of Perth, suggests that future lunar astronauts may have greater problems with dust adhesion in the middle half of the day than NASA’s Apollo missions faced in the early morning

Dust is the number one environmental hazard on the moon, yet its movements and adhesive properties are little understood,” said O’Brien, who was the principal investigator for the Dust Detector Experiment on several Apollo lunar landing missions between 1969 and 1970. His new research will be detailed in the Geophysical Research Letters.

Sticky science

The new study points out that the electrostatic adhesive forces of dust decreases as sunlight on the moon decreases. Furthermore, O’Brien believes that some sort of lunar shack for on-duty moonwalkers may be mandatory to provide for a sunlight-thwarting, dust-free working environment.

“It follows that on future lunar expeditions, powerful electrostatic adhesion of lunar dust during the middle half of each lunar day could cause greater dust problems than experienced by Apollo astronauts,” he relates.

This model by O’Brien infers that Apollo astronaut problems from clinging dust, at solar elevations much less than 45 degrees, may have been driven by other forces. Mechanical bonding properties intrinsic to lunar dust, he suggests, could explain partial success by moonwalkers in shedding gear of dust with “moon brushes.”

Detecting moon dust

Invented by O’Brien, the matchbox-sized detectors for the DDE study were planted on the moon during the Apollo 11, 12, 14 and 15 missions. O’Brien carried out that work while serving as a professor of space science at Rice University in Houston, Texas, from 1963 to 1968.

O’Brien was one of seven scientists chosen by NASA from 90 applicants to provide sophisticated instruments in remote scientific stations deployed by Apollo astronauts. While another of his projects, the Charged Particle Lunar Environment Experiment, was lost on Apollo 13, it was deployed during the Apollo 14 moon landing mission.

It turns out that NASA had misplaced its computer tapes of the experimental data but O’Brien preserved his copies.

“I started to revisit the personal Dust Detector Experiment (DDE) data in 2007 after learning in late 2006 that the sole source of data was with me,” he told SPACE.com.

Spray of debris

In another finding by O’Brien, Apollo 11’s DDE made the first measurements suggesting that rocket exhaust caused significant contamination of deployed equipment.

Apollo 11’s dust detectors, O’Brien said, showed the impact of rocket exhaust spit out from the departure of the Eagle lunar module’s ascent stage. This stage was the home, hotel and vehicle back into lunar orbit for Neil Armstrong and Buzz Aldrin, and a key step in returning them to home planet Earth.

Eagle’s liftoff from Tranquility Base caused quite a stir, environmentally speaking.

There was significant contamination of astronaut-deployed hardware by kicked-up lunar material. So much so that the spray of debris caused by the departing rocket motor led to the overheating and early failure of Apollo 11’s Passive Seismic Experiment – the first major scientific experiment put on the moon by human hands

A lesson learned here is where best to place equipment given future landings and takeoffs of moon vehicles. For Apollo 11’s DDE, it was deployed roughly 55 feet (17 meters) away from the Eagle lander.

“Such damage was a foreseen possibility… accepted on this first mission in interests of astronaut safety. These benchmark measurements on the moon appear unused and unreferenced in theoretical modeling of effects of rocket exhausts,” O’Brien explains.

Considering NASA’s plan to return humans to the lunar surface for longer stints, there’s another lesson underscored by O’Brien’s work. That is, the need to better preserve, dust off, and revisit Apollo data.