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Chandra X-ray Observatory image reveals growth of Black Holes over Billions of Years: NASA

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NASA, spacecraft
NASA plans to Crash a Refrigerator-Sized Spacecraft. VOA

Washington, Jan 6, 2017: NASA said its Chandra X-ray Observatory has obtained an image that gives astronomers the best look yet at the growth of black holes over billions of years beginning soon after the Big Bang.

This is the deepest X-ray image ever obtained, collected with about eleven and a half weeks of Chandra observing time, the US space agency said in a statement.

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The image comes from what is known as the Chandra Deep Field-South. The central region of the image contains the highest concentration of supermassive black holes ever seen.

“With this one amazing picture, we can explore the earliest days of black holes in the universe and see how they change over billions of years,” said Pennsylvania State University’s Niel Brandt, who led a team of astronomers studying the deep image.

About 70 per cent of the objects in the new image are supermassive black holes, which may range in mass from about 100,000 to 10 billion times the mass of the Sun.

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Gas falling towards these black holes becomes much hotter as it approaches the event horizon, or point of no return, producing bright X-ray emission.

“It can be very difficult to detect black holes in the early Universe because they are so far away and they only produce radiation if they’re actively pulling in matter,” team member Bin Luo of Nanjing University in China noted.

“But by staring long enough with Chandra, we can find and study large numbers of growing black holes, some of which appear not long after the Big Bang,” Luo added.

The new ultra-deep X-ray image allows scientists to explore ideas about how supermassive black holes grew about one to two billion years after the Big Bang.

Using these data, the researchers showed that these black holes in the early universe grow mostly in bursts, rather than via the slow accumulation of matter.

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The scientists also found hints that the seeds for supermassive black holes may be “heavy” with masses about 10,000 to 100,000 times that of the Sun, rather than light seeds with about 100 times the Sun’s mass.

This addresses an important mystery in astrophysics about how these objects can grow so quickly to reach masses of about a billion times the Sun in the early universe.

For the study, the team combined the Chandra X-ray data with very deep Hubble Space Telescope data over the same patch of sky.

These results were presented at the 229th meeting of the American Astronomical Society meeting in Grapevine, Texas. (IANS)

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NASA’s human ‘computer’ is still working at age 80

Sue Finely calculated rocket trajectories by hand

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Sue Finley still works at NASA
Sue Finley, 80, is still working at NASA's Jet Propulsion Laboratory in Pasadena, California. She started there in 1958 as a human "computer," calculating trajectories for rockets. VOA

Sue Finley, now 80 years old and NASA’s longest-serving female employee, recalls her early days with the space agency when she worked as a human “computer,” calculating rocket trajectories by hand at a time when computers were huge and expensive to operate.

Finley arrived at Jet Propulsion Laboratory (JPL) in Pasadena, California, in January 1958, one week before the U.S. Army launched Explorer 1, America’s first earth satellite.

“It was a very big deal,” she recalls of the launch, a response to the launches a few months earlier of the first satellites, Sputnik 1 and 2, from the former Soviet Union.

She was at JPL for Pioneer 1, the first satellite sent aloft by the newly formed National Aeronautics and Space Administration (NASA) in late 1958, which marked the beginning of the international space race.

Unmanned space probes

Since then, Finley has had a role in nearly every U.S. unmanned space probe, and some missions of other nations.

There were failures to overcome and spectacular successes, but always new goals as scientists expanded our knowledge of the earth and solar system.

“We were certainly proud,” she says of NASA accomplishments, “but you just go to the next thing.”

Finley has been through several career changes with the space agency, one of the most important when NASA phased out human computers, moving, initially, to simple electronic versions.

“We got little tiny computers,” she recalls. “One I had 16 wires, jumper cables to code with. One had 10 pegboards that you programmed with.”

As modern computers took over navigational tasks, Finley developed and tested software as a subsystem engineer.

Among her career highlights: the Vega mission, a Soviet-French collaboration with Venus, and Halley’s Comet, which received navigational help from NASA and dropped balloons into the atmosphere of Venus.

She had to change the software for the antenna that tracked the mission, “and it worked,” Finley recalls. “Everything worked. That’s what was so exciting!”

Finley has worked since 1980 on NASA’s Deep Space Network, which coordinates satellite facilities in California, Spain and Australia that allow communication with space probes.

Highlights of NASA career

Career highlights include developing software that generates audio tones sent back from spacecraft, informing engineers on the ground what is happening in space. It was first developed for the Mars missions.

Each tone has a meaning that communicates data, noted one of Finley’s colleagues, Stephen Lichten.

“If a parachute opened, it would send a tone,” Lichten, manager for special projects for the Deep Space Network, said.

“The spacecraft lets go of its heat shield, and it would send a different tone, and so engineers like Sue were here listening for those special frequencies which told them the spacecraft was telling them what it has just done,” he said.

He notes that Finley also helped develop communication arrays that combine multiple antennas to act in unison and other advances that now crucial to space missions.

Lichten once shared an office with Finley and says she inspired her younger colleagues.

“There was a parade of people coming in constantly, to ask her advice, to ask her questions,” he recalls. “This was during the Venus balloon mission days and I realized that Sue was regarded as sort of a guru at JPL.”

Finley has been involved with nearly every advance in space communications in recent decades, and she continues her work today, Lichten said.

There are many more women at NASA today than there were when she started, and Finley said she tells young women to be inquisitive.

“I tell them to never be afraid to ask questions, never be afraid to say you don’t know,” she said.

After nearly six decades at the space agency, a mother of two grown sons and a mentor to her colleagues, Finley has no plans of retiring.

“There’s nothing else I want to do,” she said. “And so far, they need me.”

As they have since the earliest days of the space agency. (VOA)

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20 Years of Changing Seasons on Earth Captured into 2½ Minutes by NASA

NASA captured 20 years of changing seasons in a striking new global map of the home planet that shows Earth's fluctuations as seen from space

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The Changing seasons of the Earth
The Changing seasons of the Earth has been captured by NASA. Wikimedia.

NASA captured 20 years of changing seasons on Earth in a striking new global map of the home planet.

The data visualization, released this week, shows Earth’s fluctuations as seen from space.

The polar ice caps and snow cover are shown ebbing and flowing with the seasons. The varying ocean shades of blue, green, red and purple depict the abundance — or lack — of undersea life.

“It’s like watching the Earth breathe. It’s really remarkable,” said NASA oceanographer Jeremy Werdell, who took part in the project.

Two decades — from September 1997 to this past September — are crunched into 2½ minutes of viewing.

Werdell finds the imagery mesmerizing. “It’s like all of my senses are being transported into space, and then you can compress time and rewind it, and just continually watch this kind of visualization,” he said Friday.

Werdell said the visualization shows spring coming earlier and autumn lasting longer in the Northern Hemisphere. Also noticeable to him is the receding of the Arctic ice caps over time — and, though less obvious, the Antarctic, too.

On the sea side, Werdell was struck by “this hugely productive bloom of biology” that exploded in the Pacific along the equator from 1997 to 1998 — when a water-warming El Nino merged into cooling La Nina. This algae bloom is evident by a line of bright green.

In considerably smaller Lake Erie, more and more contaminating algae blooms are apparent — appearing red and yellow.

All this data can provide resources for policymakers as well as commercial fishermen and many others, according to Werdell.

Programmer Alex Kekesi of NASA’s Goddard Space Flight Center in Maryland said it took three months to complete the visualization, using satellite imagery.

Just like our Earth, the visualization will continually change, officials said, as computer systems improve, new remote-sensing satellites are launched and more observations are made. (VOA)

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Astronomers Discover the ‘Biggest Stellar Puzzle’, Bizarre Star that Refuses to Die

The study calculated that the star that exploded was at least 50 times more massive than the Sun and probably much larger.

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This star shines brighter every time it explodes. Read to know more! (representative image) Wikimedia

New York, November 9, 2017 : An international team of astronomers has made a bizarre discovery – a star that refuses to stop shining despite exploding more than once over a period of 50 years.

The explosions of stars, known as supernovae, have been observed in the thousands and in all cases they marked the death of a star.

But a new study, published in the journal Nature, challenges known theories about the death of stars. Their observations included data from Keck Observatory on Maunakea in Hawaii.

“The spectra we obtained at Keck Observatory showed that this supernova looked like nothing we had ever seen before. This, after discovering nearly 5,000 supernovae in the last two decades,” said study co-author Peter Nugent from Lawrence Berkeley National Laboratory in the US.

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“While the spectra bear a resemblance to normal hydrogen-rich core-collapse supernova explosions, they grew brighter and dimmer at least five times more slowly, stretching an event which normally lasts 100 days to over two years,” Nugent said.

The supernova, named iPTF14hls, was discovered in September 2014 by the Palomar Transient Factory. At the time, it looked like an ordinary supernova.

Several months later, astronomers at Las Cumbres Observatory in the US noticed the supernova was growing brighter again after it had faded.

When astronomers went back and looked at archival data, they were astonished to find evidence of an explosion in 1954 at the same location.

This star somehow survived that explosion and exploded again in 2014.

“This supernova breaks everything we thought we knew about how they work. It’s the biggest puzzle I’ve encountered in almost a decade of studying stellar explosions,” said lead author Iair Arcavi, a NASA Einstein postdoctoral fellow at LCO and the University of California Santa Barbara.

The study calculated that the star that exploded was at least 50 times more massive than the Sun and probably much larger.

Supernova iPTF14hls may have been the most massive stellar explosion ever seen. The size of this explosion could be the reason that conventional understanding of the death of stars failed to explain this event.

Astronomers continue to monitor the supernova, which remains bright three years after it was discovered. (IANS)