Wednesday, December 29, 2010

Backyard Astronomers Discover Black Holes and Other Wonders


Backyard astronomer Gus Johnson
Photo: VOA
Backyard astronomer Gus Johnson

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Amateur astronomer Gus Johnson didn't set out to witness what scientists say is the first ever observed birth of a black hole. But that's just what he did in 1979.  His discovery of Supernova 1979c was only the third supernova in another galaxy ever detected by an amateur. But it has become one of the most important and studied since.  Amateur astronomers have been making discoveries for at least 400 years, dating to Galileo's spotting of Jupiter's moons. The hobby helps professional scientists every day.
Johnson likes the quiet and he likes the dark.  But clouds and sub-zero temperatures are working against him as he stargazes near his home in Western Maryland.


"Well, Jupiter went behind a cloud so we have the moon," said Johnson.



Johnson has been stargazing for 50 years, and tonight he's invited some kids to join him.  He has a near photographic memory of hundreds of star positions and he loves to share what he knows.



"That planet has a diameter 11 times that of the Earth," he said.



Johnson is the maintenance man at Deep Creek's Lake Nature Center.  He's also an avid reader of Sky and Telescope magazine. In 1979, he was featured in the magazine - for discovering a supernova that scientists now believe is the newest and nearest black hole.



"When I came to M100 [galaxy]  there was this little star that for some reason caught my attention," said Johnson. "I don't know why, and later on when I checked the photograph it was not on the photograph and that proved to be the the Supernova1979c."


Was he pretty proud?



"Yes I was," he replied.  "And I am.  And thankful too because so few people actually get to discover things."



Backyard astronomers have been making discoveries for centuries dating back to Galileo, whom amateurs claim as one of their own. His degree was in art.  The famous Comet Hale-Bopp was discovered in 1995 by two amateurs, one of whom did not even own a telescope. He was using a friend's. And in 2007, volunteers in an online astronomy project discovered the "green pea" galaxies, so-named because they appear small and greenish in images.


Astrophysicist Kim Weaver was part of the NASA team that announced last month that Gus Johnson's supernova, or exploding star,  was likely the birth of a black hole, a region in space where nothing can escape, not even light. 



"We want to watch how this system evolves and changes in its youthful stages from when it's first born to when it grows into a child and a teenager," said Weaver.



Scientists believe that black holes are born often in the universe. But to actually see it happen, well that's a story. 



When Johnson spotted the star more than 30 years ago, he put out an alert, and telescopes including NASA'S powerful Chandra X-Ray Observatory have been watching it ever since.



We caught up with Weaver at the Goddard Space Flight Center in Maryland where she works.  



"This is what we think happens around a black hole, this ecreting material gets sucked into the orbit," she said.



She told us that while some astronomers dismiss the work of so-called citizen scientists, they do put thousands more eyes on the cosmos, which is a good thing.



"They don't have access to the large telescopes that professionals have access to but what they can do is they have the freedom to be able to use smaller telescopes any time they want to look all over the sky," said Weaver.



Professionals, Weaver says, tend to focus on smaller areas and on fainter objects further away.  Another problem: 



"Professional astronomers have created tons and tons of data," she said. "There are not enough professionals to look at all those data."



That's where backyard astronomers come in.



"So this is the first telescope I ever got.  It's my favorite," said Caroline Moore.  Moore has has an observatory in her backyard, with top of the line telescopes that she and her father use to track the ever-shifting heavens above New York State.  



Two years ago, at age 14, she made a major discovery, not with a telescope but with a computer, scanning hundreds of photos as part of an online search team.  



"I discovered the least luminous supernova ever to be observed, and I am the youngest person ever to discover a supernova so it kind of makes it a double interesting thing," she said.



Moore says supernova hunting is competitive. 



"Maybe you will find there is some kind of thing on another planet that will help you cure cancer and we won't know that if we don't take even the smallest steps in journeying outside our planet a bit," she said.



Back in Maryland, Gus Johnson observes fresh-fallen snow and an iced-over Deep Creek Lake.  There's something almost sad about his intense love of the environment, even with its fleeting nature. 



But his discovery, that he holds onto.

Johnson wasn't looking for a supernova that night, it was entirely accidental.  But, now he looks for them.
"It's kind of the grand realities of existence," said Johnson. "The Earth and everything we know is such a minute part of the universe.  Watching the creation of God.  That is pretty spectacular stuff."

Sunday, December 26, 2010

North magnetic pole racing toward Siberia?

The north magnetic pole (NMP), also known as the dip pole, is the point on Earth where the planet's magnetic field points straight down into the ground. Scottish explorer James Clark Ross first located the NMP in 1831 on the Boothia Peninsula in what is now northern Canada, and with the planting of a flag claimed it for Great Britain. 

But the NMP drifts from year to year as geophysical processes within Earth change. For more than 150 years after Ross's measurement its movement was gradual, generally less than 15 kilometers per year. But then, in the 1990s, it picked up speed in a big way, bolting north–northwest into the Arctic Ocean at more than 55 kilometers per year. If it keeps going it could pass the geographic north pole in a decade or so and carry on toward Siberia. But why?

One compelling explanation appears in the December 21 Eos, the weekly transactions of the American Geophysical Union. In their Eos article (subscription required), and ina longer paper published earlier in 2010 in the Journal of Geophysical Research–Solid Earth, Arnaud Chulliat of the Institute of Earth Physics of Paris and his colleagues venture that a twisting molten plume beneath the Artic could be the cause:

 According to some recent models, plumes of less dense fluid form at the inner core boundary and subsequently rise within [a cylinder] whose central axis is the Earth’s rotation axis. Such plumes undergo a strong helical motion due to the Earth’s rapid rotation, a phenomenon also observed in laboratory experiments with water. In the core, helical plumes advect and twist the magnetic field lines, forming what scientists call "polar magnetic upwellings." 
Those upwellings, unloaded into the Arctic mantle, could produce intense patches of magnetic activity on the sort of decade-long timescales needed to explain the NMP's sudden acceleration. (The authors compare these patches to a kind of terrestrial version of sunspots.) And magnetic field measurements show dramatic shifts near the New Siberian Islands that seem to fit the bill.

"What happened under the New Siberian Islands at the core surface is that the rate of change of the magnetic field changed by a large amount during the 1990s," Chulliat says. That activity, he and his colleagues have found, could account for a large portion of the NMP's acceleration. But whether magnetic field changes under the New Siberian Islands and the speeding north magnetic pole ultimately arise from a twisted plume of fluid rising through the core remains unproved, Chulliat and his co-authors note. A resolution of the mystery will await better modeling, along with more data from satellites monitoring the Arctic's magnetic environment. The necessity of satellites, interestingly enough, is a consequence of the pole's recent movement—as the NMP drifts farther out to sea, it becomes harder and harder to reach the region with magnetometer-equipped aircraft. Compass Photo credit:http://schools.bcsd.com