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    Sagittarius Discovery: S0-102's Blazing Fast Orbit Around The Milky Way's Black Hole
    By News Staff | October 4th 2012 02:32 PM | 19 comments | Print | E-mail | Track Comments
    Black holes may not be so dangerous to stars after all. The discovery of a star named S0-102 may help reveal whether Albert Einstein was right in his fundamental prediction of how black holes warp space and time - it orbits the enormous black hole at the center of our Milky Way galaxy in a blazing 11.5 years. 

    Black holes, which form out of the collapse of matter, have such high density that nothing can escape their gravitational pull, not even light. They cannot be seen directly, but their influence on nearby stars is visible and provides a signature. Einstein's theory of general relativity predicts that mass distorts space and time and therefore not only slows down the flow of time but also stretches or shrinks distances. 

    Before this discovery, astronomers knew of only one star with a very short orbit near the black hole: S0-2, with an orbit of 16 years. The "S" is for Sagittarius, the constellation containing the galactic center and the black hole. 



    W. M. Keck Telescopes on Mauna Kea, Hawaii, observing the galactic center. The lasers are used to create an artificial star in the Earth's upper atmosphere, which is then used to measure the blurring effects of the lower atmosphere (the effect that makes the stars twinkle in the night sky). The blurring gets corrected in real time with the help of a deformable mirror. This is the adaptive optics technique. Credit: Ethan Tweedie

    "I'm extremely pleased to find two stars that orbit our galaxy's supermassive black hole in much less than a human lifetime," said
    Andrea Ghez, leader of the discovery team and a UCLA professor of physics and astronomy. Most of the stars have orbits of 60 years or longer, she said.  "It is the tango of S0-102 and S0-2 that will reveal the true geometry of space and time near a black hole for the first time. This measurement cannot be done with one star alone." 

    "Today, Einstein is in every iPhone, because the GPS system would not work without his theory," said Leo Meyer, lead author of the study. "What we want to find out is, would your phone also work so close to a black hole? The newly discovered star puts us in a position to answer that question in the future." 

    "The fact that we can find stars that are so close to the black hole is phenomenal," said Ghez. "Now it's a whole new ballgame, in terms of the kinds of experiments we can do to understand how black holes grow over time, the role supermassive black holes play in the center of galaxies, and whether Einstein's theory of general relativity is valid near a black hole, where this theory has never been tested before. It's exciting to now have a means to open up this window. This should not be a neighborhood where stars feel particularly welcome,. But surprisingly, it seems that black holes are not as hostile to stars as was previously speculated."


    Over the past 17 years, Ghez and colleagues have used the W.M. Keck Observatory, which sits atop Hawaii's dormant Mauna Kea volcano, to image the galactic center at the highest angular resolution possible. They use a powerful technology, which Ghez helped to pioneer, called adaptive optics to correct the distorting effects of the Earth's atmosphere in real time. With adaptive optics at the Keck Observatory, Ghez and her colleagues have revealed many surprises about the environments surrounding supermassive black holes, discovering, for example, young stars where none were expected and seeing a lack of old stars where many were anticipated.

    "The Keck Observatory has been the leader in adaptive optics for more than a decade and has enabled us to achieve tremendous progress in correcting the distorting effects of the Earth's atmosphere with high–angular resolution imaging," Ghez said. "It's really exciting to have access to the world's largest and best telescope. It is why I came to UCLA and why I stay at UCLA."

    In the same way that planets orbit around the sun, S0-102 and S0-2 are each in an elliptical orbit around the galaxy's central black hole. The planetary motion in our solar system was the ultimate test for Newton's gravitational theory 300 years ago; the motion of S0-102 and S0-2, Ghez said, will be the ultimate test for Einstein's theory of general relativity, which describes gravity as a consequence of the curvature of space and time.

    "The exciting thing about seeing stars go through their complete orbit is not only that you can prove that a black hole exists but you have the first opportunity to test fundamental physics using the motions of these stars," Ghez said. "Showing that it goes around in an ellipse provides the mass of the supermassive black hole, but if we can improve the precision of the measurements, we can see deviations from a perfect ellipse — which is the signature of general relativity."

    As the stars come to their closest approach, their motion will be affected by the curvature of spacetime, and the light traveling from the stars to us will be distorted, Ghez said.

    S0-2, which is 15 times brighter than S0-102, will go through its closest approach to the black hole in 2018.

    The deviation from a perfect ellipse is very small and requires extremely precise measurements. Over the last 15 years, Ghez and her colleagues have dramatically improved their ability to make these measurements.


    Published in Science.

    Comments

    Hank
    Well, it could be circling the drain.
    MikeCrow
    There's not much difference is there?

    Did you see my theory of the end of the world? There's a stars(?) mass of hydrogen gas that's going to fall in the that SMBH sometime over the next year. Since it's already fallen in (what 15,000 years ago?), aliens (not the acid for blood ones) with ftl spaceships already know that a grb is headed our way, and will vaporize everything on earth. Well they came here thousands of years ago, and warned us that in another couple months, zap, poof!
    Their hope was that we'd build spaceships (they left instructions, you know), and we'd move someplace safe.
    Unfortunately Predators, didn't kill all of the Aliens(the ones with acid for blood), the Aliens then killed everyone who knew how to actually build the spaceships.

    So..... ZAP, poof!

    Well, it could have happened like that.........
    Never is a long time.
    Gerhard Adam
    ...what 15,000 years ago...
    Yah, right.  It was 20,000 years ago, so if you can't even get that part right, then why should I trust the accuracy of the rest of your theory. :)
    Mundus vult decipi
    MikeCrow
    Well, taking the time to go look up the correct distance didn't make it a better tale (so I didn't, but prefaced it with a "what"), and besides if you're getting all pedantic it's more like 25,000 light years away.
    Never is a long time.
    Gerhard Adam
    So you're admitting that your theory might not be air-tight?
    Mundus vult decipi
    MikeCrow
    I'm admitting noth-thang!
    Never is a long time.
    Hank
    15, 20, now 25K? I deny all science from this point on because this issue has not been settled.
    Gerhard Adam
    So are you placing Mi Cro under house arrest, Pope Hank?
    Mundus vult decipi
    Hank
    No, it isn't like he said the tides only happen once a day or something equally insightful that would warrant an all-expenses paid Italian villa.
    Gerhard Adam
    Yes, but can you really be sure that he would not have have said it given the chance?
    Mundus vult decipi
    Hank
    If anyone invokes epistemology I am checking out.
    Gerhard Adam
    But how will you know, with any degree of confidence, whether someone has invoked epistemology or not?
    Mundus vult decipi
    MikeCrow
    You act as if I died!

    Beside, I thought what I said was insightful!

    Who else has tried the 2012 Mayan end of the world to a real event that hasn't happened for us yet, yet took place 25 thousand years ago, UFO's, Aliens, FTL space travel and a whole string of sequels from 2 movies franchises into one tidy package!
    Never is a long time.
    MikeCrow
    all-expenses paid Italian villa

    I'd sign up for that!
    Never is a long time.
    MikeCrow
    Am just trying to get lighting to strike twice
    Never is a long time.
    Gerhard Adam
    It already does that ...
    Mundus vult decipi
    Bonny Bonobo alias Brat
    The lasers are used to create an artificial star in the Earth's upper atmosphere, which is then used to measure the blurring effects of the lower atmosphere (the effect that makes the stars twinkle in the night sky). The blurring gets corrected in real time with the help of a deformable mirror. This is the adaptive optics technique.
    What? Scientists are creating artificial stars in the upper atmosphere! This sounds a bit worrying to me, but then I am a worrier :(
    My article about researchers identifying a potential blue green algae cause & L-Serine treatment for Lou Gehrig's ALS, MND, Parkinsons & Alzheimers is at http://www.science20.com/forums/medicine
    MikeCrow
    They are creating a point light source, not a thermal nuclear reaction.
    The point light source is used to measure atmospheric turbulence, and adaptive optics then compensate for said turbulence allowing higher detailed astrophotography, that allows imaging that rivals the Hubble from Earth.
    It is this technique that has spurred the creation of many very large visible light telescopes.
    The name artificial star is because the lasers can create a star anywhere in the sky, as opposed to having to image where natural stars are in the correct location.
    Never is a long time.
    Bonny Bonobo alias Brat
    The lasers are used to create an artificial star in the Earth's upper atmosphere, which is then used to measure the blurring effects of the lower atmosphere (the effect that makes the stars twinkle in the night sky). 
    Also, hopefully this activity doesn't have anything remotely to do with the unexpected and unexplained giant breaches that now keep occurring in the Earth's magnetosphere? :-
    Dec. 16, 2008: NASA's five THEMIS spacecraft have discovered a breach in Earth's magnetic field ten times larger than anything previously thought to exist. Solar wind can flow in through the opening to "load up" the magnetosphere for powerful geomagnetic storms. But the breach itself is not the biggest surprise. Researchers are even more amazed at the strange and unexpected way it forms, overturning long-held ideas of space physics."At first I didn't believe it," says THEMIS project scientist David Sibeck of the Goddard Space Flight Center. "This finding fundamentally alters our understanding of the solar wind-magnetosphere interaction."

    I'm sure that all of these scientists must be communicating with each other and they couldn't possibly be laser gun trigger happy could they?

    My article about researchers identifying a potential blue green algae cause & L-Serine treatment for Lou Gehrig's ALS, MND, Parkinsons & Alzheimers is at http://www.science20.com/forums/medicine