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posted by Dopefish on Wednesday February 19 2014, @04:30PM   Printer-friendly
from the reconnoiter-the-dark-matter dept.

weeds writes:

"This has been going on for some time and the date of closest approach keeps getting pushed back. Here is the latest report from the New York Times on the approach of a gas cloud called G2 towards the Galactic Center.

Black holes, which are the ultra-dense, collapsed objects predicted by Einstein's theory of general relativity, are often depicted as voracious feeders whose extraordinary gravity acts like a one-way membrane: Everything is sucked in, even light, and virtually nothing leaks out.

Now, for the first time, astronomers may have a chance to watch as a giant black hole consumes a cosmic snack.

In March or April, the gas cloud G2, which has been hurtling toward the center of the Milky Way, is expected to collide with Sagittarius A*, a black hole that lies just 26,000 light-years away from Earth."

 
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  • (Score: 4, Interesting) by Zinho on Wednesday February 19 2014, @04:38PM

    by Zinho (759) on Wednesday February 19 2014, @04:38PM (#2579)

    Can anyone comment on the light show we're expecting from this event? I've heard that dropping a bunch of mass into a black hole is a good way to get a bunch of EM emissions. I'm hping for some pretty pictures, and that any gamma radiation is pointed somewhere else :P

    --
    "Space Exploration is not endless circles in low earth orbit." -Buzz Aldrin
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  • (Score: 5, Informative) by weeds on Wednesday February 19 2014, @04:53PM

    by weeds (611) on Wednesday February 19 2014, @04:53PM (#2600) Journal
    • (Score: 3, Informative) by martyb on Wednesday February 19 2014, @05:37PM

      by martyb (76) Subscriber Badge on Wednesday February 19 2014, @05:37PM (#2645) Journal

      Weeds(611) [soylentnews.org] wrote:

      Wikipedia has a pretty decent explanation: http://en.wikipedia.org/wiki/Sagittarius_A*#Discov ery_of_G2_gas_cloud_on_an_accretion_course/

      Thanks for the Wikipedia link! Among the links I found there, I found this one especially interesting: "Sgr A* -- Swift Monitoring Program 2013/2014 [swift-sgra.com] which states, in part:

      This is the home page for the Swift monitoring campaign of the Galactic center. Using almost daily observations since 2006, this program has provided a unique baseline to study the long-term X-ray behavior of the central super-massive black hole Sgr A*. We post daily updates of the Swift data to allow for a quick response if the activity of Sgr A* changes due to its interaction with the approaching gas cloud "G2".

      Lots of historical data, pretty pictures(!), and even *more* links to sources and write-ups.

      For those who want to keep up with the happenings there, it also mentions:

      If you would like to receive an automatic update via email when flaring behavior is detected, please email: swift.sgra 'at' gmail.com.

      I, for one, am anxiously awaiting what may happen, and what we'll learn!

      --
      Wit is intellect, dancing.
      • (Score: 1) by tftp on Thursday February 20 2014, @12:24AM

        by tftp (806) on Thursday February 20 2014, @12:24AM (#3002) Homepage

        I, for one, am anxiously awaiting what may happen, and what we'll learn!

        Why am I reminded of that scene in the movie Independence Day when a bunch of UFO crazies gather on some roof and cheerfully look into the barrel of a Zettawatt gamma laser? :-)

    • (Score: 1) by isaac on Wednesday February 19 2014, @07:16PM

      by isaac (500) on Wednesday February 19 2014, @07:16PM (#2745)

      Perinigricon is definitely my word of the day.

      -Isaac

  • (Score: 3, Informative) by xiox on Wednesday February 19 2014, @06:22PM

    by xiox (692) on Wednesday February 19 2014, @06:22PM (#2692)

    There will be flares up in brightness in various wavebands. The variation in brightness and spectrum with time will tell us about the accretion processes taking place. In other black holes, the material appears to form a disc of accreting material. It has to lose angular momentum before it gets swallowed by the black hole. The innermost part of the accretion disc is seen by X-ray emission (reflection) and can be very variable.

    The cloud is also pretty small (a few solar masses), so you're not going to get a dangerous outburst!

  • (Score: 5, Informative) by gilgalad55 on Wednesday February 19 2014, @08:54PM

    by gilgalad55 (314) on Wednesday February 19 2014, @08:54PM (#2843)

    Almost certainly no gamma rays, although NASA's Fermi Gamma-ray Space Telescope is now operating in an observing profile that will give it good exposure to Sgr A* in case something does.

    To get gamma rays, you usually need some highly relativistic particles, thus something to accelerate them. When objects fall into black holes, they can (though they don't always) convert a significant fraction of their rest mass energy into heat and light. However, that still falls far short of the particle energies you need to generate gamma rays. Instead, the hot matter glows brightly in optical and X-ray. The plasma movement through the strong magnetic fields of the disc can also generate synchrotron radiation, which peaks in the cm-mm radio band.

    Some accreting black holes in other galaxies do emit powerful jets, which in turn emit gamma rays. When we see the gamma rays, the jets are pointed nearly directly at the earth, giving a strong relativistic boost to the signal.

    reddit-style source: I am an astrophysicist working with Fermi and radio telescopes.

  • (Score: 1) by mcgrew on Wednesday February 19 2014, @09:34PM

    by mcgrew (701) <publish@mcgrewbooks.com> on Wednesday February 19 2014, @09:34PM (#2883) Homepage Journal

    You might try actually (gasp) READING THE ARTICLE. They really don't know, but it's pretty certain you won't see it without a really big telescope.

    But there should be a few pretty pictures. But whatever happens, we will certainly learn something.

    What interested me is... this cloud is my birthday cake! It's supposed to happen in a time frame from three weeks before to three weeks after my birthday. I get a cosmic light show on my birthday!

    Hey, you, get offa my cloud...

    --
    Free Martian whores! [mcgrewbooks.com]
    • (Score: 1) by Zinho on Thursday February 20 2014, @02:39PM

      by Zinho (759) on Thursday February 20 2014, @02:39PM (#3459)

      You might try actually (gasp) READING THE ARTICLE. They really don't know, but it's pretty certain you won't see it without a really big telescope.

      Wait, this "article" you speak of, what is it?

      Oh, do you mean the FA in RTFA; are we doing that here? I'm confused...

      Of course, your response lets me know that TFA wouldn't have answered my question anyhow ;^)

      --
      "Space Exploration is not endless circles in low earth orbit." -Buzz Aldrin