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Swirling galaxies?

  1. Jul 17, 2005 #1
    When I look at pictures of swirling galaxies. The swirling patterns look very much like clouds swirling around the eye of a hurricane.

    This would imply that it is space itself that is being pulled toward the vortex of the galaxy and the stars are tagging along. Just like a hurricane pulls the clouds toward its vortex by pulling the air and a wirlpool pulls floating objects toward its vortex by pulling the water.

    I'm thinking that the black hole sucks in stars, and then spews out the dust at another point in space where another galaxy is formed. If another black hole is in its path, it could then become another swirling galaxy.

    I think that if the black hole at the center of a galaxy was just a source of gravity, the stars would follow a straight line toward it even if it was spinning.

    If it is space that is being pulled toward the black hole, wouldn't it mean that space has mass?

    Water must have mass in order for a whirlpool to exist, and air has mass in order for a tornado or hurricane to exist.

    If space can move, doesn't this imply that space has substance or mass?
  2. jcsd
  3. Jul 17, 2005 #2


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    The mechanism for a hurricane and whirlpool are completely different than those for a galaxy. The stars of a spiral galaxy are not being drawn to the center, they are simply orbiting the center and orbits nearer the center are faster. Besides not all galaxies are spiral. even if the mechanism was the same it does not imply that space is being pulled towards the center. In a galaxy, the stars themselves are the equivalent of the air in a hurricane or the water in a whirlpool.
    After it has cleared out the local neighborhood, central black holes don't "suck in" anymore stars, the remaining stars simply remain in orbit
    No, you would still have to account for conservation of angular momentum. As stars further out move in they would have to travel around the center at more revolutions per time unit, and you would get a spiral effect. But again, this is not what is happening with galaxies.
    As per my point above you do not need space being pulled to a blackhole to explain the spiral shape of a galaxy. In fact you don't need to have a black hole at the center at all.
    The stars of the galaxy themselves have mass and that's all that needed for a spiral galaxy to exist
    While General Relativity predicts an effect called "frame dragging" . It is not dependent on space having substance or mass. It is also a very slight effect that is magnitudes smaller than what needed to explain spiral galaxies.
  4. Jul 17, 2005 #3
    What do you base this obsevation on? Merely the photos of swirling galaxies?

  5. Jul 17, 2005 #4
    The last post was meant for Pocket, not Janus. :blush:
  6. Jul 17, 2005 #5
    Pocketwatch, I think it might be good for you to read up a little bit on black holes. This site:http://en.wikipedia.org/wiki/Black_holes provides good information about the formation and structure and size and other subjects pertaining to black hole. You question was good, but I think this might help clear up some questions you may have. I don't mean this as an attack on you, please don't take it that way. I hope that helps. :smile:

  7. Jul 18, 2005 #6
    Some of my observations, misskitty are based on pictures of swirling galaxies.

    Most are based upon an experiment I conducted.

    Here's how it went:

    I went to my local hardware store and purchased an aluminum cone. The kind that they use for the top of some chain link fence posts, and some glue.

    At home I set to work.

    First I cut off the tip with a hacksaw. Then I stood it with the point up on a drill press and drilled a 3/8 inch hole. Then sanded it smooth.

    For the other end of the device, which is about 2 1/2 inches in diameter, I cut a round plate from 1/4 inch thick clear plexiglass using a holesaw on the drillpress. It was about 3 1/8 inches in diameter.

    Then I cut a 2 1/2 inch hole in the round plate and sanded it smooth.

    I put the circular disk flat on a table, applied some epoxy to the big end of the cone, stuck it in the hole in the plexiglass until it was flush with the table.

    After the glue hardened, I used a hacksaw to cut about 20 grooves in the plexiglass disk and the top edge of the aluminum cone.

    The grooves were about 1/8 in deep in line with the inner circumference, and equally spaced around it.

    Next I removed the centerdrill from the 3 1/8 holesaw and cut another plate from the plexiglass.

    After sanding the edges of the plate, I glued it on top of the disk over the grooves using super glue.

    After a little more sanding, I was ready to test it.

    I placed the pointed end in my mouth and drew my breath in through it.

    It made a whistling sound as the air spun in the chamber indicating that it worked.

    For the experiment, I had to buy a pack of cigarettes since no one at home smoked.

    To begin, I stuck the small end of the cone in the suction hose of a shopvac, taping it in with duct tape.

    I switched on the shopvac and the air began to wirl rapidly in the vortex chamber.

    After lighting a cigarette, I let the smoke get drawn into the chamber by holding the filter end to the intake grooves of the disk.

    After switching off the vacuum cleaner, I observed what had happened.

    The smoke left beautifully formed spiral lines on the inside the clear plate.

    At the beginning of the spiral, the lines were spaced apart and thicker.

    As it progressed to the center of the chamber, the spiral lines became thinner and more circular.

    At the very center of the chamber there was a clear circular spot about 1/2 inch in diameter that the smoke did not stain.

    The results:

    The spiral begins wide because the air is spinning slowly and is in a rapidly decaying orbit toward the center of the vortex where the pressure is the lowest.

    As the air and smoke moves closer to the center and the velocity increases, the spiral lines become thinner and more circular.

    The spinning air never comes closer than about 1/4 inch from the center.

    After reaching that point, the air begins to spin toward the hole in the small end of the cone and is ejected.

    Now, applying this to a gravity source such as a black hole Janus, I can see that it should work pretty much the same way like you said. The gravity source taking the place of the lower pressure in my vortex chamber.

    My question is:

    Does the black hole eject the star gases the way the vortex chamber ejects the air and smoke since the stars are spinning too fast to crash into the singularity.

    Hope this is not too long winded.
  8. Jul 18, 2005 #7


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    No. because The stars of a galaxy are not being drawn into the center black hole. In fact, you can have a spiral galaxy without any blackhole at the center at all.
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