Gravitational Variances in Space

  1. Hello,

    Once free of a planet's gravity, isn't one then subject to the primary force that governs that galaxy (ex. the massive black hole in the center of the Milky Way), in addition to the one that governs its solar system? What are the numerical values of these forces? Variances would occur with distance, but has anybody tried to measure these as independant forces, or can these values only be summed up only as one value? Also, if you were maintaining a constant speed of propulsion towards the center of the Milky Way, wouldn't you accelerate as you got closer?

    Last edited: Sep 10, 2011
  2. jcsd
  3. Drakkith

    Staff: Mentor

    Well, first of all the supermassive black hole at the center of our galaxy is NOT what is governing the galaxy. The matter that orbits the center of the galaxy does so because the collective gravity of the galaxies mass itself combined with the rotation pulls it into a disc shape. The black hole is only a very small portion of the total mass of the galaxy. (Also, dark matter is presumed to be one of the primary sources of mass that holds the galaxy together)

    Constant speed of propulsion? Do you mean you were "coasting" there with zero acceleration due to your own engines? If so, then yes, you would begin to accelerate as you approached the high mass of the center of the galaxy.
  4. Yale University:

    "There is increasing evidence that galaxies and supermassive black holes form and evolve together, exerting mutual feedback that governs the galaxy dynamics and the black hole mass. During their growth phase, supermassive black holes are readily visible as Active Galactic Nuclei (AGN)."
  5. No not "coasting," constant speed after achieving the desired speed to perform the test.

    Thank you for responding
  6. Drakkith

    Staff: Mentor

    Not sure why you linked this, as it doesn't disagree with my statement. The formation of the galaxy and supermassive black hole are related and the black hole obviously effects the galaxy through its gravitational interaction. However it is not the main thing that holds the galaxy together, as I said above.

    That is coasting.
  7. Ahhh - no. "Coasting" implies you took your foot of the gas and are in the process of deceleration.

    Coasting as defined by motor's control training:
    "The natural rate of deceleration of a motor when the power is removed. Coasting is the simplest deceleration method."
  8. Drakkith

    Staff: Mentor

    Coast: verb (used without object): to continue to move or advance after effort has ceased; keep going on acquired momentum. "We cut off the car engine and coasted for a while."
    Coast: verb (used with object): to cause to move along under acquired momentum. "to coast a rocket around the sun."

    While it usually is meant in terms of coasting in a car, it is applicable to any movement after whatever force is accelerating you is removed.
    Last edited: Sep 13, 2011
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