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Does the milkyway orbits anything ? like sun orbiting center blackhole of our galaxy

  1. Jan 6, 2013 #1
    Does the milkyway orbits anything ?? like sun orbiting center blackhole of our galaxy

    Does the milkyway orbits anything ?? like sun orbiting center blackhole of our galaxy
    i have this question bcoz
    our moon moves towards(orbiting) earth but cant reach or hit earth bcoz earth moves towards(orbiting) sun
    but even earth cant hit sun bcoz sun moves towards(orbiting) our galaxy centered big mass black hole but even our sun cant reach or hit center of our galaxy
    so its shows that even our center of galaxy big black hole moves towards(orbiting) something??
    if yes towards what ??
     
  2. jcsd
  3. Jan 6, 2013 #2

    Drakkith

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    Re: Does the milkyway orbits anything ?? like sun orbiting center blackhole of our ga

    Our galaxy is bound to the other galaxies in our "Local Group", which includes the Large and Small Magellanic Clouds, The Andromeda Galaxy, and the Triangulum Galaxy. (Among others.) It's not quite an "orbit" like our planet is around our Sun, it's more like a multiple star system with each star orbiting a center of mass that varies wildly over time, leading to chaotic movement. Although in about 4 billion years our galaxy will merge with the Andromeda galaxy as the two collide.

    Both the Earth and the Moon orbit around a common center of mass between themselves. This center of mass point orbits the Sun. So you could say both the Earth and the Moon orbit around each other AND AT THE SAME TIME they orbit the Sun together.

    Similar to the above situation, the Earth and Sun orbit around a common center of mass, which itself orbits the galaxy. Contrary to popular belief the supermassive black hole at the center of our galaxy is NOT what it holding us in orbit. (But it does add to the gravitational pull of course) The mass of the stars, planets, dust, and gas inside of our own orbit FAR outdoes the mass of the black hole. It is the combination of all this mass, including the black hole, that holds us in our orbit. (I'm ignoring dark matter at the moment, but it has a significant effect too)
     
  4. Jan 7, 2013 #3

    Drakkith

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    Staff: Mentor

    Re: Does the milkyway orbits anything ?? like sun orbiting center blackhole of our ga

    Spras, any questions should be posted in a thread, not PM'd, that way everyone can see the answers!

    All orbits are either elliptical if they are closed orbits, (meaning they stay in orbit), or hyperbolic. (If an object comes in, swings by another object, and has enough speed not to be captured) It only depends on the speed of the orbiting object. Purely circular orbits do not exist.

    A "thing"? That depends on what you mean by a "thing". It isn't something that can be touched, measured, or anything else, yet our math accurately describes reality by saying spacetime is curved in certain ways. And it certainly isn't made up of subatomic particles. All objects and everything within the universe exist "within" spacetime. All this means is that if I want to describe a system of objects I must assign coordinates to each one. This requires 3 numbers for their spatial position, XYZ, and one more for their time coordinate if I want to track them over time. Hence 4 dimensions, 3 of space and 1 of time.


    This is not correct as far as we know. Here's a few links for you.
    http://en.wikipedia.org/wiki/Metric_expansion_of_space
    http://en.wikipedia.org/wiki/Big_bang_theory

    Pay close attention to what is in those articles, AND what ISN'T in those articles.
    They mention nothing about white wholes or anything like that. The truth is that we have no idea what the universe was like near the beginning, or if there was something "before the universe" and whatnot. The expansion of space does not require something to exist outside of spacetime or the universe either.

    No problem. Just try to take a little more time when writing your posts and use correct grammar, spelling, etc as best you can. Text speak, like "bcuz" is frowned upon here. It is hard to read and makes it seem like you didn't put any effort into writing your post. (And who wants to respond to someone who didn't take the time and effort to ask a proper question?)
     
  5. Jan 7, 2013 #4
    Re: Does the milkyway orbits anything ?? like sun orbiting center blackhole of our ga

    thanks for the links, i understand a lot
    i am new here
    i know my english is so bad
    i will try to improve it.

    Thanks a lot for all.
     
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