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Floating in space and angles of galaxies

  1. Jan 16, 2015 #1
    With the way our universe looks, different galaxies are angled in various ways from our perspective. What is the cause of this?

    My initial thoughts would be based on how spacetime is curved, or maybe it's because of the angle of rotation of the black hole at the center of those galaxies (provided the galaxy has one - can galaxies form without a BH?)

    And a final thought: I've always thought of space much like a bowl of jello in the regard of how the positions of galaxies and such "sit" in outer space. Maybe that's where some of my confusion comes from?

    Any help with understanding these things would be greatly appreciated :)
     
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  3. Jan 16, 2015 #2

    Bandersnatch

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    The point is, there is no cause. That is, there are no known large-scale processes that could orient the galaxies in any particular direction over any other, so they are oriented randomly.
    There are some statistical reasons for certain orientations being more prevalent (i.e., there are more "ways" to see a galaxy from its side than from its poles), but in essence it's the same as if you took a big bowl of galaxies, shook it up real good and thrown them around every which way.
     
    Last edited: Jan 16, 2015
  4. Jan 16, 2015 #3
    I see. Is this something that scientists are actively trying to learn about, or is it just accepted to be random?
     
  5. Jan 16, 2015 #4

    Bandersnatch

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    It's accepted because no non-randomness has been found so far. It's not a hard exercise, one could conceivably do it from home by pulling inclination data from a galaxy database and comparing the distribution with a randomly generated one (while taking care to account for axial symmetry).
     
  6. Jan 16, 2015 #5
    Thanks bandersnatch. I was hoping for a different answer, but I understand what you're saying. Maybe I'll dig into the available data just for fun :p
     
  7. Jan 16, 2015 #6

    DaveC426913

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    What are you expecting to observe? Is there some reason you are expecting large-scale galaxy orientation to have an orientational bias?
     
  8. Jan 16, 2015 #7
    I wasn't expecting to observe anything, really. I was just curious if there was any known reason or theory on the orientation of galaxies and why they aren't uniform.

    If you're referring to my comment about digging into the available data, it's just to see what's been documented and such. Nothing more than just general interest and curiosity :)
     
  9. Jan 16, 2015 #8

    DaveC426913

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    You mean 'why they are randomly oriented', yes?

    Well, the simplest reason is the null hypothesis - i.e. it is essentially the default. They have no bias to their orientation because that's what you would expect if there is no phenomenon affecting them.

    The question I'd expect you to ask is 'is there a bias, and if so, what might be the cause?'
     
  10. Jan 16, 2015 #9
    Interesting.

    Would that be along the same lines as "why are planets spinning?", as in, that it's the default state? (I believe I read that in another thread here somewhere, but I could have misunderstood)

    So if I understand correctly, their orientation doesn't appear to have an underlying mechanic or phenomena, so it's the default position for a galaxy, but does that rule out that there could be a phenomena that we just aren't aware of? Is there anything theorized that could alter the orientation of a galaxy or ecliptic path of planets that wouldn't require a catastrophic event (no collisions or merging of galaxies)?
     
  11. Jan 16, 2015 #10

    DaveC426913

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    The revolutions of planets in a system is definitely related. They all arise from the common origin of the stellar system.

    I am still struggling with your viewpoint. Are you asserting that galaxies, as they are now, do have an observed bias in their orientation? Or are you asserting that they do not have any observed bias in their orientation?

    It seems to me that, before entering into an analysis of causes for correlation, you must first establish if there is an observed bias.
     
  12. Jan 16, 2015 #11
    I believe I am saying there is a bias in their orientation. Every image of deep space that I've seen always appears to have galaxies in varying orientations, such as this image: http://hyperphysics.phy-astr.gsu.edu/hbase/astro/astpic/deepsec.jpg

    I do apologize if there is any confusion on my question(s) or if I'm not very clear, I'm very new to this area of study :)
     
  13. Jan 16, 2015 #12

    DaveC426913

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    Bias means one orientation is preferred over others (i.e. galaxies seem to "line up"). A bias is the opposite of an even (or random) distribution.

    Evenly/randomly-distributed would not need an explanation; whereas a bias in distribution would invite an explanation.
     
  14. Jan 16, 2015 #13
    Ooops! Totally misunderstood what you meant. In that case, no, I don't believe there is a bias in orientation as it does appear to be randomly distributed. I was thinking that maybe the orientation was determined by the way a galaxy was formed and it's impact on the curvature around it, but I really have no basis for that thought.
     
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