will galaxies collide?

Discussion in 'Astronomy, Exobiology, & Cosmology' started by aerosimon, Feb 4, 2002.

  1. aerosimon Registered Member

    Messages:
    17
    this may soung stupid but since nothing in the universe is stationary (unless it is in reference to another object) and galaxies have their own and different velocities travelling through the universe, will galaxies collide with each other?
     
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  3. Adam §Þ@ç€ MØnk€¥ Registered Senior Member

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    I've seen a picture of galaxies in the middle of collision, but can't recall the name of the thing.
     
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  5. Boris2 Valued Senior Member

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    1,094
    <img src=http://www.astronomy.com/content/static/images/2207.jpg>


    <img src=http://www.astronomy.ohio-state.edu/Gallery/n4038.gif>


    Galaxies do collide but it would be extremely rare for individual stars in the galaxies to actually collide. The gravity of each will distort the shapes of the galaxies.

    The Milky Way and Andromeda Galaxy are on a collision course.
     
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  7. ismu ::phenomenon::. Registered Senior Member

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    468
    collide or swell

    According to Enstein's theory, Universe might be in collapsing state or expanding state. Consequence for the first guess, it will be creating a blackhole. For the second guess, we'll lost the sun.

    May be it's came from equation including a square-root in it. The squared value could be a negative or positive. I'm not so familiar with retivity theory. May be someone knew this stuff better.
     
  8. Adam §Þ@ç€ MØnk€¥ Registered Senior Member

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    7,415
    Thanks for the pictures. Whether the universe is expanding or not, gravitational influences are reaching out to each other all over the place, so if there WAS a Big Bang, it is doubtful everything would be expanding directly outward from a single point or whatever.
     
  9. Boris2 Valued Senior Member

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    1,094
    Black Holes exist in spacetime. If the universe where to collapse, current theories backed by observation say it wont, in a "Big Crunch" spacetime would also collapse. You may end up with a singularity but as there would be no space outside this singularity you could not observe it.
     
  10. wet1 Wanderer Registered Senior Member

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    8,616
    I guess coming into the conversation late is better than never...

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    NGC 1410/1409: Intergalactic Pipeline
    Credits: William C. Keel (Univ. Alabama, Tuscaloosa), NASA
    These two galaxies are interacting in a surprising way, connected by a "pipeline" of obscuring material that runs between them over 20,000 light-years of intergalactic space. Silhouetted by starlight, the dark, dusty ribbon appears to stretch from NGC 1410 (the galaxy at the left) and wrap itself around NGC 1409 (at right). A mere 300 million light-years distant in the constellation of Taurus, the pair's recent collision has likely drawn out this relatively thin lane of material which is only about 500 light-years wide. Though the Hubble Space Telescope image dramatically illustrates how galaxies exchange matter when they collide, it also presents challenges to current pictures of galaxy evolution. The titanic collision has triggered star formation in NGC 1410 as evidenced by its blue star forming regions, yet NGC 1409 remains devoid of hot, young blue stars even though observations indicate that material is flowing into it. Bound by gravity, these two galaxies are doomed to future collisions, merging over time into one.



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    Sagittarius Dwarf to Collide with Milky Way
    Credit: R. Ibata (UBC), R. Wyse (JHU), R. Sword (IoA)
    Our Galaxy is being invaded. Recent observations indicate that in the next 100 million years, the Sagittarius Dwarf galaxy will move though the disk of our own Milky Way Galaxy yet again . The Sagittarius Dwarf (Sgr), shown as the extended irregular shape below the Galactic Center, is the closest of 9 known small dwarf spheroidal galaxies that orbit our Galaxy. Don't worry, our Galaxy is not in danger, but no such assurances are issued for the Sagittarius Dwarf: the intense gravitational tidal forces might pull it apart. Oddly, however, Sgr's orbit indicates that is has been through our Galaxy several times before, and survived! One possibility is that Sgr contains a great deal of low-density dark matter that hold it together gravitationally during these collisions.

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    Closeup of Antennae Galaxy Collision
    Credit: B. Whitmore (STScI), F. Schweizer (DTM), NASA
    It's a clash of the titans. Two galaxies are squaring off in Corvus and here are the latest pictures. When two galaxies collide, however, the stars that compose them usually do not. This is because galaxies are mostly empty space and, however bright, stars only take up only a small amount of that space. But during the slow, hundred million year collision, one galaxy can rip the other apart gravitationally, and dust and gas common to both galaxies does collide. In the above wreckage, dark dust pillars mark massive molecular clouds, which are being compressed during the galactic encounter, causing the rapid birth of millions of stars.
     
  11. Lua Registered Senior Member

    Messages:
    42
    galaxies do collide, but it's a very rare phenomena due to the fact that the universe is mostly consisted of space without matter (galaxies, stars,...). It's something like the earth, more water (oceans) than earth (continents, islands).


    there wasn't a "single point" in the big bang, because to be able to have a point, you need space, and the space was just creathed within the big bang. There wasn't even a "before" in the whole big bang scenario. It's very difficult for us to understand because our brain is so habituated to interpret in "this" or "that" (e.g. in "exist" or "not exist"), that's why quantium mechanics, for example, that gives us something we're not used to handle on our day by day, is so hard to assimilate (even einstein denied it).
     
    Last edited: Feb 4, 2002
  12. Lua,

    Before the Big Bang there was the Big Crunch, and before the Big Crunch there was the Big Bang again. And since this cycle has occured an infinite amount of times, everything is repeating itself exactly,over and over again. Therefore, I will be typing this post again in about 40-50 billion years.

    Tom
     
  13. Lua Registered Senior Member

    Messages:
    42
    well, tom, that's one of th theories.... i myself prefer the one that the universe wil expand forever until it dies in the cold dark vaccum. but that would be a good explanation of deja-vu, açtough i think it's highly unlikly that the same atoms that are in me and you would combine again in the same way.

    i hope i don't have to be in this world in 40-50 billion years. you mean, start all over again? talking about boring...
     
  14. Boris2 Valued Senior Member

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    1,094
    Did a search of the archives and couldn't find your post of 45 billion years ago.

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    What kind of show is Porfiry running here. Sheesh.

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  15. thed IT Gopher Registered Senior Member

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    1,105
    Joeblow

    The idea that the Universe is cyclically repeating is an anaethema to Physics. It means that everything has existed for infinity and will always exist. Strange as it may seem, that is harder to understand than Lua's description of where Cosmology is at.

    Having a universe that has always existed just does not 'feel' right somehow.
     
  16. thed IT Gopher Registered Senior Member

    Messages:
    1,105
    Forgot to add

    It's generally accepted that M31, the Andromeda Galaxy, will collide with us in about 4 or 5 billion years.
     
  17. Lua,

    "although i think it's highly unlikly that the same atoms that are in me and you would combine again in the same way."

    Yes it's very unlikely. But since the universe is infinite, it went through this cycle an infinite amount of times. So, out of the infinite cycles, there is a 100% chance that once the atoms combined in exactly the same way they did previously. And when that happened once, it will keep repeating itself forever. It comes down to the fact that there is a 100% chance that we are repeating ourselves over and over again.

    Thed,

    It's true that it's hard to understand that the universe always existed. Remember, matter and energy cannot be destroyed or created, they can only be converted. Therefore, the universe was and will always exist in one form or another. Let's say for a second that you can make something out of nothing. That would mean that:

    0=1

    If 0=1 then:

    0=5,0=25,5=67,45=0,etc..

    As you can see if the universe was made from nothing, there would be no physical laws because math would collapse.

    Tom
     
  18. (Q) Encephaloid Martini Valued Senior Member

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    19,125
    But since the universe is infinite

    Common misconception. The 2-d balloon analogy is somewhat good in explaining this misnomer. The universe very well could be finite. We are struck with an illusion of infinity. Kind of a 'house of mirrors.'

    It's true that it's hard to understand that the universe always existed. Remember, matter and energy cannot be destroyed or created, they can only be converted. Therefore, the universe was and will always exist in one form or another. Let's say for a second that you can make something out of nothing.

    How do you account for these 'Pillars of the Big Bang Model?'

    Expansion of the Universe
    Origin of the cosmic background radiation
    Synthesis of the light elements
    Formation of galaxies and large-scale structure

    Thed of course will provide an excellent rebuttal.
     
  19. Q,

    You misunderstood me. I meant that the universe is infinite in time, not space. In space it has to be finite.

    And just because matter cannot be created or destroyed doesn't mean that the universe is always the same. I believe in an infinite amount of "bangs" and "crunches".

    Tom
     
  20. Rambler Senior Member Registered Senior Member

    Messages:
    509
    Hi All,

    JoeBlow,

    Isn't it also true that prior to Planck Time (really early in the big bang process) the laws of physics that govern our universe at the moment did not exist or were indeed able to be broken...hence an assumption that matter cannot be created could be altogether wrong???? if we believe inflation theory then matter was able to break the speed of light..which to me atleast say's the laws of physics at that time were different to what we see now.


    Just a thought
     
  21. Guildenstern Registered Member

    Messages:
    4
    Hi.

    Yes, galaxies colide. However these procedures can take a long time, perhaps even tens of billions of years.

    It has well been said that the stars INSIDE the two galaxies will not collde themselves (unless there are some rare occasions when the do), because the distance between most stars is so vast while the stars them selves are so small, that teh chance to a full headed collision is very slim.

    In the NASA web page or at JPL's, there should be several fine animation to describe the issue.

    Cheers,

    Guildenstern
     
  22. bettysfetish Registered Member

    Messages:
    2
    There is nothing to refer to. Nothing remains "static", and yes Galaxies do collide. However as one other reply mentioned this would take a long, long time.
    Anyone out there willing to debate the correlations between Science and Religion's explaination of the creation of the universe in "our" space and time? Did we start from a speck the size of a mustard seed or the size of a suitcase, or mabey the size of a "66" Buick Electra?, and then expand to something the size of our galaxy in a fraction of a second? Or did it "really" take only about 5000 years? Ya know they might "Both" be right.
     
  23. Rambler,

    Maybe at the time of the Big Bang, there were simpler physical laws(since matter was less complex), but there were laws. If it is found that matter did travel faster than light right after the Big Bang, then that would question our interpretation of the physical laws, not the physical laws themselves.

    Tom
     
    Last edited by a moderator: Feb 6, 2002

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