Results 1 to 17 of 17

Thread: Discussion: Biggest Collision in the Universe

  1. #1
    Join Date
    Jul 2003
    Posts
    28,033
    SUMMARY: An international team of scientists have discovered one of the most powerful events since the Big Bang: a collision between two galaxy clusters, which is smashing millions of stars into each other. The galaxy clusters are colliding like hurricanes, tossing individual galaxies out into interstellar space, and creating shockwaves more than 100-million degrees hot. Although the cluster, Abell 754, has been known for a long time, the astronomers used the ESA's XMM-Newton X-Ray Observatory to trace back the interactions and collisions with great detail, and get a much deeper understanding about how the Universe's largest structures are still forming.

    What do you think about this story? Post your comments below.

  2. #2
    Join Date
    Nov 2003
    Posts
    1,233
    Interesting.

    ". . . the largest structures in the Universe are essentially still forming in the modern era."

    "The construction boom may soon be over in a few more thousand million years though."

    "A mysterious substance dubbed 'dark energy' appears to be accelerating the Universe's expansion rate."

    ". . . observations of galaxy clusters such as Abell 754 will help to better define dark energy and also dark matter, an ‘invisible’ and mysterious substance that appears to comprise over 80 percent of a galaxy cluster's mass."

    Sounds like these mysteries may soon be solved.

    With kind regards,

    Oliver
    http://www.umr.edu/~om

  3. #3
    Guest Guest
    What power and Energy !
    , thankfully no Galaxy will ever be blasting into us creating huge shockwaves and starbursts

    thankfully no Galaxy will hit us,
    or will it ? :huh:

  4. #4
    StarLab Guest
    It seems you are ill-informed; it is a common knowledge within the scientific community that in two billion years' time, Andromeda will collide with our galaxy. If our solar system is at that time on one half of the galaxy, it will be sucked into the colliding pair of black holes. If on the other side, we'll be flung in the the far reaches of space. But such a cosmic event is nothing compared to the event described in this article.
    One question: what is the difference between dark matter, antimatter and dark energy? :unsure: :huh: :blink: :mellow: -_- :wacko: h34r:

  5. #5
    Join Date
    Jul 2005
    Location
    Massachusetts, USA
    Posts
    21,881
    Originally posted by StarLab@Sep 24 2004, 09:26 PM
    it is a common knowledge within the scientific community that in two billion years' time, Andromeda will collide with our galaxy. If our solar system is at that time on one half of the galaxy, it will be sucked into the colliding pair of black holes. If on the other side, we'll be flung in the the far reaches of space.
    Common Knowledge? Actually, while it is true that M31 has a velocity component toward us, there is no conclusive evidence that it is coming straight at us. There's every reason to think that it will make a near miss, which would disrupt our outer spiral arms a bit, perhaps creating another couple of dwarfs like the Magellenic clouds, and creating a period of star forming activity. It is NOT the case that half of the galaxy will be sucked into a pair of merging black holes.
    what is the difference between dark matter, antimatter and dark energy?
    We have observed anti-matter particles such as positrons which are positively charged electrons, anti-protons, which are negatively charged protons, etc. Every particle has an antiparticle. When these particles are charged, the anti-particle has the opposite charge, but all other characteristics are the same. When a particle hits its anti-particle, the two anihilate each other.

    Dark matter is still subject to a lot of debate. Currently, most research assume that it is some form of particle that is electrically neutral, does not interact much with normal matter, and is moving slow enough that it is gravitationally bound to galaxies and clusters. There is about six times as much dark matter as normal matter in the universe.

    Dark energy is something that pushes the universe apart, and accounts for about 70% of all the mass & energy in the universe. Less is known about this than about dark matter.
    Forming opinions as we speak

  6. #6
    Guest Guest
    The article says...nearby head-on collision. How near is it?

  7. #7
    Join Date
    Jul 2005
    Location
    Massachusetts, USA
    Posts
    21,881
    Originally posted by Guest@Sep 25 2004, 04:48 PM
    How near is it?
    The article also says this:
    Abell 754 is relatively close, about 800 million light years away.
    800 million light years is about one fifteenth as far away as the most distant galaxies we've been looking at. On the other hand it is about 400 times as far away as M31 in Andromeda [our nearest big neighbor].

    So, it is close in some sense, that is, it is cosmologically recent enough that we can say such things may still be happening now.
    Forming opinions as we speak

  8. #8
    Guest Guest
    A small quibble:


    "smashing millions of stars into each other"


    Most of you problably know this, but for the record, I'll make a few comments on how this could be misinterpreted. Firstly, this is a collision between clusters of galaxies, so most of what is colliding is the thin hot gas which is not in stars at all and yet makes up more of the mass of a cluster than stars do. Furthermore, even in a "head on" galaxy collision, the probability of individual stars colliding is very small. Just looking at the stars, galaxies are still mostly empty space and effectively pass through one another. Most of the energy goes into tidal disruption and heating.

  9. #9
    Guest Guest
    Thank you. Facinating.

  10. #10
    Guest Guest
    I have a question for all the smart people out there. If this collision is 800 million light years away, and considering the little I know about light years, is it possible that this occurence occurred at about 800 million years ago, or am I not aware of our technology's abilities. Thanks alot

  11. #11
    Join Date
    Jul 2003
    Posts
    4,562
    800 million light years away means the light traveled 800 million years to get here. You are correct.

  12. #12
    Join Date
    Feb 2004
    Posts
    734
    A light year is the distance light has travelled in a year. In this case the galaxy is 800 million light years away, which means that everything we're seeing now happened 800 million years ago.

  13. #13
    Join Date
    Sep 2004
    Posts
    57
    Originally posted by StarLab@Sep 24 2004, 09:26 PM
    it is a common knowledge within the scientific community that in two billion years' time, Andromeda will collide with our galaxy. If our solar system is at that time on one half of the galaxy, it will be sucked into the colliding pair of black holes.
    Even if Andromeda did someday collide with our galaxy the chances of their central super massive Black Holes getting close enough to merge is fantastically small. It's estimated that "our" black hole has the mass of about 4 million suns so it's diameter is about 15 million miles while Andromeda's mass is about 30 million suns so it's a little larger than the orbit of Venus. On galactic scales this is rather tiny. Depending on their relative approach velocities it should be easy for any astronomer to calculate how close they could get before either going into orbit around each other or merging. If I were to guess (and I will ) I'd say a couple of light years. Even if it was 100 light years, this is still a very small bulls eye.

  14. #14
    Planetwatcher Guest
    It seems you are ill-informed; it is a common knowledge within the scientific community that in two billion years' time, Andromeda will collide with our galaxy.
    I won't be here to see that. I don't know about the rest of you, but I already have plans for that night.
    A light year is the distance light has travelled in a year. In this case the galaxy is 800 million light years away, which means that everything we're seeing now happened 800 million years ago.
    Which would have place that event as occuring before even the Devion fossel age.
    I'm having difficultiy finding anything on that period. Oh well it was a long time ago, and our collision is a long long time from now. I don't need to know much more because it's not like we need to evacuate or anythin like that.

  15. #15
    Join Date
    Sep 2003
    Posts
    34
    Can anyone tell me if you would actualy see stars collidng or is it just the gasses? Surely with the timespans involved in these collisions there wouldnt be much to see even if you had a ringside seat? :huh:

  16. #16
    Join Date
    Jul 2005
    Location
    Massachusetts, USA
    Posts
    21,881
    Originally posted by mark mclellan@Sep 27 2004, 07:41 AM
    Can anyone tell me if you would actualy see stars collidng or is it just the gasses? Surely with the timespans involved in these collisions there wouldnt be much to see even if you had a ringside seat?
    There is a kind of star sometimes seen in globular clusters called 'blue stragglers'. These are thought to be the results of the collisions of old red stars [all star in globular clusters are old].

    So collisions can happen, but it may not be so spectacular as you might imagine. Suppose that one of the stars is in a red giant phase [increasing the likelyhood of a hit by a factor of ten thousand]. The other star would enter the thin gas envelope and experience some drag, perhaps enough to slow it down for a capture orbit. The smaller star could end up entering and exiting the envelope several times over a few thousand years, and eventually settle into a close orbit, where it would consume the gas envelope through gravitational forces and accretion.

    This would be very different and much slower than the big splat that we like to imagine.
    Forming opinions as we speak

  17. #17
    Join Date
    May 2004
    Posts
    440
    A common question around here is about life, but in this case I suppose that note about a "100-million degree" shockwave pretty much cleared that table.

    downunder, if we were playing golf and wondered if the balls would collide, I'd say you were right, but that is not the case. Most of our descriptions of matter binding into stars and planets and all this happening in the environment of a collection of stars in a galaxy that orbits, if not spirals into, a more massive center--all are driven by the balances of forward momentum and gravity. Two galactic masses moving in an intersecting vector will find that line of travel bent closer by the mutual gravitational attraction. The more massive the objects are the more certain they will still more closely interact, or did I miss something .

    As with most other such major objects it won't have to be a direct blow but more like a spiral dance to their collision, if not a more certain bending of directions and shearing of things more losely bound, I might expect. Besides, the galactic centers are not just a simplisticly single black hole but an aggregate gravitational force of numerous black holes and other massive stellar bodies. With all of that in such close proximity there isn't much room to maneuver, so I'm sure there is an opportunity for a "ringside seat" to actually see stars colliding, if Mark actually had the time. :blink:

    I like StarLab's question on the dark matter/dark energy. If dark matter was pushing galaxies along more swiftly, suppose that dark energy were pushing light along more swiftly and so we are getting a compressed picture? I expect the writer missed it, but then what do we really know of that stuff anyway :huh:

    Somebody wake me up when Andromeda gets closer. Wait, didn't I hear about some small galaxies or clusters in our "neighborhood" that might have been fragments of a relatively recent collision? A few years back there was a piece somewhere, hmm, I think they popularly called this little galaxy/star cluster "snickers", as in it was "peanuts" in comparison to our galaxy, so we might have some evidences of a galaxy collision a little closer to home. hmmm.... :unsure:

Similar Threads

  1. Discussion: Biggest Eruption in the Universe
    By Fraser in forum Universe Today
    Replies: 15
    Last Post: 2010-May-14, 09:39 PM
  2. Biggest Collisions in the Universe
    By Fraser in forum Universe Today
    Replies: 4
    Last Post: 2007-Jul-20, 10:46 PM
  3. Biggest 3-D Map of the Universe
    By Fraser in forum Universe Today
    Replies: 1
    Last Post: 2006-May-17, 02:31 PM
  4. Biggest Collision in the Universe
    By Fraser in forum Universe Today
    Replies: 1
    Last Post: 2005-Sep-08, 05:26 PM
  5. Discussion: Biggest Stars Make the Biggest ...
    By Fraser in forum Universe Today
    Replies: 6
    Last Post: 2005-Jan-29, 03:42 PM

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •