Galaxy crash sparks biggest spiral

 
VLT/Galex image of NGC 6872 Galex revealed a wealth of new stars at the galaxy's outer reaches

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Astronomers have spotted the largest known spiral galaxy - by accident.

A team was looking through data from the Galaxy Evolution Explorer (Galex) satellite for star-forming regions around a galaxy called NGC 6872.

But they were shocked to see a vast swathe of ultraviolet light from young stars, indicating that the galaxy is actually big enough to accommodate five of our Milky Way galaxies within it.

The find was reported at the American Astronomical Society meeting in the US.

NGC 6872, a galaxy about 212 million light-years away in the constellation Pavo, was already known to be among the largest spiral galaxies.

Near it sits a lens-shaped or lenticular galaxy called IC 4970, which appears to have crashed through the spiral in recent astronomical times.

Rafael Eufrasio of the Catholic University of America and Nasa's Goddard Space Flight Center and colleagues from the University of Sao Paulo in Brazil and the European Southern Observatory in Chile were interested in a number of regions away from the galaxy.

"I was not looking for the largest spiral - it just came as a gift," Mr Eufrasio told BBC News.

Galex - a space telescope designed to search for the ultraviolet light that newly born stars put out - hinted that NGC 6872 was made much larger in size by the collision.

The team went on to use data from a range of other telescopes including the Very Large Telescope, the Two Micron All-Sky Survey and the Spitzer space telescope - each of which sees in a particular set of colours, in turn evidencing stars of varying ages.

They found the youngest stars in the outer reaches of the galaxy's enormous spiral arms, getting progressively older toward the centre.

That suggests a wave of star formation that travelled down the arms, set off by the collision with IC 4970, with the newest stellar neighbourhoods pushing the galaxy into the top spot in terms of size.

"It's been known to be among the largest for two decades, but it's much larger than we thought," explained Mr Eufrasio.

"The galaxy that collided with the [central disc of NGC 6872] splashed stars all over the place - 500,000 light-years away."

A simulation of the galactic collision suggests it happened 130 million years ago A simulation of the galactic collision suggests it happened 130 million years prior to the situation we see today

Besides being one for the record books, NGC 6872 updates the catalogue of known galaxy smash-ups, demonstrating how dramatically galaxies can be changed and added to by collisions.

"It shows the evolution of galaxies in the larger context of the Universe - how the large galaxies we had before were accreted from small clumps in the early Universe," Mr Eufrasio said.

"We're just seeing one example of two interacting galaxies but in the past that happened much more often - that's how the big [spiral galaxy] discs we have were probably formed. Putting that in a larger context, it's a very cool system."

 

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  • rate this
    -1

    Comment number 251.

    I'm torn between wanting to know more about the universe around us and being scared that if we get out there, we'd just spoil it like we have this planet!

  • rate this
    0

    Comment number 250.

    244. redrobb
    .If they discovered this by accident, one can only hope the huge celestial object hurtling towards earth does not go un-observed...
    ---
    A) This galaxy IS 130 million light years away.
    B) Earth is so incredibly tiny compared to those photos you can't comprehend it
    C) If an enormous object (the size of a galaxy?) does hurtle at earth what can we going to do to stop it? Diddly Squat.

  • rate this
    +1

    Comment number 249.

    spam spam spam spam
    "Just because we presently do not have evidence of anything being faster than light, does not mean such does not exist"

    True, no scientist should utterly discount the possibility, but we must look to the evidence we have which tells us that the probability of FTL travel is very small.

    Still, I suspect that before Einstein, Time Dilation would have been a ridiculous concept.

  • rate this
    +4

    Comment number 248.

    Despite the few who keep saying "Why are we wasting money on this?" I would much prefer to see these stories on the TV News than countries at war that we have no geographic proximity to... such as Syria, all day every day.

    If the Government was serious about making kids interested in science, GET THIS ON BBC NEWS TELEVISION SHOWS!!!!

  • rate this
    +2

    Comment number 247.

    228.Mightiest Martlet
    "God made it"

    Actually, I just asked him and he said "no that's not one of mine, I've been on holiday. Gabriel, have you been playing with the creation game again? I tolld you to stop that 2000 years ago"

  • rate this
    -3

    Comment number 246.

    lol my girlfiend is always pointing out to me in Father Ted style "far away = small."

    The god squad will never go away. They and the scientists are just two tribes, they needn't always be at war.

  • rate this
    +1

    Comment number 245.

    "spam spam spam spam
    Just because we presently do not have information/evidence of anything being faster than light, does not mean such does not exist."

    Two problems: one theoretical (relativity tells us it requires infinite energy to make a massive object FTL); the other existential: there should be evidence of the future affecting the past and changing the present. We don't see such evidence

  • rate this
    -1

    Comment number 244.

    And all made by GOD?...............If they discovered this by accident, one can only hope the huge celestial object hurtling towards earth does not go un-observed...

  • rate this
    -5

    Comment number 243.

    It is obvious that science is controlling our present day to day lives.Do you know what is the most needed thing in our life?It is relief.When random human killings,global warming,disasters come in front to ruin our life,we can look for a shelter in such discoveries.Scientists are blessed by God to find newer things and understand our universe
    WE LOVE SCIENCE,WE LOVE DISCOVERIES

  • rate this
    +1

    Comment number 242.

    I'm so glad I took out Galaxy crash insurance now.

  • rate this
    +3

    Comment number 241.

    re96 vorkosigan

    then what came before god?

    even with all the scientific uncertaintly, using god does not fill in any of the blanks.You are left with the same questions.If god created the big bang then who or what created god?how can god just exist forever?how does god exist without time and space?just as many holes as currect scientific understanding

  • rate this
    +1

    Comment number 240.

    204.spam spam spam spam

    Just because we presently do not have information/evidence of anything being faster than light, does not mean such does not exist.

    Not long ago, this spiralling galaxy existance was not known, to totally reject possibility of something being faster than light is not reasonable, or scientific



    Black holes are so powerful they bend light and relatively eat it

  • rate this
    +4

    Comment number 239.

    Religion is the opposite of discovery. Without religion, we would have been on the verge of colonising on other planets by now.

  • rate this
    +16

    Comment number 238.

    217.Donkzilla

    "Looking up at the sky at night, the stars and galaxies are light years from each other. Yet we can see and perceive these vast distances in an instant. Therefore our minds' eyes are faster than the speed of light.
    God 1 - 0 Science"

    I'm reminded here of that Father Ted episode where Ted is attemtping to explain the relative sizes of toy and real cows to Dougal!

  • rate this
    +2

    Comment number 237.

    To some, the wonders of the universe point towards a creator God. To others, it points towards the wonders of the randomness of our Universe. Two groups of people playing a giant game of tug-of-war and forgetting to simply stand and look. Please can we do that just once, just stand and marvel without the slightest hint of enmity. We might just get along a whole lot better then.

  • rate this
    +3

    Comment number 236.

    217....Yet we can see and perceive these vast distances in an instant. Therefore our minds' eyes are faster than the speed of light.
    God 1 - 0 Science
    -----------------------

    You can only 'think' as fast as an electrical signal can be sent along a nerve which can vary between 2 to 200 mph; which is 3million times slower than electricity in a wire

    Why bring your god into the conversation?

  • rate this
    +4

    Comment number 235.

    Stargazing live weekly please BBC!

  • rate this
    +2

    Comment number 234.

    214.TheyCallMeTheWonderer
    Just now
    However some versions of inflation theory suggest that for a very brief instant after the big bang the expansion was faster than light

    +++

    Why not?

    1) Acoustic wave rather than electromagntic ( c is function of permeability and permitivity of free space)

    2) Free space was not yet there to limit speed (see above)

  • rate this
    -9

    Comment number 233.

    222.

    You jump to conclusions too easily. I don't believe in the big fairy or in god. But that doesn't mean god can't score a random goal in the first half. Maybe you can say something scientific to score an equiliser before the full time whistle?

  • rate this
    0

    Comment number 232.

    The ability to realize our insignificance in the universe actually makes us the most significant. As for as we know! Astronomy rules.

 

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