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Post by jandl100 on Jul 8, 2018 6:02:58 GMT
The giant elliptical galaxy at the centre of the image has been busy gobbling up smaller galaxies over the past billion years or so. Successive collisons seem to have created concentric shock waves blasting out. The smaller spiral galaxy is in the process of assimilation.  |
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Post by ChrisB on Jul 8, 2018 6:23:38 GMT
Fabulous image!
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Post by liffy99 on Jul 8, 2018 6:29:12 GMT
Sadly (or perhaps luckily for potential inhabitants) one would see very little of this beauty of galaxies in such seemingly close proximity.
The reality is that they are so diffuse (stars many light years apart from each other) it would seem like two very thin mists mingling, and oh so slowly.
But the sheer scale of the cosmos is staggering. I once tried to illustrate this to a young nephew with an orange representing the sun, and placing a lentil (Earth) nearly 40’ away. And in cosmological terms thats so close its scary. When distances extend to light years you very quickly run out of garden, or even county !
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Post by jandl100 on Jul 8, 2018 7:24:50 GMT
A simulation of galaxy formation out of primordial matter and dark matter (whatever the hell that is, but it's gravitational effects tend to dominate at galactic scales).
Fascinating to see the natural creation of spiral structure - and it's an amazingly violent process!
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Post by MartinT on Jul 8, 2018 15:36:24 GMT
Everything to do with stars is pretty violent. I think orbital motion is common among approaching objects so spirals are almost inevitable.
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Post by jandl100 on Jul 8, 2018 16:14:20 GMT
Yep, angular momentum is conserved!
Nonetheless, current theory is that giant elliptical galaxies (i.e. formless blobs) are created from the accumulation of many spiral galaxies.
I'm not quite sure how that works!
Do you remember Nigel Calder's "The Violent Universe" series and book for the BBC? Many years ago .... let's see .... 1969. Wow.
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Post by MartinT on Jul 8, 2018 17:43:05 GMT
1969? No, I don't remember it but will look it up.
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Post by liffy99 on Jul 9, 2018 8:47:32 GMT
Dark Matter ?
Well, Lidl had some on special a couple of weeks ago but now I cant seem to lay my hands on it anywhere.
Must be the same stuff that my specs are made of . . .
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Post by Deleted on Jul 9, 2018 17:33:21 GMT
The giant elliptical galaxy at the centre of the image has been busy gobbling up smaller galaxies over the past billion years or so. Successive collisons seem to have created concentric shock waves blasting out. The smaller spiral galaxy is in the process of assimilation. So incredibly beautiful. Then you contemplate the incomprehensible scale and it blows your mind. And you then you realise this is just a tiny speck in a corner of what is the visible universe. Then you start to think about the vast majority of matter in the universe being undetectable. Then you think about what lies beyond. The whole subject is utterly entrancing to me. Thanks for posting. |
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Post by jandl100 on Jul 9, 2018 20:04:06 GMT
I found this simulated image 'overlay' astonishing when I first came across it. This is how the Andromeda M31 galaxy (the nearest large galaxy to us) would look in our night sky if it was bright enough to be seen with the naked eye - or if our eyes just happened to be a lot more sensitive - compare it to the size of the moon as we see it.  -- I wonder if nocturnal animals with highly adapted night-sensitive vision do see it like this? |
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Post by MartinT on Jul 9, 2018 20:45:42 GMT
That makes it humongous, which of course we know. Then remember that it's 2,500,000 light years away....
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Post by jandl100 on Jul 10, 2018 6:20:52 GMT
This photo of a 3-galaxy merger came up on my Facebook feed today. Apparently known as The Bird or Tinkerbell galaxy.  2 spiral galaxies top left and right, and an irregular galaxy coming in from the bottom of the merger. www.eso.org/public/images/eso0755a/I suspect that they will pass through each other this time round and then circle round and come back together again leaving huge trails of gas encompassing some frantic star formation kicked off by the additional pressure and gravity.  |
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Post by jandl100 on Jul 15, 2018 14:19:17 GMT
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Post by jandl100 on Nov 16, 2018 7:51:16 GMT
This, apparently, is the most luminous galaxy ever seen.  This image is an artist's impression based on the best available data. A 4 way collision. Depending on your perspective this is either a central galaxy cannibalising 3 of its neighbours, or the central galaxy is being attacked by a bunch of galactic thugs. The thugs are losing. There's also a 4 billion solar mass black hole at the centre of the central galaxy which is stirring things up a bit. This galactic punch up is 12.4 billion light years away, and so was happening 12.4 billion years ago. I wonder what it looks like now? www.jpl.nasa.gov/news/news.php?feature=7282&utm_source=iContact&utm_medium=email&utm_campaign=nasajpl&utm_content=daily20181115-1Just to show that astronomers do have a sense of humour ... "W2246-0526 falls into a special category of particularly luminous quasars known as hot, dust-obscured galaxies, or Hot DOGs."  |
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Post by ChrisB on Nov 16, 2018 8:09:54 GMT
Wow, that's great Jerry. I love these threads of yours!
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Post by MartinT on Nov 16, 2018 8:14:13 GMT
There's also a 4 billion solar mass black hole at the centre of the central galaxy which is stirring things up a bit. A black hole of 4 billion solar masses. Boggle.  |
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Post by jandl100 on Nov 16, 2018 8:19:53 GMT
It's mostly the 4 billion solar mass black hole (1,000 times bigger than the one at the centre of our own galaxy, the Milky Way) that is causing the exceptional brightness, being fed by instreaming material from the surrounding 3 galaxies. Here's the interconnectivity of the 4 galaxies at radio wavelengths based on recent data from the ALMA array of radio telescopes ...  |
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Post by jandl100 on Nov 16, 2018 8:24:15 GMT
In fact, the very existence of galaxy structures and black holes of this size this early in the age of the universe is a major problem for current cosmological theories. How did things clump together and get going so soon?
Something very fundamental is not yet understood!
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Post by jandl100 on Nov 16, 2018 8:47:52 GMT
This is quite a good vid about black hole sizes
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Post by MartinT on Nov 16, 2018 13:20:06 GMT
That's a cracking video, Jerry.
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