I think it's a galaxy behind the spiral foreground.
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What is more interesting to me is that the foreground galaxy appears to have 2 bright cores. Suggesting a well advanced merging?
I recently watched a documentary in which a theoretical physicist who modelled galactic collisions stated that when galaxies collide they "always" formed spherical galaxies. This has never made sense to me. My thought would be that it depends on trajectory and angular momentum, there seems to be evidence of galaxies colliding and retaining spiral structure in many of this sites images and this one lends weight to the reasoning. We know that planetary ring formation (eg Saturn) is affected by orbital resonance, is it so difficult to foresee gravitational resonance of galactic cores merging and forming spirals? The obvious difference being time. In the Saturnian system rings form because of the short distance gravity has to travel, at intergalactic distance gravity would form spiral resonances around two or more objects rotating around each other. It isn't possible to factor in that which we do not know but it seems reasonable that if 'dark matter' is gravitational then it would also be affected by angular momentum, the assumption being also that dark matter rotates as all other matter does. We could further infer that dark matter isn't uniform, that it has variation in density.
In the 1970's when black holes became the fashion to discuss, I believed that they would be the brightest objects in the sky since it seemed reasonable to me that they would accrete stars around them. I thought it more reasonable that far from being 'black' they would be the centre of galaxies. This has now become the accepted wisdom it seems
When I hear planetary formation discussed, it surprises me that it took so long (and an astronaut with bag of salt) to find that small particles would become charged in space and so aggregate. I heard astronomers and theorists say they couldn't make models that had large Jupiter sized planets form close in to their star. It always made sense to me that as gravity pulled the accretion disk inward it would be most dense closer in. Planetary interaction then accounting for the migration outward, this has recently been adopted as the most likely scenario especially since the discovery of so many large extra-solar planets close in to their stars.
The adoption of the 'dark' nomenclature to explain what is not known I find depressing and yet theorists will then continue to look for evidence to support that theory rather than remaining open to other possibilities. In psychology this is known as a state where preconception determines your interpretation of evidence. I will not be surprised if one day it is found that red shift occurs as a property of space rather than simply a speed related 'Doppler shift'. If light travelling through large tracts of space is affected (much the way light is affected passing through water) then this would account for distance but give no indication of speed. Stating that Doppler shift is the only thing that can account for red shift after saying we don't know what 95% of the universe is made of strikes me as hubris.
We know light is affected by gravity. We also know gravity behaves like light, it obeys the inverse square law. It is now accepted that there is much more 'stuff' than we can actually see around visible objects in the universe and this 'dark matter' is emitting gravity. Gravity never falls to zero, every object in the universe no matter how distant is gravitationally connected no matter how 'weak' the effect. The idea that an object is in a straight line away from us (that only 'large' gravitational fields affect it's path) is simply not reasonable to me. When we look at distant objects we look through a confluence of interacting gravitational fields. When we look at the universe we see galaxies form into structure under gravitational influence - filaments etc. I make a prediction - the better telescopes get, the more the age of the universe is revised up (this has already been happening) until it reaches the point where accepted theory can't account for it.
My feeling is that an experiment to directly measure whether the universe is expanding is within the reach of current technology and equipment already deployed. If rather than flitting across the sky and inferring expansion by comparing different objects, we take measurement of one very distant object over time and compare whether the red shift is occurring at the expected rate. A short study was done along these lines and it lead to the 'inflation' theory. It was faster than expected. The inference being the universe was speeding up, rather than that the piece we were looking through was becoming denser. I tend to think of Akum's razor, is it more logical to assume the expansion suddenly speeded up or that something we were looking through was changing? I think we should do a much longer study on the most distant object we can accurately measure for as long a possible meanwhile mapping dark matter as accurately as possible. It would then be interesting to see if change in red shift correlated with current thinking or dark matter distribution.
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Budgieye
moderator
Thank you for your long comment. Since it covers many topics, here are some links to more reading.
p1. the galaxy might have two bright cores, see links in
2.10 double nuclei and shell galaxies created by two revolving nuclei http://talk.galaxyzoo.org/#/boards/BGZ0000001/discussions/DGZ0000wrb?page=2&comment_id=53d8b8a1db90c76710000f89
p. 2 Are ellipticals always the results of collisions?: simulations and reserach are being done see
1.3 Galaxy Classification and formation and evolution http://talk.galaxyzoo.org/#/boards/BGZ0000001/discussions/DGZ0000wrb?page=1&comment_id=53d8b71c0d43f776b0001074
p6 "Does gravity affect light" is a two level question.
easy level
Gravity does not bend the path of the light. Gravity warps spacetime, and the light still thinks that it is going in a straight line.
hard level:
Does light have mass? Maybe a little, but very little, and can't be detected.
http://imagine.gsfc.nasa.gov/ask_astro/relativity.html#961102
I will not be surprised if one day it is found that red shift occurs
as a property of space rather than simply a speed related 'Doppler
shift'.Redshift is caused by the expansion of the universe. This is the current theory, and a theory is an explanation that fits the facts.
p7
apparently scientist think that it is better to measure many objects, and take an average.
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