Quasars: Near or far?

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Icy
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Quasars: Near or far?

Post by Icy »

Hi everyone,

I have a question about quasars. I've heard that some astronomers do not believe quasars are really far from us. But what properties would an object need in order to have a redshift as high as quasar's, but still be no further than say a billion light-years from the Milky Way?

Thank you,
Icy.


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Post by joe »

I suppose the more obvious reasons are that they are actually moving very fast (but much closer) or are dense enough to have a gravitational effect on the light emitted from them. There are theories that suggest that quasars are dense objects ejected (in pairs) from parent galaxies at high speed. These have high redshifts which decreases as a new galaxy forms from the core. This results, the proponents argue, in two or three galaxies interacting at different redshifts. Look up information on Halton Arp, if you haven't done so already, to get a flavour of the controversy. Unfortunately, a lot of this stuff is found on sites with a "non-astronomical agenda".
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Post by Icy »

Thank you very much for your help, Joe. I will look at the articles by Halton Arp. I wasn't able to find much of info before, but I will try again.
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cigarshaped
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Quasars: Near or far?

Post by cigarshaped »

Hi Icy & Joe,

Another step from distant quasar to daughter galaxy is the "Gravitational lensing" idea. This tries to suggest that coincidentally a distant quasar has been lensed into 2 or sometimes 4 images, symmetrically around the galaxy.

Apart from the statistical odds against such an event happening more than once, have a look at the Thunderbolts team view of this:
Gravitational Lensing or Birth of a Theory?.

You might read this paragraph:
[quote]Peratt, following Alfven, considers that galaxies and quasars form in “pinchesâ€
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Post by Cliff »

Dear Cigarshaped
Although I am a big admirer of Halton Arp, there seem to be good reasons to believe the gravitational lens theory (eg similarity of their spectra).
With regards to the statistical evidence you mention suggesting lensing can happen very rarely I suspect the staistics are selective nonsense.
Best of luck from Cliff
PS the Universe may not be infinitely large but it is pretty big, even the visible bit. If some of these nearby quasars are as close as some suggest they are and are moving so fast then presumably someday someone will actually observe their changes in position relative to their mother galaxies ?
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Re: Quasars: Near or far?

Post by Paul S »

cigarshaped wrote:Apart from the statistical odds against such an event happening more than once
What are the statistical odds of this happening more than once?
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cigarshaped
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Quasars: Near or far?

Post by cigarshaped »

Paul S
What are the statistical odds of this happening more than once?
Infinitesimal! In the vastness of space with the distances involved we are bending all the statistical chances as Don Scott suggests below:
Gravitational Lensing Misused Again
and again:
Gravitational Lensing or Death of a Theory?
and if you it in print:The Electric Sky
Not that I get a penny from this!

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Re: Quasars: Near or far?

Post by Paul S »

cigarshaped wrote:Infinitesimal! In the vastness of space with the distances involved we are bending all the statistical chances as Don Scott suggests below
Chris, none of this material you are linking to tells me what the statistical chances are.

By my reckoning they are not that low at all.

Consider that holding up a grain of sand to the sky at arms length and you will typically be covering ten thousand galaxies in the observable universe. And that's only one thirteen millionth of the area of the sky. These can be seen in the Hubble Ultra Deep Field shots.

There are hundreds of thousands of quasars that are potentially visible, we've only scratched the surface so far.

The likelihood of some being behind a galaxy are quite good, IMO.
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Quasars: Near or far?

Post by cigarshaped »

Paul S
The likelihood of some being behind a galaxy are quite good, IMO.
And how do you decide that they are BEHIND a galaxy and not co-located?

Would I be right - classical method to assume low brightness and high redshift? So if an object is dimmer and apparently more energetic (Hi z) it MUST be further away... :?:
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Re: Quasars: Near or far?

Post by joe »

cigarshaped wrote:And how do you decide that they are BEHIND a galaxy and not co-located?
You were commenting on the odds of a favourable line-up of a presumed distant quasar and a nearer galaxy. You can't shift the goalposts just yet. :roll:
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Re: Quasars: Near or far?

Post by Paul S »

cigarshaped wrote:And how do you decide that they are BEHIND a galaxy and not co-located?
Yes, redshift; and they exactly follow Einstein's gravitational lensing prediction - even if he didn't believe the phenomenon would ever be seen.

If these things are jetting sideways out of galaxies then doesn't that makes any redshift calculations deliver quite bizarre results? Maybe I am misunderstanding the guy's theory. For us to see that sort of redshift from an object that is moving more perpendicular to our pov than parallel would surely be a truly amazing speed - maybe one that we would probably detect over time (especially since they are likely to have a strong perpendicular vector component). I don't know, I haven't done the maths and I'd hope someone's done it already.

On the whole, it seems the chap is an electrical engineer by profession and an amateur astronomer in his leisure time. His beef seems to be that astrophysicists these days are obsessed with gravity and have no time for the basics of Maxwell era electromagnetics. But there must be a large number of astrophysicists out there who are fully versed in Maxwellian physics. I'd be very cautious until I was able to look at some peer review material - of which I could not find any ... which is telling in itself.

Gravitational lensing seems much more likely and obvious, since it was predicted.
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Re: Quasars: Near or far?

Post by joe »

Paul S wrote:For us to see that sort of redshift from an object that is moving more perpendicular to our pov than parallel would surely be a truly amazing speed
I haven't read a great deal of the theory but presumably if these offspring galaxies are ejected at speed along our line of sight then we should find some of them blue-shifted. Are there any? I'm missing something, obviously. I'm sure there are no blue-shifted quasars.
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Re: Quasars: Near or far?

Post by Paul S »

joe wrote:if these offspring galaxies are ejected at speed along our line of sight then we should find some of them blue-shifted. Are there any?
Good point. It'd have to be a bizarre phenomenon for it only ever to happen pointing away from us.
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Quasars: Near or far?

Post by cigarshaped »

Paul S:
joe wrote:
if these offspring galaxies are ejected at speed along our line of sight then we should find some of them blue-shifted. Are there any?
Joe:
Good point. It'd have to be a bizarre phenomenon for it only ever to happen pointing away from us.
We've wandered off target here slightly. You are applying the conventional view of redshift to Halton Arp's idea. Instead of motion and distance we should be talking about energy levels. The direction of motion has little to do with the redshift of these proto galaxies. The quasars gently plough through space along the axis of their mother galaxy but their particles are raised to much higher energy levels following their expulsion. Arp's maps show distinct pairs of objects at amazingly similar z-values, going in opposite directions away from the central galactic core.

When viewed with conventional blinkers on this puts them light years behind the galaxy and thus assumed to be twin images, smudgy images are blamed on the 'lens' rather than the fact that quasars are naturally dimmer while they are raised to the high energy state.

As in the typical case of Abell 2218:Farthest galaxy
The galaxy is just 2,000 light-years across. That's far smaller than our own Milky Way, which is roughly 100,000 light-years in diameter.

Analysis of the galaxy revealed its light had been shifted into redder wavelengths, or redshifted. The farther away an object is in our expanding universe, the faster it is moving and the larger its redshift.

The team was less confident about the precise redshift they had measured, estimating it as between 6.6 and 7, Ellis said. Any value in the range would still place the galaxy as the farthest known object, he added.

The galaxy also has a stronger ultraviolet signal than that seen in younger star-forming galaxies.
Note UV light is the sign of plasma discharge, especially high energy sources.

Chris
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Post by Paul S »

So a quadruply imaged Einstein cross is four of these supposed ejecta, then?

Your comment on UV is interesting; however I've read that the uv characteristics you mention are to do with stellar compositions in early galaxies.
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