NGC 7331 Galaxy looks bent (APOD 22 Oct 2008)

[Nereid]

Thanks very much Chris!

If you're interested Sputnick (or anyone else), I think it's fascinating to explore why "what the human eye would see if it were capable of zooming in on space objects" seems so boring, so pale, compared with the visual representations of data that are Calar Alto Observatory (or HST or ...) images.

[emc]

[snip]...No doubt Sputnick (and emc?) does not count these three kinds of digital alteration...[snip]

Hi Neried,

Just wanted to try and clear your question mark beside my username…. BTW – you can call me Ed if you like. I used emc because it seemed be appropriate for identifying the typist when I signed up to the forum.

All images on my computer screen are digitally “altered” in several ways from the “real” world. I don’t have a problem with any of that and I would not enjoy the APODs as much if they were stark.

It seems to me that regardless of the filtering from saturation from cosmic ray hits and all the other data processing physics… electrons, photons, lenses, CCDs, film, internet, etc., that the images could be displayed in an “enhanced” version that simulates the human visible spectrum. I think it would add an interesting dimension to occasionally see the “normal” human eye version in overlay or underlay of an APOD. Are you telling us that this is not possible?

[bystander]

Anyone else like to take a shot at suggesting how one could go about finding out whether NGC 7331 is, in fact, 'deformed' in some way, in its centre section?

From an earlier discussion.

It looks as if the bluish outer area is tilted up on the right and down on the left with respect to the brighter inner half of the disk which appears more horizontal.

Indeed, agreed. The center looks like a huge ball, which sagged through the ice and is now partially floating on water.

I notice another sort of asymmetry in 7331. Around the center there is a glow. What i call Above is where the Deer Lick group is visible, below is where the bright blue 'spiked' star is visible. The glow below is broader than the glow above. This might be an optical illusion, so i cut out 7331 (without the Deer Lick group) and rotated 7331 over 4 possible angles. Independently of the orientation of the rotated image, the glow (originally) below looks to me broader than the glow above.

Yet it may still be an illusion. Above, the spiral arms add an overwhelming light intensity, outradiating the central glow.

Other assymetries should be measurable, like is the nucleus off-center? As to how you would determine the warpage of the disk, I haven't a clue, but it certainly appears warped.

[Nereid]

[snip]...No doubt Sputnick (and emc?) does not count these three kinds of digital alteration...[snip]

Hi Neried,

Just wanted to try and clear your question mark beside my username…. BTW – you can call me Ed if you like. I used emc because it seemed be appropriate for identifying the typist when I signed up to the forum.

All images on my computer screen are digitally “altered” in several ways from the “real” world. I don’t have a problem with any of that and I would not enjoy the APODs as much if they were stark.

It seems to me that regardless of the filtering from saturation from cosmic ray hits and all the other data processing physics… electrons, photons, lenses, CCDs, film, internet, etc., that the images could be displayed in an “enhanced” version that simulates the human visible spectrum. I think it would add an interesting dimension to occasionally see the “normal” human eye version in overlay or underlay of an APOD. Are you telling us that this is not possible?

Hi Ed,

Not sure if you'd read Chris' excellent post before you wrote this (that I'm quoting), but anyway ...

Let's parse APODs a bit first; let's exclude all APODs that are 'of Earth, from Earth' (example), and 'from Earth using just an ordinary camera' (example, example - note that even those taken with colour film do not precisely convey what your eyes would see if only you'd been there at the time), all those which include a component beyond the visual waveband, and all those which include a 'narrow band filter' component. That's quite a significant fraction of all APODs by the way.

With the caveat that some aspects are not 100% faithful wrt what the human eye would see (e.g. contrast and brightness), many APODs of the Moon would fit your request, whether taken from Earth (example) or off it (example).

Ditto for planets and moons other than Earth and the Moon, with the caveat about enhanced contrast and boosted colours perhaps stressed, some examples: Mars from Earth, another Mars from Mars, Saturn, Rhea.

I'll skip the Sun.

Stars (other than the Sun)? Here's where one's individual sense of what's OK wrt the inevitable differences between images obtained using telescopes and cameras and what your eye would see becomes important. For example, your eye never sees diffraction spikes (Pleiades example) so all images with them visible automatically fail to meet your criteria. Colours are just as problematic; here's the Pleiades without diffraction spikes but I think the colour contrast is far too great (and the intensity contrast far too unreal), and here's another example - if the intensity were sufficient to excite the cones in your eyes, I expect the perceived colours would be subtle.

For galaxies there's no doubt: what the human eye sees, even with excellent equipment and dedication, is nothing like almost all APODs - if you live in the southern hemisphere, take a look at the Magellanic Clouds from a dark site (on a moonless night), that's what galaxies look like.

Nebulae - planetary, HII, supernova remnants, etc - present their own, unique, challenges. There's a lively discussion in some amateur circles about how to accurately photograph (or represent) the colours in these, especially planetaries dominated by the [OIII] lines. Leaving aside questions of contrast and intensity, the difficulty is that for many of these nebulae most (almost all) the visible light comes from just a few lines, such as the green lines of [OIII]. So to get an accurate (= faithful to what the eye would see) representation, the filter/detector/processing must accurately match the human rods+cones+visual system response wrt those lines ... and that's very difficult! There may be some APODs which succeed; does any reader know of any?

[emc]

Hi Neried and Chris,

Thank you both for such excellent postings!

Chris,

I very much enjoyed Larry’s sketches… he even includes a “how to sketch” gif anim. Your point is brought out well by the modern day return to astronomy basics.

Neried,

No I hadn't read Chris's post when I submitted my last one. I struggle with writing but enjoy the challenge and usually I spend a good bit of time in MS Word before posting... then frantically try and edit out my grammatical mistakes afterward.

And I think I understand the problems you describe in “presenting” a “human eye” rendering from the mass of “outside the human eye spectrum” data present in a typical APOD. So I am concluding that it is not possible.

BTW - This is one of the most enjoyable threads I have participated in. 8)

[bystander]

Is there any indication that NGC 7331 has companions? According to what I can discover, NGC 7337, NGC 7335, and NGC 7336 are all at least 10 times further away than 7331, and thus probably not interacting. There are two smudges to the top left of 7331. One just to the left of that magnificent barred sprial, NGC 7337, the other smudge below that. To the left of those smudges there are wisps that could possibly be star streams.

The high-res picture shows lots of background galaxies.

[emc]

Is there any indication that NGC 7331 has companions? According to what I can discover, NGC 7337, NGC 7335, and NGC 7336 are all at least 10 times further away than 7331, and thus probably not interacting. There are two smudges to the top left of 7331. One just to the left of that magnificent barred sprial, NGC 7337, the other smudge below that. To the left of those smudges there are wisps that could possibly be star streams.

The high-res picture shows lots of background galaxies.

I wonder if there could be some invisible force accounting for the distortion. The theory of dark energy causing the universe to expand kind of falls under this category... I think... so could there be some perturbance in the dark energy... say an eddy current (always liked that name ) that can deform a galaxy?

[Chris Peterson]

I wonder if there could be some invisible force accounting for the distortion. The theory of dark energy causing the universe to expand kind of falls under this category...

The effects of dark energy are neglible over the small distance across galaxies or over gravitationally bound galaxy clusters.

Personally, I see no real evidence of distortion in NGC7331, just a mild illusion from the location of the arms and dust lanes. It is largely impossible to tell much about the 3D structure of any galaxy from an optical image. It isn't uncommon for galaxy images to give the impression that the core is tilted, or is above or below the disk. This isn't usually the case, however. This galaxy doesn't have any interacting galaxies near it, nor does it appear to have undergone a collision or merger.

[emc]

That's what I thought too, that it was an illusion. But it was fun to imagine a dark energy eddy current for a few minutes.

I know you're speaking relatively but it's takes some adjusting to comprehend galactic spans as small.

[Nereid]

How to go about working out if NGC 7331 is (truly) distorted/"warped" (and if so, how) vs whether it's some kind of optical illusion?

What do y'all think of this approach?

Start with a study of thousands of carefully compiled images of ('spiral') galaxies. Conclude that they have the following structural components, wrt the (visual waveband) light they emit (or absorb): a central bulge, a (more or less) flat disk which contains (spiral) 'arms' and (sometimes) a 'bar'. (there's also a 'nucleus', but we'll ignore that here).

The disks are stars, gas (inc. plasma) and dust; the bulges are stars (where 'stars' includes an occasional planetary nebula); the stars and gas are transparent to light, the dust is not.

From a careful study of 'face on' and 'edge on' spirals, work out what the distribution of light (UV to radio) is, both broadband and in lines (e.g. a particular molecular transition in CO, or molecular hydrogen); from this develop a 3D model of this distribution, both for an 'average' spiral and for how it varies over all spirals. Be especially careful to distinguish colours (broadband or lines) which are likely to be affected by dust from those which are likely to be unaffected; consider ways to trace dust alone.

From your 3D model (which is actually a class of models), and the estimated angle of 'tilt' for NGC 7331, construct a model of NGC 7731 with a small number of free parameters (e.g. amount of dust, type and number of arms). Decide on an objective measure of 'goodness of fit', crunch your model against the quantitative data that is 'the Calar Alto Observatory observation of NGC 7331' to minimise the delta, and bingo! If your model is within the (predetermined) range of 'acceptable', according to your (predetermined) 'goodness of fit' measure, and contains no 'warp', then the perceived warp is an optical illusion!

[Chris Peterson]

How to go about working out if NGC 7331 is (truly) distorted/"warped" (and if so, how) vs whether it's some kind of optical illusion?...

Sounds very complex, and therefore likely to be prone to error. A simpler approach, which does not depend on examining other galaxies, is just to measure the actual rotational velocity as a function of radius (which is easy to to, because this galaxy is significantly oblique). Now you can just use gravitational theory to tell if there is some sort of discontinuity between different parts.

[Sputnick]

Not far off topic -

Light - it is suggested that light travels in waves, is composed of 'particles' (photos) and according to something I read probably in Scientific American more light passes through a small diameter hole than can be explained by the holes size.

What if the 'ray' or 'beam' of light corkscrews its way through space. Hold a wine
corkscrew's screw up horizontally parallel to your eyes .. the screw looks like waves somewhat eh .. with the highs and lows of the screw's 'blade' being 'wavy'.

So .. if light is a continuous entity having all the photons joined with no separation and corkscrewing through the dark matter-dark energy they would go faster than each wave fighting the resistance of the matter-energy .. and if the tip of the screw enters a tiny hole all the other particles .. the full width of the screw .. would follow.

(?)

[Nereid]

Not far off topic -

Light - it is suggested that light travels in waves, is composed of 'particles' (photos) and according to something I read probably in Scientific American more light passes through a small diameter hole than can be explained by the holes size.

What if the 'ray' or 'beam' of light corkscrews its way through space. Hold a wine
corkscrew's screw up horizontally parallel to your eyes .. the screw looks like waves somewhat eh .. with the highs and lows of the screw's 'blade' being 'wavy'.

So .. if light is a continuous entity having all the photons joined with no separation and corkscrewing through the dark matter-dark energy they would go faster than each wave fighting the resistance of the matter-energy .. and if the tip of the screw enters a tiny hole all the other particles .. the full width of the screw .. would follow.

(?)

Seems like a topic for the Café ... though at first glance my guess is it has no 'legs' at all ... because (for starters) I can't see how it could be made to square with the quite unambiguous results from a classic experiment such as the two-slit experiment (especially versions done with 'one photon at a time').

BTW, do you happen to know which issue of Scientific American contained the article you remember (about light and corkscrews)?

If you'd like to pursue development of your idea further, I've got some suggestions on how you might go about it, and websites that might be of some assistance ...

[Sputnick]

(?)

Seems like a topic for the Café ... though at first glance my guess is it has no 'legs' at all ... because (for starters) I can't see how it could be made to square with the quite unambiguous results from a classic experiment such as the two-slit experiment (especially versions done with 'one photon at a time').

BTW, do you happen to know which issue of Scientific American contained the article you remember (about light and corkscrews)?

If you'd like to pursue development of your idea further, I've got some suggestions on how you might go about it, and websites that might be of some assistance ...

Nereid,

At first glance the earth is flat.

Yes, please send your suggestions for development.

The Scientific American did not mention corkscrews .. I just came up with that idea yesterday. I've read so many SA I can't begin to remember which one held the information about more light going through a small hole than size accounts for.

Two slit experiment - might be explained by the particle experiment which duplicates results in particles when one particle is manipulated, even though the 'twin' particle is seperated by hundreds of miles.

[emc]

We were talking earlier in this thread of "what the human eye can see"… and I wondered why an APOD couldn’t contain an overlay of both the enhanced (outside visual bandwith) and normal human eye images. I found an excellent example in the Asterisk* café of what I was trying to explain… I was unsuccessful getting my thoughts across but maybe neufer's Asterisk* cafe post will help...

http://asterisk.apod.com/vie ... hp?t=14561

neufer’s post contains comparison images from multiple bandwidths. His resource is http://orbitingfrog.com/blog/tag/moon/

Thanks Art!

[bystander]

I wondered why an APOD couldn’t contain an overlay of both the enhanced (outside visual bandwith) and normal human eye images.

You mean like this?

http://www.nasa.gov/images/content/2859 ... img5.4.jpg

http://asterisk.apod.com/vie ... hp?t=14596

[emc]

I wondered why an APOD couldn’t contain an overlay of both the enhanced (outside visual bandwith) and normal human eye images.

You mean like this?

http://www.nasa.gov/images/content/2859 ... img5.4.jpg

http://asterisk.apod.com/vie ... hp?t=14596

Yeah! 8)

[Nereid]

(?)

Seems like a topic for the Café ... though at first glance my guess is it has no 'legs' at all ... because (for starters) I can't see how it could be made to square with the quite unambiguous results from a classic experiment such as the two-slit experiment (especially versions done with 'one photon at a time').

BTW, do you happen to know which issue of Scientific American contained the article you remember (about light and corkscrews)?

If you'd like to pursue development of your idea further, I've got some suggestions on how you might go about it, and websites that might be of some assistance ...

Nereid,

At first glance the earth is flat.

Indeed.

So ... ?

Yes, please send your suggestions for development.

BAUT's Against the Mainstream section (be sure to read the BAUT Rules first, before you start posting there), and PhysicsForums' Independent Research section (double ditto, re rules).

The Scientific American did not mention corkscrews .. I just came up with that idea yesterday. I've read so many SA I can't begin to remember which one held the information about more light going through a small hole than size accounts for.

So be it; if you do decide to develop your idea further, it may be worth your while to dig up the article ...

Two slit experiment - might be explained by the particle experiment which duplicates results in particles when one particle is manipulated, even though the 'twin' particle is seperated by hundreds of miles.

You're thinking of 'entangled states' perhaps?

Sorry to tell you this, but that won't work as an explanation ... there are plenty of variants of the classic two-slit experiment in which the photons (or electrons or atoms or molecules) are most assuredly not in entangled states.

Here's a suggestion, if I may: find a good teacher and a good physics course and go at it full bore. The two 'goods' will ensure your curiosity and enthusiasm is kept thoroughly alive, and the combo will give you the basics of both the state of current knowledge (quantum mechanics, in this case) and the tools.

[apodman]

I used emc because ...

e=mc²

My real initials are jel, but I don't use them because it makes people think of Jello, so apodman it is.

[emc]

I used emc because ...

e=mc²

I'm flattered you made this association. 8)

My real initials are jel, but I don't use them because it makes people think of Jello, so apodman it is.

jel / jell (verb) = to solidify, take shape, and/or get along well together 8)

[astrolabe]

Hello All,

Last Aug. I mentioned this but didn't post the link, d'oh. Does anyone have a link to the results of this workshop?

http://www.astro.unipd.it/omega08/

Any info or interest would be gregariously welcomed!

[Nereid]

Hello All,

Last Aug. I mentioned this but didn't post the link, d'oh. Does anyone have a link to the results of this workshop?

http://www.astro.unipd.it/omega08/

Any info or interest would be gregariously welcomed!

If you follow the links on that page, you'll find that the various authors have until 15 Nov to get their material to the editors of a journal, for (later) publication. Here is the ToC of that journal; perhaps the next issue will contain those proceedings?

If any of the proceedings have already appeared in arXiv, then I expect a search by author will find them ...

[astrolabe]

Hello Nereid,

First time, I believe, we've conversed. Many thanks.

[madbadgalaxyman]

Yes, NGC 7331 is obviously non-planar.

There is a very large existing literature that has studied warps, bends, and position angle changes in the disks of spiral galaxies.

This literature has proved that non-planar spiral galaxies are the rule, and planar galaxies are the exception.

cheers,
madbadgalaxyman

[adrianxw]

Been a while since I looked at this thread, it wandered into some directions I did not intend, pictures/graphics/photographs. Got a note that there was a new post, and thought, after reading through, that a documentary I watched earlier this week was seriously relevent. It makes you wonder if many of the things in the thread here are simply meaningless? What does the eye/brain system actually see?

Do you see what I see?