Comments on: Bridge Across Space: "Keenan's System" by Martin Winder and Dietmar Hager

By: Tammy Plotner

Tammy Plotner — Mon, 04 Aug 2008 19:12:07 +0000

i loved the works of castenada…

By: Joe Schomer

Joe Schomer — Thu, 31 Jul 2008 15:18:33 +0000

The high horsepower engine of real science is healthy scepticism requiring infinite doubt and scrutiny. There's always something missing. Detective Colombo always has just one more question. The ultimate democratic process of discovery.
There are Newtonian Apples constantly falling everywhere and curious young Newtons observing and speculating. What if the classic Hubble Red Shift falls to something nobody ever considered? It'll make a strange universe even stranger. Consider quiet shy Einstein working at a dull job in a patent clerk's office pondering space and time. Somewhere, as we speak, there's some serious off the wall intuitive thinking occurring that could will change EVERYTHING!
(Carlos Castenada called that instructive inner voice 'the whispering of the Nagual.')

By: Jon Hanford

Jon Hanford — Sun, 27 Jul 2008 01:10:13 +0000

According to the paper by Roche(2006), the bridge "(has) the blue colours of stars 0.2-0.4 Gyr old stars" . Earlier VLA radio observations of the bridge saw substantial amounts of HI (neutral hydrogen) gas. Gravitational attraction between the two galaxies has pulled this bridge of hydrogen away from both galaxies & it seems that conditions are favorable for star formation from this raw material. Spitzer infrared images show only weak emission from dust in the bridge, indicating low dust content. Also, visible light spectra of the bridge show no emission lines in the bridge, so little star formation is currently taking place here. In the future, the bridge may fragment into Tidal Dwarf Galaxies (TDGs) or fall back into the gravitational grips of the two galaxies. Under the right conditions NGC 5216 & 5218 may stay gravitationally bound and coalesce into a single (elliptical) galaxy far into the future. But just think of the view from a planet orbiting a star in the bridge between the two galaxies!

By: Tom

Tom — Sat, 26 Jul 2008 23:56:26 +0000

Are there any theories as to what these bridges are composed of? What could be the reason for the pulling of matter across the expanses of space!? This is just baffling to me!

By: ScepticTim

ScepticTim — Sat, 26 Jul 2008 20:56:26 +0000

My thanks to Jon Hanford. A quick scan of the papers that you referenced solves the supposed red shift discrepancy and eliminates the need to explain the apparent differing velocities of the galaxies.

By: Jon Hanford

Jon Hanford — Sat, 26 Jul 2008 19:17:58 +0000

The paper referenced by Tammy in this article by Beverly Smith is I believe arXiv:astro-ph/0610562 (2006). Links to all 3 papers I referenced can be found at the Nasa Extragalactic Database (NED) & the SIMBAD database. Including links to some of these papers in future articles would be greatly appreciated & may help to clear up or detail issues mentioned in some articles (or not, depending on the reader). Anyway, thanks again for articles of this type.

By: Jon Hanford

Jon Hanford — Sat, 26 Jul 2008 18:53:31 +0000

Two recent papers on Arp 104 may be of particular interest here: arXiv:astro-ph/0701452 (2007 referencing CO & HI studies) and arXiv:astro-ph/0605015 (2006 referencing imaging & spectra w-'cross-fueling' occuring). In the second paper by Roche, SDSS redshifts are given for: NGC 5218 z=0.009783 (2933km/s) & NGC 5216 z=0.009804 (2939km/s). I, too, was careful with the decimal places. The second paper also concurs with Tammy's statement that the blue bridge between the galaxies is composed of young, blue stars 200-400 My of age. This system is one of my favorite interacting galaxy pairs and I complement Tammy for writing up this informative, thought-provoking article. Hope to see more like it in the future.

By: ScepticTim

ScepticTim — Sat, 26 Jul 2008 17:00:13 +0000

Great article Tammy. I wonder if the red shift difference here can be attributed to differences in velocity of the two galaxies due to either their orbiting, after interaction, about a common centre of mass or some other change in their original trajectories, causing one of the pair to accelerate towards us while the other has been accelerated away?

By: Tyler Durden

Tyler Durden — Fri, 25 Jul 2008 22:55:52 +0000

Good news for inhabits on 5216 or 5218. They can easily colonize two galaxies for the price of one by sending waves of colony ships along the bridge.

By: Bill

Bill — Fri, 25 Jul 2008 21:35:32 +0000

John, Maybe my post with the source links will show up after a moderator clears it. I found the redshifts:

NGC5216 z = .0979
NGC5218 z = .009643

I was careful with the decimal places.

By: Bill

Bill — Fri, 25 Jul 2008 21:31:37 +0000

John, I found

NGC5216 z = .0979 from

http://www.iop.org/EJ/article/1009-9271/6/1/002/chjaa_6_1_002.pdf

NGC5218 z = 0.009643 from

http://cdsweb.u-strasbg.fr/cgi-bin/bibobj?2002A%26A…387…40M&NGC+5218

I would have preferred these from a common source. The SIMBAD link did not have 5216.

An interesting contrast, if these sources are correct.

And apologies, I am but an imaginary astronomer.

By: Timber

Timber — Fri, 25 Jul 2008 21:24:20 +0000

something of an aside, several years ago Halton Arp made a presentation at either the Winter Star Party or the Texas Star Party (can't remember which) at which time i bought one of his DVD's, about half of which is in Danish (?). Is anyone familiar with his DVD and might know of a translation somewhere and if it might be available? Thanks

By: John Mendenhall

John Mendenhall — Fri, 25 Jul 2008 19:24:17 +0000

Nowhere in this article are the redshifts of the component galaxies mentioned. Would any of the (real) astronomers out there care to enlighten us?

By: H-town Mack

H-town Mack — Fri, 25 Jul 2008 18:58:10 +0000

So, I'm too late and Megatron has already created a spacebridge there! Seriously, I wonder if ET's have figured out a way to use that "bridge" to some effect. As in bridging the distance in less time than normal.

By: joe

joe — Fri, 25 Jul 2008 18:24:20 +0000

So it black holes can keep light from escaping, and they spaghettize everything at the event horizon, why couldn't blackholes stretch light wavelength?

The larger the black hole the greater the redshift? Is that possible?

By: Tammy Plotner

Tammy Plotner — Fri, 25 Jul 2008 18:18:45 +0000

If anyone still has doubts, they really need to look a Zwicky's work. He stated that the rediscovery of the pair caused some "merry confusion" and then set to work trying to solve the riddle. One thing all three astronomers shared (Keenan, Arp and Zwicky) was they were all somewhat outcasts – but who can deny what you see when you look at Zwicky's photographic plate? (Now added.) He was quick to point out: " It is likewise a common feature of many connected double nebulae that only one of them shows a distinct countertide."

The very coolest part is that another Arp pair of interacting galaxies – Arp 285 (NGC 2856/4), have also been studied (Beverly Smith et. al) just a couple of months ago for the same basic phenomena. "This system contains a striking example of "beads on a string": a series of star-formation complexes ~1 kpc apart. These "beads" are found in a tail-like feature that is perpendicular to the disk of NGC 2856, which implies that it was formed from material accreted from the companion NGC 2854… Our model suggests that bridge material falling into the potential of the companion overshoots the companion. The gas then piles up at apogalacticon before falling back onto the companion, and star formation occurs in the pile-up… this feature is part of a expanding ripple-like "arc" created by an off-center ring-galaxy-like collision between the two disks."

If this can occur in one Arp pair – why not another? After all, Zwicky himself states, "As in all other cases, it will be worthwhile to make further attempts at obtaining spectrograms of the faint luminous intergalactic formations in Keenan's system. So far it can only be said that these appear blue and show no emission lines, from which fact we conclude that they consist of stars."

By: Bill

Bill — Fri, 25 Jul 2008 17:11:18 +0000

It's good to see alternatives to the widely accepted interpretation of redshift in a main article. Kudos to UT for allowing alternative views in the articles and for allowing the free-ranging discussions.

By: Mark

Mark — Fri, 25 Jul 2008 17:10:33 +0000

Tammy thanks for the prompt response on a controversial subject (a rarity)!

I'm curious … do you have any idea if the majority of astronomers still have doubts about whether the galaxies in Keenan's system are really interacting? If they don't have doubts, how do they maintain their redshift = distance theory? (As far as I know Arp is still generally viewed as an outcast … am wrong about that?)

Thanks again for responding!

By: Aodhhan

Aodhhan — Fri, 25 Jul 2008 16:48:01 +0000

Bravo Mark!

In all due respect to Mr. Hubble, I too question the doppler red shift on objects when it comes to the "Big Picture". Especially when it takes a star moving approximately 1900 miles/second to change just 1% in the frequency of light. As red as some of the furthest galaxies (from us) are, they would have to be moving away at blinding speeds.

There are a lot of different thoughts on different things with this subject. Coherent Raman Interactions to name one.
I'll shut up there, because I can ramble all day about this!

Therefore, there must be something else which is stretching the wavelengths (or broadening of spectral lines if you prefer) over time and or distance. Figure it out, and you'll probably find the Nobel Prize for physics on your mantle!

Great choice for an article Tammy!

By: Tammy Plotner

Tammy Plotner — Fri, 25 Jul 2008 16:14:44 +0000

Wooo hooo! I just love it when readers are sharp…

Damn fine reasoning, Mark. Tests for large-scale systematic errors in maps of galactic reddening have also occurred concerning this particular Arp pair and they were included in a survey of galaxy redshifts in 1983. From what I can gather of the Tonry model, radial velocity redshift measurements can be impacted by gravitational pull between galaxies as well.

As for Arp being right? Yep. This is also my opinion. Redshift is not the know all and end all indicator of distance!

By: Mark

Mark — Fri, 25 Jul 2008 15:23:10 +0000

IF I recall correctly, Arp contends that redshift is not an indication of recession speed or distance from earth but is caused by something else. Part of his evidence was interacting galaxies which had widely different redshifts. This meant that the galaxies had to be close to each other, but their different redshifts would indicate that they are far away from each other. Since their interaction meant that they really were close to each other, this meant that the redshift = distance interpretation must be wrong. Those who disputed Arp would question whether or not the galaxies were really interacting or whether this was a superimposed illusion. It sounds like it is being freely acknowledged that Arp was right about at least some of his interacting galaxies. Am I reading this right? If so, doesn't that mean that Arp is right about redshift not being an indicator of distance?