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Fraser
2005-Aug-16, 04:44 PM
SUMMARY: Using NASA's Spitzer Space Telescope, astronomers have created a detailed survey of the structure of the Milky Way. Based on this evidence, they think the shape of the Milky Way is more complex than a plain old spiral. Our galaxy seems to have a long central bar, approximately 27,000 light-years in length. From our vantage point going around the Sun, we see this bar at a 45-degree angle.


View full article (http://www.universetoday.com/am/publish/uw-madison_survey_reveal_new_look_for_milkyway.html)

What do you think about this story? Post your comments below.

om@umr.edu
2005-Aug-16, 05:19 PM
Interesting.

First a news story confirming the old view of the shape of the Milky Way.

Then another news story saying that shape is not correct.

With kind regards,

Oliver
http://www.umr.edu/~om

lswinford
2005-Aug-16, 06:46 PM
http://imgsrc.hubblesite.org/hu/db/2005/01/images/a/formats/small_web.jpg

In that famous "barred galaxy" we have what appears to be two galactic arms trailing behind in a distinct spiral as the galaxy turns. Our new picture for our galaxy is considerably more complex, more messy.

What would hold the bar (which in our case is obviously more stubby) and what causes the residual arms? Is this material poured out from the center (bar) which streams along its slowing spiral behind? Or is the center spinning faster than the extremities? If we were viewing rivers, the "V"s of branches, as our new illustration provides arms that fork, point in the direction of flow. Is the obverse the case here, where we are simply down-stream from a flow away from the center? Or are we in a stream of consolidation in a spiral slide down into the center?

Essentially, which way is this thing turning?

buzzlightbeer
2005-Aug-16, 07:46 PM
like a big sink draining ... we are but an ant destined to be sucked away unless we find a way out of it.... is that rite?

TuTone
2005-Aug-16, 09:32 PM
Question: What's in the middle of the Milky Way?

suitti
2005-Aug-16, 10:02 PM
The first report of a central bar i'd heard was from a radio survey. It claimed that we are on one end of the bar. Now its bigger and is at 45 degrees.

In 5,000,000,000 years, M31 will come plowing through, and it will be moot.

I can't wait.

cran
2005-Aug-16, 11:11 PM
I presume that changing from a 'normal' spiral galaxy to a more complex 'barred' spiral, is meant to be a promotion? :huh:

TuTone, what's in the middle is thought to be a rather large but not overly active black hole.

buzzlightbeer, not necessarily - that would depend upon the growth of influence of the central mass - but, I wouldn't worry too much about falling into the centre of the galaxy... after all, the Milky Way and Local Group of galaxies all appear to be drawn towards an even more massive concentration of mass called 'The Great Attractor' :)

Just in time for our genetic descendants (if any) to look for a new home, suitti :D

buzzlightbeer
2005-Aug-17, 04:07 AM
wow ur rite! thank you!

here (http://archive.ncsa.uiuc.edu/Cyberia/Cosmos/Movies/Ostriker_5a.mov) is a video clip with Jeremiah Ostriker from Princeton University talking about The Great Attractor. this (http://archive.ncsa.uiuc.edu/Cyberia/Cosmos/GtAttractor.html) is the web page that has more info and a link to that video. very interesting stuff!

cran
2005-Aug-17, 07:59 AM
Yes it is... has anyone suggested yet that The Great Attractor might be the remnant core of the Big Bang? :huh: Like, y'know...the actual centre of the universe? :unsure:

buzzlightbeer
2005-Aug-17, 04:35 PM
I'll ask!

lswinford
2005-Aug-17, 05:58 PM
Binary stars are interesting things. Some of them are star pairs that have a center of gravity and mutual interaction. Some binary stars are but "apparent" binaries, no relation except being in our line of sight so they look like binaries.

I'm not saying that the Local Group of galaxies is merely appearances, but with the scatter of galaxies and galaxy groups in their seemingly random motion (if it were regular motion, we would simply plot trajectories backward and discover where the original Big Bang was--and without this some are saying that there was no center from which all was spewn, so there was no Big Bang), there is the possibility that some galaxies may be moving independent of gravity--which Ostriker seems to find necessary,

This motion can only be accounted for by gravitational attraction, even though the mass that we can observe is not nearly great enough to exert that kind of pull. The only thing that could explain the movement of Andromeda is the gravitational pull of a lot of unseen mass--perhaps the equivalent of 10 Milky Way-size galaxies--lying between the two galaxies.

To be fair, in context, he's obviously discussing "dark matter" ("a lot of unseen mass"). But when we see galactic collisions, something overshot the intervening attractive mass were that what sent them on their collision trajectories.

Sorry, Cran, :( the answer is not going to be so simple as to point to the center of the universe, not anywhere around here, at least using common astronomical/cosmological notions that are permitted to be discussed in this forum under current rules, as I've been told. ;)

Guest_James
2005-Aug-17, 10:05 PM
Dudes, "it's a milky way bar!" LOL

buzzlightbeer
2005-Aug-17, 10:52 PM
LOL!!!! good one james!!!!

http://www.theonlinecandyshop.com/ProductImages/MILKYWAY.jpg

cran
2005-Aug-18, 12:30 AM
:D Well done, Buzz and guest_James; I wondered how long it would be before someone made the connection...


if it were regular motion, we would simply plot trajectories backward and discover where the original Big Bang was--and without this some are saying that there was no center from which all was spewn, so there was no Big Bang
:huh: but lswinford, isn't that exactly what Hubble did? (the man, not the telescope), which seemed to confirm Lemaitre's 'cosmic egg' idea ... and that since then, others have been refining observations and measurements of hundreds of thousands of individual galaxies ... which led to the view of the mutual interactions of the Local Group, and the discovery of thousands of galaxies (including our own) all apparently converging on one location in space-time (dubbed 'The Great Attractor')? :unsure: excuse me, this is meant to be a thread about 'The Galaxy's New Clothes' B) , not about cosmology and Big Bang stuff :wacko:

lswinford
2005-Aug-18, 06:16 PM
Look again. It has long been known that in almost anyplace you look, if you can leave the exposure on long enough there will be more, more, and still more galaxies in the distance. Hoyle, with his steady-state fiasco, was only able to see so far when making his argument wherein he coined the "big bang" expression fo the opposing theory. Since, including but not limited to, the Hubble Space Telescope has illustrated for us a deeper, and far older, universe.

http://imgsrc.hubblesite.org/hu/db/2005/20/images/a/formats/small_web.jpg

"...not looking at any particular target...." (http://hubblesite.org/newscenter/newsdesk/archive/releases/2004/21/)

Perhaps you mean this: http://hubblesite.org/newscenter/newsdesk/...s/2004/28/text/ (http://hubblesite.org/newscenter/newsdesk/archive/releases/2004/28/text/)

BTW: I think it is interesting that we have pictured an early universe from some supposedly "12.5 billion years" (next to last paragraph) past, but how did we jump 12.5 bly ahead of the light that the Hubble camera's caught, as in we are here now to catch something so long ago, something that was reflecting our beginnings. I suspect we are seeing snapshots of something that is beginning to be what we have since became, and in the meanwhile they too might more resemble our near universe than what we are glimpsing from a destinctly more ancient universe.

Meanwhile, maybe we look like Andromeda, something Hale suggested.

buzzlightbeer
2005-Aug-18, 11:26 PM
Originally posted by cran@Aug 17 2005, 07:59 AM
Yes it is... has anyone suggested yet that The Great Attractor might be the remnant core of the Big Bang? :huh: Like, y'know...the actual centre of the universe? :unsure:
i asked nasa about that and they said:

Dear Buzz:


The Great Attractor is a local concentration of galaxies in our relatively nearby cosmic neighborhood. It has a relatively small effect on the microwave background radiation.

To the best of our knowledge, the universe does not have a "center". Rather, the universe is expanding everywhere at the same rate with very small exceptions due to objects like the Great Attractor perturbing the general expansion.

I hope this helps.

cran
2005-Aug-20, 03:17 AM
BTW: I think it is interesting that we have pictured an early universe from some supposedly "12.5 billion years" (next to last paragraph) past, but how did we jump 12.5 bly ahead of the light that the Hubble camera's caught, as in we are here now to catch something so long ago, something that was reflecting our beginnings.
I have an idea about that, lswinford... but it doesn&#39;t belong here... it belongs in the "wacko theories" - sorry, "alternative theories" thread, and is waiting for me to >gulp&#33;< present it to the jury :(

Thanks for doing the asking, Buzz ... the reply is pretty much what I would have expected ... and it still doesn&#39;t knock over my ideas... :wacko: ... only, since I&#39;ve been with UT, I&#39;ve been discovering how many of my thoughts have already been presented by others (not just here, but &#39;out in the real world&#39; by people with letters after their names... <_< )