Solar System 'traverses all of the spiral arms of the Milky Way during 225my orbit ?!

And it was in 1975 that it was discovered that most stars in the spiral arms move at the same speed, which would mean that the solar system stays roughly in the same relative location in the arms.

 

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No Alex, and something I would have done at the drop of a hat normally.

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Remember though, as your Avatar says, "Arguing with a crank - useless"
Hence my reluctance to re post those links.

I was also told by an Astronomer once [the same one that actually informed me of the "wave density" theory] that another theory holds that spiral arms are relatively short lived within the life span of a maturing galaxy, and that these density waves come and go.
He preferred Lin and Shu's theory though.

NOTE: The same theory has also been used to explain some of the aspects of Saturn's rings.

 

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Yep, which raised the hypothesis [at that time] of DM.
According to density wave theory though, the speed the stars move through the density wave [traffic jam] is not the same speed that the density wave itself rotates with the galaxy proper.

 

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http://burro.cwru.edu/Academics/Astr222/Galaxies/Spiral/spiral.html
Imagine the spiral pattern is a density wave. It rotates through the galaxy at a fixed angular speed, called the pattern speed. In the inner parts of the galaxies, stars are moving faster than the pattern speed, and overtake the density wave (like you passing the grannies). In the outer parts of the galaxies, stars move more slowly than the pattern speed, and the spiral arms overtake the stars
http://burro.cwru.edu/Academics/Astr222/Galaxies/Spiral/spiral.html

 

Same speed, not same angular velocity, so stars closer in to the center complete an orbit in less time than those further out. Only those stars that orbit at a distance where their orbital period matches the drift of the density waves would stay in the same location of the spiral arms.

 

Janus58, so does our Solar System 'orbit at a distance where (our Solar System's) orbital period matches the drift of the density waves' ?

Did you read the "Universe Today" Links from my Post #39 ?

To Wit :

- the ^^above quoted^^ from, and more at : http://www.universetoday.com/85300/a...tic-evolution/
- the ^^above quoted^^ article references the Royal Astronomical Society’s National Astronomy Meeting in Wales on April 20, 2011 - more at this Link :http://www.ras.org.uk/news-and-pres...ew-theory-of-evolution-for-spiral-galaxy-arms
And :

- the ^^above quoted^^ from, and more at : http://www.universetoday.com/86056/t...y-wave-theory/
- the ^^above quoted^^ article references "OBSERVATIONAL EVIDENCE AGAINST LONG-LIVED SPIRAL ARMS IN GALAXIES", which is viewable as a "free" .pdf at this Link : http://arxiv.org/PS_cache/arxiv/pdf/1105/1105.5141v1.pdf

Janus58, in your 2 Posts in this Thread you have only posted about the "Density Wave" theory. The information that I "quoted" and Linked ^^above^^ is from 2011.
Has the "Density Wave" theory been 'salvaged' in the last 3 or 4-years?
Has the 'question' related to the "Density Wave" theory been 'settled' in the last 3 or 4-years?

Janus58, are either of your 2 Posts in this Thread meant to help "clarify the issue" that I raised relating to the "Bold quote" in the OP? To Wit :

 

In the spirit of 'future reference', Trippy : There is no need to "Upper Case" my initials. I am not in any way "special", so dmoe will suffice.

The Universe Today article fairly well covered the "Abstract" of the article, so I Linked to the actual .pdf instead of the "Abstract", but here is the "Abstract" :

- the ^^above quoted^^ from : http://arxiv.org/abs/1105.5141

Oh, and the '404 error' was possibly due to how I "pasted" the Links. I believe they are working now.

 

The incumbent theory as to why spiral arms are what they are, and density wave theory, has been mainstream accepted theory since the mid sixties.
The orbital period of the solar system around the galaxy is about 225 million years.
During that orbital period, our solar system traverses all of the spiral arms, and also has an osscillation above and below the equatorial plain of the Milky Way.

That is the accepted mainstream theory.
Although that is the incumbent accepted cosmological theory, it does not mean that further research, further observations, alternative hypothesis etc, do not take place and like all theories, is a continued exersise in progress.

The same happens in even more concrete theories such as the BB.
There are alternatives, its just that they don't stand up to observational data as well as the incumbent BB.

 

Trippy, the ^^above^^ is Fig. 3, at your Link : http://iopscience.iop.org/0004-637X/626/2/844/fulltext/61945.text.html#fg2

The ^^above^^ is Fig. 2, at your Link.
The following is from your Link (some Bold added by dmoe):

- the ^^above quoted^^ from, and more at : http://iopscience.iop.org/0004-637X/626/2/844/fulltext/61945.text.html#fg2

Trippy, according to the Link you provided, and the information therein, "diamonds mark time intervals of 100 Myr back in time from the present (top diamond)", it would apparently take at least 500 million years for our Solar System to "traverse" all of the spiral arms of the Milky Way galaxy, referencing Fig. 3 at your Linked Page.

Trippy, this goes against the "Bold quote" in the OP :

Trippy, 'the spiral density wave hypothesis' is what it is, and I am NOT 'prefer(ring) one of the alternatives'.
The 'the spiral density wave hypothesis' was first introduced into this Thread by Janus58, in his Post # 3.

It was then 'appropriated' by paddoboy to 'derail the Thread' away from his "Onus" to provide True Scientific Evidence to support his claim :

 

Your continued denying, and distorting of facts is amazing dmoe.
And your continued lack of intestinal fortitude to admit you were wrong in the first instant, is even more amazing, but for yourself, par for the course.
I would venture to say Trippy did no more than make a slip up.

The mainstream accepted theory of spiral arms is "density waves" and this requires the Sun to traverse all of our spiral arms.
Other hypothesis exist, as with most theories. You should know that.
I mean you yourself are on record for not accepting the BB.
Couple that with the fact that YEC's are also rather fanatically anxious to disprove current accepted scientific theories which includes spiral arm concept and density wave theory with galaxies....
http://pseudoastro.wordpress.com/20...alaxies-wind-up-too-fast-for-an-old-universe/
http://podcast.sjrdesign.net/shownotes_092.php
http://apps.usd.edu/esci/creation/age/content/creationist_clocks/spiral_galaxies.html

So in fact, it is you trying your darndest to "save face" and also to derail the thread away from proper and recognised scientific methodology.
I repeat just for you dmoe,
Although that is the incumbent accepted cosmological theory, it does not mean that further research, further observations, alternative hypothesis etc, do not take place and like all theories, is a continued exersise in progress.

The same happens in even more concrete theories such as the BB.
There are alternatives, its just that they don't stand up to observational data as well as the incumbent BB.


http://burro.cwru.edu/Academics/Astr222/Galaxies/Spiral/spiral.html

http://www.astronomynotes.com/ismnotes/s8.htm

 

Again your dishonesty shows through like a beacon dmoe.
Even if the 500 million years for our solar system to traverse the MW was factual, it still has the potential with time, to travel through all arms around the MW, which you originally claimed "IT DID NOT".

So again, more red herrings, more avoiding the issue of ever admitting that you are wrong again and more dishonesty.

 

Here's another scientific paper on the Sun's detailed, mathematically deduced path around the MW while traversing all spiral arms.

>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
ABSTRACT
We present a calculation of the Sun’s motion through the Milky Way over the last 500 million yr. The integration is based on estimates of the Sun’s current position and speed from measurements with Hipparcos and on a realistic model for the Galactic gravitational potential. We estimate the times of the Sun’s past spiral arm crossings for a range of assumed values of the spiral pattern angular speed. We find that for a difference between the mean solar and pattern speed of p ¼ 11:9 0:7 km s1 kpc1, the Sun has traversed four spiral arms at times that appear to
correspond well with long-duration cold periods on Earth. This supports the idea that extended exposure to the higher cosmic-ray flux associated with spiral arms can lead to increased cloud cover and long ice age epochs on Earth.

http://iopscience.iop.org/0004-637X/626/2/844/pdf/61945.web.pdf

extract:
Leitch & Vasisht (1998) argue that mass extinctions may also
preferentially occur during spiral arm crossings. However, they
proposed that a spiral pattern speed of p ¼ 19 km s1 kpc1 is
required to find consistency between times of mass extinctions
and spiral arm crossings, and if correct, then the relationship
between ice ages and arm crossings would apparently be ruled
out because p ¼ 19 km s1 kpc1 is too large for the interarm
crossing time to match the intervals between IAEs (see Figs. 2
and 3). We show the times of the five major mass extinctions as
crosses in Figures 1–3 (Raup & Sepkoski 1986; Benton 1995;
Matsumoto & Kubotani 1996). We see that in fact the lower
value of p ¼ 14:4 km s1 kpc1 ( p ¼ 11:9 km s1
kpc1, as shown in Fig. 3) also leads to a distribution of mass
extinction times that fall close to or within a spiral arm passage,
so the association of mass extinctions with arm crossings may
also be viable in models with pattern speeds that are consistent
with the ice age predictions.
Our calculation of the Sun’s motion in the Galaxy appears to
be consistent with the suggestion that ice age epochs occur
around the times of spiral arm passages as long
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>

As we can see the incumbent "wave density" theory besides solving the "winding problem", can also explain plenty more as detailed above.

 

paddoboy, that is the exact same "Paper" referenced by Trippy and myself in Posts # 68 and # 71, titled "ICE AGE EPOCHS AND THE SUN’S PATH THROUGH THE GALAXY" by D. R. Gies and J. W. Helsel.

The fact of the matter is that this Thread is NOT about any 'hypothesized correlation' between "ICE AGE EPOCHS AND THE SUN’S PATH THROUGH THE GALAXY".

However, if, and I repeat, if you had actually studied the "Paper", you would know that nowhere in the "Paper" does it state that "our solar system traverses all of the spiral arms...of the Milky Way" during a single orbital period.

BTW : You have authored 34 Posts in this Thread (so far!) paddoboy, and you have yet to follow 'proper and recognised scientific methodology' by simply providing "supporting evidence" to back up your 'claim' that is the "Issue" and "Topic" of this Thread.

The "Onus" is on you paddoboy, to provide said "supporting evidence" to back up your 'claim' :

As for the following :

If you read my Post # 39, or possibly just the Links in my Post # 39 :
- http://www.universetoday.com/85300/a-new-spin-on-galactic-evolution/
- http://www.ras.org.uk/news-and-pres...ew-theory-of-evolution-for-spiral-galaxy-arms
- http://www.universetoday.com/86056/testing-the-spiral-density-wave-theory/
- http://arxiv.org/PS_cache/arxiv/pdf/1105/1105.5141v1.pdf

These "articles" and "Papers" from 2011 clearly indicate that the "wave density" theory is probably not as 'near certain'(sic) as you evidently perceive it to be.

 

You surely shout a lot..

What bugs you so much about this?

 

Dr_Toad, 'upper case' letters are for "SHOUTING".
Bold is for "emphasis".

This is, first and foremost, supposed to be a Science Forum.
Young people or students of any age may read this Forum to learn or expand their knowledge.
They should not be presented any information that is unsupported by real scientific evidence.

 

Fight it all you like dmoe, the wave density theory of spiral arms is the incumbent theory, and that means the Sun traverses all the arms of our galaxy.
Now your obvious record for opposing the scientific method, peer review, and near certain cosmological theories like the BB are well known, as is your sympathy towards creationists and the like.
The forum are able to add 2 + 2 dmoe, and the answer is obvious.

Typical reverse cry of the YEC's and Alternative hypothesis pushers!
No my dear friend, the onus is on you.
I'm supporting the incumbent model that answers many questions and fits better than others. :shrug:

Gain attention?

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Me?

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And you would without a doubt, be the worst example possible for them.

 

Are you able to read? We do know your interprative abilities certainly lack logic.....

And that supports wave density theory and what I have been saying.