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Crossing the galactic plane

by Dingo69
Tags: galactic, plane
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russ_watters
#19
Aug28-08, 05:45 AM
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Well, you are saying contradictory things. The earth's equator can be defined and located with exquisite precision. An imaginary line, for sure, but one with a clearly-defined position. But at the same time, you seem to acknowledge no such level of accuracy is possible for the galactic plane. It is both imaginary and only locatable by estimation.

This is because a galaxy is not a single coherent object (unlike earth), it's 100 billion, so finding the plane of rotation is really just averaging the orbital planes of all the objects in it.

Lets try a different angle: You're an astronomer and you want to do a research project to better locate the galactic plane. I'm your boss/funding source. What does your proposal say? Why are you doing the project? Why is it worthy of funding (not to mention your time and effort)? What theory are you attempting to test/phenomena are you trying to explore?
schroder
#20
Aug28-08, 08:19 AM
P: 373
Quote Quote by russ_watters View Post
Well, you are saying contradictory things. The earth's equator can be defined and located with exquisite precision. An imaginary line, for sure, but one with a clearly-defined position. But at the same time, you seem to acknowledge no such level of accuracy is possible for the galactic plane. It is both imaginary and only locatable by estimation.

This is because a galaxy is not a single coherent object (unlike earth), it's 100 billion, so finding the plane of rotation is really just averaging the orbital planes of all the objects in it.

Lets try a different angle: You're an astronomer and you want to do a research project to better locate the galactic plane. I'm your boss/funding source. What does your proposal say? Why are you doing the project? Why is it worthy of funding (not to mention your time and effort)? What theory are you attempting to test/phenomena are you trying to explore?

As a scientist (but not an astronomer) I was simply interested in how accurately we can determine the position of our solar system within the galaxy. One parameter would be the distance from the center, which I believe has been determined to be approximately 26,000 lyr. Another would be the distance from the plane of the disk, which is what I was asking about. However, for whatever reason, it seems no straight forward answers are forthcoming. And, with all due respect, Russ, you are not my boss!
rollthedice
#21
Sep19-08, 08:55 AM
P: 1
The mayan culture used the stars to create their calender. it only makes sence that they believed once they reached a point where they couldnt predict the placement of the stars in the sky that time ends because there way to keep time ends.i agree with the y2k-mayan calender similarities. we worried about our computers and how they keep time as the mayans worried about how their (computer) kept time. anyone can say hey this is the day the world will end all im saying is give me some proof some hard scientific evidence that says we wont exsist beyond dec 2012 then i might believe it. dont just come at me with the calander of an ancient culture. even as advanced as they were theres no way that their calander holds that kind of merit.
Vanadium 50
#22
Sep19-08, 09:29 AM
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I don't understand why this doesn't just die.

(1) The claim that celestial mechanics predicts the earth will pass through the galactic center on December 21, 2012 is false.

(2) The claim that celestial mechanics predicts the earth sun and galactic core will form a line on December 21, 2012 is false.

(3) The claim that the Mayan calendar cannot represent a date after December 21, 2012 is false.

I don't think there is a single true statement in the set.
Utwig
#23
Sep21-08, 02:33 PM
P: 15
Hi,

Interesting that a lot of the replies were very quick to dismiss the existence of the galactic plane/equator/whatever you want to call it. I’m guessing the ones quick to dismiss the whole thing are probably not involved in any studies like the one referenced in the link below..

http://www.sciencedaily.com/releases...0915210506.htm

From various other articles I have read, it doesn’t look like we can put an exact time and date on the passage, but it should happen at some point in the next 7 years or so.

As for the Mayans, I don’t think their calendar stops on the date mentioned, it just notches up to another set of numbers (like 1999 to 2000) I remember reading somewhere its in base 15 where the prediction it stops assumes its in base 8 or something.

I doubt any of what I have written really helps, but it is debate, and that is what science is all about isn’t it? well that and peer review. Good luck on your quest to pin the date down though, let us know what you dig up in your efforts, I’ll certainly read it with an open mind.

Utwig
russ_watters
#24
Sep21-08, 03:09 PM
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Quote Quote by Utwig View Post
From various other articles I have read, it doesn’t look like we can put an exact time and date on the passage, but it should happen at some point in the next 7 years or so.
Do you have any sources for that? I posted image caps of planetarium software that does not support that.
Utwig
#25
Sep21-08, 03:31 PM
P: 15
Hi,

Nah, not really, it was something I remember reading while looking for the orbital period of Sol around the galaxy itself. As it wasn’t the focus of the study at the time it just got filed under ‘Interesting junk I can bore the crap out of people at parties with’, hence the word should rather than will.

If I come across a firm article again, Ill note the link and post it up.

What software do you have? I’m on the look out for something I can use to show my little boy how to locate stars with, he saw his first shooting star last night and is well chuffed up!

Utwig
russ_watters
#26
Sep21-08, 09:37 PM
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Starry Night: http://www.starrynightstore.com/
raedwulf
#27
Dec25-08, 12:39 PM
P: 2
The conventional scientific basis for the implications of 21-12-2012 have been developed by Dr Paul A LaViolette. His work concerns the existence of high-energy waves that propagate along the galactic plane with the singularity at the centre as their source. Broadly, two effects are noted as we cross the elliptic. The region of space in which we will be travelling will be dustier and the sun and all the planets will be hotter as the heliosphere becomes compromised. As we cross the elliptic, we will be at some risk in being inundated by a wave of intense radiation.

The first effect has already been confirmed. We are presently passing through an exceedingly dusty region of local space. The sun and the planets are also heating and the outer planets have already undergone magnetic reversals.

As for the likelihood of the second, beyond the confirmation of much of Mr LaViolette's research, one might consider the following recent and very shocking revelation of the decay of the solar heliosphere and terrestrial magnetosphere.

http://science.nasa.gov/headlines/y2...iantbreach.htm

Regards,

raedwulf
Vanadium 50
#28
Dec25-08, 04:02 PM
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I'm afraid that Dr. LaViolette's work is largely crackpottery, and unsupported by the link you posted.

And here's the problem with this kind of crackpottery - it's infinitely flexible. In 2012 there will be a gravitational alignment...no, a pole flip...no, a dark tenth (I guess 9th, now that Pluto has been demoted) planet....no, some sort of danger in the galactic plane.

There are only two common themes in all of this. 2012 is common, and the fact that these are totally devoid of evidence is common.
raedwulf
#29
Dec25-08, 05:20 PM
P: 2

Dear Vanadium:

You have mistaken me for someone else.
I said nothing about


"a gravitational alignment...no, a pole flip...no, a dark tenth (I guess 9th, now that Pluto has been demoted) planet....no, some sort of danger in the galactic plane"


and, as for whether my link supports or refutes my reference, I will leave that up to the readership. The news is very recent, very interesting, and not alarming for nothing. It begs the question as to how the heliosphere is being degraded and what implications exist to the significant impairment of its protection.

Seems pretty hot.
You can quote me on that.

Respectfully,
raedwulf

Nereid
#30
Dec26-08, 10:30 AM
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Quote Quote by raedwulf View Post

Dear Vanadium:

You have mistaken me for someone else.
I said nothing about


"a gravitational alignment...no, a pole flip...no, a dark tenth (I guess 9th, now that Pluto has been demoted) planet....no, some sort of danger in the galactic plane"


and, as for whether my link supports or refutes my reference, I will leave that up to the readership. The news is very recent, very interesting, and not alarming for nothing. It begs the question as to how the heliosphere is being degraded and what implications exist to the significant impairment of its protection.

Seems pretty hot.
You can quote me on that.

Respectfully,
raedwulf

The link does not support your reference*.

That particular piece of news is, indeed, recent; however, the kind of events reported are quite common, and so nothing to be alarmed about.

What does "the heliosphere is being degraded" mean?

* if you think it does, how about you write a paper on it and get it published in a relevant, peer-reviewed journal?
russ_watters
#31
Dec26-08, 01:47 PM
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Quote Quote by Vanadium 50 View Post
I'm afraid that Dr. LaViolette's work is largely crackpottery....
To put a finer point on it, his website states explicitly that his purpose is to circumvent the scientific process. The guildelines of PhysicsForums state that discussions here are constrained to adhere to the scientific process. Please keep that in mind in further posts, raedwulf.
LURCH
#32
Dec26-08, 02:09 PM
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Now, it seems to em a recall hearing one fairly reasonable connection between the Mayan calender and Doomsday. It was theorized by some that the periodical mass extinctions found in the geological record are caused by meteorite impacts, and these impacts are caused by some external influence altering orbits within the asteroid belt. I can't recall, ATM, where I read this, but some astronomers were speculating that the Solar system's passage through the more densely populated space of the galactic plain may subject it to gravitational forces that effect the asteroids.

I'm going to see if I can find a reference to that theory. It's a bit thin, but not too implausable.
Vanadium 50
#33
Dec26-08, 07:44 PM
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Lurch, I think you're thinking about Gillman and Erenler, International Journal of Astrobiology , Volume 7, Issue 01, January 2008, pp 17-26.

While the idea is intriguing, I don't think the evidence presented is terribly strong. I'll confess that the authors lack of use of significant figures put me in a bad mood, but essentially they argue that periodicities of mass extinctions correlate with the periodicities of the orbital motion of the sun - when it enters various spiral arms, and when it crosses the midplane.

I see two problems. One is that Spitzer measurements indicate that there aren't as many arms as Gillman and Erenler thought. The other is that they show no evidence of when the sun crosses the midplane; Gillman and Erenler pick one mass extinction as a guess as when the sun crosses the midplane and then show that other extinctions also correlate - but this is a far cry from evidence.

Now, onto 2012. The claim that the Mayan calendar can't represent dates after 2012 is just plain wrong: it would be exactly analogous to claiming our calendar can't represent dates after 2100. Even if it were true, the idea that a calendar deficiency somehow indicates the end of the world is just silly. If you use Gillman and Erenler as support for this, their paper suggests that we have tens of millions of years before we cross the galactic plane, not 7. Furthermore, the idea that there is a specific date where there is a problem doesn't accurately reflect the scale of things: the sun moves about 10 million miles per day. So the "danger zone" would be mighty thin. In fact, any sort of reasonable thickness to some putative danger zone, coupled with the time it would take for the purported mechanism to work would mean that the entire Mayan calendar covers this kind of event.

I'm afraid that the idea of 2012 is wrong on so many levels that it's difficult to tell where one error stops and the next begins.
DaveC426913
#34
Dec26-08, 07:47 PM
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Or, more generally,

Quote Quote by Vanadium 50 View Post
I'm afraid that the idea of 2012 is wrong on so many levels that ...
... I can't fathom how this thread has remained unlocked for as long as it has.
LURCH
#35
Dec28-08, 03:41 PM
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Quote Quote by Vanadium 50 View Post
Lurch, I think you're thinking about Gillman and Erenler, International Journal of Astrobiology , Volume 7, Issue 01, January 2008, pp 17-26.

While the idea is intriguing, I don't think the evidence presented is terribly strong. I'll confess that the authors lack of use of significant figures put me in a bad mood, but essentially they argue that periodicities of mass extinctions correlate with the periodicities of the orbital motion of the sun - when it enters various spiral arms, and when it crosses the midplane.

I see two problems. One is that Spitzer measurements indicate that there aren't as many arms as Gillman and Erenler thought. The other is that they show no evidence of when the sun crosses the midplane; Gillman and Erenler pick one mass extinction as a guess as when the sun crosses the midplane and then show that other extinctions also correlate - but this is a far cry from evidence.
Although that wasn't the article I read ( I read this about 10-15 yrs ago), it sounds almost identicle. I remember thinking that the periods were all wrong. A galactic year is about 250 MY. So, we would cross the galactic plane every 125 (or so). This would be half the frequency of periodic extinction events. I had not heard of the extra orbital dynamics added by including orbtis around the Orion arm.
CosmologyTPA
#36
Jan1-09, 06:58 PM
P: 3
Additional info regarding galactic plane crossing and mass extinctions. I would consider Cambridge a pretty reliable source.

http://journals.cambridge.org/action...ct?aid=1804088


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