Great Attractor
Great Attractor
What has the most recent observations and research uncovered about The Great Attractor, that spot in the universe where most observable galaxies seemed to be heading?
RJ Emery
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orin stepanek
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Hi RJ
The latest on the great attractor is summed up nicley in this paper
http://arxiv.org/pdf/astro-ph/0603692
Having spoken to the authors the deal is that they have found several new clusters and filaments which lie on the far side of the MW, and hence are difficult to detect. They now reckon that over 70% of the mass of the great attractor is accounted for, the rest is presumably mostly directly through the disc of the MW and very difficult to see.
The mystery of the great Attractor seems to be mostly solved, though there is still some work to be done tracking down what is responsible for the infall onto the GA from the far side.
The latest on the great attractor is summed up nicley in this paper
http://arxiv.org/pdf/astro-ph/0603692
Having spoken to the authors the deal is that they have found several new clusters and filaments which lie on the far side of the MW, and hence are difficult to detect. They now reckon that over 70% of the mass of the great attractor is accounted for, the rest is presumably mostly directly through the disc of the MW and very difficult to see.
The mystery of the great Attractor seems to be mostly solved, though there is still some work to be done tracking down what is responsible for the infall onto the GA from the far side.
Astro,
I was looking through the paper you had linked to your post and noticed something interesting. The velocity graphs resemble spectral charts. So I looked up this http://antwrp.gsfc.nasa.gov/apod/ap060423.html for comparison and it reminded me of DNA charts. A question popped into my head about this.
If DNA markers can be utilized to run tests to determine parentage of offspring and to determine sibling status, could spectral markers be used to determine sibling status with respect to stars? (Would 3rd or 4th generation stars which collapse from the same cloud of gas that was expelled from the same prior generation parent star have the same spectral markers?) It almost seems like a spectral fingerprint might be similar to a DNA fingerprint.
I was looking through the paper you had linked to your post and noticed something interesting. The velocity graphs resemble spectral charts. So I looked up this http://antwrp.gsfc.nasa.gov/apod/ap060423.html for comparison and it reminded me of DNA charts. A question popped into my head about this.
If DNA markers can be utilized to run tests to determine parentage of offspring and to determine sibling status, could spectral markers be used to determine sibling status with respect to stars? (Would 3rd or 4th generation stars which collapse from the same cloud of gas that was expelled from the same prior generation parent star have the same spectral markers?) It almost seems like a spectral fingerprint might be similar to a DNA fingerprint.
Potentially you can do something like that, though it is much more complicated than a DNA analysis, because the vast majority of the DNA will be the same from generation to generation, but in stars the different sizes of stars present in the population will lead to different enrichments due to the different elements they can fuse up to.
Stars that form from the same gas cloud do generally have the same composition, the best example of this is the stars of globular clusters, which all seem to have formed at the same time from the same material. Some people recently did an analysis on GCs like you suggest here
http://arxiv.org/pdf/astro-ph/0605210
so they look at the ratio of alpha elements to iron, which is usually understood as the ratio of elements made in type 1a to type 2 supernovae (i think its that way round). This ratio tells you about how quickly the stars formed from gas previously enriched by a previous generation of stars. This is because Type 2 supernovae are caused by giant stars that run out of fuel and explode, they do this rapidly, within about 100Myr of the start of the star formation event. Type 1a supernovae take much longer to occur becuase they are due to material from a companion star piling onto a white dwarf (eventually pushing the star over the chandrasekhar limit), this usually doesnt happen for several Gyr after the burst of star formation.
Stars that form from the same gas cloud do generally have the same composition, the best example of this is the stars of globular clusters, which all seem to have formed at the same time from the same material. Some people recently did an analysis on GCs like you suggest here
http://arxiv.org/pdf/astro-ph/0605210
so they look at the ratio of alpha elements to iron, which is usually understood as the ratio of elements made in type 1a to type 2 supernovae (i think its that way round). This ratio tells you about how quickly the stars formed from gas previously enriched by a previous generation of stars. This is because Type 2 supernovae are caused by giant stars that run out of fuel and explode, they do this rapidly, within about 100Myr of the start of the star formation event. Type 1a supernovae take much longer to occur becuase they are due to material from a companion star piling onto a white dwarf (eventually pushing the star over the chandrasekhar limit), this usually doesnt happen for several Gyr after the burst of star formation.
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harry
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Hello All
Most elements from Hydrogen to Iron, nickel,silicon are made from fusion within the solar envelope.
The extra ordinary energy expelled during a supernova produces the heavy elements that are allowed to remain in their atomic state away from a star solar envelope which ususally breaks down elements larger than Iron.
Most elements from Hydrogen to Iron, nickel,silicon are made from fusion within the solar envelope.
The extra ordinary energy expelled during a supernova produces the heavy elements that are allowed to remain in their atomic state away from a star solar envelope which ususally breaks down elements larger than Iron.
Harry : Smile and live another day.
Are you referring, perchance, to the thoroughly debunked "Iron Sun" idea (Dr Manuel, Michael Mozina)?harry wrote:Hello All
Most elements from Hydrogen to Iron, nickel,silicon are made from fusion within the solar envelope.
The extra ordinary energy expelled during a supernova produces the heavy elements that are allowed to remain in their atomic state away from a star solar envelope which ususally breaks down elements larger than Iron.
If so, would you be prepared to defend this idea, in terms of its internal consistency and consistency with good observational and experimental results?
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harry
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Hello Neried
Mate what is your opinion?
Others give their opinions.
As for the iron star. Our sun has not been dominated by Iron.
You said
Where did you hear that Prof Manuel has been thoroughly debunked with respect to the Iron sun. If you have info please forward them to me or respond here.
I have an open mind. All doors open and none closed.
Mate what is your opinion?
Others give their opinions.
As for the iron star. Our sun has not been dominated by Iron.
You said
Yes 100%. We are here to discuss issues. But never close doors on ideas, that some people think are wild.If so, would you be prepared to defend this idea, in terms of its internal consistency and consistency with good observational and experimental results
Where did you hear that Prof Manuel has been thoroughly debunked with respect to the Iron sun. If you have info please forward them to me or respond here.
I have an open mind. All doors open and none closed.
Harry : Smile and live another day.
That is strange Harry because that is exactly what O Manuel claims in his paperAs for the iron star. Our sun has not been dominated by Iron.
http://arxiv.org/pdf/astro-ph/0609509
Check out figure 7. and this line from the next page
Sounds pretty iron dominated to me, if you look at the plots, which are logged, you see that Manuel is in fact claiming that the sun has 1000 times as much Iron as hydrogen. Although this depends on what he actually means by abundance, still, he is saying the Sun has more Iron than Hydrogen.The Sun formed on the collapsed core of a supernova (Fig. 2) and consists mostly of elements (See right side Fig. 7) produced in the SN interior - Fe, O, Ni, Si, and S
Re Manuel and Mozina ("Sun has a solid iron surface"), I've already posted some opinions (you may need to read the threads in my post to get an appreciation of my opinion), in the Inner Core of our Sun thread.harry wrote:Hello Neried
Mate what is your opinion?
Others give their opinions.
As for the iron star. Our sun has not been dominated by Iron.
You said
Yes 100%. We are here to discuss issues. But never close doors on ideas, that some people think are wild.If so, would you be prepared to defend this idea, in terms of its internal consistency and consistency with good observational and experimental results
Where did you hear that Prof Manuel has been thoroughly debunked with respect to the Iron sun. If you have info please forward them to me or respond here.
I have an open mind. All doors open and none closed.
For some other opinions, I really do wonder why much crackpot, pseudo-science (and even anti-science) material appears in internet discussion fora that are explicitly (and sometimes avowedly scientific in their approach) about astronomy, astrophysics, cosmology, and space science.
For the genuinely curious, my opinion is that it is, most of the time, fairly easy and straight-forward to work out why this crackpot and pseudo-science is flawed ... just apply the native critical thinking that almost all Homo sapiens individuals are equipped with.
For those who choose to abandon critical thinking, I offer these three opinions*:
When was the last time you jumped off the top of a 20 storey building, without a parachute (etc), and expected to not go splat on the ground below? You've never done that? So remind me again why you think General Relativity does not describe, to a high degree of accuracy, how the universe works?
When you read these words, on the monitor of your PC, with the help of the internet, do you think those words are merely a figment of your imagination? No? So remind me again why you think that Quantum Mechanics (or the Standard Model of particle physics) does not describe, to the highest degree of accuracy that any theory in science has been tested, how the universe works?
How often do you think (or read, or hear) "1 plus 1" and conclude "5"? That's not happened to you? So remind me again why you think {insert your favourite crackpot or pseudo-science theory of astronomy, astrophysics, cosmology or space science here} is wholly consistent, with math, equations, numbers and stuff?
*this is a WIP (work in progress); these three seek to highlight three killer inconsistencies - with GR, with quantum theory (QED in the example above, but the Standard Model works too), and mathematical. If any reader has a pithier, punchier way of cutting to the chase, with respect to 'wild' ideas in astronomy (etc) that are internally inconsistent, inconsistent with well-established theories whose domains of applicability overlap (i.e. GR and/or QM, or some subsets), or (above all) with good experimental or observational results ... I'd love to hear it!
