Thanks Erik and Patrick for taking a shot at answering my question! There are stars between galaxies. Errant ejected stars, and bridge stars between interacting galaxies at least. How this applies to my specific question is open. I'd buy spectral evidence, red or blue shift of the cepheids consistent with galactic rotation. Any known data? It would be fun to get a really high resolution photo and count the number of clear point stars both in 'front' of Andromeda and say a galactic diameter above and below. If the stars are local or in between the count per square unit should be the similar whereas more stars should be counted in 'front' of the galaxy if associated with the galaxy. Thanks again for the response. Steve
The Cepheid distance scale has required statistical help to give us an accurate distance to M31. The initial value of the distance has been corrected by a factor of 2 from the time that the first Cepheid measurements were done with the 100 inch on Mount Wilson. The best atmospheric resolution prior to adaptive optics was seldom less than an arc second. At the distance of M31 that means a cone of space 10 light years accross. That is wide enough to pick up stray stars within M31 that are in front of or behind the Cephied being studied. These strays are too dim to be resolved as companions but still bright enough to mess up the measurement of the Cepheid. This was resolved by statistics. Take the distance value to M31 from dozens of different Cepheids and the numbers will give a broad range of values. But this range will have a hard edge at the upper end where you have a few samples with no stray light from optical companions. It took awhile but that's how we resolved the present value of distance to M31. It's also the reason why the supernovae distance scale is based on thousands of sample points. So we can calibrate the scale to a much higher degree over time. It's also the reason that the SDSS is doing the spectrum on millions of galaxies not just a few dozen. Statistics. It's where the rubber meets the road in science. DT
Dan,
So what you are saying is that there have been enough measurements to keep Cephied distance values as valid? It would seem that any changes in Cephied luminosity values could easily be applied to Hubble's calculations to adjust that constant if it needs to be. It would be shame if Sandage's lifetime work was thrown out. They did apply a lot of mathematical corrections for atmospheric conditions and they did suspect Cephieds where shedding material as they moved threw space. They just had no proof. I imagine the Spitzer Scope has simplified the corrections some a deal. IE, atmospheric conditions no longer need be considered. One thing is for certain cosmologist are excellent in Math. Erik The Cepheid distance scale has required statistical help to give us an
accurate distance to M31. The initial value of the distance has been corrected by a factor of 2 from the time that the first Cepheid measurements were done with the 100 inch on Mount Wilson.
The best atmospheric resolution prior to adaptive optics was seldom less than an arc second. At the distance of M31 that means a cone of space 10 light years accross. That is wide enough to pick up stray stars within M31 that are in front of or behind the Cephied being studied. These strays are too dim to be resolved as companions but still bright enough to mess up the measurement of the Cepheid.
This was resolved by statistics. Take the distance value to M31 from dozens of different Cepheids and the numbers will give a broad range of values. But this range will have a hard edge at the upper end where you have a few samples with no stray light from optical companions.
It took awhile but that's how we resolved the present value of distance to M31. It's also the reason why the supernovae distance scale is based on thousands of sample points. So we can calibrate the scale to a much higher degree over time. It's also the reason that the SDSS is doing the spectrum on millions of galaxies not just a few dozen.
Statistics. It's where the rubber meets the road in science.
DT
_______________________________________________ Utah-Astronomy mailing list Utah-Astronomy@mailman.xmission.com http://mailman.xmission.com/cgi-bin/mailman/listinfo/utah-astronomy Visit the Photo Gallery: http://www.slas.us/gallery2/main.php Visit the Wiki: http://www.utahastronomy.com
Erik, Nobody says Cepheid variables aren't valid as an indicator; what my story says is that the distance scale using them needs some revision. That was the first sentence. One of the problems is that apparently not all of them are shrinking at the same rate -- of those that were surveyed in the follow-up study, checking for that condition, only 25 percent were. So how do you treat a variable that looks and acts the same as delta Cep but may not be shrinking in the same way? Is it at the same distance or not? -- Joe --- On Sun, 1/16/11, erikhansen@thebluezone.net <erikhansen@thebluezone.net> wrote:
From: erikhansen@thebluezone.net <erikhansen@thebluezone.net> Subject: Re: [Utah-astronomy] RE Cepheids To: "Utah Astronomy" <utah-astronomy@mailman.xmission.com> Date: Sunday, January 16, 2011, 10:54 AM
Dan,
So what you are saying is that there have been enough measurements to keep Cephied distance values as valid?
It would seem that any changes in Cephied luminosity values could easily be applied to Hubble's calculations to adjust that constant if it needs to be. It would be shame if Sandage's lifetime work was thrown out.
They did apply a lot of mathematical corrections for atmospheric conditions and they did suspect Cephieds where shedding material as they moved threw space. They just had no proof. I imagine the Spitzer Scope has simplified the corrections some a deal. IE, atmospheric conditions no longer need be considered. One thing is for certain cosmologist are excellent in Math.
Erik
The Cepheid distance scale has required statistical help to give us an
accurate distance to M31. The initial value of the distance has been corrected by a factor of 2 from the time that the first Cepheid measurements were done with the 100 inch on Mount Wilson.
The best atmospheric resolution prior to adaptive optics was seldom less than an arc second. At the distance of M31 that means a cone of space 10 light years accross. That is wide enough to pick up stray stars within M31 that are in front of or behind the Cephied being studied. These strays are too dim to be resolved as companions but still bright enough to mess up the measurement of the Cepheid.
This was resolved by statistics. Take the distance value to M31 from dozens of different Cepheids and the numbers will give a broad range of values. But this range will have a hard edge at the upper end where you have a few samples with no stray light from optical companions.
It took awhile but that's how we resolved the present value of distance to M31. It's also the reason why the supernovae distance scale is based on thousands of sample points. So we can calibrate the scale to a much higher degree over time. It's also the reason that the SDSS is doing the spectrum on millions of galaxies not just a few dozen.
Statistics. It's where the rubber meets the road in science.
DT
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Joe,
I got the jist of the article and I read your article I thought it was very good. All I said, was that saying it "vastly" complicated Cephieds as distance indicators was over stated. There seems to have always been some assumed error and this was taken into account by Hubble and Sandage. Overby mentions the mathematics as a somewhat impossible task. I am sorry if that offended you or if you misunderstood what I said. The quote at the end of the article indicated that it was a huge problem. I assume the individual was somewhat quoted out of context, something the media seems to have knack of. Right, Patrick?. "To undertake executions for the master executioner (Heaven) is like hewing wood for the master carpenter. Whoever undertakes to hew wood for the master carpenter rarely escapes injuring his own hands. " Lao-tzu, from the opening of "Lonely Hearts of the Cosmos" Erik Erik, Nobody says Cepheid variables aren't valid as an indicator; what my
story says is that the distance scale using them needs some revision. That was the first sentence. One of the problems is that apparently not all of them are shrinking at the same rate -- of those that were surveyed in the follow-up study, checking for that condition, only 25 percent were. So how do you treat a variable that looks and acts the same as delta Cep but may not be shrinking in the same way? Is it at the same distance or not? -- Joe
--- On Sun, 1/16/11, erikhansen@thebluezone.net <erikhansen@thebluezone.net> wrote:
From: erikhansen@thebluezone.net <erikhansen@thebluezone.net> Subject: Re: [Utah-astronomy] RE Cepheids To: "Utah Astronomy" <utah-astronomy@mailman.xmission.com> Date: Sunday, January 16, 2011, 10:54 AM
Dan,
So what you are saying is that there have been enough measurements to keep Cephied distance values as valid?
It would seem that any changes in Cephied luminosity values could easily be applied to Hubble's calculations to adjust that constant if it needs to be. It would be shame if Sandage's lifetime work was thrown out.
They did apply a lot of mathematical corrections for atmospheric conditions and they did suspect Cephieds where shedding material as they moved threw space. They just had no proof. I imagine the Spitzer Scope has simplified the corrections some a deal. IE, atmospheric conditions no longer need be considered. One thing is for certain cosmologist are excellent in Math.
Erik
The Cepheid distance scale has required statistical help to give us an
accurate distance to M31. The initial value of the distance has been corrected by a factor of 2 from the time that the first Cepheid measurements were done with the 100 inch on Mount Wilson.
The best atmospheric resolution prior to adaptive optics was seldom less than an arc second. At the distance of M31 that means a cone of space 10 light years accross. That is wide enough to pick up stray stars within M31 that are in front of or behind the Cephied being studied. These strays are too dim to be resolved as companions but still bright enough to mess up the measurement of the Cepheid.
This was resolved by statistics. Take the distance value to M31 from dozens of different Cepheids and the numbers will give a broad range of values. But this range will have a hard edge at the upper end where you have a few samples with no stray light from optical companions.
It took awhile but that's how we resolved the present value of distance to M31. It's also the reason why the supernovae distance scale is based on thousands of sample points. So we can calibrate the scale to a much higher degree over time. It's also the reason that the SDSS is doing the spectrum on millions of galaxies not just a few dozen.
Statistics. It's where the rubber meets the road in science.
DT
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Erik, the quote at the end of my blog was not out of context. It's annoying for you to say I take quotes out of context. I do not. And I did not in the 40 years I was a reporter. Ask anyone I've interviewed or quoted. And while you're at it, read the NASA press release about the recent Cepheid findings, from which I took the quote -- not out of context. Please get your facts straight before impugning my journalistic integrity. -- Joe Bauman --- On Sun, 1/16/11, erikhansen@thebluezone.net <erikhansen@thebluezone.net> wrote:
From: erikhansen@thebluezone.net <erikhansen@thebluezone.net> Subject: Re: [Utah-astronomy] RE Cepheids To: "Utah Astronomy" <utah-astronomy@mailman.xmission.com> Date: Sunday, January 16, 2011, 1:01 PM
Joe,
I got the jist of the article and I read your article I thought it was very good.
All I said, was that saying it "vastly" complicated Cephieds as distance indicators was over stated. There seems to have always been some assumed error and this was taken into account by Hubble and Sandage. Overby mentions the mathematics as a somewhat impossible task. I am sorry if that offended you or if you misunderstood what I said. The quote at the end of the article indicated that it was a huge problem. I assume the individual was somewhat quoted out of context, something the media seems to have knack of. Right, Patrick?.
"To undertake executions for the master executioner (Heaven) is like hewing wood for the master carpenter. Whoever undertakes to hew wood for the master carpenter rarely escapes injuring his own hands. " Lao-tzu, from the opening of "Lonely Hearts of the Cosmos"
Erik
Erik, Nobody says Cepheid variables aren't valid as an indicator; what my
story says is that the distance scale using them needs some revision. That was the first sentence. One of the problems is that apparently not all of them are shrinking at the same rate -- of those that were surveyed in the follow-up study, checking for that condition, only 25 percent were. So how do you treat a variable that looks and acts the same as delta Cep but may not be shrinking in the same way? Is it at the same distance or not? -- Joe
--- On Sun, 1/16/11, erikhansen@thebluezone.net <erikhansen@thebluezone.net> wrote:
From: erikhansen@thebluezone.net <erikhansen@thebluezone.net> Subject: Re: [Utah-astronomy] RE Cepheids To: "Utah Astronomy" <utah-astronomy@mailman.xmission.com> Date: Sunday, January 16, 2011, 10:54 AM
Dan,
So what you are saying is that there have been enough measurements to keep Cephied distance values as valid?
It would seem that any changes in Cephied luminosity values could easily be applied to Hubble's calculations to adjust that constant if it needs to be. It would be shame if Sandage's lifetime work was thrown out.
They did apply a lot of mathematical corrections for atmospheric conditions and they did suspect Cephieds where shedding material as they moved threw space. They just had no proof. I imagine the Spitzer Scope has simplified the corrections some a deal. IE, atmospheric conditions no longer need be considered. One thing is for certain cosmologist are excellent in Math.
Erik
The Cepheid distance scale has required statistical help to give us an
accurate distance to M31. The initial value of the distance has been corrected by a factor of 2 from the time that the first Cepheid measurements were done with the 100 inch on Mount Wilson.
The best atmospheric resolution prior to adaptive optics was seldom less than an arc second. At the distance of M31 that means a cone of space 10 light years accross. That is wide enough to pick up stray stars within M31 that are in front of or behind the Cephied being studied. These strays are too dim to be resolved as companions but still bright enough to mess up the measurement of the Cepheid.
This was resolved by statistics. Take the distance value to M31 from dozens of different Cepheids and the numbers will give a broad range of values. But this range will have a hard edge at the upper end where you have a few samples with no stray light from optical companions.
It took awhile but that's how we resolved the present value of distance to M31. It's also the reason why the supernovae distance scale is based on thousands of sample points. So we can calibrate the scale to a much higher degree over time. It's also the reason that the SDSS is doing the spectrum on millions of galaxies not just a few dozen.
Statistics. It's where the rubber meets the road in science.
DT
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Joe,
Again you are seriously misunderstanding, and the only thing I questioned was your post that it "vastly" changed the science. Very little of my comments on this thread were directed at you, or your article. Only the ones that are start with Joe are a direct response to you. The quote in question: "Everything crumbles in cosmology studies if you don't start up with the most precise measurements of Cepheids possible," said Pauline Barmby of the University of Western Ontario, Canada. The NASA article seems to say it does not have great affect, which you seem to agree then it ends with saying "everything crumbles". I thought I was defending the work of Sandage and Hubble. I think Barmby probably says more than that and I would have liked her to expand on that statement, the NASA article should have been more in depth on what the real consequence. It is not you I am saying is taking it out of context. That quote seems to indicate that all the measurements crumble, which you seem to disagree with also. The comment was also somewhat sarcasim direct toward people who feel scientist sensationalize and fabricate findings Erik Erik, the quote at the end of my blog was not out of context. It's
annoying for you to say I take quotes out of context. I do not. And I did not in the 40 years I was a reporter. Ask anyone I've interviewed or quoted. And while you're at it, read the NASA press release about the recent Cepheid findings, from which I took the quote -- not out of context. Please get your facts straight before impugning my journalistic integrity. -- Joe Bauman
--- On Sun, 1/16/11, erikhansen@thebluezone.net <erikhansen@thebluezone.net> wrote:
From: erikhansen@thebluezone.net <erikhansen@thebluezone.net> Subject: Re: [Utah-astronomy] RE Cepheids To: "Utah Astronomy" <utah-astronomy@mailman.xmission.com> Date: Sunday, January 16, 2011, 1:01 PM
Joe,
I got the jist of the article and I read your article I thought it was very good.
All I said, was that saying it "vastly" complicated Cephieds as distance indicators was over stated. There seems to have always been some assumed error and this was taken into account by Hubble and Sandage. Overby mentions the mathematics as a somewhat impossible task. I am sorry if that offended you or if you misunderstood what I said. The quote at the end of the article indicated that it was a huge problem. I assume the individual was somewhat quoted out of context, something the media seems to have knack of. Right, Patrick?.
"To undertake executions for the master executioner (Heaven) is like hewing wood for the master carpenter. Whoever undertakes to hew wood for the master carpenter rarely escapes injuring his own hands. " Lao-tzu, from the opening of "Lonely Hearts of the Cosmos"
Erik
Erik, Nobody says Cepheid variables aren't valid as an indicator; what my
story says is that the distance scale using them needs some revision. That was the first sentence. One of the problems is that apparently not all of them are shrinking at the same rate -- of those that were surveyed in the follow-up study, checking for that condition, only 25 percent were. So how do you treat a variable that looks and acts the same as delta Cep but may not be shrinking in the same way? Is it at the same distance or not? -- Joe
--- On Sun, 1/16/11, erikhansen@thebluezone.net <erikhansen@thebluezone.net> wrote:
From: erikhansen@thebluezone.net <erikhansen@thebluezone.net> Subject: Re: [Utah-astronomy] RE Cepheids To: "Utah Astronomy" <utah-astronomy@mailman.xmission.com> Date: Sunday, January 16, 2011, 10:54 AM
Dan,
So what you are saying is that there have been enough measurements to keep Cephied distance values as valid?
It would seem that any changes in Cephied luminosity values could easily be applied to Hubble's calculations to adjust that constant if it needs to be. It would be shame if Sandage's lifetime work was thrown out.
They did apply a lot of mathematical corrections for atmospheric conditions and they did suspect Cephieds where shedding material as they moved threw space. They just had no proof. I imagine the Spitzer Scope has simplified the corrections some a deal. IE, atmospheric conditions no longer need be considered. One thing is for certain cosmologist are excellent in Math.
Erik
The Cepheid distance scale has required statistical help to give us an
accurate distance to M31. The initial value of the distance has been corrected by a factor of 2 from the time that the first Cepheid measurements were done with the 100 inch on Mount Wilson.
The best atmospheric resolution prior to adaptive optics was seldom less than an arc second. At the distance of M31 that means a cone of space 10 light years accross. That is wide enough to pick up stray stars within M31 that are in front of or behind the Cephied being studied. These strays are too dim to be resolved as companions but still bright enough to mess up the measurement of the Cepheid.
This was resolved by statistics. Take the distance value to M31 from dozens of different Cepheids and the numbers will give a broad range of values. But this range will have a hard edge at the upper end where you have a few samples with no stray light from optical companions.
It took awhile but that's how we resolved the present value of distance to M31. It's also the reason why the supernovae distance scale is based on thousands of sample points. So we can calibrate the scale to a much higher degree over time. It's also the reason that the SDSS is doing the spectrum on millions of galaxies not just a few dozen.
Statistics. It's where the rubber meets the road in science.
DT
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I understand perfectly, Erik, and I do apologize for going off -- it's a bad habit I've always had, a kneejerk reaction when I think I'm under attack. It dates from my abused childhood. Best wishes, Joe --- On Sun, 1/16/11, erikhansen@thebluezone.net <erikhansen@thebluezone.net> wrote:
From: erikhansen@thebluezone.net <erikhansen@thebluezone.net> Subject: Re: [Utah-astronomy] RE Cepheids To: "Utah Astronomy" <utah-astronomy@mailman.xmission.com> Date: Sunday, January 16, 2011, 3:59 PM
Joe,
Again you are seriously misunderstanding, and the only thing I questioned was your post that it "vastly" changed the science. Very little of my comments on this thread were directed at you, or your article. Only the ones that are start with Joe are a direct response to you.
The quote in question: "Everything crumbles in cosmology studies if you don't start up with the most precise measurements of Cepheids possible," said Pauline Barmby of the University of Western Ontario, Canada. The NASA article seems to say it does not have great affect, which you seem to agree then it ends with saying "everything crumbles". I thought I was defending the work of Sandage and Hubble. I think Barmby probably says more than that and I would have liked her to expand on that statement, the NASA article should have been more in depth on what the real consequence.
It is not you I am saying is taking it out of context. That quote seems to indicate that all the measurements crumble, which you seem to disagree with also. The comment was also somewhat sarcasim direct toward people who feel scientist sensationalize and fabricate findings
Erik
Erik, the quote at the end of my blog was not out of context. It's
annoying for you to say I take quotes out of context. I do not. And I did not in the 40 years I was a reporter. Ask anyone I've interviewed or quoted. And while you're at it, read the NASA press release about the recent Cepheid findings, from which I took the quote -- not out of context. Please get your facts straight before impugning my journalistic integrity. -- Joe Bauman
--- On Sun, 1/16/11, erikhansen@thebluezone.net <erikhansen@thebluezone.net> wrote:
From: erikhansen@thebluezone.net <erikhansen@thebluezone.net> Subject: Re: [Utah-astronomy] RE Cepheids To: "Utah Astronomy" <utah-astronomy@mailman.xmission.com> Date: Sunday, January 16, 2011, 1:01 PM
Joe,
I got the jist of the article and I read your article I thought it was very good.
All I said, was that saying it "vastly" complicated Cephieds as distance indicators was over stated. There seems to have always been some assumed error and this was taken into account by Hubble and Sandage. Overby mentions the mathematics as a somewhat impossible task. I am sorry if that offended you or if you misunderstood what I said. The quote at the end of the article indicated that it was a huge problem. I assume the individual was somewhat quoted out of context, something the media seems to have knack of. Right, Patrick?.
"To undertake executions for the master executioner (Heaven) is like hewing wood for the master carpenter. Whoever undertakes to hew wood for the master carpenter rarely escapes injuring his own hands. " Lao-tzu, from the opening of "Lonely Hearts of the Cosmos"
Erik
Erik, Nobody says Cepheid variables aren't valid as an indicator; what my
story says is that the distance scale using them needs some revision. That was the first sentence. One of the problems is that apparently not all of them are shrinking at the same rate -- of those that were surveyed in the follow-up study, checking for that condition, only 25 percent were. So how do you treat a variable that looks and acts the same as delta Cep but may not be shrinking in the same way? Is it at the same distance or not? -- Joe
--- On Sun, 1/16/11, erikhansen@thebluezone.net <erikhansen@thebluezone.net> wrote:
From: erikhansen@thebluezone.net <erikhansen@thebluezone.net> Subject: Re: [Utah-astronomy] RE Cepheids To: "Utah Astronomy" <utah-astronomy@mailman.xmission.com> Date: Sunday, January 16, 2011, 10:54 AM
Dan,
So what you are saying is that there have been enough measurements to keep Cephied distance values as valid?
It would seem that any changes in Cephied luminosity values could easily be applied to Hubble's calculations to adjust that constant if it needs to be. It would be shame if Sandage's lifetime work was thrown out.
They did apply a lot of mathematical corrections for atmospheric conditions and they did suspect Cephieds where shedding material as they moved threw space. They just had no proof. I imagine the Spitzer Scope has simplified the corrections some a deal. IE, atmospheric conditions no longer need be considered. One thing is for certain cosmologist are excellent in Math.
Erik
The Cepheid distance scale has required statistical help to give us an
accurate distance to M31. The initial value of the distance has been corrected by a factor of 2 from the time that the first Cepheid measurements were done with the 100 inch on Mount Wilson.
The best atmospheric resolution prior to adaptive optics was seldom less than an arc second. At the distance of M31 that means a cone of space 10 light years accross. That is wide enough to pick up stray stars within M31 that are in front of or behind the Cephied being studied. These strays are too dim to be resolved as companions but still bright enough to mess up the measurement of the Cepheid.
This was resolved by statistics. Take the distance value to M31 from dozens of different Cepheids and the numbers will give a broad range of values. But this range will have a hard edge at the upper end where you have a few samples with no stray light from optical companions.
It took awhile but that's how we resolved the present value of distance to M31. It's also the reason why the supernovae distance scale is based on thousands of sample points. So we can calibrate the scale to a much higher degree over time. It's also the reason that the SDSS is doing the spectrum on millions of galaxies not just a few dozen.
Statistics. It's where the rubber meets the road in science.
DT
Utah-Astronomy mailing list Utah-Astronomy@mailman.xmission.com http://mailman.xmission.com/cgi-bin/mailman/listinfo/utah-astronomy Visit the Photo Gallery: http://www.slas.us/gallery2/main.php Visit the Wiki: http://www.utahastronomy.com
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Hi All,
no worries Joe and have ironed this out, plenty of miscommunication on both sides. I hope the abused childhood was not to serious. I would describe my childhood as one of privilege with only a few older sibling issues. Erik I understand perfectly, Erik, and I do apologize for going off -- it's a
bad habit I've always had, a kneejerk reaction when I think I'm under attack. It dates from my abused childhood. Best wishes, Joe
--- On Sun, 1/16/11, erikhansen@thebluezone.net <erikhansen@thebluezone.net> wrote:
From: erikhansen@thebluezone.net <erikhansen@thebluezone.net> Subject: Re: [Utah-astronomy] RE Cepheids To: "Utah Astronomy" <utah-astronomy@mailman.xmission.com> Date: Sunday, January 16, 2011, 3:59 PM
Joe,
Again you are seriously misunderstanding, and the only thing I questioned was your post that it "vastly" changed the science. Very little of my comments on this thread were directed at you, or your article. Only the ones that are start with Joe are a direct response to you.
The quote in question: "Everything crumbles in cosmology studies if you don't start up with the most precise measurements of Cepheids possible," said Pauline Barmby of the University of Western Ontario, Canada. The NASA article seems to say it does not have great affect, which you seem to agree then it ends with saying "everything crumbles". I thought I was defending the work of Sandage and Hubble. I think Barmby probably says more than that and I would have liked her to expand on that statement, the NASA article should have been more in depth on what the real consequence.
It is not you I am saying is taking it out of context. That quote seems to indicate that all the measurements crumble, which you seem to disagree with also. The comment was also somewhat sarcasim direct toward people who feel scientist sensationalize and fabricate findings
Erik
Erik, the quote at the end of my blog was not out of context. It's
annoying for you to say I take quotes out of context. I do not. And I did not in the 40 years I was a reporter. Ask anyone I've interviewed or quoted. And while you're at it, read the NASA press release about the recent Cepheid findings, from which I took the quote -- not out of context. Please get your facts straight before impugning my journalistic integrity. -- Joe Bauman
--- On Sun, 1/16/11, erikhansen@thebluezone.net <erikhansen@thebluezone.net> wrote:
From: erikhansen@thebluezone.net <erikhansen@thebluezone.net> Subject: Re: [Utah-astronomy] RE Cepheids To: "Utah Astronomy" <utah-astronomy@mailman.xmission.com> Date: Sunday, January 16, 2011, 1:01 PM
Joe,
I got the jist of the article and I read your article I thought it was very good.
All I said, was that saying it "vastly" complicated Cephieds as distance indicators was over stated. There seems to have always been some assumed error and this was taken into account by Hubble and Sandage. Overby mentions the mathematics as a somewhat impossible task. I am sorry if that offended you or if you misunderstood what I said. The quote at the end of the article indicated that it was a huge problem. I assume the individual was somewhat quoted out of context, something the media seems to have knack of. Right, Patrick?.
"To undertake executions for the master executioner (Heaven) is like hewing wood for the master carpenter. Whoever undertakes to hew wood for the master carpenter rarely escapes injuring his own hands. " Lao-tzu, from the opening of "Lonely Hearts of the Cosmos"
Erik
Erik, Nobody says Cepheid variables aren't valid as an indicator; what my
story says is that the distance scale using them needs some revision. That was the first sentence. One of the problems is that apparently not all of them are shrinking at the same rate -- of those that were surveyed in the follow-up study, checking for that condition, only 25 percent were. So how do you treat a variable that looks and acts the same as delta Cep but may not be shrinking in the same way? Is it at the same distance or not? -- Joe
--- On Sun, 1/16/11, erikhansen@thebluezone.net <erikhansen@thebluezone.net> wrote:
From: erikhansen@thebluezone.net <erikhansen@thebluezone.net> Subject: Re: [Utah-astronomy] RE Cepheids To: "Utah Astronomy" <utah-astronomy@mailman.xmission.com> Date: Sunday, January 16, 2011, 10:54 AM >Dan,
So what you are saying is that there have been enough measurements to keep Cephied distance values as valid?
It would seem that any changes in Cephied luminosity values could easily be applied to Hubble's calculations to adjust that constant if it needs to be. It would be shame if Sandage's lifetime work was thrown out.
They did apply a lot of mathematical corrections for atmospheric conditions and they did suspect Cephieds where shedding material as they moved threw space. They just had no proof. I imagine the Spitzer Scope has simplified the corrections some a deal. IE, atmospheric conditions no longer need be considered. One thing is for certain cosmologist are excellent in Math.
Erik
The Cepheid distance scale has required statistical help to give us an > accurate distance to M31. The initial value of the distance has been > corrected by a factor of 2 from the time that the first Cepheid > measurements were done with the 100 inch on Mount Wilson. > > The best atmospheric resolution prior to adaptive optics was seldom less > than an arc second. At the distance of M31 that means a cone of space 10 > light years accross. That is wide enough to pick up stray stars within M31 > that are in front of or behind the Cephied being studied. These strays > are too dim to be resolved as companions but still bright enough to mess > up the measurement of the Cepheid. > > This was resolved by statistics. Take the distance value to M31 from > dozens of different Cepheids and the numbers will give a broad range of > values. But this range will have a hard edge at the upper end where you > have a few samples with no stray light from optical companions. > > It took awhile but that's how we resolved the present value of distance to > M31. It's also the reason why the supernovae distance scale is based on > thousands of sample points. So we can calibrate the scale to a much > higher degree over time. It's also the reason that the SDSS is doing the > spectrum on millions of galaxies not just a few dozen. > > Statistics. It's where the rubber meets the road in science. > > DT > > > > >
> Utah-Astronomy mailing list > Utah-Astronomy@mailman.xmission.com > http://mailman.xmission.com/cgi-bin/mailman/listinfo/utah-astronomy > Visit the Photo Gallery: http://www.slas.us/gallery2/main.php > Visit the Wiki: http://www.utahastronomy.com >
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Thanks Erik, It was pretty serious abuse but I'm a grown man and should be able to put things like that behind me. Usually I do. Best wishes, Joe --- On Sun, 1/16/11, erikhansen@thebluezone.net <erikhansen@thebluezone.net> wrote:
From: erikhansen@thebluezone.net <erikhansen@thebluezone.net> Subject: Re: [Utah-astronomy] RE Cepheids To: "Utah Astronomy" <utah-astronomy@mailman.xmission.com> Date: Sunday, January 16, 2011, 6:18 PM
Hi All,
no worries Joe and have ironed this out, plenty of miscommunication on both sides. I hope the abused childhood was not to serious. I would describe my childhood as one of privilege with only a few older sibling issues.
Erik
I understand perfectly, Erik, and I do apologize for going off -- it's a
bad habit I've always had, a kneejerk reaction when I think I'm under attack. It dates from my abused childhood. Best wishes, Joe
--- On Sun, 1/16/11, erikhansen@thebluezone.net <erikhansen@thebluezone.net> wrote:
From: erikhansen@thebluezone.net <erikhansen@thebluezone.net> Subject: Re: [Utah-astronomy] RE Cepheids To: "Utah Astronomy" <utah-astronomy@mailman.xmission.com> Date: Sunday, January 16, 2011, 3:59 PM
Joe,
Again you are seriously misunderstanding, and the only thing I questioned was your post that it "vastly" changed the science. Very little of my comments on this thread were directed at you, or your article. Only the ones that are start with Joe are a direct response to you.
The quote in question: "Everything crumbles in cosmology studies if you don't start up with the most precise measurements of Cepheids possible," said Pauline Barmby of the University of Western Ontario, Canada. The NASA article seems to say it does not have great affect, which you seem to agree then it ends with saying "everything crumbles". I thought I was defending the work of Sandage and Hubble. I think Barmby probably says more than that and I would have liked her to expand on that statement, the NASA article should have been more in depth on what the real consequence.
It is not you I am saying is taking it out of context. That quote seems to indicate that all the measurements crumble, which you seem to disagree with also. The comment was also somewhat sarcasim direct toward people who feel scientist sensationalize and fabricate findings
Erik
Erik, the quote at the end of my blog was not out of context. It's
annoying for you to say I take quotes out of context. I do not. And I did not in the 40 years I was a reporter. Ask anyone I've interviewed or quoted. And while you're at it, read the NASA press release about the recent Cepheid findings, from which I took the quote -- not out of context. Please get your facts straight before impugning my journalistic integrity. -- Joe Bauman
--- On Sun, 1/16/11, erikhansen@thebluezone.net <erikhansen@thebluezone.net> wrote:
From: erikhansen@thebluezone.net <erikhansen@thebluezone.net> Subject: Re: [Utah-astronomy] RE Cepheids To: "Utah Astronomy" <utah-astronomy@mailman.xmission.com> Date: Sunday, January 16, 2011, 1:01 PM
Joe,
I got the jist of the article and I read your article I thought it was very good.
All I said, was that saying it "vastly" complicated Cephieds as distance indicators was over stated. There seems to have always been some assumed error and this was taken into account by Hubble and Sandage. Overby mentions the mathematics as a somewhat impossible task. I am sorry if that offended you or if you misunderstood what I said. The quote at the end of the article indicated that it was a huge problem. I assume the individual was somewhat quoted out of context, something the media seems to have knack of. Right, Patrick?.
"To undertake executions for the master executioner (Heaven) is like hewing wood for the master carpenter. Whoever undertakes to hew wood for the master carpenter rarely escapes injuring his own hands. " Lao-tzu, from the opening of "Lonely Hearts of the Cosmos"
Erik
Erik, Nobody says Cepheid variables aren't valid as an indicator; what my
story says is that the distance scale using them needs some revision. That was the first sentence. One of the problems is that apparently not all of them are shrinking at the same rate -- of those that were surveyed in the follow-up study, checking for that condition, only 25 percent were. So how do you treat a variable that looks and acts the same as delta Cep but may not be shrinking in the same way? Is it at the same distance or not? -- Joe
--- On Sun, 1/16/11, erikhansen@thebluezone.net <erikhansen@thebluezone.net> wrote:
> From: erikhansen@thebluezone.net <erikhansen@thebluezone.net> > Subject: Re: [Utah-astronomy] RE Cepheids > To: "Utah Astronomy" <utah-astronomy@mailman.xmission.com> > Date: Sunday, January 16, 2011, 10:54 AM > >Dan, > > So what you are saying is that there have been enough > measurements to keep > Cephied distance values as valid? > > It would seem that any changes in Cephied luminosity values > could easily > be applied to Hubble's calculations to adjust that constant > if it needs to > be. It would be shame if Sandage's lifetime work was thrown > out. > > They did apply a lot of mathematical corrections for > atmospheric > conditions and they did suspect Cephieds where shedding > material as they > moved threw space. They just had no proof. I imagine the > Spitzer Scope has > simplified the corrections some a deal. IE, > atmospheric conditions no > longer need be considered. One thing is for certain > cosmologist are > excellent in Math. > > Erik > > > > The Cepheid distance scale has required statistical help to > give us an > > accurate distance to M31. The initial value of > the distance has been > > corrected by a factor of 2 from the time that the > first Cepheid > > measurements were done with the 100 inch on Mount > Wilson. > > > > The best atmospheric resolution prior to adaptive > optics was seldom less > > than an arc second. At the distance of M31 that > means a cone of space 10 > > light years accross. That is wide enough to pick up > stray stars within M31 > > that are in front of or behind the Cephied being > studied. These strays > > are too dim to be resolved as companions but still > bright enough to mess > > up the measurement of the Cepheid. > > > > This was resolved by statistics. Take the > distance value to M31 from > > dozens of different Cepheids and the numbers will give > a broad range of > > values. But this range will have a hard edge at > the upper end where you > > have a few samples with no stray light from optical > companions. > > > > It took awhile but that's how we resolved the present > value of distance to > > M31. It's also the reason why the supernovae > distance scale is based on > > thousands of sample points. So we can calibrate > the scale to a much > > higher degree over time. It's also the reason > that the SDSS is doing the > > spectrum on millions of galaxies not just a few > dozen. > > > > Statistics. It's where the rubber meets the road > in science. > > > > DT > > > > > > > > > >
> > Utah-Astronomy mailing list > > Utah-Astronomy@mailman.xmission.com > > http://mailman.xmission.com/cgi-bin/mailman/listinfo/utah-astronomy > > Visit the Photo Gallery: http://www.slas.us/gallery2/main.php > > Visit the Wiki: http://www.utahastronomy.com > > > > > >
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Joe,
I think you need more explanation, I assume you took offense when I wrote: "I assume the individual was somewhat quoted out of context". The individual here is Barnaby, who I assume you did not interview, hence not an individual you would have taken out of context. Erik Erik, the quote at the end of my blog was not out of context. It's
annoying for you to say I take quotes out of context. I do not. And I did not in the 40 years I was a reporter. Ask anyone I've interviewed or quoted. And while you're at it, read the NASA press release about the recent Cepheid findings, from which I took the quote -- not out of context. Please get your facts straight before impugning my journalistic integrity. -- Joe Bauman
--- On Sun, 1/16/11, erikhansen@thebluezone.net <erikhansen@thebluezone.net> wrote:
From: erikhansen@thebluezone.net <erikhansen@thebluezone.net> Subject: Re: [Utah-astronomy] RE Cepheids To: "Utah Astronomy" <utah-astronomy@mailman.xmission.com> Date: Sunday, January 16, 2011, 1:01 PM
Joe,
I got the jist of the article and I read your article I thought it was very good.
All I said, was that saying it "vastly" complicated Cephieds as distance indicators was over stated. There seems to have always been some assumed error and this was taken into account by Hubble and Sandage. Overby mentions the mathematics as a somewhat impossible task. I am sorry if that offended you or if you misunderstood what I said. The quote at the end of the article indicated that it was a huge problem. I assume the individual was somewhat quoted out of context, something the media seems to have knack of. Right, Patrick?.
"To undertake executions for the master executioner (Heaven) is like hewing wood for the master carpenter. Whoever undertakes to hew wood for the master carpenter rarely escapes injuring his own hands. " Lao-tzu, from the opening of "Lonely Hearts of the Cosmos"
Erik
Erik, Nobody says Cepheid variables aren't valid as an indicator; what my
story says is that the distance scale using them needs some revision. That was the first sentence. One of the problems is that apparently not all of them are shrinking at the same rate -- of those that were surveyed in the follow-up study, checking for that condition, only 25 percent were. So how do you treat a variable that looks and acts the same as delta Cep but may not be shrinking in the same way? Is it at the same distance or not? -- Joe
--- On Sun, 1/16/11, erikhansen@thebluezone.net <erikhansen@thebluezone.net> wrote:
From: erikhansen@thebluezone.net <erikhansen@thebluezone.net> Subject: Re: [Utah-astronomy] RE Cepheids To: "Utah Astronomy" <utah-astronomy@mailman.xmission.com> Date: Sunday, January 16, 2011, 10:54 AM
Dan,
So what you are saying is that there have been enough measurements to keep Cephied distance values as valid?
It would seem that any changes in Cephied luminosity values could easily be applied to Hubble's calculations to adjust that constant if it needs to be. It would be shame if Sandage's lifetime work was thrown out.
They did apply a lot of mathematical corrections for atmospheric conditions and they did suspect Cephieds where shedding material as they moved threw space. They just had no proof. I imagine the Spitzer Scope has simplified the corrections some a deal. IE, atmospheric conditions no longer need be considered. One thing is for certain cosmologist are excellent in Math.
Erik
The Cepheid distance scale has required statistical help to give us an
accurate distance to M31. The initial value of the distance has been corrected by a factor of 2 from the time that the first Cepheid measurements were done with the 100 inch on Mount Wilson.
The best atmospheric resolution prior to adaptive optics was seldom less than an arc second. At the distance of M31 that means a cone of space 10 light years accross. That is wide enough to pick up stray stars within M31 that are in front of or behind the Cephied being studied. These strays are too dim to be resolved as companions but still bright enough to mess up the measurement of the Cepheid.
This was resolved by statistics. Take the distance value to M31 from dozens of different Cepheids and the numbers will give a broad range of values. But this range will have a hard edge at the upper end where you have a few samples with no stray light from optical companions.
It took awhile but that's how we resolved the present value of distance to M31. It's also the reason why the supernovae distance scale is based on thousands of sample points. So we can calibrate the scale to a much higher degree over time. It's also the reason that the SDSS is doing the spectrum on millions of galaxies not just a few dozen.
Statistics. It's where the rubber meets the road in science.
DT
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I hope I'm not too late to join in on this. I think that one of the problems with the Cepheid distance scale is that we haven't been able to get many independent distance measurements. I believe the Hipparcos database only includes 135 Cepheid variables. The NASA FAME mission was intended to make measurements that would include distances to many additional Cepheid variables. But, it was cancelled due to cost overruns and some technical issues. When the ESA GAIA mission finally launches and returns results (it is supposed to determine distances to 1 billion stars) that should help with the Cepheid calibration problem. For example, we still don't have a really precise distance value for Polaris [430 ly +/- 30] (a Cepheid variable). Clear skies, Dale.
-----Original Message----- From: utah-astronomy-bounces@mailman.xmission.com [mailto:utah- astronomy-bounces@mailman.xmission.com] On Behalf Of erikhansen@thebluezone.net Sent: Sunday, January 16, 2011 10:55 AM To: Utah Astronomy Subject: Re: [Utah-astronomy] RE Cepheids
Dan,
So what you are saying is that there have been enough measurements to keep Cephied distance values as valid?
It would seem that any changes in Cephied luminosity values could easily be applied to Hubble's calculations to adjust that constant if it needs to be. It would be shame if Sandage's lifetime work was thrown out.
They did apply a lot of mathematical corrections for atmospheric conditions and they did suspect Cephieds where shedding material as they moved threw space. They just had no proof. I imagine the Spitzer Scope has simplified the corrections some a deal. IE, atmospheric conditions no longer need be considered. One thing is for certain cosmologist are excellent in Math.
Erik
The Cepheid distance scale has required statistical help to give us an
accurate distance to M31. The initial value of the distance has been corrected by a factor of 2 from the time that the first Cepheid measurements were done with the 100 inch on Mount Wilson.
The best atmospheric resolution prior to adaptive optics was seldom less than an arc second. At the distance of M31 that means a cone of space 10 light years accross. That is wide enough to pick up stray stars within M31 that are in front of or behind the Cephied being studied. These strays are too dim to be resolved as companions but still bright enough to mess up the measurement of the Cepheid.
This was resolved by statistics. Take the distance value to M31 from dozens of different Cepheids and the numbers will give a broad range of values. But this range will have a hard edge at the upper end where you have a few samples with no stray light from optical companions.
It took awhile but that's how we resolved the present value of distance to M31. It's also the reason why the supernovae distance scale is based on thousands of sample points. So we can calibrate the scale to a much higher degree over time. It's also the reason that the SDSS is doing the spectrum on millions of galaxies not just a few dozen.
Statistics. It's where the rubber meets the road in science.
DT
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As I recall, the work by Hubble and Sandage did include other standard candles. They used some dwarf galaxies as well to derive their distance measurements. The most striking thing to me was Hubble thought the universe was 4-5 billion years old, his findings concluded it was more like 20 billion years old. Time on telescopes needs to be justified as it is very competative, it is a shame money is an issue on this. I hope I'm not too late to join in on this.
I think that one of the problems with the Cepheid distance scale is that we haven't been able to get many independent distance measurements. I believe the Hipparcos database only includes 135 Cepheid variables. The NASA FAME mission was intended to make measurements that would include distances to many additional Cepheid variables. But, it was cancelled due to cost overruns and some technical issues.
When the ESA GAIA mission finally launches and returns results (it is supposed to determine distances to 1 billion stars) that should help with the Cepheid calibration problem. For example, we still don't have a really precise distance value for Polaris [430 ly +/- 30] (a Cepheid variable).
Clear skies, Dale.
-----Original Message----- From: utah-astronomy-bounces@mailman.xmission.com [mailto:utah- astronomy-bounces@mailman.xmission.com] On Behalf Of erikhansen@thebluezone.net Sent: Sunday, January 16, 2011 10:55 AM To: Utah Astronomy Subject: Re: [Utah-astronomy] RE Cepheids
Dan,
So what you are saying is that there have been enough measurements to keep Cephied distance values as valid?
It would seem that any changes in Cephied luminosity values could easily be applied to Hubble's calculations to adjust that constant if it needs to be. It would be shame if Sandage's lifetime work was thrown out.
They did apply a lot of mathematical corrections for atmospheric conditions and they did suspect Cephieds where shedding material as they moved threw space. They just had no proof. I imagine the Spitzer Scope has simplified the corrections some a deal. IE, atmospheric conditions no longer need be considered. One thing is for certain cosmologist are excellent in Math.
Erik
The Cepheid distance scale has required statistical help to give us an
accurate distance to M31. The initial value of the distance has been corrected by a factor of 2 from the time that the first Cepheid measurements were done with the 100 inch on Mount Wilson.
The best atmospheric resolution prior to adaptive optics was seldom less than an arc second. At the distance of M31 that means a cone of space 10 light years accross. That is wide enough to pick up stray stars within M31 that are in front of or behind the Cephied being studied. These strays are too dim to be resolved as companions but still bright enough to mess up the measurement of the Cepheid.
This was resolved by statistics. Take the distance value to M31 from dozens of different Cepheids and the numbers will give a broad range of values. But this range will have a hard edge at the upper end where you have a few samples with no stray light from optical companions.
It took awhile but that's how we resolved the present value of distance to M31. It's also the reason why the supernovae distance scale is based on thousands of sample points. So we can calibrate the scale to a much higher degree over time. It's also the reason that the SDSS is doing the spectrum on millions of galaxies not just a few dozen.
Statistics. It's where the rubber meets the road in science.
DT
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Dale Hooper -
daniel turner -
erikhansen＠thebluezone.net -
Joe Bauman -
Stephen Peterson