Page 2 of 2
Re: APOD: The Einstein Cross Gravitational Lens (2013 Jan 02
Posted: Wed Jan 02, 2013 11:24 pm
by bystander
quigley wrote:Since this image is rather "old" as has been pointed out, are there any more recent, more detailed, that may be posted instead for the next go-around of the Einstein Cross Gravitational Lens? Maybe some false-color image that more clearly illustrates the structures of the quasar and the galaxy?
Here is a more recent image from Hubble (Jan 2012).
Re: APOD: The Einstein Cross Gravitational Lens (2013 Jan 02
Posted: Thu Jan 03, 2013 12:06 am
by Liohina
What about that faint nebula-like image, shaped like a barred-spiral galaxy, in front of everything else in the picture? Is that a cloud in our own galaxy, and artifact of the photography, or what?
Also, there was an article some years ago - in Scientific American, if I remember correctly - which explained that the basic architecture of gravitational lensing produces five images of the source object...which seemed kind of odd to me. But I've never seen any corroboration of that since then. What's the story on that?
Re: APOD: The Einstein Cross Gravitational Lens (2013 Jan 02
Posted: Thu Jan 03, 2013 12:14 am
by saturno2
The Einstein Cross is an illusion optica.
The light from the quasar is descomposed by the gravitational field of the
galaxy, and we see 4 objects but do not exist in reality.
Re: APOD: The Einstein Cross Gravitational Lens (2013 Jan 02
Posted: Thu Jan 03, 2013 12:24 am
by Chris Peterson
Liohina wrote:What about that faint nebula-like image, shaped like a barred-spiral galaxy, in front of everything else in the picture? Is that a cloud in our own galaxy, and artifact of the photography, or what?
That's the galaxy that is creating the gravitational lens.
Re: APOD: The Einstein Cross Gravitational Lens (2013 Jan 02
Posted: Thu Jan 03, 2013 11:21 am
by RedFishBlueFish
Chris Peterson wrote:ritwik wrote:the mainstrem explanation is that it is because of "uneven mass distribution" in the intermediary galaxy.
The definition of "mainstream" is such that if you have a problem with it, the burden is largely on you to demonstrate its deficiencies, not on the mainstream to defend its position. In fact, the mainstream position is a solid one, supported by many refereed papers (look up 'quadrupole gravitational lens').
The above website is operated by a crank, and is chock-full of pseudoscience. It does not bear discussion, and indeed, any real discussion of this kook's ideas is likely to violate the rules of this forum.
One is entirely sympathetic with the statement that "The definition of 'mainstream' is such that if you have a problem with it, the burden is largely on you to demonstrate its deficiencies..." after all, extraordinary claims require ...
However, one is not at all sympathetic with the statement "... any real discussion of this kook's ideas is likely to violate the rules of this forum" which carries with it an implicit threat.
I believe that "real discussion" is always of value. Real discussion is truly the only path to understanding between peoples. I have not, nor am I likely to seek out the above website as, putting my faith in your professional opinion, it most likely is, as so many sites are, a platform for pseudoscience. However, if someone did wish to discuss the ideas/claims/assertions made there I find it more than passing strange that such discussion could not take place here. What better place to discuss the difference between science and pseudoscience (the demarcation problem which has bedeviled science and philosophy for a very long time) than such a venue as this.
I am willing to wager that the vast majority of users of this forum are neither astronomers, astrophysicists nor scientists of any description. I certainly am not, I fly airplanes for a living. But everyone who participates here is interested in science and astronomy and this is an opportune place for scientists to speak to a willing audience about what the scientific explanation for something is, and why some other explanations for a given phenomenon are founded on pseudoscience - it is unfortunate that this rare opportunity for such discussion is apparently not to be realized.
One is reminded of Tom Paine's observation that "It is error only, and not truth, that shrinks from inquiry."
Re: APOD: The Einstein Cross Gravitational Lens (2013 Jan 02
Posted: Thu Jan 03, 2013 11:39 am
by owlice
This is a mainstream science forum; discussion of alternative theories is generally not welcome (and is indeed prohibited by the rules), as there are many other (oh, soooo many other!) places to discuss them.
Re: APOD: The Einstein Cross Gravitational Lens (2013 Jan 02
Posted: Thu Jan 03, 2013 3:16 pm
by Chris Peterson
RedFishBlueFish wrote:However, one is not at all sympathetic with the statement "... any real discussion of this kook's ideas is likely to violate the rules of this forum" which carries with it an implicit threat.
I believe that "real discussion" is always of value...
To a degree, you are correct. But the reality is, there are thousands of Internet cranks out there, and a forum like this would become hopelessly cluttered if all were treated as legitimate sources of information. I believe the moderators here generally provide reasonable leeway. For instance, an honest, topical question based on something a crank says would probably be allowed to stand. A back-and-forth discussion probably not, and simply holding up a crank website as a legitimate scientific source is neither welcome nor, generally, allowed.
As Owlice says, there are many forums out there for those who wish to discuss scientific ideas outside the mainstream (which mostly means pseudoscience). It is refreshing that this forum sticks largely with the same sort of science (and rules of discussion) encountered in the professional scientific community.
Re: APOD: The Einstein Cross Gravitational Lens (2013 Jan 02
Posted: Thu Jan 03, 2013 3:26 pm
by 60moo
And Chris / Owlice, when the mainstream itself agrees that the mainstream theory / model is incomplete, engendering at best a consensus belief, then is any challenge to the theory / model, using scientific principles e.g. observation - from people who are not convinced of the theory - generally not welcome for discussion on Starship Asterisk?
Just asking a general question.....
Re: APOD: The Einstein Cross Gravitational Lens (2013 Jan 02
Posted: Thu Jan 03, 2013 3:45 pm
by Chris Peterson
60moo wrote:And Chris / Owlice, when the mainstream itself agrees that the mainstream theory / model is incomplete, engendering at best a consensus belief, then is any challenge to the theory / model, using scientific principles e.g. observation - from people who are not convinced of the theory - generally not welcome for discussion on Starship Asterisk?
Just asking a general question.....
Perhaps this forum needs a good FAQ on what constitutes crank science and pseudoscience.
There is a huge difference between discussing the incomplete nature of most complex scientific theories, and filling in the blanks in those theories with unsupported ideas from self-published "scientists" who believe that GR is wrong and that the scientific community is out to get them. Those ideas are not welcome here.
"Mainstream" does not mean "consensus". Ideas that are not widely accepted are welcome here, as long as those ideas are coming from people with the training to properly develop them, and as long as those ideas have been at least partially vetted by passing through the peer-review and publication process.
Re: APOD: The Einstein Cross Gravitational Lens (2013 Jan 02
Posted: Thu Jan 03, 2013 4:00 pm
by owlice
Chris Peterson wrote:ideas have been at least partially vetted by passing through the peer-review and publication process.
This is key.
I've had conversations with a number of people (who have posted here) who have theories and want to know how to get them considered and accepted. I tell them to write their research up and submit the resultant paper to peer-reviewed publications. Publishing on one's own website doesn't, in and of itself, count for anything. Writing a book, in and of itself, doesn't count for anything. Having a book published, in and of itself, doesn't count for anything. The standard for science is higher than all of these.
That higher standard -- reproducible research, with methods, data, and results open for examination, written up, submitted and accepted to peer-reviewed publications -- needs to be met. It doesn't mean that all papers are correct, that amateurs don't make important contributions, that all conclusions are right, but does ensure that science is ultimately self-correcting. If someone has ideas, theories, whatever, and will not submit them for this kind of scrutiny, this is not the place to discuss those ideas, theories, whatever.
Re: APOD: The Einstein Cross Gravitational Lens (2013 Jan 02
Posted: Thu Jan 03, 2013 9:28 pm
by Ron-Astro Pharmacist
There is so much we have yet to learn about the objects we view in the sky. An object so far away as a quasar would have been unimaginable 150 years ago. I won't be around in another hundred years. But I would bet there are questions we can ask today that will have sounded very strange but have a fundamental backgrounds at that time. I am not saying all questions will turn out to be reasonable but logical questions might a have a better than average chance than illogical questions.
I appreciate this website and understand the need for keeping it's content within the relm on know science. I am sure I am not the only person who has contributed ideas outside that relm. I will again strive for that goal but some ideas just seem too interesting to keep to yourself. Sorry about that. Thanks for all the work you and your contributors do to increase our knowledge of this amazing place we find ourselves.
![Smile :)](./images/smilies/icon_smile.gif)
Ron
Re: APOD: The Einstein Cross Gravitational Lens (2013 Jan 02
Posted: Fri Jan 04, 2013 4:07 am
by owlice
RedFishBlueFish wrote:I am willing to wager that the vast majority of users of this forum are neither astronomers, astrophysicists nor scientists of any description.
That is, indeed, the case. (No one paying attention would take your wager, I'm sure!) There are a few scientists here; neufer and Chris, mainly, with a few others making occasional appearances.
Re: APOD: The Einstein Cross Gravitational Lens (2013 Jan 02
Posted: Fri Jan 04, 2013 4:21 am
by geckzilla
We try to let people say what they want but I'd hate to see this place deteriorate into the endless loops of banality that the pseudoscience arguments create. I also think eliminating and squelching those discussions actually helps people tell the difference between pseudoscience and mainstream science. Some people link to the websites without realizing what it is while others attempt to be forum warriors and martyrs. Educating the former and banning the latter keeps the forum nice and informational.
Re: APOD: The Einstein Cross Gravitational Lens (2013 Jan 02
Posted: Sun Jan 06, 2013 3:30 am
by ron-astropharmacist
I'd agree Owlice. It's a bet I wouldn't it take either. It shouldn't been wagered. The cost to credibility wasn't worth the price. Not that a non-professional deserves credibility. Obviously re-posted on your open website hasn't attracted an answer to my question. What a great opportunity posting offers to us but it's not something to use willy-nilly. I am again finding my place. Ron
Re: APOD: The Einstein Cross Gravitational Lens (2013 Jan 02
Posted: Thu Jan 24, 2013 5:47 pm
by Ron-Astro Pharmacist
Owlice - I like the pictogram or rebus you use on your posts but this APOD is a pretty good representation too...
http://apod.nasa.gov/apod/ap041121.html
Ron
Re: APOD: The Einstein Cross Gravitational Lens (2013 Jan 02
Posted: Thu Jan 24, 2013 10:14 pm
by Beyond
Shazzam
![Exclamation :!:](./images/smilies/icon_exclaim.gif)
I know owlice is the Gardian of the Codes here on the Asterisk*, but i had no idea at all that there is also a space owl (relative?) that is the Gardian of the Cosmic Codes. I wonder if SETI has ever picked up a hoot or two, but just didn't realize it?
![Mr. Green :mrgreen:](./images/smilies/icon_mrgreen.gif)
Re: APOD: The Einstein Cross Gravitational Lens (2013 Jan 02
Posted: Fri Jan 25, 2013 1:39 pm
by owlice
Ron, thank you, and I like that representation, too! It's a lovely image, and yes, quite owlie!
My Great Horned Owl picture was taken by my then-10-year-old son with a video camera; he was playing with the zoom, and one frame of the video is that shot. No cropping; the shot is all owl face. I love the shot.