Dark Matter

[glenc]

Todays amazing APOD image seems to show dark matter.
http://antwrp.gsfc.nasa.gov/apod/image/0809/macsj0025_chandrahst_big.jpg
Explanation: What happens when two of the largest objects in the universe collide? No one was quite sure, but the answer is giving clues to the nature of mysterious dark matter (http://imagine.gsfc.nasa.gov/docs/science/know_l1/dark_matter.html). In the case of MACSJ0025.4-1222 (http://www.nasa.gov/mission_pages/chandra/news/08-111.html), two huge clusters of galaxies (http://en.wikipedia.org/wiki/Galaxy_cluster) have been found slowly colliding (http://antwrp.gsfc.nasa.gov/apod/ap040612.html) over hundreds of millions of years, and the result has been imaged by both the Hubble Space Telescope (http://antwrp.gsfc.nasa.gov/apod/ap010806.html) in visible light (http://science.hq.nasa.gov/kids/imagers/ems/visible.html) and the Chandra Space Telescope (http://en.wikipedia.org/wiki/Chandra_X-ray_Observatory) in X-ray light (http://en.wikipedia.org/wiki/X-ray). Once the above visible image was recorded, the location and gravitational lens distortions (http://antwrp.gsfc.nasa.gov/apod/ap040807.html) of more distant galaxies by the newly combined galaxy cluster allowed astronomers to computationally determine what happened to the clusters' dark matter (http://en.wikipedia.org/wiki/Dark_matter). The result indicates that this huge collision has caused the dark matter in the clusters to become partly separated from the normal matter, confirming earlier speculation (http://antwrp.gsfc.nasa.gov/apod/ap080823.html). In the above combined image (http://hubblesite.org/newscenter/archive/releases/2008/32), dark matter is shown as the diffuse purple hue, while a smoothed depiction of the X-ray hot normal matter (http://map.gsfc.nasa.gov/universe/uni_matter.html) is shown in pink. MACSJ0025 (http://news.bbc.co.uk/2/hi/science/nature/7587090.stm) contains hundreds of galaxies, spans about three million light years (http://chandra.harvard.edu/photo/cosmic_distance.html), and lies nearly six billion light years away (redshift (http://www.daviddarling.info/encyclopedia/C/cosmological_redshift.html) 0.59) toward the constellation of Monster Whale (Cetus (http://www.hawastsoc.org/deepsky/cet/index.html)).

[CoombellKid]

That's an awesome picture Glen, looks like one extremely big nebulae

regards,CS

[glenc]

Yes 3Mly across, equal to the distance from here to M31. Here is some more info:
http://news.bbc.co.uk/2/hi/science/nature/7587090.stm
"The latest astronomical observations suggest that dark matter makes up some 23% of the Universe. Ordinary matter - such as the galaxies, gas, stars and planets - makes up just 4%. The remaining 73% is made up of another mysterious quantity; dark energy, which is responsible for speeding up the expansion of the cosmos."

[dannat]

AMAZING picture, not sure about the dark matter, could ot it be a few things

[ngcles]

Hi All,

Hmmm ...

The blurb that accompanied the picture had me with furrowed brows when I read it. Particularly:

"MACSJ0025 contains hundreds of galaxies, spans about three million light years, and lies ... "

How do hundreds of galaxies (even baby ones) fit within a space only 3Mly across (ie a little bigger than the distance from here to the nearest major external galaxy -- M31)? I suspect there is a zero or possibly even two zeros missing from the diameter figure here or have I got it wrong ... ?

Best,

Les D

[xelasnave]

Is it not the case that the dark matter is "drawn" in??? in other words the region it is supposed to represent in the photo has been added by reasoning that it must be where it is and so they colour it in that way...it is something we can not see or detect so how else does it appear such we can now see it..not from direct photography I suggest....rather I believe... anyways I think if they draw it in by inference that is a long stretch really...its presence is determined by gravitational influences indicating it is there...but we still do not see it.... if gravity works by push maybe there is no dark matter at all....oif course I was always going to say that....
Magic photo... how small are we...beyond our comprehension
alex

[bojan]

Alex, you are getting yourself in new trouble, and you are not out of woods from the old one (and I am not mentioning lady troubles ;) here)

Dark matter on this "drawing" WAS detected by its gravitational influence on light (bending space-time continuum or gravity pull, whatever you like more) coming from background objects. The fact that it was not "seen" or detected by some other, more "conventional" method (and what is wrong with this one?), means nothing. IT IS THERE.
Period.

[Chippy]

That is one amazing image. The dark matter aspect is interesting too. Don't think I've ever seen that many galaxies all in the one field. It's hard to get a feeling of the scale. But WOW!!!

[sjastro]

You are clutching at straws Alex.

Dark matter (and ordinary matter) can be detected by gravitational lensing.

The ordinary matter at the centre is simply gravitational attraction at work. The distribution of dark matter on either side indicates the direction of movement is largely perpendicular to our line of sight.

The fact that the dark matter component of each cluster has passed through each other is a strong indication that dark matter is largely composed of WIMPS.

A picture tells a thousand words.:)

Regards

Steven

[xelasnave]

I bet that the photo shows no dark matter but only what an artist has drawn in to represent where they believe it to be... we can not see it so I doubt if the photo is fairdinkum if it claims to have actually photograped dark matter...

Well when it started there were machos and wimps..machos have been written off as a none event so if thgere is to be dark matter the straw that they must grasp is the wimp prospect...Wimp..weakly interacting massive particles..I think it stands for...nutrinos are a candidate... but I want them for my gravity push particles:lol::lol::lol:

The models I have tried to work out...with my humble math and hill billy calculus says to me that there is no way you can add material to the outside of a galaxy such as proposed by dark matter and get the unit balanced..it is a case of the more you add the more you need to add...still I could be wrong but if attraction is at play why do they see dark energy as a pushing force??? and attraction can not hold a galaxy together... one needs an external force... again opinions only but in my opinion dark matter is bulldust and any model that needs to have a hiugh percentage of stuff to be beyond our ability to observe it ...well it needs something better... I know they infer where the dark matter is..but that relies on attraction and there is no such thing as attraction...in my view...but push fixes the dark matter problem...we dont need it at all and can have a universe where what we see is what we get...

The Razor says go simple and you have to admit my ideas are simple... ;):lol::lol::lol:

have agood one
alex:):):):):)

[xelasnave]

I can recall seeing Vera Rubin with photographic plates in a photo some 15 years ago holding them up with a caption that they have found dark matter..there was no dark matter then and there is no dark matter on the plates now....well nothing has changed there is still no dark matter recorded on any photographic plate as far as I know...and that is reasonable..because it does not exist other than in the minds of those who wish it to be there.... Given the difficulty of the GR sums I dont know how they could be worked out for the photo under discussion given the many many galaxies... how was the gravitational influence worked out for all those galaxies... I dont buy any part of if... we are expected to nod as if it is fair cop..well think about what I say..the sums..the sums...how could you draw any conclusion given the complexity...

Now I am sure someone may not agree with my view here...maybe

alex

[sjastro]

Yes you can't image dark matter. The blue area has been mapped to define the region of gravitational lensing. The pink area is the X-ray image showing the collision of matter (gas) from each cluster.

If dark matter doesn't exist then the blue and pink areas should be superimposed.



You couldn't pick a worse candidate for a push particle.:lol:

Neutrinos are the byproducts for the fusion of hydrogen nuclei. Instead of acting as a neutrino shield, the Sun becomes a source of neutrinos.Why is it then Mercury is not pushed out of it's orbit? The answer is that neutrinos do not readily interact with matter. That is a scientific fact.



So you keep on telling us. Why don't provide us with a model that shows how push gravity preserves the shape of a spiral galaxy?

I have even a better idea. I challenge you explain how push gravity can cause Type II supernovae. The current mechanism is very easily explained as an elegant combination of nucleur physics and gravity as an attractive force.

Regards

Steven

[xelasnave]

Hi Steven
I have only hit town and have not thought about such an event in fact I will have to read again the types of super nova and how current science explains them but off the top of my head in the push Universe shielding comes about by various things but a Sun spinning more rapidly will present a greater shield and therefore expose itself to higher gravity, in effect, so irrespective of the observations which I have not read really or rather have read and left anything out that may contridicte my current presentation..being realistic and recognising the extreme case of morosophery I carry...I may have read but would rather read again:D this is my short answer:thumbsup::eyepop::whistle:.. . So a Sun spins up presents a greater and greater shield to the flow until finally it implodes I guess in effect...just keep all of the current stuff that agrees with this approach:D

alex:):):)

[sjastro]

Alex,

"Morosophery" is a word I am unfamiliar with, perhaps it has something to do with an expulsion product from a certain type of grazing animal.;)

Regards

Steven

[xelasnave]

:lol::lol::lol:
Your guess is close Steven:thumbsup: however the condition refers to a situation where one has a theory and everything one encounters serves to validate the theory in the mind of the person a victim of the condition:whistle:.

and so for me everything I find supports push:D you see:P and that it the condition in opperation:rolleyes:..I see the Corona of the Sun and explain it as evidence of push..and if one accept the accoustic model indeed push rules;)..accoustic certainly works by push it seems to me:shrug:...

But push is my belief and just as a big bangger will grasp in their observations in support of the big bang so will I try to see everything in support of a push system.

Anyways looking at remnants like the Ant nebula makes me think Stars expolde in the fashion I suggested.

alex:):):)

[xelasnave]

Steven observed...........Neutrinos are the byproducts for the fusion of hydrogen nuclei. Instead of acting as a neutrino shield, the Sun becomes a source of neutrinos.Why is it then Mercury is not pushed out of it's orbit? The answer is that neutrinos do not readily interact with matter. That is a scientific fact.
'
Without commenting on Mercury or the perceived problem with a shield via the manner considered I think that nuetrinos will react with matter..they do with dry cleaning fluid I believe

alex:):):)

[sjastro]

You don't have to invent the word Alex. There's one already available, it's called prejudice.;)
It's also called anti-rationalism where one argues via opinion and not fact.



A perfect example. The facts don't seem to count in your line of thinking.

As I have mentioned on a couple of occasions the solar corona varies with the sunspot cycle which would not occur if push gravity is the mechanism.

Yet you continue to expound this point of view.



Sorry to correct you (again) but Planetary Nebulae are not the result of a Type II supernova. And your suggestion that a star that spins up may result in an explosion coveniently contradicts the conservation of angular momentum. The only way a star can greatly increase it's spin is for it's diameter to collapse.

For a type II supernova, the core collapses, the actual diameter of the star prior to the explosion does not change substantially.

Regards

Steven





alex:):):)[/quote]

[DARKMATTER]

You Rang?

[xelasnave]

Thank you Steven for your guidance.
However there is nothing you have said so far that sways me in any regard at all... I have no care that my view may be wrong in the eyes of others that is irrelevant to me..my opinion is mine and I find no difficulty in the fact there are many who can point to it being absolutely wrong.

You said........
You don't have to invent the word Alex. There's one already available, it's called prejudice.
It's also called anti-rationalism where one argues via opinion and not fact.

I think Morosophic is the word that applies...I did not invent it but it was put to me by a young physics student who felt I had all the symptoms..I could only agree as I do see push as being the way it is and that any observations fit the notion of push..and so I ask how different am I to others wgho gring their axe..big bang relies heavily upon the background radiation and yet it is clear certain galaxies appear to be in front of this radiation..do you see the problem ..well one should but big bangers do not seem to want to consider the problem because if the observations are sound the big bang is dead... and so I say I am not the only person who suffers the affliction of morosophia...

Predjudice is not an appropriate word in my view as for me it carries a suggestion of underlying hate..I dont hate the big bangers or physisists and I cant see how I am in any way predudiced but if you like the application of the word to my manner that can be you reality however it is not mine.

Steven said
As I have mentioned on a couple of occasions the solar corona varies with the sunspot cycle which would not occur if push gravity is the mechanism.

Sun spots are parts of the suface that are a result of the flow seeking to past thru the Sun..areas of higher concentration..look at a vidio and you can see what I mean...but this is my view and as far as I know this view does not have world wide support:whistle:

You said also...

Yet you continue to expound this point of view.

Of course I will..it is my view the fact that someone presents me with evidence they like does not mean I have to like it and indeed accept it....
I will expound my point of view whilst I believe in it..why wouldnt I do such?

Steven observed.........
Sorry to correct you (again) but Planetary Nebulae are not the result of a Type II supernova.
I did not mean to infer such..I had no idea what explosion created it but I selected the Ant Neb simply because if one studies it and tries to rewind the explosion it would appear that the star had been compressed at the equator and blew apart in effect in two sections...this is in my view possible evidence that as the star spins up the pressure at the equator becomes such that the star is pushed in two ....

I feel if we could talk in person my ideas would be communicated better and they may not appear as strange as they do in text.... I can expalin everything via push in my limited way and it adds up to me..morosophic or not that is the way it is for me...thanks for your interaction and i8nteresting input.

alex:):):):)

[bojan]

Alex, I said it before and I am repeating it here again:
You are talking religion here, not science.
This is a science thread, as it is clearly stated in the header:

Astronomy Science (http://www.iceinspace.com.au/forum/forumdisplay.php?f=19) (1 Viewing)
Discussions related to the Science of Astronomy, Space Exploration etc. Strictly moderated - stay on-topic, serious discussions please.

I have no more comments.

[xelasnave]

Bojan said.....
You are talking religion here, not science

I may not be scientific but what I am on about is not about religion.... I dont believe in it or that there is any supreme who created everything...
I reject the notion my views are religious and say I have the right to believe what I like..it is not as though I have approached my subject with outregaurd for what is currently available ..GR says there is no force...Newton says gravity is the force of God... I find it ammussing that you can thereofre say I am the religious one here..

Still if science regards further thought or explanation as to the actual force of gravity offencive because the current science can not take it further that is a problem for science not me...

I openned a thread in general chat which has had no takers so it seems it is not a matter for general chat either...and so I will leave off further talk about my ideas ....when you think I am being unscientific please have a look thru the stuff out there from scientists who are publishjed and tell me how statementsd of believe...re inflation, time travell via a black hole, and the possiblity of communication with another dinmention via a gravity wave present as serious science.... my views are somewhat subdued in comparrision I feel.

alex

[bojan]

Alex,
Do not take my reply as an offense, please..

Religion does not necessarily imply belief or discussion about supreme being.
Rather, it is a method used to explain things around us.

Scientific method assumes experiment (or observation of certain phenomena), hypothesis to explain them, more experiments to confirm hypothesis, working theory, prediction of new phenomena that follow from theory, confirmation of those predictions by even more experiments, acceptance of theory, and then back to the beginning, for re-checking. All in that order, no step should be missed, and all that must be possible to be repeated by anyone [properly equipped with tools (math and others) of course].

Your method is hypothesis, acceptance of hypothesis and then extrapolation to everything else, without any experimental confirmation, and without looping back.
This is what I call religious approach, and it is certainly not scientific.
By all means you have the right to your opinions, but please do not discuss them here, because this is supposed to be the discussion forum for scientific stuff, as mentioned in the header.

[sjastro]

From the point of reference of any observer in the Universe all galaxies are in front of the Cosmic Radiation Background (otherwise it wouldn't be a background:)).

So I assume your claim is that certain galaxies predate the photons that ultimately formed the background. I'd be interested if you posted this information.



Here is one of the definitions of prejudice from Dictionary.com

1.an unfavorable opinion or feeling formed beforehand or without knowledge, thought, or reason.



Unbelievable! Once again theory invented on the run........

It's pointless continuing this debate any further.

Regards

Steven

[xelasnave]

Steven said.......

From the point of reference of any observer in the Universe all galaxies are in front of the Cosmic Radiation Background (otherwise it wouldn't be a background

Sorry Steven re reference to background radiation the galaxies I was refering appear not in front but rather behind the backgro0und radiation:eyepop:...


I am sure you must be aware of these observations... it has been out there for a while... University Alabama (I will get I link for you if I have time but a goggle will turn it up)...again I did not accept that at face value because of the geographic location of the University and my concern that being in the bible belt certain results would have been welcomed more than others..the question is.... were the researchers under any pressure to down the big bang because the University board may have been all christian:shrug:.. I dont know :shrug: but my point is even though the research on the galaxy shadowing was above board I still consider they may be right or they may be wrong.. I am not set in my views, well not set the way it must be perceived by folk here... I think I am open minded and accepting of all propositions.

May I point out Steven that I did not call my idea "a theory" re Sun spots nor have I called my ideas re gravity a theory..a theory requires certain things to be a scientific theory which I have more than once addmitted as to these requirements I am inadequate (predictions, math etc)... my thoughts on gravity are ideas and I have always said so...I would never call my ideas a theory because I have seen the use of the word corrupted ...as in say in the case of calling the "idea" re "inflation" a theory..it is not a theory other than in the way a layman would use the word..it is an idea, it is no matter how important for the big bang still an idea..so why let it be called a thoery...why? ... however given that the idea of inflation was really needed to save the big bang it was quickly elevated to the status of theory... now Steven you like having a go at things that I say that you feel are wrong well if I am wrong with my assessment of the "inflation theory" please say so... your views have as much right as mine to be aired.. I have made a claim and I welcome your efforts to reject it...and if inflation is only an idea the steady state theory has as much right to presentation as does the big bang theory..



However I feel there can be no debate upon the propostion I just presented.
Not that I have considered anything in this thread as the material of a debate and for my part I would like to think I do not present my views in such a manner that it appears that I seek to exclude any others... and if it appears as such I appologise for it is not my thing..I dont care that I am the only person who likes my idea ..it is not a problem.


Maybe I missed the experiments offerred in support of the "inflation theory" and am happy to be informed that I am not up to speed on what they have done to establish their idea as a theory.

I am not against the big bang as such but from my view no one asks the hard questions..it is accepted as fact...I think there has to be a better way to arrive at what inflation seeks to solve however by blindly accepting the idea without testing then a more valid answer may escape us simply because we accepted an idea with no support.

AND given we are looking into events that are some 13 plus billion years old (accepting big bang time frame) it is extremely presumptious for anyone to say they know exactly what happened....yet they do:lol::eyepop:.. if they are not all knowing and God like such an approach can only be regarded as foolish and arrogant... there is no way of proving beyond doubt how the Universe came into existence... observations and experiment may fit the theory but such in itself still does not take us back to the start..we think we know but we should be humble enough to admit that we are after all guessing... sophisticated guessing but there is no higher plane I can elevate the process to... and so I have no problem in not falling down and worshipping the knowledge handed to me by someone who tells me they know it all.... maybe they do but I doubt it.

Anyways thats my view..I dont say that my view is correct and there can be no other views ..which I must say seems very much where you come from..and that is neither right or wrong it is just the way I perceive you approach things......

I dont throw out the big bang but I think they have been hasty in accepting evidence as clear support, background radiation for example is cited as absolute support and yet the aspect of galaxy shadowing has not been addressed as far as I know....

I am sorry however that my ideas can be seen as so difficult to discuss for some... I dont care who is right or wrong but I do enjoy hearing folks views even if they are different to mine ...

Anyways it has been nice chatting.

alex:):):):)

[sjastro]

Alex,

There are theories and there are thought experiments (or ideas).

In the simplest terms a theory is a concept to explain observation or experimental data. It may also allow specific predictions to be made which can be later verified by observation or experiment.

The BB falls into this category. The theory and the mathematics of the BB is built around the observation that galaxies are moving away from us. The Cosmic Radiation Background was predicted in 1948 and verified in 1965. The BB also correctly predicted the percentage breakdown of Hydrogen and Helium in our Universe.

A thought experiment in Physics can involve extrapolating theory into areas that cannot be defined by observation or experiment. A good example is time travel through wormholes.

The important point about thought experiments is that the laws of physics are not violated.

Unfortunately your ideas are not even thought experiments as they consistantly violate even the most basic principles in Physics.



You continuously bring up inflation theory as a way of saving the BB. May I suggest you read up on the subject. The whole point of inflation theory is to explain why the Universe ended up flat. The BB predicts three possibilities for the Universe, open, flat or closed depending on it's density.
Inflation theory is an outcome of the BB.

There are some scientists that claim we don't even need inflation theory by invoking the Anthropic principle. If the Universe wasn't flat we wouldn't be here to observe it.



This is what I found on the net regarding galaxy shadowing.
http://www.physorg.com/news76314500.html

If the microwave background is not the result of the BB and is closer to us, than the resultant background must be caused by photons being emitted by some form of intervening matter.

Galaxy clusters behind the background would have their photons scattered by this matter much like the effect of interstellar reddening. If this is not observed it is unlikely the cluster is behind the background.

If this is so the problem lies with the data or the theory about galaxy shadowing.

Regards

Steven

[xelasnave]

Thanks for the link Steven.
I did not call my idea even a thought experiment again it is my idea of how I believe things work.
I will read more of course and thank you for your help in guiding me. I do appreciate what you do for me.
I still have no net conection but I now have a new lap top at least... I tried to get a pre paid telstra connection but in two places they have sold out...I think I will buy some cheap dvd,s and relax with them...
Thank you for taking the time and although you may think I am a lost cause assure you that I like these matters and in my defence at least try to think things thru using the little informsation I pick up from the net...
regards

alex:):):)