Expansion of our universe (solar system).

Cú Giobach

rccaulfield wrote: »

To get back to the minumum distance that the expansion can be observed- 3000 mega parsecs. Andromeda is less then 1 mega parsec away so this rules out alot of the galaxies we are familiar with. Question arises, are the majority of things within this range blue shifted or not biased toward being red and blue shifted? I'd expect them certainly not to biased toward being red shifted if the expansion doesn't hold within this range and so gravity at the galactic scale can work unimpeded? .

Andromeda is 2 million ly away , 3000 mega parsecs is nearly 10 billion ly away, mull that one over

Here is a nice image to give an idea of scale. Note the scale showing a mere 100 million ly. The individual dots wouldn't even by single galaxies but clusters.

psychward

The Hill Billy wrote: »

The Universe has a finite amount of matter & energy (as far as I am aware).
It is by measuring these that we see the expansion of the Universe at a cosmic level.

what about Dark matter ? Theres a lot in the universe we can't see. That in itself doesn't prove anything but everything we see from our perspective could be illusory and a measurement error when measured from our limited constrained perspective of being stuck here. How do we know that immensely far away in some Dark zone that there isnt' another immensely huge region expanding towards us as we expand towards it ? (Even the word immense isn't immense enough to describe what I mean when I use the word immense)

rccaulfield

The Hill Billy wrote: »

The Universe has a finite amount of matter & energy (as far as I am aware).
It is by measuring these that we see the expansion of the Universe at a cosmic level.

So, is the expansion of the Universe due to increased distance between matter OR is it that the matter itself is expanding? (Ie, the relative space between atomic components is increasing.)

If is was the latter, then this would mean that it would be impossible to measure at a local level.

But if matter was expanding then the clumps of matter wud approach each other(picture the 6 and the 7 on your keyboard expanding while stationary- they will meet! Again impossible to measure at a local level but when/where does it suddenly start to be observable from earth?

Cú Giobach wrote: »

Andromeda is 2 million ly away , 3000 mega parsecs is nearly 10 billion ly away, mull that one over

Here is a nice image to give an idea of scale. Note the scale showing a mere 100 million ly. The individual dots wouldn't even by single galaxies but clusters.

Well then surely the 3000 mega parsecs figure is wrong. When hubble first gauged the red shift of galaxies they were/are all much much closer! To repeat my question on our own galaxy, did he find alot of our local stars were red shifed?

psychward wrote: »

what about Dark matter ? Theres a lot in the universe we can't see. That in itself doesn't prove anything but everything we see from our perspective could be illusory and a measurement error when measured from our limited constrained perspective of being stuck here. How do we know that immensely far away in some Dark zone that there isnt' another immensely huge region expanding towards us as we expand towards it ? (Even the word immense isn't immense enough to describe what I mean when I use the word immense)

Alot of followers of the standard model do feel that dark matter/dark energy is a bit of an add on that hasn't been justified at this point, not a fan myself but if it agrees with experiment it's right doesn't matter what anyone thinks!

Anonymo

rccaulfield wrote: »

But if matter was expanding then the clumps of matter wud approach each other(picture the 6 and the 7 on your keyboard expanding while stationary- they will meet! Again impossible to measure at a local level but when/where does it suddenly start to be observable from earth?

Well then surely the 3000 mega parsecs figure is wrong. When hubble first gauged the red shift of galaxies they were/are all much much closer! To repeat my question on our own galaxy, did he find alot of our local stars were red shifed?

Alot of followers of the standard model do feel that dark matter/dark energy is a bit of an add on that hasn't been justified at this point, not a fan myself but if it agrees with experiment it's right doesn't matter what anyone thinks!

Hill Billy: The point that it is not matter itself that is expanding has been explained ad nauseum in this thread so I'm not going to repeat it again.

rccaulfield: the figure is not wrong. But that is the figure of the hubble horizon today. When you peer through a telescope you are looking back in time! The size of the hubble horizon is smaller further back in time. For instance redshift one galaxies sent the light we see in our telescopes around 7 billion years ago. We do not see this expansion in our local galaxy since it is clumped together. We can see the fact that the universe has expanded by the fact that the wavelength of light has stretched (gotten redder) as it has passed through the universe on its path to us. Even those stars that have a redshift factor of 0.1 are around 1 billion light years away!

The standard model describes the strong, weak and electromagnetic forces. By definition adding dark energy to the mix is an add on! As for dark energy - there is abundant evidence of its existence due to the rotation speeds of the spiral arms of galaxies. They are moving so fast that unless there was a lot more mass than we observe present they would have blown themselves apart.

rccaulfield

Anonymo wrote: »

Hill Billy: The point that it is not matter itself that is expanding has been explained ad nauseum in this thread so I'm not going to repeat it again.

rccaulfield: the figure is not wrong. But that is the figure of the hubble horizon today. When you peer through a telescope you are looking back in time! The size of the hubble horizon is smaller further back in time. For instance redshift one galaxies sent the light we see in our telescopes around 7 billion years ago. We do not see this expansion in our local galaxy since it is clumped together. We can see the fact that the universe has expanded by the fact that the wavelength of light has stretched (gotten redder) as it has passed through the universe on its path to us. Even those stars that have a redshift factor of 0.1 are around 1 billion light years away!

The standard model describes the strong, weak and electromagnetic forces. By definition adding dark energy to the mix is an add on! As for dark energy - there is abundant evidence of its existence due to the rotation speeds of the spiral arms of galaxies. They are moving so fast that unless there was a lot more mass than we observe present they would have blown themselves apart.

Agreed but thats if our current understanding of the universe and general relativity is 100% correct. I'd hazard a guess that in a million years the theory won't read the same(modified in some way), but thats idle spec!

Forgive but i'm confused on the minimum noticeable distance of the expansion. Which i suppose is the crux of the thread. Earlier you mentioned 3000 mega parsecs yet in this post you speak of galaxies 1 billion light years away having a red shift factor of 0.1. I appreciate the point about inflation and that the distance the light started out at has increased vastly, but surely those 2 figures contradict? On that point how did Hubble get on with galaxies below that threshold you give?

Cú Giobach

rccaulfield wrote: »

On that point how did Hubble get on with galaxies below that threshold you give?

Here are a few graphs of some of Hubble's measurements if you're interested. Not sure how relevant they are for you, but there you go anyway
Clicking on each one will bring you to a larger image.





Taken from here and here.

rccaulfield

Cú Giobach wrote: »

Here are a few graphs of some of Hubble's measurements if you're interested. Not sure how relevant they are for you, but there you go anyway
Clicking on each one will bring you to a larger image.





Taken from here and here.

Thanks! They are at a starting range of 1 megaparsec up to 200 where the red shift/velocity starts to look very uniform? What gives thats much closer then 3000 megaparsecs?

Cú Giobach

rccaulfield wrote: »

Thanks! They are at a starting range of 1 megaparsec up to 200 where the red shift/velocity starts to look very uniform? What gives thats much closer then 3000 megaparsecs?

Can't answer that question myself rc, just about everything I know (or at least think I know) on this subject is written here already

maguffin

Anonymo wrote: »

that old chestnut! the universe isn't expanding into anything -

Just reading through this thread and noticed the above....surely it is against all the 'Laws' to state that something is expanding into nothing? and is it not a contradiction to state:

The expansion of the universe is not expansion INTO something; rather it is the expansion OF something.

if you consider that (in Nature) any system that expands MUST expand into something (otherwise how can it expand?)

Just thought I'd ask....(please don't hit me :0( )

maguffin

Cú Giobach

maguffin wrote: »

Just reading through this thread and noticed the above....surely it is against all the 'Laws' to state that something is expanding into nothing? and is it not a contradiction to state:



if you consider that (in Nature) any system that expands MUST expand into something (otherwise how can it expand?)

Just thought I'd ask....(please don't hit me :0( )

maguffin

If the universe is infinite it can't expand "into" anything, because if it goes on forever there is no outside.
If it is finite the simple answer is nobody really knows what could be "outside", because the absence of space and time is inconceivable to us but, by definition "outside" the universe would be a place where there is no space, no time, in fact no "anything" and if there is no-anything (nothing) there is no outside.

AugustusMinimus

maguffin wrote: »

Just reading through this thread and noticed the above....surely it is against all the 'Laws' to state that something is expanding into nothing? and is it not a contradiction to state:



if you consider that (in Nature) any system that expands MUST expand into something (otherwise how can it expand?)

Just thought I'd ask....(please don't hit me :0( )

maguffin

Our universe is expanding into something.

Think of it like this. Our universe has 4 dimensions. The ordinary 3 we can see and time. The universe is expanding along the 4th time dimension. In turn, this means that the other 3 dimensions are also expanding.

Think of it with the baloon idea. 2 dimensional spacial universe, which is the surface of the baloon, with the surface to the centre of the baloon being time.

As the baloon expands, it is expanding into the future. Hence, everything inside the surface of the baloon is the past. There could be an infinite amount of baloons inside the surface we live in with big bangs constantly happening.

On the other hand, there would also be an infinite amount of baloon surfaces ahead of us in the future which are also expanding. Hence, we are expanding along the time dimension into a space previously occupied by future shells.

This of course could mean that there's an infinite amount of 3 dimensional universes for every point in history and every point in the future and that there are an infinite amount of big bangs happening. Hell, they are still happening, just in the past.

maguffin

Cú Giobach wrote: »

If the universe is infinite it can't expand "into" anything, because if it goes on forever there is no outside.

This implies that if we accept the 'infinite universe' then the whole expansion theory is null and void (because it can't expand).

If it is finite the simple answer is nobody really knows what could be "outside", because the absence of space and time is inconceivable to us but, by definition "outside" the universe would be a place where there is no space, no time, in fact no "anything" and if there is no-anything (nothing) there is no outside.

Indeed, if it is inconceivable to us and no one really knows...then the reference to 'by definition...' is negated and allows for the possibility that an 'as yet not defined' space exists into which the universe is expanding.

Cú Giobach

maguffin wrote: »

This implies that if we accept the 'infinite universe' then the whole expansion theory is null and void (because it can't expand).

Think of the numbers 1,2,3,.....on to infinity.
Now stick in the .5's also 1,1.5,2,2.5,3,3.5.........you have just expanded your infinity.

Indeed, if it is inconceivable to us and no one really knows...then the reference to 'by definition...' is negated and allows for the possibility that an 'as yet not defined' space exists into which the universe is expanding.

If we don't know something then there are many possibilities.

I just wan't to add here, often people try to conceive and visualise something that is more than likely inconceivable to the primate brain, I think lesson #1 in cosmology is "leave your common sense, classical view of the world at the door".

maguffin

Cú Giobach wrote: »

Think of the numbers 1,2,3,.....on to infinity.
Now stick in the .5's also 1,1.5,2,2.5,3,3.5.........you have just expanded your infinity.

For the sake of argument, let's liken infity to a 1 foot ruler (I know...)...the ruler is 12" long (1 foot)....if we 'stick in' (as you put it above) our 1" divisions..we still have 12"...if we stick in our 0.5" divisions between the inches.. we still have 12" (ie..no expansion)...and so forth for as many sub-divisions as you like within our (notional) 12" 'infinity'. My point is that you are not actually 'sticking in' anything additional...you are merely dividing and labelling that which already exists....therefore no expansion.

Cú Giobach

maguffin wrote: »

For the sake of argument, let's liken infity to a 1 foot ruler (I know...)...the ruler is 12" long (1 foot)....if we 'stick in' (as you put it above) our 1" divisions..we still have 12"...if we stick in our 0.5" divisions between the inches.. we still have 12" (ie..no expansion)...and so forth for as many sub-divisions as you like within our (notional) 12" 'infinity'. My point is that you are not actually 'sticking in' anything additional...you are merely dividing and labelling that which already exists....therefore no expansion.

You cannot divide up infinity, half of infinity is still infinity. The finite ruler analogy wont work with infinity (it is a very messy concept).
There are also infinities of different sizes.
Check out this or try and get your head around this.

Cú Giobach

OK, that was wrong there.
You can't expand infinity, but you can expand the amount of space in an infinite universe, every point can move away from every other point to infinity, therefore constantly increasing the distance between every point, if every point in the universe is now further away than it was from every other, you have expanded space.

rccaulfield

Cú Giobach wrote: »

Can't answer that question myself rc, just about everything I know (or at least think I know) on this subject is written here already

No probs, thanks for filling my head with some of your knowledge on the subject!

rccaulfield wrote: »

Thanks! They are at a starting range of 1 megaparsec up to 200 where the red shift/velocity starts to look very uniform? What gives?- thats much closer then 3000 megaparsecs?

My question still stands if anyone wants to pick up on it- Anonymo are you still about?

Cú Giobach

maguffin wrote: »

This implies that if we accept the 'infinite universe' then the whole expansion theory is null and void (because it can't expand)

A good sleep focuses the mind.
To understand how you can create more space in an infinite space check out this. Hilbert's Hotel Paradox.
For a mathematical discussion on this see here.
In an infinite space the concept of expanding from the edges is meaningless because there are no edges, but because you can fill an infinite space with as much of anything as you want, including space, an infinite space can be expanded from the "inside" by adding more space.

maguffin

Cú Giobach wrote: »

A good sleep focuses the mind.
In an infinite space the concept of expanding from the edges is meaningless because there are no edges, but because you can fill an infinite space with as much of anything as you want, including space, an infinite space can be expanded from the "inside" by adding more space.

Where does this 'new' space come from? What is it made of? How do you insert it into the continuum of Infinity to (theoretically) expand that which is boundless?

The Hotel concept is interesting, but that was just moving and rearranging physical objects (people) within the framework of the existing infinity of rooms...not expanding Infinity itself (assuming infinity exists as an entity itself and is not just a concept of the human mind).

Cú Giobach

maguffin wrote: »

Where does this 'new' space come from?

We don't really know, this is the best we have at the moment but nobody really likes it. Dark energy.

What is it made of?

What is space made of? Depends on your definition of "space". What is space? is a philosophical question that is worthy of much discussion.

How do you insert it into the continuum of Infinity to (theoretically) expand that which is boundless?
The Hotel concept is interesting, but that was just moving and rearranging physical objects (people) within the framework of the existing infinity of rooms...not expanding Infinity itself (assuming infinity exists as an entity itself and is not just a concept of the human mind).

The empty rooms didn't exist before the people moved, so they were created by the rearrangement, as new space could be created by the rearrangement of matter in the universe, if there is more space, space has expanded.
You use the expression "within the framework of the existing infinity", this is missing the nature of infinity.
Mathematical infinity is a concept of the human mind and not a number, and whether infinity exists in the real world, we don't know.
Read the mathematical discussion on this, the answers to your questions are there, someone is arguing your very point (try googling for other discussions on the topic). You can't contemplate infinity within a finite framework.

maguffin

Cú Giobach wrote: »

The empty rooms didn't exist before the people moved, so they were created by the rearrangement, as new space could be created by the rearrangement of matter in the universe, if there is more space, space has expanded.

Ignoring infinity for a moment...in a 'real' hotel, currently full, there are no empty rooms. an empty room 'is created' when an existing guest leaves the hotel (he/she has been rearranged in space/time/location). This rearrangement and subsequent creation of an empty room has not expanded the number of rooms in the hotel...merely made available a space that already existed. Rearranging matter in the universe doesn't create 'new' space...it just frees up (if you will) that which already existed, therefore no expansion.

You use the expression "within the framework of the existing infinity", this is missing the nature of infinity.

What IS the nature of Infinity?

Cú Giobach

maguffin wrote: »

Ignoring infinity for a moment...in a 'real' hotel, currently full, there are no empty rooms. an empty room 'is created' when an existing guest leaves the hotel (he/she has been rearranged in space/time/location). This rearrangement and subsequent creation of an empty room has not expanded the number of rooms in the hotel...merely made available a space that already existed.

Indeed that is true, but since things are completely different with the infinite hotel (hence the paradox, expounded by one of the world's greatest mathematicians) the comparison is meaningless.

Rearranging matter in the universe doesn't create 'new' space...it just frees up (if you will) that which already existed, therefore no expansion.

As already explained, in the infinite hotel/universe the room/space didn't exist before the rearrangement of the people/matter.

What IS the nature of Infinity?

If you have to ask that question, why are you making definitive comments about what can or can't happen in an infinite space? Here

I note you have made no comment on the discussion I pointed you to, where someone is trying to make the same argument you are, and is being given mathematical proof of the concept.

maguffin

Cú Giobach wrote: »

If you have to ask that question, why are you making definitive comments about what can or can't happen in an infinite space? Here

The above in relation to my asking you what is the nature of infinity......I asked because you implied in the previous post that you knew the nature of infinity...I wanted your comment on its nature.
Also, I make definive comments because I am no different from you or anyone else commenting on this particular thread....we all have our own oppinions and feelings on such matters and are free to express them.
I do not stand in awe or fear of mathematicians or scientists (I was one..) and their theories....ALL theories should be challenged and discussed in new and fresh ways...not regurgitating always the same 'proofs' and examples.



[QUOTE}I note you have made no comment on the discussion I pointed you to, where someone is trying to make the same argument you are, and is being given mathematical proof of the concept.[/QUOTE]

I simply haven't looked at it yet!

Cú Giobach

maguffin wrote: »

The above in relation to my asking you what is the nature of infinity......I asked because you implied in the previous post that you knew the nature of infinity...I wanted your comment on its nature.

Actually I implied that you didn't (and I genuinely don't mean to be rude or insulting with that), I only did this because you kept making analogies and comparisons with finite examples and coming to conclusions based on these examples, which anyone with a bit of knowledge about infinity will know cannot be done.

Also, I make definive comments because I am no different from you or anyone else commenting on this particular thread....we all have our own oppinions and feelings on such matters and are free to express them.
I do not stand in awe or fear of mathematicians or scientists (I was one..) and their theories....ALL theories should be challenged and discussed in new and fresh ways...not regurgitating always the same 'proofs' and examples.

Surely if you are an ex-scientist or mathematician you understand you cannot make definitive statements based on, quote: "opinions and feelings", especially in a topic such as this which contains so many counterintuitivities, also if there is a "proof" of something, then using (or as you say regurgitating) it as many times as is necessary is what science and (especially) mathematics is about, if you can disprove something grand go ahead, but till then you cannot just dismiss it because it makes you uncomfortable or you can't understand it.

Looking at things from a different angle is brilliant and many great discoveries have indeed been made that way, so it's certainly not to be scoffed at.
By the way, I'm not here to impart knowledge but to gain it, I've learned quite a bit from being involved in these discussions that I could never have gotten by just reading them, so thanks for engaging me.

maguffin

Cú Giobach wrote: »

Actually I implied that you didn't (and I genuinely don't mean to be rude or insulting with that), I only did this because you kept making analogies and comparisons with finite examples and coming to conclusions based on these examples, which anyone with a bit of knowledge about infinity will know cannot be done.

To me Infinity has no nature of itself....it is a concept, nothing more. What makes this (and other topics) really interesting is the nature of the human minds that examine, analyse, theorise and expound on these matters. The true flavour of any idea comes from the mix of minds that conceive it and explore it. The human mind is capable of amazing things...and one of these is abstractly combining 'finite examples' with 'infinite problems'. Everything can be done...you just have to be brave enough and let go of convention.

Surely if you are an ex-scientist or mathematician you understand you cannot make definitive statements based on, quote: "opinions and feelings", especially in a topic such as this which contains so many counterintuitivities

Opinions and feelings are fundamental to human interaction on every level of society...including scientific endevour. Having 'gut feelings' and opinions is what drives us to seek out the answers. Have YOU really been devoid of 'opinions and feelings' up to this point in your life?

By the way, I'm not here to impart knowledge but to gain it, I've learned quite a bit from being involved in these discussions that I could never have gotten by just reading them, so thanks for engaging me.

No problem....been a pleasure!

maguffin

Anonymo

rccaulfield wrote: »

No probs, thanks for filling my head with some of your knowledge on the subject!



My question still stands if anyone wants to pick up on it- Anonymo are you still about?

Apologies on two fronts. Firstly because I was away from internet land over the weekend and secondly because I've caused a little bit of extra confusion.
The length scale 3000 Mpc refers to that scale at which there is no ambiguity that what's happening is due to expansion of the universe. It is the length scale today that objects are receding from us at greater than the speed of light (Note there is no information moving at greater than the speed of light so no contradiction with special relativity). As for the length scale that you can expect to see the expansion. As I said on an earlier post, expansion occurs on all scales - on smaller scales it is too small to be observable. Essentially we will observe the expansion by looking at scales that are not virialised/clumped together. Though it may not seem it, our galaxy is just such a clumped object. The Milky way is 30 k pc =0.03 Mpc across. So we need to look at scales above this to observe the expansion.

The Hubble diagram that Cu Gioblach gave earlier shows you the length scale that you can observe the expansion ... you'll see that the length scale that Hubble observed things is at the scale of the Milky Way and above, but certainly not with observations below the aforementioned scale.

Maguffin, I'd like to reiterate Cu Gioblach's point that it's great having discussions such as these on such a forum. However, it seems that you've approached the argument with a fixed point of view. Cu Gioblach made the reasonable point that you should not base 'definitive statements on,... "opinions and feelings"'. From your reply

maguffin wrote: »

Opinions and feelings are fundamental to human interaction on every level of society...including scientific endevour. Having 'gut feelings' and opinions is what drives us to seek out the answers. Have YOU really been devoid of 'opinions and feelings' up to this point in your life?
maguffin

it appears that you do just that. Your reply should have to do with the motivation to do science. However, you seem to have conflated this with how it should be carried out. You appear to reject the description given earlier as to how the universe expands ... (by every point moving apart from every other -- rather than as something expanding into something else) because it doesn't fit into our everyday experiences. Taken to the extreme, such viewpoints would reject quantum theory and general relativity!
Of course it would be interesting to try and do proper science without recourse to infinite scales. However we have a vast array of observations that fit with theories that recourse to such a concept. To reject this out of hand because of a prejudice is, I think, thoroughly unscientific. Btw this is not meant as a polemic. I'm hoping you reply to this message in a manner that shows me the error of my ways!

maguffin

Anonymo wrote: »

Maguffin,.... However, it seems that you've approached the argument with a fixed point of view. Cu Gioblach made the reasonable point that you should not base 'definitive statements on,... "opinions and feelings"'. From your reply it appears that you do just that.

I disagree...sometimes great discoveries in science are the result of 'opinions', 'feelings' and..even stranger, 'dreams'. The great Chemist Kekulé, in the 1860s, set about discovering the structure of Benzene. Kekulé spoke of the creation of the theory. He said that he had discovered the ring shape of the benzene molecule after having a reverie or day-dream of a snake seizing its own tail (this is a common symbol in many ancient cultures known as the Endless Knot). This vision, he said, came to him after years of studying the nature of carbon-carbon bonds. This was 7 years after he had solved the problem of how carbon atoms could bond to up to four other atoms at the same time. The cyclic nature of benzene was finally confirmed by the crystallographer K. Lonsdale in 1929. Was it wrong of him to postulate the structure based on his 'dream'?

Your reply should have to do with the motivation to do science. However, you seem to have conflated this with how it should be carried out. You appear to reject the description given earlier as to how the universe expands ... (by every point moving apart from every other -- rather than as something expanding into something else) because it doesn't fit into our everyday experiences.

Incorrect...I never stated that I rejected current thinking....I merely challenged it.

Taken to the extreme, such viewpoints would reject quantum theory and general relativity!

Is quantum theory and relativity sacrosanct?? Why should it not be challenged? They are only the 'best fit' answers to the questions we now pose given our current level of understanding and the current level of sensitivity of analytical apparatus.

Of course it would be interesting to try and do proper science without recourse to infinite scales. However we have a vast array of observations that fit with theories that recourse to such a concept. To reject this out of hand because of a prejudice is, I think, thoroughly unscientific.

To me, it seems the prejudice is yours, not mine. :0)

I spent nearly 40 years in the scientific community. My background is chemistry, physics, maths and also computer science. I know what the 'scientific method' is.....it is just that now, I look at things with different eyes.

maguffin

Anonymo

maguffin wrote: »

I disagree...sometimes great discoveries in science are the result of 'opinions', 'feelings' and..even stranger, 'dreams'. The great Chemist Kekulé, in the 1860s, set about discovering the structure of Benzene. Kekulé spoke of the creation of the theory. He said that he had discovered the ring shape of the benzene molecule after having a reverie or day-dream of a snake seizing its own tail (this is a common symbol in many ancient cultures known as the Endless Knot). This vision, he said, came to him after years of studying the nature of carbon-carbon bonds. This was 7 years after he had solved the problem of how carbon atoms could bond to up to four other atoms at the same time. The cyclic nature of benzene was finally confirmed by the crystallographer K. Lonsdale in 1929. Was it wrong of him to postulate the structure based on his 'dream'?



Incorrect...I never stated that I rejected current thinking....I merely challenged it.



Is quantum theory and relativity sacrosanct?? Why should it not be challenged? They are only the 'best fit' answers to the questions we now pose given our current level of understanding and the current level of sensitivity of analytical apparatus.




To me, it seems the prejudice is yours, not mine. :0)

I spent nearly 40 years in the scientific community. My background is chemistry, physics, maths and also computer science. I know what the 'scientific method' is.....it is just that now, I look at things with different eyes.

maguffin

In my view you challenged the current science based on a bias based on feeling and not on evidence. Kekulé spoke of the motivation and context of how he made his discovery. While interesting I'm sure that if the data showed him something different he would not have pursued this dream. Many of my own scientific ideas come from 'dreams'. But they have to be consistent with science for me to pursue them.

I never said quantum theory and relativity were sacrosanct. But any theory that supersedes them must agree with them in their regime of validity - just as they must agree with Newtonian physics in the low energy regime. This is an entirely reasonable position. To me it seems you've defined things to be in terms of Newtonian physics and so you will always reach an impasse. Quite how I've shown a prejudice escapes me.

It is wonderful that you are here on boards. Given your background we can all learn a lot from your perspective. However when I think a perspective is flawed I think it's good practice to point out why. I hope you will continue to do the same.

maguffin

Anonymo wrote: »

In my view you challenged the current science based on a bias based on feeling and not on evidence.

I do not reject the evidence, I accept it for what it is, however, this does not (and never will) prevent me from sticking another question mark into the mix......one should always question...for only then will new things become evident.

Kekulé spoke of the motivation and context of how he made his discovery. While interesting I'm sure that if the data showed him something different he would not have pursued this dream.

Indeed...'IF'

Many of my own scientific ideas come from 'dreams'. But they have to be consistent with science for me to pursue them.

Ideas are abstractions and possibilities and cannot initially be 'consistent with science'......to dismiss them because of this is not being scientifically adventerous.

I never said quantum theory and relativity were sacrosanct. But any theory that supersedes them must agree with them in their regime of validity - just as they must agree with Newtonian physics in the low energy regime. This is an entirely reasonable position.

...and I never said you did!.....and only the future will reveal how robust or otherwise these theories are.

Quite how I've shown a prejudice escapes me.

...as does mine!

However when I think a perspective is flawed I think it's good practice to point out why. I hope you will continue to do the same.

None of us are without flaws...it is the human condition....and I am glad you have shared yours as I (may) have mine.

maguffin

rccaulfield

Anonymo wrote: »

Apologies on two fronts. Firstly because I was away from internet land over the weekend and secondly because I've caused a little bit of extra confusion.
The length scale 3000 Mpc refers to that scale at which there is no ambiguity that what's happening is due to expansion of the universe. It is the length scale today that objects are receding from us at greater than the speed of light (Note there is no information moving at greater than the speed of light so no contradiction with special relativity). As for the length scale that you can expect to see the expansion. As I said on an earlier post, expansion occurs on all scales - on smaller scales it is too small to be observable. Essentially we will observe the expansion by looking at scales that are not virialised/clumped together. Though it may not seem it, our galaxy is just such a clumped object. The Milky way is 30 k pc =0.03 Mpc across. So we need to look at scales above this to observe the expansion.

The Hubble diagram that Cu Gioblach gave earlier shows you the length scale that you can observe the expansion ... you'll see that the length scale that Hubble observed things is at the scale of the Milky Way and above, but certainly not with observations below the aforementioned scale.
!

Ok, Thank you for that, its becoming clearer now. Its been an eye opening thread for me. My question about the observed expansion to neptune has been answered. One last thing.
Do cosmologists account for the expansion rate between galaxies near to the milky way and earth? I realise these are well within the zone where the expansion is definitely observable(3000mpcs). But as you say the expansion is happening everywhere, however if i take you up right, it cannot be observed at even our galaxies diameter due to local forces and our inability to precisely predict all forces acting at the same time, i.e gravity, etc. But nevertheless it must do something.
E.g. if we can accurately measure the mass and speed of a star on the other side of the galaxy(or a nearby galaxy if you prefer) and all forces are accounted for then the tiny expansion of space between the earth and said star must be accounted for no? Otherwise the perceived position of the star would be out? Or is the expansion simply so tiny that cosmologists are happy to leave things like that to an approximation?