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Bogie
2012-Nov-20, 03:52 PM
Over the years we have continually been improving our ability to observe the nature of things. With the LHC looking deep into particles, and high resolution deep space telescopes and radio and x-ray surveys quantifying the cosmos, where are we at today, i.e. how would you characterize the limits of our present observations of the smallest and largest structure we can say we actually see?

LPV man
2012-Nov-20, 04:07 PM
In space, observational ability is guided by the need to observe. To understand how far we have to go, we need to define the questions we need to ask. The current platform of observing equipment will answer many of the questions asked of them. Once the theory community absorb this information and set about creating the next generation of theories to explain what we are seeing. Those theories will pose questions such as observational confirmation and we will proceed to develope the equipment to attempt these confirmations

Bogie
2012-Nov-20, 05:41 PM
When we ask those questions I'm sure this has come up, but I was wondering if there was any indication of how large our universe has to be in order for the CMBR to continue to come into view in all directions. I ask that because the background energy is causally connected to the big bang event and because it is still coming into view from all directions. Would that make the smallest light years diameter that the universe could be equal to 13.7 billion times two = 27.4 bly? Or do we calculate it to be bigger?

Cougar
2012-Nov-21, 02:02 PM
I was wondering if there was any indication of how large our universe has to be in order for the CMBR to continue to come into view in all directions.

I could be wrong, but I don't think you ever escape it. In the far distant future it won't be the CMBR. It will be the cosmic radiowave background radiation.

Our astronomical observations are getting pretty darn good. There was just a report (http://hubblesite.org/newscenter/archive/releases/2012/36/image/a/) of observing a small galaxy that existed just 420 million years after the big bang!

Bogie
2012-Nov-21, 03:41 PM
I could be wrong, but I don't think you ever escape it. In the far distant future it won't be the CMBR. It will be the cosmic radiowave background radiation.

Our astronomical observations are getting pretty darn good. There was just a report (http://hubblesite.org/newscenter/archive/releases/2012/36/image/a/) of observing a small galaxy that existed just 420 million years after the big bang!I saw that. Very interesting to contemplate, given the concept of accelerating separation of the galaxies. I think of the acceleration of expansion as dark energy pushing our big bang arena spherically outward, and the ability to see light from such an early point in time after the big bang event, makes me want to reconcile expansion with what the view would look like from out there if we could view the galaxies and CMBR from there today and compare it with our view from here.

I am assuming that the age of that distant galaxy is estimated from the red shift data, wasn't it? If so, it begins to seem to tie into your post on the CMBR and newly discovered galaxies. Certainly if we were sitting in that distant galaxy and observing the galaxies and CMBR from there, theory says we would see the same consistent spread of galaxies and the same homogeneous and isotropic background radiation in all directions as we see from here. But that is not intuitive given the concept of accelerating expansion where dark energy is pushing us spherically outward.

For example, If you could plot all the galaxies in a sphere using our WMAP and Sky Survey data, and then increase the radius of the sphere by adding new space proportionately between the galaxies equal to the percentage increase in the radius so that all of the galaxies would have the same relative position in the expanded sphere, all the galaxies would appear to be moving away from each other just like we observe them to be doing. The catch is that in a finite universe we have to assume a finite number of galaxies, and so as the sphere radius increases, the density of observed galaxies would have a directional component, meaning that the further you are from the center of expansion, the more apparent the directional component would be.

I know that we can't place ourselves in the center but it wouldn't matter where you place yourself, the separation between galaxies would make it look like they were all moving away from each other, and in the growing sphere scenario they are. I just haven't been able to get over that concept of an intuitive directional aspect in the view out from different relative locations in the sphere.

Hornblower
2012-Nov-21, 05:11 PM
I saw that. Very interesting to contemplate, given the concept of accelerating separation of the galaxies. I think of the acceleration of expansion as dark energy pushing our big bang arena spherically outward, and the ability to see light from such an early point in time after the big bang event, makes me want to reconcile expansion with what the view would look like from out there if we could view the galaxies and CMBR from there today and compare it with our view from here.

I am assuming that the age of that distant galaxy is estimated from the red shift data, wasn't it? If so, it begins to seem to tie into your post on the CMBR and newly discovered galaxies. Certainly if we were sitting in that distant galaxy and observing the galaxies and CMBR from there, theory says we would see the same consistent spread of galaxies and the same homogeneous and isotropic background radiation in all directions as we see from here. But that is not intuitive given the concept of accelerating expansion where dark energy is pushing us spherically outward.

For example, If you could plot all the galaxies in a sphere using our WMAP and Sky Survey data, and then increase the radius of the sphere by adding new space proportionately between the galaxies equal to the percentage increase in the radius so that all of the galaxies would have the same relative position in the expanded sphere, all the galaxies would appear to be moving away from each other just like we observe them to be doing. The catch is that in a finite universe we have to assume a finite number of galaxies, and so as the sphere radius increases, the density of observed galaxies would have a directional component, meaning that the further you are from the center of expansion, the more apparent the directional component would be.

I know that we can't place ourselves in the center but it wouldn't matter where you place yourself, the separation between galaxies would make it look like they were all moving away from each other, and in the growing sphere scenario they are. I just haven't been able to get over that concept of an intuitive directional aspect in the view out from different relative locations in the sphere.

Intuition has been shown to be unreliable over and over again in modern cosmology and physics.

antoniseb
2012-Nov-21, 05:28 PM
... I think of the acceleration of expansion as dark energy pushing our big bang arena spherically outward, and the ability to see light from such an early point in time after the big bang event, makes me want to reconcile expansion with what the view would look like from out there if we could view the galaxies and CMBR from there today and compare it with our view from here. ...

Related to what you are discussing, One of the papers (http://arxiv.org/abs/1211.4585) in today's "Fun Papers" thread was about how we are a few years away from being able to directly measure cosmic expansion (or more precisely, change in cosmic redshift over time) using the upcoming Square Kilometer Array to carefully look at the 21cm radiation from cold Hydrogen in distant galaxies, and see how that line shifts to the red over the course of five or more years. This will enable a direct increasingly precise measurement of the effects of Dark Energy throughout most of the history of our expansion.

Bogie
2012-Nov-21, 05:28 PM
Intuition has been shown to be unreliable over and over again in modern cosmology and physics.I know; that is an often used statement to remind us that modern cosmology and physics goes that unintuitive step beyond in order to explain what our intuition tells us, because our intuitive views can't explain what we observe. It can also be a reminder that our best current theories at the micro level of the particle model and quantum mechanics, and at the macro level of Big Bang Theory and General Relativity are in some ways incompatible or at least inconsistent. I'm not being disrespectful of where we are in our consensus theories and I did say we have done the best we can do so far, but I am looking to the future where progress is surely to be made in unification.

Bogie
2012-Nov-21, 05:36 PM
Related to what you are discussing, One of the papers (http://arxiv.org/abs/1211.4585) in today's "Fun Papers" thread was about how we are a few years away from being able to directly measure cosmic expansion (or more precisely, change in cosmic redshift over time) using the upcoming Square Kilometer Array to carefully look at the 21cm radiation from cold Hydrogen in distant galaxies, and see how that line shifts to the red over the course of five or more years. This will enable a direct increasingly precise measurement of the effects of Dark Energy throughout most of the history of our expansion.Wow, excellent; I'm going to read that with the best layman understanding I can muster :).

Talk of measuring cold hydrogen in galaxies reminds me of a related link I saw to Phys.Org. I hope that source is allowed: http://phys.org/news/2012-11-galaxies-stars-problem-hydrogen-early.html

I haven't ventured into the paper yet, but from the abstract: "cosmic acceleration could be directly measured in ~125 years using current telescopes or in ~5 years using a Square Kilometer Array, but systematic effects will arise at the 1 cm/s/yr level."

I have to settle for the ~5 year method, lol.

Bogie
2012-Nov-27, 01:31 PM
Intuition has been shown to be unreliable over and over again in modern cosmology and physics.
My reply to you was made thinking you were entering a discussion instead of feeling a need to state the obvious.

Maybe my response was not what you wanted to hear, but I'm trying to discuss the limits of our ability to observe.

Observationally, starting with "space", there is what I call an apparent reality of space that we observe and it has three dimensions. Spacetime, on the other hand is not readily observable. We can observe the different rate that clocks measure time at different altitudes and different accelerations and so the change in the rate that time is measured by clocks in different energy density situations is observational. But how we explain those observations had been mathematical and theoretical for almost 100 years in the mainstream. Though the theory is supported by the observations of clocks, the point of me asking about what is observational is to be sure I am up to date on our ability to observe spacetime, i.e. is there is any progress being made in observing a physical mechanism that curves space?

NEOWatcher
2012-Nov-27, 02:14 PM
Maybe my response was not what you wanted to hear, but I'm trying to discuss the limits of our ability to observe.
My 2 cents...
I don't see it as a limit of our ability to observe, I see it as a limit to what we have experienced.
We have experience in 3 dimensions so we are used to it (and we can put time in here too). It can be described by observation, measurements, math, etc. These are all the same things that we do with spacetime and curvature.


i.e. is there is any progress being made in observing a physical mechanism that curves space?
I can also ask if there is any progress being made in observing a physical mechanism that gives us 3 dimensions or time.

Bogie
2012-Nov-27, 07:20 PM
My 2 cents...
I don't see it as a limit of our ability to observe, I see it as a limit to what we have experienced.
We have experience in 3 dimensions so we are used to it (and we can put time in here too). It can be described by observation, measurements, math, etc. These are all the same things that we do with spacetime and curvature.
Let me test my understanding of your post by putting it in my own words, so you can correct me where I misunderstand:
Are you saying, "We can only define things from what we or others we know of have experienced, observed, or are aware of. So when we define spacetime and curvature mathematically, we quantify it just like we quantify things that we can observe and measure; the only difference being that our inability to observe spacetime simply puts it into the category of as yet unseen natural law to the extent that the theory corresponds to reality."

Sorry for adding some of my own perspective, lol.




I can also ask if there is any progress being made in observing a physical mechanism that gives us 3 dimensions or time.To that I would have to say that our ability to observe our 3 D environment has certainly improved very significantly since Einstein's time.

NEOWatcher
2012-Nov-27, 07:39 PM
Are you saying...
Not even close. I'm trying to say that say that observing 3D is the same as observing curvature. It's only our interpretation of how we view them is different because it's only recently we understand it.
And I am also coming from the point of view that we have actually seen the curvature through gravitational lensing.


To that I would have to say that our ability to observe our 3 D environment has certainly improved very significantly since Einstein's time.
Again; not my point.
There has to be a "physical mechanism that curves space" (as you stated) before we can observe it (as you stated it).
So; by the same line of thinking, we observe 3D, so there has to be a "physical mechanism that [orthogonal-ized] space".

What it boils down to is that "our reality" is curved. It's just that we have been observing it to what our abilities were at the time.

Bogie
2012-Nov-27, 07:58 PM
Not even close. I'm trying to say that say that observing 3D is the same as observing curvature. It's only our interpretation of how we view them is different because it's only recently we understand it.
And I am also coming from the point of view that we have actually seen the curvature through gravitational lensing.


Again; not my point.
There has to be a "physical mechanism that curves space" (as you stated) before we can observe it (as you stated it).
So; by the same line of thinking, we observe 3D, so there has to be a "physical mechanism that [orthogonal-ized] space".

What it boils down to is that "our reality" is curved. It's just that we have been observing it to what our abilities were at the time.
Excellent. Now you see why I like to test understanding, lol. I get your perspective, but I do have some further discussion on the "our reality is curved" statement. It is true that objects and even light follow curved paths through space and those are known scientific observations.

But let me test my understanding again, lol. Are you saying that spacetime is the reality, and our perception of space as observers has some clues like the lensing effect that "prove" that space is curved by the presence of matter/energy?

Edit: This particular topic reminds me of the Four Squares of Faith in Spacetime :)

Four Squares of *Faith in Spacetime

Square 1: Spacetime is reality: You believe in Spacetime
Square 2: Spacetime is not reality: You believe in Spacetime
Square 3: Spacetime is not reality: You don't believe in Spacetime
Square 4: Spacetime is reality: You don't believe in Spacetime

Square 1: You are on the right side of reality
Square 2: You aren't really in touch with reality
Square 3: You got it right but were frowned on by the mainstream
Square 4: You are ignorant of reality

NEOWatcher
2012-Nov-27, 08:42 PM
Are you saying that spacetime is the reality, and our perception of space as observers has some clues like the lensing effect that "prove" that space is curved by the presence of matter/energy?
Basically, yes. My big problem was in trying to understand what you were saying about observations when I understand it as only a point of view instead of theory.
It kind of reminds me of people learning the Earth's surface was curved.

Hornblower
2012-Nov-27, 08:58 PM
As I think I understand it, we could argue philosophically until doomsday about what "reality" is, but an ultimate answer is not needed for continuing advance in science.

Bogie
2012-Nov-27, 09:14 PM
As I think I understand it, we could argue philosophically until doomsday about what "reality" is, but an ultimate answer is not needed for continuing advance in science.True. The scientific method is the way to go. However, do you consider science developed using the scientific method to be tentative, i.e. subject to being superseded by new developments, or not? I'll answer that so you don't accuse me of stating the obvious, lol; Of course science is tentative.

NEOWatcher
2012-Nov-27, 09:20 PM
...Of course science is tentative.
I would call it "progressive" instead of tentative since the new developments are usually found with the building blocks of the old.

Bogie
2012-Nov-27, 09:24 PM
Basically, yes. My big problem was in trying to understand what you were saying about observations when I understand it as only a point of view instead of theory.
It kind of reminds me of people learning the Earth's surface was curved.Wait, the Earth's surface is curved???? Back to the drawing board, lol.

Humor doesn't often fly well in science forums so let me try to answer you about what I am saying about observations. Apparent reality means to me that what you see is what you get. If something that can be observed cannot be explained, you then describe the mechanics of it in a way that allows it to produce what you do observe, taking all of the descriptions of accepted mechanics operating below and above the levels that we are able to observe into consideration so you can keep all the descriptions internally consistent and working together. Maintaining that internal consistency requires a continual reevaluation and update of existing descriptions of the unseen mechanics as new mechanics are added. It stands to reason that whole theories can be superseded by completely new ideas in order to maintain the internal consistency of the described laws.

Bogie
2012-Nov-27, 09:47 PM
I would call it "progressive" instead of tentative since the new developments are usually found with the building blocks of the old.
This is a link that I use as the basis for referring to the "tentativeness of science" (http://arstechnica.com/science/2006/10/5609/). Progressiveness of science is also true, but it is not the same thing because it has a built in bias toward existing science, and gives a disadvantage to "outside of the box" scientific investigation when it comes to funding and recruiting.

kzb
2012-Nov-29, 06:39 PM
I'm sure in a previous thread on the CMBR it was stated that, at some point in the future, we will be passed by the last photon of this background radiation ?

antoniseb
2012-Nov-29, 06:59 PM
... at some point in the future, [will we] be passed by the last photon of this background radiation?

No, not if the current models are correct. We will keep seeing slightly further away with slightly more redshifted (cooler) radiation forever.

Hornblower
2012-Nov-29, 08:28 PM
This is a link that I use as the basis for referring to the "tentativeness of science" (http://arstechnica.com/science/2006/10/5609/). Progressiveness of science is also true, but it is not the same thing because it has a built in bias toward existing science, and gives a disadvantage to "outside of the box" scientific investigation when it comes to funding and recruiting.

Can you give us any examples of "outside of the box" ideas that you think are being unfairly snubbed?

Bogie
2012-Nov-30, 01:10 AM
Can you give us any examples of "outside of the box" ideas that you think are being unfairly snubbed?
Excuse me Hornblower, but the phrase "unfaily snubbed" doesn't literally translate to my usage of the word "disadvantaged" in regard to funding and recruiting. Before we get off into specific "outside the box" ideas, let's discuss how an idea could be disadvantaged by the "progressiveness" of science as defined by NEOWatcher, i.e. new developments are usually found with the building blocks of the old. My point was that if it is known that new developments usually stem form existing theory, then there is a general acceptance of the supporting theory or theories, and they are being built upon as a result of the peer review process or by using the peer reviewed paper as a starting point for further calculations or modifications. Is that too far from reality to lead me to conclude that there could be a bias toward funding work that builds on existing work when questions and appropriate avenues of investigation come out of the peer review process? And as for the recruiting of scientific and mathematical talent, if a person is seeking a position in a newly funded project, wouldn't it help if that person had been involved in some of the related projects that were building blocks leading to the new project? That is all I was saying when I tried to distinguish between "tentativeness" as described in the link I gave, and the concept of "progressiveness" of science mentioned by NEOWatcher.

Bogie
2012-Nov-30, 01:23 AM
I'm sure in a previous thread on the CMBR it was stated that, at some point in the future, we will be passed by the last photon of this background radiation ?
There is some logic to that concept if you are saying that space is not stretching, which I am OK with you saying, :). But maybe you are not saying that at all. Care to elaborate on the source of the statement that the last photon would pass us?

No, not if the current models are correct. We will keep seeing slightly further away with slightly more redshifted (cooler) radiation forever.Let me test my understanding of that aspect of the current model; I think you are referring to big bang theory with inflation, isn't it? The stretching of the wave length of the light coming toward us from all directions as space stretches would cool the CMB that reaches us over time. In addition to the stretching of space as the universe expands, the rate of recession of the remote reaches of our universe accelerates. The combination of the two effects would make it possible that the rate of acceleration in stretching could mean that there are distant portions of the causally connected big bang universe receding at closer and closer to the speed of light?

antoniseb
2012-Nov-30, 02:05 AM
... there are distant portions of the causally connected big bang universe receding at closer and closer to the speed of light?
Yes, everything you said is right except this part. The CMB is coming from part of the universe that is expanding away from us at almost 1100 times the speed of light.

Bogie
2012-Nov-30, 02:12 AM
Yes, everything you said is right except this part. The CMB is coming from part of the universe that is expanding away from us at almost 1100 times the speed of light.Yikes man, that is dizzying.

What is the explanation for the faster than light expansion?

antoniseb
2012-Nov-30, 02:16 AM
... What is the explanation for the faster than light expansion?
I don't know what it is you don't know, so an explanation without doing the whole description would be impossible.
I suggest looking at wikipedia, or some other broader explanation.

ASTRO BOY
2012-Nov-30, 02:16 AM
Yikes man, that is dizzying.

What is the explanation for the faster than light expansion?

The Universal rule that nothing can exceed "c" applies to mass or anything with mass.
Space/time and light has no mass.

Bogie
2012-Nov-30, 03:11 AM
I don't know what it is you don't know, so an explanation without doing the whole description would be impossible.
I suggest looking at wikipedia, or some other broader explanation.
Fair enough. I think it was the superluminal or exponential inflation in the first 10^-37 or so seconds, but I just didn't realize that the expansion momentum was transferred to the particles when they formed. But I can imagine it if that is the case.

Bogie
2012-Nov-30, 04:03 AM
The Universal rule that nothing can exceed "c" applies to mass or anything with mass.
Space/time and light has no mass.
I can understand that. The stretching of space of course adds to the observed faster than light motion away from us I suppose, so Antoniseb's statement would equate that stretching that has accumulated to equate to 1100 times the speed of light at the far reaches of our big bang universe after some 13.7 billion years of stretching, including the exponential inflation in the first instant? At least that is my take on it. What do you think?

antoniseb
2012-Nov-30, 12:34 PM
... I think it was the superluminal or exponential inflation in the first 10^-37 or so seconds, but I just didn't realize that the expansion momentum was transferred to the particles when they formed. ...
There is no expansion momentum. There never was a time (even during inflation) when any two points in space were next to each other and separated faster than c. This whole business of exceeding c is, as you said in a later post, cumulative expansion over a large area. Note that ASTRO BOY doesn't have it right... we've seen photons from massive things (quasars, galaxies, GRBs, etc) that are moving away from us faster than c. A photon emitted 380,000 years after the big bang (after inflation ended) has a redshift of about 1089. That photon started in our direction locally going much faster than local expansion, and so progressed into parts of space with lower and lower cosmological relative velocities to us, and eventually got seen by us as part of the CMB, shifted from UV light down to microwaves. All along the way, space was expanding while the photon traversed it.

Bogie
2012-Nov-30, 02:24 PM
There is no expansion momentum. There never was a time (even during inflation) when any two points in space were next to each other and separated faster than c. This whole business of exceeding c is, as you said in a later post, cumulative expansion over a large area. Note that ASTRO BOY doesn't have it right... we've seen photons from massive things (quasars, galaxies, GRBs, etc) that are moving away from us faster than c. A photon emitted 380,000 years after the big bang (after inflation ended) has a redshift of about 1089. That photon started in our direction locally going much faster than local expansion, and so progressed into parts of space with lower and lower cosmological relative velocities to us, and eventually got seen by us as part of the CMB, shifted from UV light down to microwaves. All along the way, space was expanding while the photon traversed it.
I'd agree that "expansion momentum" isn't the right phrase to describe current theory. Space being added or stretching between galaxies accounts for the observed separation of the galaxies/groups in all directions from any point in the observable universe. I know current theory is that the invariant speed of light combined with the stretching of space accounts for the raw redshift data, and now I see your reference to the source of the CMB is light emitted from ... and here is my question: The CMB light escaped when the opacity lifted. Is the CMB light that escaped after opacity lifted but before the formation of galaxies? Certainly atoms, mostly hydrogen existed or formed at that point in time almost simultaneously across the inflated and expanding universe. Is it in accord with theory that there was a first round of fast burning hydrogen superstars that must have formed soon after the hydrogen atom dominated universe became transparent. Is it accepted theory that those superstars burned and exploded, leaving the remnant black holes surrounded by huge dust clouds that then formed the stars to complete the formation of the galaxies that we observe today? Is the CMB from the pre-galaxy light from the first round of hydrogen superstars?

A friend just pointed this paper out to me: http://arxiv.org/PS_cache/arxiv/pdf/1002/1002.4278v3.pdf

My first glance is that the paper describes acceleration of the addition of space between the galaxies is something like a universal cooling effect caused by the cold horizon relative to the contents within the horizon. The warmer universe isn't pushing as in the mysterious force of dark energy, but instead, the colder horizon is pulling us out into it.

It is interesting how that theory corresponds with my newly gained understanding of current theory in that the CMB will continue to come from all directions and will cool over time. The rate that the earliest galaxies are receding from us is faster than the speed of light and so the CMB will never stop coming, it will just be coming cooler, possibly for reasons that the paper seems to suggest (in my first glance layman view).

I do have a question about the value of K in equation (6). Is it some tiny (10^-30) fraction of a degree or do the other values in the equation make it warmer, though obviously not close to our ~2.7K?

Bogie
2012-Dec-04, 06:34 PM
OK, never mind that, I have a question about the other end of the observable scale:

I have a question that I think I know the answer to, but I want to get some confirmation. According to the "oscillating model" of the atom and molecules, I think photons are described as packets of quanta that are emitted by electrons as the electrons jump down in energy state. Energy is conserved and the photon equals the energy of the change in state of the electron. My question is, does that packet of photon energy exist as an in-tact packet of quanta which is called the photon particle as it propagates through space, only displaying wave characteristics when its path is interrupted by an experiment like the two slits where interference patterns are observed, or is that too simple of a description of the photon in its particle state?

Shaula
2012-Dec-04, 06:36 PM
Photons don't have distinct particle and wave states - these are just descriptions we use to model them. A photon is always a photon.

Bogie
2012-Dec-04, 06:53 PM
Do they get their status of just "always photons" by being emitted as packets of quanta from electrons where their energy is equal to the reduction in energy of the electron emitting them? Is this one of those Schrodinger's cat things? We don't know or won't say until we look?

Shaula
2012-Dec-04, 06:55 PM
A photon's energy, when created by an electromagnetic transition, is set by the change in energy level of the electron, yes.

Bogie
2012-Dec-04, 07:02 PM
So its a wave-particle until we observe it, and after we observe it we can say it displayed particle characteristics or it displayed wave characteristics, but any photon could do both. So when it is exposed as a spot on a photo plate, it has displayed its particle nature. Is there a name for the event of changing from a wave-particle to an observed particle on the film?

Shaula
2012-Dec-04, 07:44 PM
Are you talking about decoherence or wavefunction collapse? Before it interacts with a measuring device like film it is in an indeterminate state. Then it interacts and a set of properties are measured. This interaction can generally be modelled in a variety of ways, as a wavefunction, particle interaction, wave interaction or whatever. We do not observe a particle. We observe a change in state of a molecule in the film that can be explained as a discrete particle interaction with it at a fixed time and location. That is just the easiest way to do it. We could also model it using wavefunctions. A photon does not ever 'turn into' a particle or wave. We just model it that way for convenience. At all times a photon is described by a wavefunction which can interact with other objects in ways that yield measurements of given properties at a given time.

Bogie
2012-Dec-04, 11:44 PM
Are you talking about decoherence or wavefunction collapse? Before it interacts with a measuring device like film it is in an indeterminate state. Then it interacts and a set of properties are measured. This interaction can generally be modelled in a variety of ways, as a wavefunction, particle interaction, wave interaction or whatever. We do not observe a particle. We observe a change in state of a molecule in the film that can be explained as a discrete particle interaction with it at a fixed time and location. That is just the easiest way to do it. We could also model it using wavefunctions. A photon does not ever 'turn into' a particle or wave. We just model it that way for convenience. At all times a photon is described by a wavefunction which can interact with other objects in ways that yield measurements of given properties at a given time.
That is very helpful. Thanks for putting that bit of science into perspective for me. Sometimes I go along thinking in terms of light as if we can see it, lol. [more of my humor that is rarely appreciated]

Shaula
2012-Dec-05, 06:25 AM
It is s trap just about everyone falls into now and then (I do it all the time). You start treating the model as real. What you need to focus on is what you actually are recording. So are absolutely right - we never see light as a series of wave or billiard balls. We take measurements and these mental (and scientific) models are how we interpret them. Sadly the quantum world is really, really hard to develop a 'common sense' mental picture for!

Bogie
2012-Dec-05, 01:04 PM
Thank you for understanding my humor :).

As a result, let me risk over reaching in this forum and ask if you or any members would grade the following as if it was student answer on an open book essay test with a letter grade from E or F to A:


When we refer to the raw redshift data, or the consistent ~2.7K temperature of the cosmic microwave background, both are recognized as well understood and quantified electromagnetic phenomena; wave energy traversing the relative vacuum of the open space that separates the stars and galaxies. Whether seen in the redshifted light from stars and galaxies, or the thermalized light whose wavelength has stretched out during thirteen billions years of traversing an ever expanding universe, they represent the continuous arrival of photons that were emitted by the earliest atoms, stars and galaxies in our expanding big bang connected arena of space; our observable universe. Their journeys are characterized as self-propagating electromagnetic wave energy originating from the electrons of atoms and molecules, and their propagation through space is dependent on their individual transverse electric and magnet fields propelling them through space at the invariant speed of light without the need or presence of any medium.

Individual photons can't tell us their wavelength or energy, but their discrete packets of energy are quantized and we are able to determine their wavelengths and frequencies from a beam of starlight because we know their discrete energies are separated by multiples of Planck's constant. Knowing that, light spread physically into a spectrum is understood to reveal the wavelength and frequency of the photons that make it up. Though the light from that distant past seems to be a seamless, continuous flow to us from all directions, it isn't technically seamless, and in fact it is mechanically discrete packets of energy that are mathematically characterized as continuous waves with crests and troughs that correspond to the frequencies and wavelengths that we are able to indirectly observe. I say indirectly because we are not detecting and quantifying individual packets of energy moving through space, even thought that is theoretically what is arriving. A beam of starlight consists of trillions and trillions of photons described as wave-particles covering a wide range of energies, and given our tools and theories, we can quantify an incoherent light beam in to wavelengths and energies, and can detect both the wave nature and particle nature of light through experiments like the two slits, and the photoelectric effect.

Photon energy, and the associated atomic scale particles occupy the quantum realm of science, quantum mechanics, meaning that all of the energies involved change in discrete amounts, or quanta. However, science also deals with quantum mechanical nature of the atomic and sub-atomic realm in a mathematical context as if light was a continuous wave scoring out a mathematically two dimensional wavy path through space. That mathematical model is based on the wave-particle duality of quantum particles, the uncertainty principle, and the wavefunction which reduces to probabilities the location and momentum of the individual photons and particles. The math deals with complex numbers and linear functions, and that gives rise to the concept of a harmonic oscillation, a resonance so to speak, produced by atoms and molecules.

As a result, the quantum realm is a dynamic and chaotic non-classical realm where the ground state is never at rest in the classical sense of zero kinetic energy and a particle is not something that can be located and followed individually, only in aggregate mass and/or in mathematical theory.
(1087)

Bogie
2012-Dec-13, 02:00 AM
OK, forget that. Next question:

The perihelion of Mercury includes an explanation of ~40*arcsec per century attributed to general relativity.

Is that ~40 aresec the effect of the curvature of spacetime by the *presence of the Sun, over and above the Newtonian effect of the inverse square law?

Hornblower
2012-Dec-13, 03:25 PM
In the GR model, the entire orbital motion is an effect of the spacetime curvature, not just the small perihelion advance. For practical work such as calculating a good ephemeris, we can do a good job by fudging the Newtonian formula so that the radius term is slightly different from a true inverse square.

blueshift
2012-Dec-13, 04:48 PM
So its a wave-particle until we observe it, and after we observe it we can say it displayed particle characteristics or it displayed wave characteristics, but any photon could do both. So when it is exposed as a spot on a photo plate, it has displayed its particle nature.I would think this over again. Something exposed as a spot on a photo plate will still hold a particle/wave duality. No matter how small the spot on the photo plate is, we must take into account that more than one observer in the room where the experiment is taking place can observe the spot. Something had to spread to both sets of eyes, assuming there are two observers in the lab looking at the photo plate. That something is a wave.

Strange
2012-Dec-13, 05:10 PM
So its a wave-particle until we observe it, and after we observe it we can say it displayed particle characteristics or it displayed wave characteristics, but any photon could do both. So when it is exposed as a spot on a photo plate, it has displayed its particle nature. Is there a name for the event of changing from a wave-particle to an observed particle on the film?

I would say it depends on what you are observing. If you measure wavelike properties (e.g. frequency, wavelength) then it will appear to be wavelike. If you measure particle-like properties (umm ... spin? momentum? which slit it went through) then it will appear particle-like. Kind of obvious, in a way.

But what is it "really"? It is something that has properties some of which we associate with waves in the macro-scale world and some we associate with particles. But it isn't either of these. It is a photon.

Bogie
2012-Dec-13, 05:38 PM
I would say it depends on what you are observing. If you measure wavelike properties (e.g. frequency, wavelength) then it will appear to be wavelike. If you measure particle-like properties (umm ... spin? momentum? which slit it went through) then it will appear particle-like. Kind of obvious, in a way.

But what is it "really"? It is something that has properties some of which we associate with waves in the macro-scale world and some we associate with particles. But it isn't either of these. It is a photon.
I want to thank all three of you for the much appreciated help. That darn photon; we'd love our photons if we could ever get our arms around them.

This is off the wall, but would anyone venture a few words, maybe fifty or a hundred words on the nature of a photon in aether theory? Don't hate me for asking, but I am old enough to remember those days (just kidding, but close, lol).

blueshift
2012-Dec-13, 06:48 PM
If the aether exists then the aether is either at rest with respect to earth or it is moving with respect to the earth. If it is at rest with respect to earth then the Copernican Principle has to be thrown own because the earth would then be a special place that the rest of the universe is reacting to. Secondly, an aether that shares earth's motion would make starlight refract and changes in refraction should occur as the earth changes its direction in the aether.

If the aether moves with respect to the earth, then there must be some direction the aether is moving and our orbital journey would take us moving in different directions relative to the aether. The measured speed of light should change with time and that doesn't happen. So if one does an experiment with a beam splitter, there should be different arrival times of light at the target detectors placed at orthogonal angles to one another when the apparatus is rotated with each experiment. That doesn't happen.

Another conjecture would be that the aether moves in all directions at once. Then light would have to move in all directions at once but it would not obey the inverse square law since the aether doesn't. If the aether does obey the inverse square law then it has curvature.

Bogie
2012-Dec-13, 07:11 PM
If the aether exists then the aether is either at rest with respect to earth or it is moving with respect to the earth. If it is at rest with respect to earth then the Copernican Principle has to be thrown own because the earth would then be a special place that the rest of the universe is reacting to. Secondly, an aether that shares earth's motion would make starlight refract and changes in refraction should occur as the earth changes its direction in the aether.

If the aether moves with respect to the earth, then there must be some direction the aether is moving and our orbital journey would take us moving in different directions relative to the aether. The measured speed of light should change with time and that doesn't happen. So if one does an experiment with a beam splitter, there should be different arrival times of light at the target detectors placed at orthogonal angles to one another when the apparatus is rotated with each experiment. That doesn't happen.

Another conjecture would be that the aether moves in all directions at once. Then light would have to move in all directions at once but it would not obey the inverse square law since the aether doesn't. If the aether does obey the inverse square law then it has curvature.

Wow, SomeBody has thought about this. Can we be friends? Just kidding, friends is so "old hat" in the forums, but part of the reason I have to avoid CosmoQuest except for specific questions is that I don't need infractions for suggesting anything that isn't generally accepted theory, except to the extent of asking questions that go beyond. Your response was so "aware" and responsive that I didn't even count to see if you went over the 100 words (I know, I'm a card).

Bogie
2012-Dec-14, 03:48 PM
New question: I have an old book called, Looking at the Invisible Universe, about 150 pages on very basic science history about light. They start with scientists producing sparks by rubbing various materials with silk, and then they mention Maxwell who was a mathematician interested in electricity and magnetism, and inspired by the discoveries of electromagnetism. Give EM, the prediction was made that there should be some sort of electromagnetic wave. "[Maxwell's] theory predicted at precisely what speed these electromagnetic waves should move; and the curious thing was that the predicted speed was exactly the speed of light, which had been measured many years before."

My question is, what were the factors, observations or data, that Maxwell put together mathematically to make the accurate prediction of the speed of light? What numbers or quantifications came together to lead to the result?

Shaula
2012-Dec-14, 03:51 PM
There is actually a derivation of the speed of light in a thread in ATM - see this post (http://cosmoquest.org/forum/showthread.php/140104-Could-Time-be-just-another-Space-Dimension?p=2088656#post2088656)

Bogie
2012-Dec-15, 01:29 AM
There is actually a derivation of the speed of light in a thread in ATM - see this post (http://cosmoquest.org/forum/showthread.php/140104-Could-Time-be-just-another-Space-Dimension?p=2088656#post2088656)

OK, I'm piecing it together from Serway & Beichner's Physics For Scientists and Engineers.

In the meantime:

1.67261*10^-27/9.1095*10^-31=1.8361161e^-59
This is supposed to be the mass of a proton divided by the mass of an electron, which is ~1,836.*
How does*1.8361161e^-59 get converted to ~1,836?

Hornblower
2012-Dec-15, 02:04 AM
OK, I'm piecing it together from Serway & Beichner's Physics For Scientists and Engineers.

In the meantime:

1.67261*10^-27/9.1095*10^-31=1.8361161e^-59
This is supposed to be the mass of a proton divided by the mass of an electron, which is ~1,836.*
How does*1.8361161e^-59 get converted to ~1,836?

When dividing one power of 10 by the other one, you added the exponents when you should have subtracted.

Bogie
2012-Dec-15, 02:12 AM
When dividing one power of 10 by the other one, you added the exponents when you should have subtracted.I let Google do the calculation, so are you saying I submitted it imporperly?
So that would result in the decimal point being moved three to the right from 1.836 to 1836.?

Hornblower
2012-Dec-15, 02:32 AM
I let Google do the calculation, so are you saying I submitted it imporperly?
So that would result in the decimal point being moved three to the right from 1.836 to 1836.?

I don't know what you did or how you did it, but your result is too small by a factor of 10^62, which is exactly what happens if you add the given exponents rather than subtracting them. If, in plugging numbers into an online calculator, you accidentally omitted the minus sign in the second factor, the outcome would be the same.

Bogie
2012-Dec-15, 03:18 AM
I don't know what you did or how you did it, but your result is too small by a factor of 10^62, which is exactly what happens if you add the given exponents rather than subtracting them. If, in plugging numbers into an online calculator, you accidentally omitted the minus sign in the second factor, the outcome would be the same.
Yes, I see exactly what you mean. Look what happens when I submit it like this: 1.67261*10^-27/9.1095*10^31=1836.11614249, which is what it should be. Thanks, it was a little thing but I wanted it to work to give me the right ratio of electron mass to proton mass.

Shaula
2012-Dec-15, 05:28 AM
Try putting brackets around the numbers next time. The precedence operators in whatever you are using read that as 1.67261*(10^-27/9.1095)*10^-31 whereas you want 1.67261*10^-27/(9.1095*10^-31) which is identical to 1.67261*10^-27/9.1095*10^31 using standard precedence rules. Or use exponents 1.67261e10^-27/9.1095e10^31 if it supports them

Bogie
2012-Dec-15, 05:20 PM
Both (1.67261*10^-27)/(9.1095*10^-31)=1836.11614249 and 1.67261*10^-27/9.1095*10^31=1836.11614249 work on Google, so you know.

Bogie
2012-Dec-15, 05:55 PM
The electron on average according to Serway is ~.05 nanometers from the proton in a hydrogen atom. Let's just say the atom is in the ground state. Would someone know and be able to tell me how they measure that average distance. Or it is strictly based on Coulomb's and law minus Newton's law, and some mathematics?

Shaula
2012-Dec-15, 06:18 PM
To get that you need quantum mechanics - electrons don't orbit, they form a delocalised system known as an orbital. I am guessing that 0.5nm is the radius at which the sum probability of the 1s orbital is equal to a half.

Classical electrodynamics won't work for electrons, I am afraid. Even in the Bohr model you have to insert an arbitrary "There are no states below this" state as the ground.

Bogie
2012-Dec-15, 06:35 PM
I didn't think it was an actual measurement so you confirmed that, and I am fine with quantum mechanics except I like to have a feel for something that applies to real physical observations as a departure point. Sometimes I begin to feel that the observational physics is all in the macro realm. I'm wrong about that ... aren't I? After all, Planck's constant was observational, wasn't it, though it came from intense trial and error over years of study; once the constant was pinned down we had the basis for quantization of the charges of particles. That is thought of as observational evidence of the quantum realm isn't' it??? And the oil drop experiment, and Cavendish, and Coulomb, all observational too.

BTW, See this quote," Thus, using his experimental apparatus, Thomson was able to determine the charge-to-mass ratio of the electron. Today, the accepted value of *is 1.758819610 C kg^-1."
Am I correct to refer to the units as Coulomb's per kilogram as if it was C/kg?

Shaula
2012-Dec-15, 07:48 PM
The orbital nature of electrons has effects that we can observe. We can even image them fairly directly with atomic force microscopes. It also explains the otherwise complicated behaviours of the transition elements. Even things like the colour of some metals, mercury's low boiling point - these are all linked in to orbitals.

And you are correct, charge to mass ratios are C/kg.

Bogie
2012-Dec-15, 10:12 PM
I believe in the orbitals :). And the outer layers of electrons of the metals are quite generous with their electrons as is also evident in the photoelectric effect, conductivity, induction, etc.. And the energy level of photons is even quantified or at least confirmed by the energy of electrons that bounce out of the surface of metals under different wavelenghts but not different intensities of light. There certainly is enough observational data to become familiar with, but getting a grasp of the nature of the relationship between the electron and the proton is hard for me. I'm still looking for the secret that is the common denominator of all field and charge observations defined at a level that a simple layman can feel good about. I'm not being critcal, just acknowledging my ignorance.

Bogie
2012-Dec-17, 04:27 AM
This is the Titan and some images that do show electrons:
http://www.fei.com/products/transmission-electron-microscopes/titan.aspx
http://www.fei.com/resources/image-gallery/list.aspx?prod=titan

Look at the atomic arrangement of various materials in those images. Do you see the atoms there? Isn't that fine?!

Is there any instrument today that images the atoms with any better resolution, maybe even to show suggestions of a visual of anything that could be said to reveal or hint at electron orbitals?

Shaula
2012-Dec-17, 06:36 AM
Well - atomic force microscopes have imaged molecular orbitals.
See: http://www.nature.com/nchem/journal/v3/n4/full/nchem.1008.html

These are slightly bigger than atomic ones but still show the fuzzy, extended nature of the orbital

Bogie
2012-Dec-17, 04:51 PM
Well - atomic force microscopes have imaged molecular orbitals.
See: http://www.nature.com/nchem/journal/v3/n4/full/nchem.1008.html

These are slightly bigger than atomic ones but still show the fuzzy, extended nature of the orbital
I agree, that does look like what we are seeing. The nucleus is certainly deep down in the center of the fuzzy object. And it does stand to reason that the presence of the electrons would come out fuzzy.

My question is: The ability to see this level of resolution is from recent years and I have been hearing about orbitals for what seems like a number of years, maybe even before the observations we are looking at. Which came first, the resolution of the observations or the orbital theory, and what are the clues that lead to the adoption of an orbital model for electrons? They must explain some observed characteristics of matter or chemical reactions or the movement of charge or something?

Shaula
2012-Dec-17, 05:02 PM
Orbital theory came first. It was based on the simple fact that no classical model of an electron works. If an electron is in orbit it is being accelerated. Accelerated charges radiate. Even using the get-out-clause that the lowest state has nowhere to go this is a problem. We either throw away the idea of orbits or we throw away a lot of EM theory. So there had to be a better way. QM gave us that. By doing the maths (basically just solving the Schrodinger equation for the atom) physicists managed to reproduce hydrogen's spectrum - without putting in the quantum numbers by hand. That was a big hint that things were going well. Since then the evidence has poured in. Orbitals explain the bond angles in a range of compounds (hybridisation), they explain how ethene and other atoms like that end up with a delocalised electron system, the behaviour of the transition metal - loads of things.

Bogie
2012-Dec-17, 05:15 PM
Orbital theory came first. It was based on the simple fact that no classical model of an electron works. If an electron is in orbit it is being accelerated. Accelerated charges radiate. Even using the get-out-clause that the lowest state has nowhere to go this is a problem. We either throw away the idea of orbits or we throw away a lot of EM theory. So there had to be a better way. QM gave us that. By doing the maths (basically just solving the Schrodinger equation for the atom) physicists managed to reproduce hydrogen's spectrum - without putting in the quantum numbers by hand. That was a big hint that things were going well. Since then the evidence has poured in. Orbitals explain the bond angles in a range of compounds (hybridisation), they explain how ethene and other atoms like that end up with a delocalised electron system, the behaviour of the transition metal - loads of things.

Thank you, that should keep me busy for awhile. No more questions ... except maybe, how come you know all this stuff? Credentials would be nice (aside from knowing everything about physics, lol) if you are in the habit of sharing them.

Shaula
2012-Dec-17, 05:33 PM
I wouldn't say I had any major league credentials. I did Physics, Chemistry, Maths at A-level, went to university and did a 4 year MPhys (just general physics, no big specialities). I then went on to work as a researcher in a physics related field. There is a bit of a physics theme there I am afraid. Plus I have kept reading.

Bogie
2012-Dec-22, 10:52 PM
Just a quick question: Looking at orbitals and their various shapes and energies, and looking at the layman level chapter in an old (2000) chemistry book in the sub-chapter on Wave Properties of Matter and Wave Mechanics, they are getting into electrons as standing waves right after they briefly mention Erwin Schrodinger on the wave nature of matter. They quickly say, "... His work and the theory that developed from it are highly mathematical. Fortunately, we need only a qualitative understanding of electronic structure, and the main points of the theory can be understood without all the math."

They characterize the orbitals at a given energy to be calculated using the wave function, and they refer to the shape of the electron wave and its energy. Does the "shape" of an orbital refer to the three dimensional space within which, according to probabilities, the particular electron can be found relative to the nucleus when the atom is at a certain level of excitement and will remain within that unchanged space until an energy change within the atom occurs (which in practice, I suspect, change occurs in the next instant, lol.)?

And about the standing wave nature of the electron: is the shape of the orbital while it has that particular shape and energy said to be a standing wave, and does that mean that the wave is two dimensional and in its natural action within that orbital can be anywhere within that three dimensional space? Or have I gotten off track on thinking this through?

Shaula
2012-Dec-22, 11:07 PM
They characterize the orbitals at a given energy to be calculated using the wave function, and they refer to the shape of the electron wave and its energy. Does the "shape" of an orbital refer to the three dimensional space within which, according to probabilities, the particular electron can be found relative to the nucleus when the atom is at a certain level of excitement and will remain within that unchanged space until an energy change within the atom occurs (which in practice, I suspect, change occurs in the next instant, lol.)?
Yes, the shape is a map of the three dimensional position probability function derived from the solutions to the wave equation.


And about the standing wave nature of the electron: is the shape of the orbital while it has that particular shape and energy said to be a standing wave, and does that mean that the wave is two dimensional and in its natural action within that orbital can be anywhere within that three dimensional space? Or have I gotten off track on thinking this through?
Not really sure what you mean here - the wavefunction is dependent on spatial and temporal dimensions (x,y,z,t). The standing wave solutions are basically Spherical harmonics (http://en.wikipedia.org/wiki/Spherical_harmonics). The 3D space you are looking at is the probability of finding the electron, you never 'find' a wavefunction as they are not really physical things. They are representations of the properties of a system.

Bogie
2012-Dec-22, 11:29 PM
Yes, the shape is a map of the three dimensional position probability function derived from the solutions to the wave equation.Good, then the shape is a volume of space in three dimensions.


Not really sure what you mean here - the wavefunction is dependent on spatial and temporal dimensions (x,y,z,t). The standing wave solutions are basically Spherical harmonics (http://en.wikipedia.org/wiki/Spherical_harmonics). The 3D space you are looking at is the probability of finding the electron, you never 'find' a wavefunction as they are not really physical things. They are representations of the properties of a system.
What I'm getting at is the discussion in my most recent Chemistry book, in the Chapter about Atomic and Electronic Structure, refers to the electron in particular as a standing wave, but in general I take the discussion about standing waves to be referring to matter waves in general being standing waves. I guess I could ask, does the quantum mechanical model of the atom that uses orbitals (which are referred to as standing waves) for the electrons, also refer to the quarks in the nucleons as standing waves also?

Thanks for the link to Spherical Harmonics. I'm going to look at it.

Shaula
2012-Dec-23, 06:57 AM
As I understand it anything in which you have a stable spatial configuration due to confinement in a potential can be described in terms of standing waves. Quarks I am a little less sure of because they are confined in a really non-symmetric potential so I cannot (in my head) visualise what is going on. I'd need to go read up on this to be honest!

Bogie
2012-Dec-23, 03:18 PM
I Googled "Are quarks standing waves", and got a variety of interesting links. None of them seem to represent themselves as generally accepted theory so I won't post them, but the consensus is that quarks are standing waves; I think that is generally accepted quantum mechanics.

Bogie
2012-Dec-24, 04:48 PM
In addition to Shaula's excellent response, elsewhere I got this response in a related discussion: The shape of an orbital is the zone in which the electron (treated as a particle) is said to exist with probability=1, given that it exists at any particular radius and time as the wavefunction Ψ(r,t). These orbital zones can be arrived at by integrating the wavefunction over volume, and setting the result equal to 1. (The sum of the probabilities is equal to 1).

Upon solving in spherical coordinates, you get, for each combination of quantum numbers, the equations which describe these shapes. Here (http://panda.unm.edu/Courses/Finley/P262/Hydrogen/WaveFcns.html) you find tabulated the various solutions for each case. Also see slide 3 here (http://laude.cm.utexas.edu/courses/ch301/lecture/ln3f07.pdf).[/QUOTE]Interestingly, my chemistry book, "Chemistry - Matter and Its Changes", Brady, Russell, Holum, 2000 edition, covers that material better than my most current physics book, also a 2000 edition, "Physics For Scientists and Engineers Fifth Edition", Serway and Beichner. I am not interested in confirming the math, only in understanding the principle behind the wavefunction and quantum numbers as they are used to define the orbitals, and I may be wrong but I doubt if very many layman would want to try to develop the math necessary to show the orbital configurations for all of the energy levels of even the simple hydrogen atom that correspond to the Rydberg equation that gives the spectral lines. I wonder, does the Rydberg equation apply to all atoms and spectral lines?

And to those who can contemplate such a task I direct my next question:

Does the current quantum mechanical model of the atom with the orbitals calculated using the wavefunction,
and the quantum numbers, yield results that correspond to the full range of energy levels that cover all of the absorption lines of light by all of the atoms in the periodic table as given by the Rydberb equation, i.e. can we create an orbital configuration for every spectral line of all atoms, and is it an elegant calculation?

Shaula
2012-Dec-24, 05:23 PM
The problem is that there is slightly more to it than just the pure solutions. The basic QM approach works well for lighter atoms but get more complicated to work through as you go up the table. The issues start to some with the transition elements and heavier atoms. As you go further out the energy between successive shells tends to decrease. You also start getting complicated interactions between electrons. So take Chromium or Copper. In these elements the Nd shells and the (N-1)s shells are so close that the expected configuration (two electrons in the s shells, d shell not filled) is actually slightly less favourable than a d-electron pairing up with the s shell electron to fill the d shell. Things like this happen all the time. So do electron orbital hybridisations and complicating factors. So to work through the full QM treatment becomes enormously complex.

So I guess the answers are: Yes you can get all the energy levels if you throw enough computing power at it, Yes we can identify a transition that is responsible for the lines but the calculation of it is rather brute force and very complex.

Bogie
2012-Dec-24, 08:09 PM
So we are not calling it elegant?

Thanks for the response, which really justifies my question in my feeble mind. I think the math and the quantum mechanics are excellent tools to sort out the reality as best they can, and it seems pretty good as far as it goes. Now we obviously have fields and charges involved with each orbital configuration and the complexity of those fields and energies and their interactions, spin, Pauli exclusion principle, and whatnot, as we build up the complexity of the atoms and molecules, Yikes ... is there really a professional community that includes some number of people who can grasp the leading edge of all this and answer what they think is the unifying thread that runs through all this? Or is there some mood of disarray among them as to what the answers might be that would finally lead to the Eureka moment of understanding the true nature of the infinitesimal?

Shaula
2012-Dec-24, 09:00 PM
The underlying equations are fairly simple - it is the interactions between them that make things complex. And people are working on better ways to calculate things for complex systems. I don't think it is the world of the infinitesimal that is the problem - the rules there are simpler. It is complex, interacting systems that are hard, multi-body non-perturbative calculations.

Thanatos
2012-Dec-27, 11:23 PM
We are are approaching the theoretical limit of our capability to explore the universe in the EM spectrum. Neutrino and gravity wave detectors are the logical successors. We have made a few such devices, but, they are still primitive.

Bogie
2012-Dec-28, 12:18 AM
We are are approaching the theoretical limit of our capability to explore the universe in the EM spectrum. Neutrino and gravity wave detectors are the logical successors. We have made a few such devices, but, they are still primitive.What we actually observe, and what we figure is going on mathematically might be said to represent what we know about the EM spectrum. I personally have a long long ways to go to understand particles and forces, but I don't think the science of exploring EM will slow down and wait; there has to be still a huge body of knowledge to uncover and science is very creative in ways to test and explore. You are right, as far as I know, that we are at or close to some very difficult limitations to overcome.

You mention neutrinos as one area for possible advancements in our devices to explore them, and from what I have read casually in the media we continue to learn more and more about them, and yet they are hard to detect and hard to understand from the limited observations we have. Have you kept up to date on neutrino news and advancements, and if so, where do you think better devices and detection of neutrinos will take us?

Thanatos
2012-Dec-28, 03:37 AM
This summarizes the current state of neutrino astronomy
'Neutrino Astronomy - A Review of Future Experiments' http://arxiv.org/abs/1210.2058

Frank Merton
2012-Dec-28, 09:18 AM
We are are approaching the theoretical limit of our capability to explore the universe in the EM spectrum. Neutrino and gravity wave detectors are the logical successors. We have made a few such devices, but, they are still primitive.I don't understand why you say this, but it occurs to me there may be some limiting factor in the nature of light that I don't know about. It may be that we are now getting back to the point where the very earliest objects can be seen, and we can get no earlier, but that doesn't mean we still couldn't vastly improve our ability to see their details.

Bogie
2012-Dec-29, 12:58 AM
This summarizes the current state of neutrino astronomy
'Neutrino Astronomy - A Review of Future Experiments' http://arxiv.org/abs/1210.2058Very interesting paper and a Google search for Icecube Neutrino telescope lead to a great deal of informative pages. It will be interesing to follow the neutrino news about those new "telescopes".

Thanatos
2012-Dec-29, 07:10 AM
I don't understand why you say this, but it occurs to me there may be some limiting factor in the nature of light that I don't know about. It may be that we are now getting back to the point where the very earliest objects can be seen, and we can get no earlier, but that doesn't mean we still couldn't vastly improve our ability to see their details.Agreed. It was not my intent to suggest we cannot see more of the EM universe than we do at present, but, pushing observation back beyond the reach of the EM spectrum [pre-CMB] is where the really interesting stuff still lurks.