Dark Energy & Void Bubbles

[CraigS]

Hubble rules out one alternative to dark energy (http://www.physorg.com/news/2011-03-hubble-alternative-dark-energy.html)



Riess also says the present uncertainty figure should 'be cut in two' before the James Webb takes over (launch date later this decade).

As well as Dark Matter, Dark Energy is here to stay folks !

Cheers

[mswhin63]

I had a thought a few months ago that planetary motion within a Galaxy could produce a motion pulling the outer spiral arms towards the centre giving the effect of dark matter. as we don't have a lot of starts about planetary motion within the Galaxy I thought this may have been a factor.

Since starting university, it looks as though somebody's already looked at angular motion within the Galaxy spiral arms relating to dark matter, and it appears that there is still too much the matter symptoms out there compared to a theoretical possibility of angular motion.

Was a nice thought though, but I am not going to discount it entirely as it may still forma calculation that could be used to determine how much Dark matter there is.

So I'm going to have to start to agree with you that Dark matter and Dark energy are here to stay for a while at least.

[Robh]

Craig,

Thanks for that. Most interesting.
So, I guess we're not the centre of a big bubble!

But just how much more complicated are things going to get? If dark energy exists, its nature is going to be even more elusive than dark matter.

Regards, Rob

[CraigS]

Hi Rob;
Your questions got me thinking ..

1. How complicated are things going to get?:

My question is: Why would you expect there to be a limit to complexity in nature ?

Perhaps the question could be interpreted as how complicated is our explanation for the expansion of the universe going to get ? This broadens the discussion and gets away from the cynicism associate with 'Things' of Darkness (ie: DM and DE).

2. If dark energy exists:

Dark Energy is a hypothesis. Dark matter and dark energy also evolved from observation.
The theoretical aspects are derived from mainstream theory and are not invented.
Dark energy has it's origins in quantum field theory. It attempts to explain the cosmological constant as a vacuum energy fluctuation.
Neither dark matter nor dark energy, involves "new" physics. It's an increasing crossover of QFT into cosmology and celestial mechanics.

(As an aside: the fundamental problem with dark matter is that if it does exist it will impact on the Standard Model in particle physics. If dark matter turns out to being ordinary matter observed at a different wavelength then no such problem exists, for example).

The hypothesis of Dark Energy doesn't rule out other explanations. If these gain momentum into the future, we may never have to explain the nature of Dark Energy.

Also, regardless of whether the energy is Dark or not, we still have difficultly in explaining the true nature of 'ordinary' energy. We can explain its behaviours, but can we truly explain its fundamental mechanisms ? Does normal energy really exist, or are we only observing its effects and state changes?
(I'm not sure I can answer this question, myself .. :question: ).

Cheers

[Karls48]

Craig, although you are most likely vehemently disagree with me all of this is just pure speculations. Until we are able to visit the star that that is close to us we are able to reasonably describe what interaction exist between two close by solar systems.
Until we are able to roam our Galaxy at will, we will not know for sure how our Galaxy works.
Until we are able to visit some neighbouring galaxy we wont be absolutely sure that laws of physics that govern our reality are same as they are couple hundred thousand light years distant.
I got no doubt that you are exceptionally intelligent and well-informed person. And I must admit that some twenty or thirty years ago I had similar approach to the science.
All what I’m asking from you is sit back and have look on history of the mankind and the science. I seems that our understanding of the reality of our surroundings is expanding logarithmically as it has been indeed in the past. But history shows that that understanding of reality has been many times totally wrong. Indeed if our course of scientific knowledge is correct, in few centuries (given logarithmic increase in our understanding) we should be able to understand the Universe for what it is and adjust our existence to be independent of our planet.
I see that as very unlikely. I do support research and the discoveries in all the fields of the science. What I do object is that today’s scientist (same as some of the learned men in the time gone past) present their musing abound the reality as ultimate knowledge or the truth of the reality.
Many say that maths rule all of the science. I do not dispute that. Then take our collective knowledge of the physics and cosmology from around 1000 BC and calculate what should be our knowledge in the 2500 AD.
Regards
Karl

[CraigS]

Hi Karl;
Oh boy .. where to start ?

Ok. Humans acquire knowledge because we have memory.

Without the past, we have no knowledge.

The future (for us) hasn't happened yet .. so we can't possibly learn anything from a future, which doesn't exist for us yet.

We can 'true' up our knowledge, (acquired from the past and present), once the future has arrived.

In cosmology, we assume the laws of physics are the same everywhere. This may not be so - in fact. How could we possibly confirm this quantitatively ? By looking through our telescopes, we are again looking out into the past. Once again all we have learned comes from this past.

The 'Truth' you seem to be alluding to, will never be attainable for humans who exist in the present. (I know of no other humans, come to think of it).

Science presents us with a framework (or a 'story') which, because of its consistency and logic, enables us to extrapolate from the knowledge we have accumulated in the past. Can you demonstrate for me that this extrapolation is invalid ?

There are many, many instances where Scientific hypothesis and theories, have been confirmed to be so. Until someone can rule out a hypothesis built upon established scientific laws, it may as well be the truth you seek.

I do not look to Science for the Truth. DM and DE are hypotheses. These will only lead to the Truth, if you seek such a goal in the first place. Give it up .. and your problems disappear in an instant !

I do not understand your statement about maths ruling science. I find this too difficult to comprehend.
:)
Cheers

[Robh]

Craig,

An interesting point and depends on how we define "the limit to complexity".
In earlier times, man put the Earth at the centre of the universe. Nice and simple. In the geocentric model, everything just rotated around the Earth.
Copernicus put the Sun at the centre of the universe with his heliocentric model. Galileo related the laws of nature to mathematics e.g. the trajectory of a projectile is a parabola. Kepler formalised the laws of planetary motion.
Newton formulated the universal law of gravitation, the three laws of motion and used calculus to describe planetary motion.
Einstein derived the special and general theories of relativity.
The universe is found to be much bigger than we thought and contains other island universes or galaxies. Hubble helps establish the universe is expanding.

Historically, each individual builds on the knowledge of others and finds some new insight that escapes others around them. The insight often depends on observations made from new technologies e.g. Galileo and the telescope. Invariable, the models become ever more complex and we seem to gain a more accurate understanding of the operation of the system. Our understanding depends on our capacity to provide a generally understood model upon which a mathematical framework can be built that further extends our understanding.

A mathematical model allows us to test our understanding of the system by comparing its predictions with future observations. In fact, we both simplify and complicate our understanding with each progression. The model helps us picture the reality but the mathematical description proposed by the model becomes ever more complex. Thus, in special relativity, the model pictures light traveling at the same speed relative to all observers but the mathematical description leads to non-intuitive realities such as length contraction and time dilation.

One would think (and this is my view) that there would be a point at which one could construct a finite set of basic modeled principles that would provide an explanation of the physics that leads to the overall structural of the universe. I guess they call it "the theory of everything". Newton's law of gravitation went a long way to explaining the dynamics of a lot of systems. GR extended this to exotic bodies like Black Holes. Current quantum models describe a finite set of basic particles. In comparison, complex biological organisms reduce to a finite set of molecules and the code (DNA) to produce the organism is finite. That is not to say that there is no more to be discovered. Example, the formulation of GR still led to new discoveries such as Black Holes, relativistic jets and frame dragging. But these new discoveries come in under the umbrella of existing theoretical knowledge.

Each new correction and extension of an existing model, requires an extraordinary leap of both insight and intellectual expression. The leaps made by Newton and Einstein were nothing short of extraordinary. In fact, each new leap now requires something more extraordinary and is becoming increasingly beyond the mind of one person to solve. Isolated, "stab in the dark" hypotheses are coming thick and fast and unification is becoming increasingly more difficult as theories reach way beyond the current technology to confirm them as either true or false.

My point about the the universe is that either there is finite complexity or it is a bottomless pit, in which case it is going to be beyond man's evolved intellectual capacity to resolve.

Regards, Rob.

[astroron]

Thankyou for the above post Rob:thanx:
Very well thought out. :thumbsup:
Cheers

[CraigS]

We are self-referential - how did that come about, anyway ?



Rob;
Great post. I really appreciate it. Very deep. Cool.

And I get your point now ...

As an aside, I’m not even sure that finite complexity, is necessarily within our capacity to ‘resolve’. :question:

I also find it amusing that we don’t even know how the human brain works and yet, this is the source which creates all the physical and mathematical models we reference. How do we know that the human brain can’t achieve loftier goals, and greater capacities, when we don’t even know how it works ?

What if we’re all wired into the fabric of the universe and our capacity is just as unbounded as the universe but we just can’t see it ? After all, the similarities between the two are quite pronounced !

Your post also contains an element of the fundamental human motivator ie: the almost desperate need to find the answer to it all. Part of the chase for the 'answer', results in the evolution of our thinking. This is another way of saying the journey is where the rewards will come from, I suppose.

At the end of the day, does it really matter whether or not the questions get answered … and does it really matter how 'far-off-the-mark' we are ? After all, the 'mark' is presently, (and probably always will be), all in our minds !

:)

Cheers