Cosmology and Comprehension

The non amateur stuff. Hawking, black holes, that sort of thing

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Cliff
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Post by Cliff »

Dear Davep
Could there be a theory that there is intelligent life on other worlds?
Best wishes from the Grumpy Old Codger Cliff
Cliff
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Post by Cliff »

Dear DaveP
Sorry but as far as I am concerned Professor Fabian is possibly rather playing on words. Why give things names and then say the names are meaningless or at least dont mean what they seem to.
I suspect that Professor Fabian either does not properly understand Dark Matter and Dark Energy, or possibly does not like the potential consequences. By all accounts we do not know what gravity really is or how it is "transmitted" or as far as I know how fast it travels?
And we have been observing the consequences of gravity for a long time.
As far as I am concerned Dark Energy and Dark Matter throw a lot of spanners in a lot of works irrespective of what professor Fabian says.
I used to be a civil engineer (although I never rose to any great heights in the profession), when I was a young trainee I could never understand why contract documents said that a job woould be done for £X (ie Xpounds) but when the job was actually finished it cost £Y (Y pounds). However, those documents were something everybody accepted, no seemed to dared query there correctness.
Eventually the ICE standard contract documents got changed and made sense. The penny must have dropped.
To answer one of your queries elsewhere, yes it makes sense to have new theories from time to time but nowadays I am inclined to think there are perhaps too many; and even too many professors perhaps.
Best wishes from the Grumpy Old Codger Cliff
KendalAstronomer
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Post by KendalAstronomer »

Sorry but as far as I am concerned Professor Fabian is possibly rather playing on words. Why give things names and then say the names are meaningless or at least dont mean what they seem to.
That is not what he is saying. Just that the meanings colloquially ascribed to them aren't the meanings meant for them. By 'Dark' they mean unobserved, just as the Dark Ages weren't an era of dimness, but rather intellectual inertia. By Matter and Energy they are saying the effects of these things are similar to matter or similar to the effects of energy. No claim is made to what they actually are. What they 'seem' to be is entirely subjective to whoever reads the words and what context those words are in, and is therefore an entirely moot point.
I suspect that Professor Fabian either does not properly understand Dark Matter and Dark Energy, or possibly does not like the potential consequences
Why? All he said, according to DavePs post is that there is often a wide misconception about what the names mean and too much read into the individual words. I have known no-one working in the field who would disagree with that, whether sceptic or evangelecist. Are you claiming to fully understand the concepts?
As far as I am concerned Dark Energy and Dark Matter throw a lot of spanners in a lot of works irrespective of what professor Fabian says.
You're suggesting the theories worked beforehand? This is the main joy of astrophysics - working out one spanner at a time. Large surveys such as WMAP, Supernova studies etc constantly create observational constraints on Dark Energy and Dark Matter, so eventually the evidence will begin to point one way or the other in a more definitive manner than now. Patience, just a matter of technology.
To answer one of your queries elsewhere, yes it makes sense to have new theories from time to time but nowadays I am inclined to think there are perhaps too many; and even too many professors perhaps.
Yes, it would be wonderful if in one massive eureka moment, the word of cosmology was solved. But that won't happen and even if it did, the number of professors required to go through the theory with a fine toothcomb, like the many minds that worked out Newton's theories to the final ends for nearly three centuries afterwards, and those still working on Einstein's theories (coming up with Dark Matter and Dark Energy in the process) would be massive.

Better that we attack the problem from as many angles as possible and have plenty of people to prove or disprove each theory and hypothesis by following it to destruction. In my own work on the aurora, historically many theories came along, but they tended to simply be ignored with the result that it wasn't until the early part of the twentieth century that a coherent theory of how the aurora were formed came about. And it took another fifty years of people simply not believing it until satellites noticed the particle fluxes moving as the theory had suggested.
davep
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Post by davep »

Cliff wrote:Could there be a theory that there is intelligent life on other worlds?
Right now or any time soon? I can't imagine that there could. Do you think there could be such a theory? What would it look like?

We do, of course, have theories relating to how life can form and, even better, we actually know that life in the universe is a fact (like gravity is a fact, for example).
Cliff wrote:Sorry but as far as I am concerned Professor Fabian is possibly rather playing on words. Why give things names and then say the names are meaningless or at least dont mean what they seem to.
Quite the opposite, but KendalAstronomer has done an excellent job of saying everything I would have said so I won't repeat that.
Cliff wrote:As far as I am concerned Dark Energy and Dark Matter throw a lot of spanners in a lot of works irrespective of what professor Fabian says.
Exactly! The "Dark Matter Problem" is, in effect, a bit like pointing at a machine that isn't working to the known spec and saying "there's a spanner in the works". It might actually be a spanner that's causing the problem, or it could be something else that has the same effect that a spanner in the works would have.
Cliff wrote:To answer one of your queries elsewhere, yes it makes sense to have new theories from time to time but nowadays I am inclined to think there are perhaps too many; and even too many professors perhaps.
A theory describes our current level of understanding of something. Saying there are too many theories is a little like saying we have formed an understanding about too many things.

As for too many professors -- how many are there in the world, what's the optimum level, how's it decided and how far over it do you think we are?
Cliff
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Post by Cliff »

Dear Davep
By me saying there might be too many theories is perhaps my polite way of suggesting that much of what is said is of no real significance (rubbisj even!).
Going back thirty years or more an academic friend of mine said in the world of academics it was essential to publish papers. I do not think he thought very much was really good about many of the papers that were published. I suspect things are even worse nowadays.
More anon.
Best wishes from the Grumpy old codger Cliff
Cliff
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Post by Cliff »

Big Bang in Pieces
The Wilkinson Microwave Anisotropic Probe (WMAP) mission was sent up in 2001 to create a map of the heat left over from the Big Bang. First results in 2003 suggested that wishes had been granted. WMAP provided a value of 13.7 billion years +or- 200 million for the age of the Universe.
But now WMAP is giving cosmologists more than they bargained for. Vast amounts of data sent back give hints that the Big Bang theory is showing its age.
During the 1990s astronomers found evidence that the expansion of the Universe is accelertating. Distant supernovae explosions suggest the Universe is in the grip of anti-gravity - so-called "dark energy".
WMAP suggests ordinary matter makes up only 4% of the Universe. In the cosmos ordinary matter is outnumbered more than 5 to 1.
Omega needs to be exactly 1 if the Universe is both infinite and "flat". WMAP suggests Omega is 1.02 (although WMAP has an estimated error of 0.02 ! )
Inflation is a vague idea and theorists are still unable to account for the force fields required to make "Inflation" work.
Dark Matter
According to WMAP most of the Universe consists of dark matter.
Dark Energy
Mid 1990 supernova observations hinted Dark Energy to be the strongest driving force in the cosmos.
Microwave Background anomalies
WMAP suggests that the heat left over from the Big Bang is more evenly spread than expected from the theories of lumpiness of the early Universe.
Formation of Galaxies.
There is still no fundamental theory to explain how the Big Bang could lead to the vast collection of stars and galaxies seen throughout space.
Apparently even star formation cannot yet be adequately explained!

Supporting the standard Big Bag model
Is the Big Bang model in trouble?
It is worrying that our best models have to have both dark matter and dark energy, which looks suspicious. But the Big Bang model based on these (dm and DE) does give a good fit.
What could explain WMAP data problems?
There are some unexplained anomalies in the WMAP data. Although instrumental effects or over interpolation of statistics seem to be more likely the problem.
what dark clouds are on the horizon for the Big Bang?
There are no great concerns about the Big Bang model itself, but we may be reaching the limits of what we can learn about it.

Against the standard Big Bang model
What challenges does WMAP pose the Big Bang?
WMAP provides more information than the WMAP team actually use to advance their "standard" cosmological model. The information used by the WMAP team compared with that they ignore is like an island in an ocean.
Could WMAP anomalies be simple experimental errors?
WMAP provides very "clean" information.
Apparently the WMAP team does not say what criteria they use to justify use or not using WMAP information.
What future for the standard Big Bang theory?
The forthcoming "Planck Probe" will open research on what the replacement theory should be.
Please do not blame the Grumpy Old Codger Cliff for the above! (except for any inadvertent spelling or grammatical mistakes!).
davep
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Post by davep »

Cliff wrote:Big Bang in Pieces
Is the Big Bang model in trouble?
Against the standard Big Bang model
Nice summary of many of the puzzles being worked on at the moment. So what does this tell you?
Cliff wrote:By me saying there might be too many theories is perhaps my polite way of suggesting that much of what is said is of no real significance (rubbisj even!).
While I wouldn't argue with the idea that the need to publish is a problem (I've had a few academic friends talk to me about this -- but that's more a problem of business than science -- although it's a problem for science) I'm not seeing how you relate this to there being "too many theories". Take your list of puzzles that you posted: how do you think those puzzles can be better understood if people don't work on them?
Cliff wrote:It is worrying that our best models have to have both dark matter and dark energy, which looks suspicious.
How does it look suspicious and why is it worrying?
KendalAstronomer
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Post by KendalAstronomer »

Just come back from a seminar on the polarisation of the CMB using WMAP and QUaD data... nearly recovered.

WMAP provided a lot more than just the temperature map. The major concern for cosmologists at the time wasn't that the data had to be rough to a certain level, but that it had to be smooth to a certain level - roughly one degree in the sky. This is due to inflation bringing certain effects from particle physics from the plank scale up to their current scale. There was an upper limit on inflation and so an upper limit on the variations. The fine detail hadn't been worked out as closer examination of the initial conditions of the universe were required, and as of yet the information hasn't been collated.

A temperature profile was also produced by WMAP, whose shape fitted in extremely well with the cosmological models of the time - and this is a more important facet of the work. The initial part of the curve is due to scattering of photons in the early universe. There are then oscillations predicted and observed to do with ordinary baryonic matter oscillating in dark matter created gravitational potentials. The fit of the baryon oscillation theory model to WMAP data is incredibly good. The final part of the graph shows the oscillations dying away as the universe expands and dissipates and everything settles down and stops oscillating. This part of the theory doesn't get alot of attention as it isn't exactly the easiest bit of science communication, but it holds the tentative evidence that there has been an inflationary big bang event. I am very interested in the far left of the graph, were the really early bit of the universe seems to diverge from the standard cosmological model. But as you say, the European Planck probe will be an order of magnitude better than WMAP so better reserve judgement from that point.

But the real fun begins after this. Cosmologists don't need the universe to be flat, they merely need it to be quite near to flat for their models to agree with the current observations. 'Quite near' is the sort of vagueness that now sets in as all further graphs probing the early universe begin to suffer from not being accurate enough to tell between one model and another.

WMAP seemed to give both a lot of confirmation as well as consternation to the cosmological community, suddenly required to fit their theories to observations that simply weren't imagined when the theories were set up. Planck will further muddy the waters, I suspect, killing off some of the areas of doubt.

WMAP

Of course, all data released to the public contains a number of assumptions, some reliable, some not, about what has happened to the data in transmission. In this case, we're talking about the passage of photons in the past fourteen billion years or so, during which they are gravitationally lensed, scattered, shifted and all sorts of other horrors occur. Modelling this foreground could be another way of proving/disproving what the WMAP team say they see.

The current best models have both Dark Energy and Dark Matter in them because that is what the data interpolating the model's results says there should be. Whether that is due to a philosophical problem, a data problem or an analysis problem or if it is a real effect, only time and a lot of analysis and rejigging of the models will tell.

At the moment, there are a large amount of different theories using effectively the same model but with different paramters in them. Cosmologists have narrowed down and constrained the parameters a little, but until they and their nature are really nailed, there won't be a single model brought out and the arguments over what the data shows with repect to the standard models always seem a little bit of a curate's egg, with the final refrain being "I'm sure when [insert handy new mission here] sees first light, we'll be able to constrain [insert effect, parameter or unfeasibly large error bar on graph here] a little"

As for all these "unexplained" things like star formation, inflation and exact temperature variations on the CMB - at least two of these are particle physics problems, not cosmology. Cosmologists are there to say "we see inflation" or "stars could've formed at this time" rather than "the mechanism for this is..." they're big picture people, and others deal with the minutia. At least, that's how it looks to me.

Still, gives me something to listen to and be glad I'm not a cosmologist. At least if we are reaching the limits on what we can learn from the Big Bang model, we have people to seek out that information and base the next step, if needs be, on it.
joe
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Post by joe »

Smiley that is a thumbs up.

Questions, bits of answers, hypotheses, doubt, certainty, surprise, disappointment, reinforcement, it's all part of discovery and knowledge. This is what makes the subject so fascinating, it's cutting edge. It may all crumble tomorrow or when Planck reports back but you have to admit it's impressive stuff :roll:
200mm Newtonian, OMC140, ETX90, 15x70 Binoculars.
Cliff
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Post by Cliff »

Dear Davep and Kendal Astronomer
Thanks for your comments.
I was interested in what response there might be. Actually the "Big Bang in Pieces" does not state my own opinions, it is in fact a summary ( in which I have stuck to the original as much as I possibly can) of an article in the latest "Focus" magazine actually entitled Big Bang in pieces by Robert Matthews.
The "Yes" comments in support of the article's comments, were made by Dr Richard Lieu(University of Alabama), the "No" against the article, by Professor Andrew Liddle (University of Sussex).
By the way with regards to the use of the term "dark" in the context of dark energy and dark matter I am a bit surprised that anyone should need it explaining that it is used in the sense it is.
As I said I have been a long time Big Bang supporter but recently I have been more and more seriously beginning to wonder ?
I may well be doing theoretical scientists an injustice but it does seem to me that there is an ever increasing amount of scientific papers written, including stuff on the internet. Could be a case of too many cooks might spoil the broth if they are not careful!
Best wishes from the Grumpy Old Codger Cliff
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