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Several kinds of astronomical observations, interpreted in the framework of the standard Friedmann-Robertson-Walker cosmology, have indicated that our universe is dominated by a Cosmological Constant. The dimming of distant Type Ia supernovae suggests that the expansion rate is accelerating, as if driven by vacuum energy, and this has been indirectly substantiated through studies of angular anisotropies in the cosmic microwave background (CMB) and of spatial correlations in the large-scale structure (LSS) of galaxies. However there is no compelling direct evidence yet for (the dynamical effects of) dark energy. The precision CMB data can be equally well fitted without dark energy if the spectrum of primordial density fluctuations is not quite scale-free and if the Hubble constant is lower globally than its locally measured value. The LSS data can also be satisfactorily fitted if there is a small component of hot dark matter, as would be provided by neutrinos of mass 0.5 eV. Although such an Einstein-de Sitter model cannot explain the SNe Ia Hubble diagram or the position of the `baryon acoustic oscillation' peak in the autocorrelation function of galaxies, it may be possible to do so e.g. in an inhomogeneous Lemaitre-TinyTree-Bondi cosmology where we are located in a void which is expanding faster than the average. Such alternatives may seem contrived but this must be weighed against our lack of any fundamental understanding of the inferred tiny energy scale of the dark energy. It may well be an artifact of an oversimplified cosmological model, rather than having physical reality.
The Following User Says Thank You to neutralino For This Useful Post:
Re: Is the Evidence for Dark Energy Secure? -
11-10-2007, 07:40 AM
So, it seems that there are some physicists who are not convinced with dark energy. Of course, this line of thought is not all that new. It all boils down to future observations, in my opinion. Either we will see that the standard model is confirmed to even more accuracy, or we will see some anomolies that point out something else is going on out there. Either way, it's a very exciting time for cosmology!
The Following 3 Users Say Thank You to neutralino For This Useful Post:
Re: Is the Evidence for Dark Energy Secure? -
11-20-2007, 11:29 AM
What if 'dark matter' is the main body of the Universe? And 'matter' is 'dark matter' manifested into form? What if 'dark matter' forms into maybe 'strings' or something else, in order to become more, like 'Quarks'?
I remember over 30 years ago when photo's of galaxies where in negative form, how they looked like whirlpools, in an ocean of something. I am trying to find some of these on the internet, so I can link to them for others to see. Maybe someone else can find one.
Allen.
"Paradox of Potential popped Aware." ~Allen Barrow
"I have no special talents. I am only passionately curious." ~Albert Einstein 1879 - 1955
"Condemnation without Investagation is the Heigth of Ignorance" ~Albert Einstein
"In questions of science, the authority of a thousand is not worth the humble reasoning of a single individual." ~Galileo Galilei.
What would be the mechanism behind the reformations? If indeed quarks are fabricated from dark matter, what would its(dark matter) dimensions be? As I would imagine it to be infinitesimally small, and maybe this is why we cannot detect it or perhaps our methods of measurement is insufficient (e.g. the SI quantities and such that we use are merely measuring the end products of interactions between more fundamental systems?)
Best regard
Zelta
"Science is organized knowledge. Wisdom is organized life"
"But although all our knowledge begins with experience, it does not follow that it arises from experience."
"Happiness is not an ideal of reason, but of imagination."
What would be the mechanism behind the reformations? If indeed quarks are fabricated from dark matter, what would its(dark matter) dimensions be? As I would imagine it to be infinitesimally small, and maybe this is why we cannot detect it or perhaps our methods of measurement is insufficient (e.g. the SI quantities and such that we use are merely measuring the end products of interactions between more fundamental systems?)
Best regard
Zelta
Zelta, Thanks for the link. Even though that is the type of photo I am talking about, there are way better examples. I linked one here, http://http://www.pbase.com/strongma...image/55271714, that is of the angle needed to really see it. Tilted toward the line of sight is even better. When you see one I am talking about, you will be surprised at how real it looks.
Because we can not see or capture a quark to see what it is made of, we are probably a long way from knowing what the dimensions are. But there is no doubt in my mind that we, and the Galaxies that we are traveling in, are floating on a sea of wavelengths that do have very small dimensions, much smaller then the Quarks.
There has been enough scientific proof, that there is more then meets the eye, with the interactions of Galaxies and their environment. Having seen those photo's 30 years ago I have always pictured the Universe this way. As an ocean of very small wavelengths (radiation).
Allen.
"Paradox of Potential popped Aware." ~Allen Barrow
"I have no special talents. I am only passionately curious." ~Albert Einstein 1879 - 1955
"Condemnation without Investagation is the Heigth of Ignorance" ~Albert Einstein
"In questions of science, the authority of a thousand is not worth the humble reasoning of a single individual." ~Galileo Galilei.
Re: Is the Evidence for Dark Energy Secure? -
11-22-2007, 04:01 AM
Pop,
Thanks for the new link, it is much clearer. The usage of the words wavelength and radiation seem to fall into very strict rules, can you please elaborate?
I am also still curious on the mechanism behind the reformations.
Best regards
Zelta
"Science is organized knowledge. Wisdom is organized life"
"But although all our knowledge begins with experience, it does not follow that it arises from experience."
"Happiness is not an ideal of reason, but of imagination."
Re: Is the Evidence for Dark Energy Secure? -
11-23-2007, 02:54 PM
Quote:
Originally Posted by Profpat
Hi everyone; Could those very small radiation wavelengths be called or described as strings?Pat
No, no, no, no, no, etc... Yet you could, but you'd be very wrong...
Lloyd
"To develop the skill of correct thinking is in the first place to learn what you have to disregard. In order to go on, you have to know what to leave out; this is the essence of effective thinking." Kurt Godel "Time and space are modes in which we think and not conditions in which we live." Albert Einstein "The uncertainty principle is an absolute, finite, universal constant." L.G. "The tick-tick-tick of the cesium atom is a sliding-time-scaler constant of all finite universal motion." L.G.