The Cosmological Parameters 2005

In summary, a new update on the best estimates of the main cosmological parameters has been released, as of year-end 2005. These estimates include the Hubble parameter, the dark energy density, and the Omega number, which indicates the spatial flatness of the universe. The values for these parameters have not changed significantly, with the Hubble parameter remaining at 73 km/s per Megaparsec. However, there is still debate over the accepted value of Hubble's constant, with some suggesting a lower value of 63.2 km/s per Megaparsec. This discrepancy raises questions about the precision of current cosmological measurements.
  • #1
marcus
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this just came out

http://arxiv.org/abs/astro-ph/0601168

it is an update, as of year-end 2005, of the best estimates of the values of the main cosmological parameters

like the Hubble parameter
and the dark energy density (or cosm. const.)
and the Omega number which is used to indicate how close to being spatially flat the universe is.

AFAIK there are no surprises here, the Hubble parameter is still 73 km/s per Megaparsec, and so on. but here it is if you want an up-to-date reference on the basic numbers
 
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  • #2
Nice review!

Looking forward to see what the new data from WMAP will tell us. Rumours say they will be released any day (as if we havn't heard that before...:rolleyes:).
 
  • #3
Interestingly, there still seems to be debate over the accepted value of Hubble's constant.

That paper gives the LCDM-WMAP fitted value of
H0 = 73 ± 3 km/sec/Mpsc whereas Tammann's paper The Ups and Downs of the Hubble Constant gives the value:
A proposed solution is summarized here. The conclusion is that H0 = 63.2 +/- 1.3 (random) +/- 5.3 (systematic) on all scales. The expansion age becomes then (with Omegam = 0.3, OmegaLambda = 0.7) 15.1 Gyr
The two values are almost consistent if we take the extreme limit on the lower error bar for the 'WMAP' value (70) and the extreme limit on the upper error bar for the 'Tammann' value (69.8), but one wonders if the age of 'precision cosmology' is not so precise after all.

Garth
 
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  • #4
I cast aside Tamman's paper with predudice. He appears to ignore a great deal of good observational evidence.
 

Related to The Cosmological Parameters 2005

1. What are the cosmological parameters?

The cosmological parameters are a set of values used to describe the properties of the universe, such as its age, size, and composition. These values are based on observations and mathematical models of the universe.

2. How are the cosmological parameters determined?

The cosmological parameters are determined through various methods, including observations of the cosmic microwave background radiation, measurements of the expansion rate of the universe, and studies of the distribution of galaxies. These measurements are then analyzed and combined to determine the most accurate values for the parameters.

3. What is the significance of the 2005 update to the cosmological parameters?

The 2005 update to the cosmological parameters was a result of new data and advancements in technology that allowed for more precise measurements. This update provided a more accurate understanding of the universe's properties and helped refine our models of cosmology.

4. How do the cosmological parameters impact our understanding of the universe?

The cosmological parameters play a crucial role in our understanding of the universe as they provide key insights into its origin, evolution, and composition. They also help us test and refine theories of cosmology, such as the Big Bang theory, and provide valuable information for future research and exploration.

5. Have there been any significant changes to the cosmological parameters since 2005?

Yes, there have been updates to the cosmological parameters since 2005 as new data and technology continue to improve our understanding of the universe. However, the 2005 update remains a crucial milestone in our understanding of the cosmological parameters and has provided a solid foundation for future research and discoveries.

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