This is a portion from an article that can be found at the BBC News, in their “science an environment” section. Maybe this will help some of you astronomy fans to realize that dark energy, dark matter, and black holes are real entities that are being investigated with real scientific tools. That they are being investigated in a meaningful manner. That these subjects are being explored, and that our understanding of these subjects are being influenced by our observations, and not the other way around. That we are learning about our universe, and are not making things up. Light on the dark energy mystery  Astronomers have observed and analysed the effect of dark energy, the exotic form of energy thought to dominate the Universe, on galaxy clusters. Using Nasa's Chandra x-ray space telescope, researchers watched the growth of dozens of clusters. They say dark energy appears to be retarding the clusters' development. "Putting all of this data together gives us the strongest evidence yet that dark energy is the cosmological constant, or in other words, that 'nothing weighs something'," said Alexey Vikhlinin, who led the research from the Smithsonian Astrophysical Observatory in Cambridge, US. "A lot more testing is needed, but so far Einstein's theory is looking as good as ever." It appears that dark energy makes up about 70% of the energy in the Universe, with dark matter accounting for a further 25% and "normal" matter just 5%. The fact that observations appear to tally with the notion of a cosmological constant is further confirmation that Einstein's general theory of relativity applies at large scales, the astronomers say. he current research project, conducted over many years, involved observing hot gas inside galaxy clusters. Some of those observed are relatively close in space, others are halfway across the Universe. The clusters grew more slowly than would have been indicated by the visible galaxies. The explanation is that dark energy is stretching space. "This result could be described as 'arrested development of the Universe'," said Dr Vikhlinin. "Whatever is forcing the expansion of the Universe to speed up is also forcing its development to slow down." The new findings can now be combined with other evidence on dark energy coming from study of supernovae, the cosmic microwave background and the way galaxies are distributed across the cosmos.

Dusty_Matter : Thanks for the info. Have you seen any new info. on the LIGO gravity wave search?

No.  Last I heard it was being upgraded and might come back online in 2014.  I haven't really been following it though.

Dusty_Matter : Thank you.

G'day from the land of ozzzz

 Hello Dusty  

What do you think Dark Matter or Dark Energy is?

http://arxiv.org/abs/0806.2320

Revealing the properties of dark matter in the merging cluster MACSJ0025.4-1222

Authors: Maruša Bradač (1), Steven W. Allen (2), Tommaso Treu (1), Harald Ebeling (3), Richard Massey (4), R. Glenn Morris (2), Anja von der Linden (2), Douglas Applegate (2); ((1) UCSB, (2) KIPAC, Stanford, (3) UoHawaii, (4) Edinburgh)

(Submitted on 13 Jun 2008 (v1), last revised 23 Jul 2008 (this version, v2))

Abstract: We constrain the physical nature of dark matter using the newly identified massive merging galaxy cluster MACSJ0025.4-1222. As was previously shown by the example of the Bullet Cluster (1E0657-56), such systems are ideal laboratories for detecting isolated dark matter, and distinguishing between cold dark matter (CDM) and other scenarios (e.g. self-interacting dark matter, alternative gravity theories). MACSJ0025.4-1222 consists of two merging subclusters of similar richness at z=0.586. We measure the distribution of X-ray emitting gas from Chandra X-ray data and find it to be clearly displaced from the distribution of galaxies. A strong (information from highly distorted arcs) and weak (using weakly distorted background galaxies) gravitational lensing analysis based on Hubble Space Telescope observations and Keck arc spectroscopy confirms that the subclusters have near-equal mass. The total mass distribution in each of the subclusters is clearly offset (at >4sigma significance) from the peak of the hot X-ray emitting gas (the main baryonic component), but aligned with the distribution of galaxies. We measure the fractions of mass in hot gas (0.09^{+0.07}_{-0.03}) and stars (0.010^{+0.007}_{-0.004}), consistent with those of typical clusters, finding that dark matter is the dominant contributor to the gravitational field. Under the assumption that the subclusters experienced a head-on collision in the plane of the sky, we obtain an order-of-magnitude estimate of the dark matter self-interaction cross-section of sigma/m < 4cm^2/g, re-affirming the results from the Bullet Cluster on the collisionless nature of dark matter.

 

Hi Harry, I don't know.

Harry Costas : Thanks for the info.

G'day from the land of ozzzzz

As I'm reading through papers, some are interesting some I agree with and some I disagree.

Reagrdless, I do not want my opinion to affect your opinion.

 

http://arxiv.org/abs/0806.1742

Impact of Point Source Clustering on Cosmological Parameters with CMB Anisotropies

Authors: Paolo Serra, Asantha Cooray, Alexandre Amblard, Luca Pagano, Alessandro Melchiorri

(Submitted on 10 Jun 2008)

Abstract: The faint radio point sources that are unresolved in cosmic microwave background (CMB) anisotropy maps are likely to be a biased tracer of the large-scale structure dark matter distribution. While the shot-noise contribution to the angular power spectrum of unresolved radio point sources is included either when optimally constructing the CMB angular power spectrum, as with WMAP data, or when extracting cosmological parameters, we suggest that clustering part of the point source power spectrum should also be included. This is especially necessary at high frequencies above 150 GHz, where the clustering of far-IR sources is expected to dominate the shot-noise level of the angular power spectrum at tens of arcminute angular scales of both radio and sub-mm sources. We make an estimate of source clustering of unresolved radio sources in both WMAP and ACBAR, and marginalize over the amplitude of source clustering in each CMB data set when model fitting for cosmological parameters. For the combination of WMAP 5-year data and ACBAR, we find that the spectral index changes from the value of $0.963 \pm 0.014$ to $0.959 \pm 0.014$ (at 68% c.l.) when the clustering power spectrum of point sources is included in model fits. While we find that the differences are marginal with and without source clustering in current data, it may be necessary to account for source clustering with future datasets such as Planck, especially to properly model fit anisotropies at arcminute angular scales. If clustering is not accounted and point sources are modeled with a shot-noise only out to $l \sim 2000$, the spectral index will be biased by about 1.5$\sigma$.

 

G'day from the land of ozzzzz

oops I deleted the repeat post.

 

No dark energy mystery is not yet solved!!!! Neither by einstein nor by hubble this passage just describes the thing which is already researched it cannot solve a mystery!!!!

Neither the title, nor the article implies that the mystery has been solved.  It shows only that there is evidence for it.