Omega Centauri -- The Glittering Giant of the Southern Skies

December 2, 2008
The globular cluster Omega Centauri -- with as many as 10 million stars -- is seen in all its splendor in this image captured with the WFI camera from ESO's La Silla Observatory. The image shows only the most central part of the cluster -- the full cluster appears almost as big as the full moon on the sky. The field of view of this image is about half a degree. North is up, East is to the left. This color image is a composite of B, V and I filtered images. Note that because WFI is equipped with a mosaic detector, there are two small gaps in the image which were filled with lower quality data from the Digitized Sky Survey. Can you find them? Credit: ESO/EIS

Sparkling away at magnitude 3.7 and appearing nearly as large as the full moon on the southern night sky, Omega Centauri is visible with the unaided eye from a clear, dark observing site. Even through a modest amateur telescope, the cluster is revealed as an incredible, densely packed sphere of glittering stars. But astronomers need to use the full power of professional telescopes to uncover the amazing secrets of this beautiful globular cluster.

This new image is based on data collected with the Wide Field Imager (WFI), mounted on the 2.2-metre diameter Max-Planck/ESO telescope, located at ESO's La Silla observatory, high up in the arid mountains of the southern Atacama Desert in Chile. Omega Centauri is about 150 light-years across and is the most massive of all the Milky Way's globular clusters. It is thought to contain some ten million stars!

Omega Centauri has been observed throughout history. Both the great astronomer Ptolemy and later Johann Bayer catalogued the cluster as a star. It was not until much later, in the early 19th century, that an Englishman, the astronomer John Frederick William Herschel (son of the discoverer of Uranus), realised that Omega Centauri was in fact a globular cluster. Globular clusters are some of the oldest groupings of stars to be found in the halos that surround galaxies like our own Milky Way. Omega Centauri itself is thought to be around 12 billion years old.

Recent research into this intriguing celestial giant suggests that there is a medium sized black hole sitting at its centre. Observations made with the Hubble Space Telescope and the Gemini Observatory showed that stars at the cluster's centre were moving around at an unusual rate — the cause, astronomers concluded, was the gravitational effect of a massive black hole with a mass of roughly 40 000 times that of the Sun.

The presence of this black hole is just one of the reasons why some astronomers suspect Omega Centauri to be an imposter. Some believe that it is in fact the heart of a dwarf galaxy that was largely destroyed in an encounter with the Milky Way. Other evidence points to the several generations of stars present in the cluster — something unexpected in a typical globular cluster, which is thought to contain only stars formed at one time. Whatever the truth, this dazzling celestial object provides professional and amateur astronomers alike with an incredible view on clear dark nights.

Source: ESO

Explore further: Some Globular Clusters May Be Leftovers From Snacking Galaxies

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1 / 5 (6) Dec 03, 2008
Caused by anti-gravity matter:-

not rated yet Dec 08, 2008
I fail to see why this is caused by AGM (I have read the link).
Could you clearify this for me?
not rated yet Dec 10, 2008
Me thinks TimESimmons has a couple of accounts on PhysOrg and posting his link to get more attention to his site
not rated yet Dec 11, 2008
Could be a good possibility.
The anti-gravity-matter theory is interesting though be i cant find any calculations on the subject. That's a pity. Any good physisist (or astronomer) will take a theory serious when the calculations are correct.
1 / 5 (1) Dec 12, 2008
Ah Thecis. What is it you want me to calculate?
1 / 5 (2) Dec 12, 2008
Also Thecis:- Globular Clusters are dense groups of usually old stars orbiting within a galaxy disc. According to the AGM theory they are fragments of the dense cores of old galaxies that have been captured by a new galaxy and are slowly being torn apart by AGM drag and tidal forces.

A Globular Cluster is surrounded by anti-gravity matter and is subject to anti-gravity matter wind as it orbits. However its density is so high that it has excluded anti-gravity matter from between the stars within the cluster. The critical density at which this happens is called the AGM Exclusion density.

The AGM Exclusion density has the effect of causing groups of stars to behave as if they pass through a phase change as the gain internal kinetic energy and reduce in density. Globular clusters (and galaxy cores) are the dense, low internal kinetic energy, liquid-like phase. Most of the stars in a galaxy disc are the higher internal kinetic energy, less dense gas-like phase.

When a (liquid-like phase) galaxy core is captured by another galaxy it behaves like water sprayed into dry air. At first it splits into droplets but the over time the droplets evaporate. A Globular Cluster is just such a droplet. In time its stars will be stripped away and separated and its interstellar gasses and plasma will become molecular clouds within he galaxy disc.


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