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Even G1 contains a black hole! January 17, 2007

Posted by dorigo in astronomy, Blogroll, internet, news, science.

Thanks to Kea for commenting a former post here, directing me to an article I had not read at int.stsci.edu. The article describes the ongoing searches for black holes in globular clusters of other galaxies.

Through it I got to know that the massive globular G1 in the Andromeda galaxy, 2 million light years away from us but still bright enough to be observable with amateur-sized instruments, contains a black hole weighing about 20,000 solar masses. G1 is the middle fuzzball in the green circle (the two other dots are foreground stars belonging to our galaxy).

Spectacular news! Especially since I did see G1 one month ago, see https://dorigo.wordpress.com/2006/12/15/my-first-andromeda-globular-cluster/ …


1. Kea - January 17, 2007

Amazing stuff, isn’t it? And note the finding that BH mass always scales with the mass (star matter) in its environment. I’d like to know how the Concorde Cosmology explains THAT!

2. dorigo - January 17, 2007

Yes, the observation that the black hole mass seems to always be a 0.5% or so fraction of the container body’s mass is intriguing.

Could it be a hint that we are observing the universe in a particular state ? The fraction must be a function of time if the black holes are what keeps the systems together.

I am not familiar with the Concorde Cosmology! (blush) I promise this is the last time I get embarassed by my ignorance on this…


3. Kea - January 18, 2007

Tommaso, the Concorde Cosmology is the standard one with Dark Energy and billiard ball type galaxy formation and colliding black holes etc. They don’t usually spell it with an ‘e’ on the end – that was Louise’s idea. And yes, you are right, in the new cosmology cosmological epoch (measured ‘locally’) is an important concept, and many basic observational parameters will be related to it.

4. dorigo - January 19, 2007

Ah, I see. Thanks for the explanation. I am now in the process of browsing through the new book by Perkins on particle astrophysics – an easy read for starters.
One thing the mass relation seems to tell me, with my limited knowledge of these facts, is that we could be seeing the universe in a situation where by chance an equivalence holds between the ratio of BH mass and container for different containers.
Hmmm that smells of anthropic reasoning, doesn’t it ? The other option is that there is a relation between the rate at which black holes collect material around them and the rate at which they eat their lunch…

5. Doug - January 20, 2007

dorigo on 19 JAN writes “… by chance an equivalence holds between the ratio of BH mass and container for different containers.”

I do not disagree with this statement, but instead only offer two alternative perspectives.

1 – Perhaps for equivalence, one might be able to substitute equilibrium or optimum which are from the applied mathematical language of “Dynamic Noncooperative Game Theory” by Tamer Basar and Geert Jan Olsder, revised 1999 from 1982. These authors refer to their work as a type of representation theory. There is emphasis on the Isaacs condition for the Hamilton-Jacobi. [From my prespective, game theory appears to be so constucted as to encompass set, topology and probability theories (and perhaps other mathematical theories).]

2 – Perhaps the 0.5% ratio is a constant as “The fraction must be a function of time …” [dorigo on 17 JAN] in a manner related to the speed of light [distance per time].

6. dorigo - January 21, 2007

Hi Doug, yes, probably equilibrium is a better concept. However I am confused by your citation of game theory – probably because I am not well enough learned in cosmology. Maybe you can be less cryptic for the benefit of the rest of us ?


7. Doug - January 23, 2007

Hi dorigo

If I am cryptic, it is only because I am still learning mathematical game theory and therefore inept in my expression.

I speculate, hopefully with insight, that Nature, including cosmology, physics and biology, have an economy based upon specific gauge / scale energy exchanges that influence function, longevity and existence.

In this manner, the applied mathematics of the Nobel category of economics may be applied to other sciences.

This is like Wolfram, but perhaps broader, since cellular automata tend to use rules. I think that equilibia (saddle point, Nash or Stackelberg) may result from any interaction of entities, capable of energy exchange, allowed to be a players. Such interactions probably have a mathematical representation in game theory

Other references:

1 – Paul-André Melliès [Google can translate French into English]
CSL 2006 and LiCS 2005 vintage talks

2 – Steven M. LaValle, ‘Planning Algorithms’, 2006

3 – Game theory, From Wikipedia

8. dorigo - January 23, 2007

Hmmm, I sort of understand your point now. I am still confused, but at a higher level. Your approach of finding similarities between quite different systems, however, is certainly useful.
Equilibrium is a very particular case in the dynamics of a system, and the conditions for its occurrence must thus be quite general.

9. Doug - January 25, 2007

There is a Nature letter dealing with “infotaxis” for chemostasis that is comparable to what I am trying to express. I provide the editor’s summary.

Nature: Volume 445 Number 7126 pp339-458
Editor’s Summary 25 January 2007 Information trail
Chemotactic bacteria are guided towards the source of a nutrient by local concentration gradients. That works on the microscopic scale, but at larger scales such local cues are unreliable pointers — for example, wind or water currents may disperse odours sought by foraging animals. Using statistical techniques, Vergassola et al. have developed a general search algorithm for movement strategies based on the detection of sporadic cues and partial information. The strategy, termed ‘infotaxis’ as it maximizes the expected rate of information gain, could find application in the design of ‘sniffer’ robots

News and Views: Mathematical physics: On the right scent
Searching for the source of a smell is hampered by the absence of pervasive local cues that point the searcher in the right direction. A strategy based on maximal information could show the way. Dominique Martinez

Letter: ‘Infotaxis’ as a strategy for searching without gradients
Massimo Vergassola, Emmanuel Villermaux and Boris I. Shraiman


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