Black Holes, Galaxies & Stars

Now that much of the inferred population of the universe's black holes has been found the overall picture seems to be like this.

In their youth, galaxies form stars and black holes together as the primordial gas and subsequently added dust (you don't get dust until the first generation of supernovae have gone pop and spilled their heavier elements - "metals" in astronomical terminology). The black holes at the centres of galaxies grow until they become quasars and the intensity of their own radiation holds back the very material they need to grow further, which leads to the general observation that central black holes are typically about 0.2% of galaxy mass (I think that's the right figure).

[Side note - now we have found the hidden population of black holes, we can infer something about quasar structure by comparing the numbers we can see directly with those we see indirectly through the infra-red etc. from surrounding dust.]

If this picture is broadly correct, then there should be a typical upper mass-limit for organically grown black holes.

My conclusion from all this: central black holes of greater mass should be indicative of galactic mergers and the mass of such holes might even be a proxy for the number of mergers that have occurred in the course of a particular galaxy;s history (complicated of course by the original size of the galaxy cluster etc.). It is interesting to consider that, whilst the specifics would always remain vague (barring identification of specific sub-populations of stars by e.g. velocity, age, etc. - we can do this for the Milky Way, and have found the remnants of several mergers this way, but it becomes increasingly difficult the further away a target galaxy is), one might be able to infer something about the original sizes of clusters, super-clusters etc. in the early universe from present day observations; or, running the logic in reverse, the more we learn about early cosmological structure, the more we may be able to infer about the dynamics of galactic mergers.

Just a thought. Just more Stuff.

Update on IT

About 1/3rd of the way through the mark-up, and out of idle curiosity decided to to a word-count: 150,082 words.

I started making the corrections etc around 4th September (about 7 weeks ago, but ~2 weeks lost to travel, dentistry, visits from friends etc., so let's say 5 weeks work) when the word count must have been around 146,000...

Whoa! That means by the time I've finished the mark-up it will probably have grown to ~160,000 words - and that's before I put in the two missing episodes, put back in the right place a (small) chunk I took out recently and rewrite the one remaining absolutely awful chunk... oops! We could be heading for a novel of ~180,000+

Good news for insomniacs.

Marshall McLuhan

Marshall McLuhan is, as far as I am concerned, famous for two things:

1. Occurring in a Genesis song called Broadway Melody (on The Lamb Lies Down on Broadway), and
2. Coining the phrase "the medium is the message"

However, I think the message needs updating. It was one of those nice-bar (Szimpla probably), nice-conversation questions: has modern technology (mobile phones, the internet) destroyed communication? My wife claimed that communication was now so casual that we no longer said very much to each other. Once upon a time, a telephone call was an event - one had to go to the phone, and the callee had to go to their phone in order to converse; it was not inexpensive and a quiet environment was preferred so that one could concentrate on the substance of the call. Ditto letters (I say "ditto", you say "diddoh") - pen, paper, envelopes, stamps and a trip to the postbox. Wow! A letter was even more of an event that a phone call.

Then we got the fax; faxing was for (almost) everyone (unlike telex - anyone remember that? Is it still used?). Then we got mobile phones - or, rather, phones that could in principle be lugged around. Then we got the net. And finally everything got smaller, faster, cheaper (and some of it blew up on the launchpad or dived straight into Mars at umpteen miles per hour - or was it km/s... I think that (a metric-imperial unit mixup) was the problem) and it became trivial to communicate.

So now we chat, txt, email, blog, upload videos, mashups etc. etc. etc. at the drop of a proverbial hat (whatever happened to hats?).

Conclusion: how we do these things is no longer important. That we communicate almost at will over arbitrary distances with friends, family, colleagues - anyone - about anything, at any time of our choosing is far more significant.

The result is that the medium is no longer the message - the message is the message.

Twinkle, Twinkle...

If a picture paints a thousand words... then why can't I paint you? No, that's not right at all - this is not a Telly Savalas shrine! What I meant to say was, whilst images may be incredibly powerful - conveying as they do messages in content, style, form and medium - a word, like scents, may be a key to unlock a treasury of memories.

For reasons which, though recent, I have already forgotten, I was looking up the word "vivific" (which means, incidentally, "Life-giving, enlivening, vivifying" according to the OED) and suddenly remembered a little rhyme my grandfather taught me, a variation on "Twinkle, Twinkle, Little Star", which goes like this...

Scintillate, scintillate
Globule vivific,
Fain would I fathom
Thy nature specific.
Loftily poised
In the ether capacious
Strongly resembling
A gem carbonaceous.

And again, thanks to the internet I now know where he got it from: one John Raymond Carson. (though when he wrote it I don't know)

Aw! Isn't that nice?

Bored, Fed Up, Tired

Today I be mostly wasting time - hence "On Salamanders". Having marked up the printout of the book ("IT") - all 400+ pages with copious amounts of purple ink (couldn't find a red pen) I am now ploughing through the mark-up and correcting things.

Unfortunately, a single wrong word can completely bugger a metaphor or, worse, series of linked metaphors; and the rhythm and the flow and... and it can take hours to change that single word because it's like pulling on a loose thread in a sweater: paragraphs to either side start to come unravelled and then they have to be re-written.

So I've given up for today having just had to sweep a nice one-man-cavalry-charge metaphor under a 3 hour long metaphorical carpet.

Alas, IT is much improved by all this editing... but when will it be finished? It feels like a Sisyphean task of epic proportions... and my liver's giving me gyp too... I need a drink...

Ah! The Agony and The Ecstasy. When will it be finished? When IT is done.

On Salamanders (again)

What is natural? Where should we looked for the telos of a thing - and how should we value it?

Why should we care? Why do I care? Because I've just I've just been gobsmacked by a preposterous assertion about "genetic purity".

Are you sitting comfortably? Yes? Then I'll begin.

According to this story, it seems that the native California tiger salamander (an endangered and protected species in the US) has been interbreeding with introduced Texan tiger salamanders (tsk! tsk!). Unexpectedly though, the offspring seem to show "hybrid vigour", a characteristic more typical of plant hybrids. Technically, a hybrid is the offspring of parents of different species, and to have vigour means in this context that the organism survives not just well, but better than either of its progenitors (and by survives better I mean surviving and having more offspring - it's no good just lasting forever if you don't breed, evolutionarily speaking).

Where hybrid vigour arises, one may therefore expect the hybrid to displace both progenitors, unless (remember the important "on average" - which can be defined in terms of population extent, environmental range, niche qualities etc.) the progenitors nonetheless survive better than their hybrid offspring in particular environments.

Picture: Three types of salamander larvae: native California tiger salamanders (Ambystoma californiense), barred tiger salamanders (Ambystoma tigrinum mavortium), and the hybrid offspring born when the two species mated. (Credit: Bruce Delgado, U.S. Bureau of Land Management) [Used without permission]


And?


Apparently this "raises difficult questions" because whilst some might say that hybrids should be tolerated since "they are favored [sic] by natural selection, and 'improve' the original species", some others - this is the good bit - "might consider hybrids to be genetically impure and regard them as threats to the native salamanders, their competitors and their prey."

How on earth could the hybrids be genetically impure? They are not Californian tiger salamanders, nor are they Texan tiger salamanders - they are what they are. They are pure salamander. Yes, they are different to both progenitors but what is the justification for choosing either to be the standard for "tiger salamanderness" against which the newcomer should be assessed?

The issue implies some sort of telos for which we should have due regard, in much the same way as opponents of genetic "engineering" might object to the modification of pigs (for example as sources of tissue for xenotransplants) for destroying the "pigness" of the pigs concerned.

Whilst I don't intend to debate the philosophical status or significance of telos at any great length ("great" clearly being a relative term), the question nonetheless has to be asked: where or how could telos have its origin? Before sperm and egg combine, they might be considered to have their own telos, but once the egg has been fertilised both lose their separate identity. Where does the telos go, or how is it transformed - and if it can be transformed or vanish naturally, what limitation should we impose upon ourselves with respect to any alteration we might wish to make?

Many might claim (thank god this isn't academic and I don't have to supply citations to support such assertions!) that God - particularly, and hence the initial capital, the deity of one of the monotheistic religions such as Christianity, Judais, and Islam) - takes care of telos, its origination and continuation. But take any such idea too literally and we would be unable to breed animals or plants using even the old-fashioned methods; we would instead have to content ourselves with whatever offspring occurred by chance (and I'll skate over the difficulty of what to do with a particularly nice - but entirely natural - strain of wheat, for example, that just catches your eye... should you favour its seeds over those of its less appealing neighbours when you plant your next crop?).

Whatever claims might actually be made, sooner or later one must stand upon the edge of Ginnunga Gap between the icy purity of deontological ethics and the industrial heat of pragmatism, utilitarianism, etc. - and just stare across: there is no pleasant balmy island in between. If one adheres to the idea that God decides the way things are, then no mortal idea of harm or benefit can affect the status quo.

Or can it? God has traditionally given human beings Free Will (by which I mean that various traditions claim this for their deity, rather than the interesting (but not very useful idea) that God has traditions, and that one of them is to give human beings Free Will whenever he creates them) and free will implies choice.

The real question is how we exercise that choice - and in particular the criteria to be used in weighing our choices.

I cannot see that we can value one species higher than another a priori. We can - and should, I suggest - value diversity above homogeneity, and for that reason (trying to bring this post to a end without boring the pants of everyone - including myself) we should be delighted at the emergence of these hybrid salamanders and we should endeavour to preserve the native Californian tiger salamanders as a distinct species.

If the two objectives are in conflict in California, then as long as both Californian and Texan salamanders exist elsewhere (and continue to be able to interbreed!) we could perhaps consider the extermination of the xeno-salamanders. We would lose the prospect of further delights arising from the development of the hybrids (unless we put them somewhere else, or breed them in captivity, or...) but whereas, given the criteria specified, we can have them back at any time, unless we can reverse engineer the Californian salamander and resurrect it should it die out, as things stand once they're gone they're gone and it would seem better to try to protect them now.

Salamanders are also interesting for some very non philosophical reasons, mostly to do with their folklore: they were supposed to be immune to fire... but do you really want to hear about that too?