Size perspective on stars, planets and moons

Here's a rare opportunity to gain some perspective on celestial bodies, courtesy of Wikipedia.

In the first set of pictures, the order of magnitude successively builds up through our planets and different types of stars.

perspectives: Earth, planets, Sun, and other stars

NOTE: to view better, click on the image to expand, or see the original

(1) = Mercury, Mars, Venus, Earth;
(2) = tiny Earth against far larger twins Neptune and Uranus, then gas giants Saturn and Jupiter;
(3) = tiny Jupiter and red dwarf star Wolf 359, next to the Sun (a white main sequence G star), then, white main sequence A star Sirius A, near neighbour (8.6 light years) and our brightest actual star;
(4) = tiny Sirius next to orange giant star Pollux, then red giant Arcturus, then Aldebaran, another orange giant;
(5) = tiny Aldebaran and blue supergiant Rigel, next to red supergiants Betelgeuse and Antares
and finally
(6) = Antares, hypergiant S Doradus, red supergiant KY Cygni, and red hypergiant VV Cephei A*.


It's a very useful way to represent varying orders of magnitude. Resolution is better in the original, where the names are clearer*.

By contrast, another way of comparing them is by mass - this gives an idea of density rather than size (volume) above - this shows that some of the stars above are relative puffballs.  Solar mass is typically used: one solar mass (M_o is the mass of our sun, or about 2x10³⁰ kg.  Using that measure:
Wolf 359 (red dwarf) = 0.09 M_o
Sun (white G) = 1 M_o
Sirius A (white A) = 2 M_o
Pollux (orange giant) = 1.9 M_o
Arcturus (red giant) = 1.1 M_o
Aldebaran (orange giant) = 1.7 M_o
Rigel (blue supergiant) = 17 M_o
Betelgeuse (red supergiant)  = 18 M_o
Antares (red supergiant) = 15 M_o
S Doradus (hypergiant) = 45 M_o
KY Cygni (red supergiant) = 25 M_o
VV Cephei A (red hypergiant) = uncertain! - 25 - 100 M_o

Update 11-Aug-10:
A new star was announced in July, the most massive found yet.  Called R136a1, its mass is said to be 265 M_o - so that is now the current upper limit for mass.


Our nearest neighbours, Venus and Mars, are quite different from each other, in composition as well as size. Mars' radius is only about twice that of the moon. Venus is closer to the sun than Earth; its oceans were boiled away 4 billion years ago. Mars has traces of ice, but no liquid water, as its atmosphere is (now) too thin.

It's worth scanning through the full originating article on stars, for some points of interest. Our sun is quite small compared to other stars, but there are some that are smaller (and denser), having burnt out and collapsed. The article also lists the various types of star by name, but actual stellar classification is much more complicated.

The other picture shows various moons of the solar system in scale against Earth.

Moons of the solar system, compared to Earth
for better resolution, click on the image to expand, or see the original

This includes the two biggest moons, Jupiter's Ganymede (rock and ice, often featured in science fiction stories) and Saturn's Titan (dense atmosphere, surface liquid), which are both larger than the smallest planet, Mercury (which is slightly larger than the third biggest, Callisto at bottom). Our moon is the largest of any rocky planet in our system, having broken off from Earth early in planetary formation after Earth was hit by an object of about the size of Mars.


*You can also look at the current Wikipedia holding on relative sizes, which shows our system's full planet range.  You can also scan through the Wikipedia list of most massive stars.  Note the discussion there, indicating there remains some uncertainty at the big end (which is largely theoretically inferred), to the extent that the various Wikipedia articles and pictures have inconsistencies.

Turnbull performs as expected

Former Prime Minister Paul Keating offered current Prime Minister Kevin Rudd some advice about the then-new opposition leader: He's brilliant, he's fearless... and he's got bad judgment.

(Reported by Peter Hartcher in Saturday's Sydney Morning Herald.)


Keatings words could easily be Turnbull's epitaph. If you're going for the PM's jugular, it pays to have more evidence than a single email - as Turnbull found out, it could be forged.

The fact that Turnbull pushed it so hard - and with such personal arrogance in one or two conversations - is fully reflected in the three opinion polls released today, which show a plummet in support for Turnbull and the Liberals. Of course, he'll survive this... and could well lead the Liberals to defeat at the next election - for precisely the reasons I expected when Turnbull was on his way up.

Irrationality in economics and housing

Orthodox economics is often assumed - by both lay people and economists - to be a bastion of rationalism, where 'free markets' dictate optimal outcomes.

Of course, this rationality is not true, and the optimality begs the question of what or who a given free market outcomes favours. And whether we, as a society, want - 0r know - all of the ramifications of a particular outcome. This is one reason we legislate.

In economics as in all human endeavours, there is a frequently-hidden lack of rationality in human behaviour. With some experience with economics, it becomes apparent that 'free markets' lie at the intersection of rational determinism and irrational human psychology. Those at the libertarian end of the spectrum who favour removing the shackles of legislation are often ignorant of, or concealing, the full implications of such action.

Ross Gittens, the Sydney Morning Herald's Economics Editor, is fond of exposing the oddities of economic outcomes due to human behaviour. His latest commentary pertains to the effects of the government's First Home Owners Grants. On the face of it, the grants might sound laudible: with a housing market that is increasingly beyond the reach of new owners, taxpayers subsidise new entrants; and at the moment the economic stimulation would be a good thing.

However. The grants have been entrenched since 2000, well before the economy needed stimulating. Although they are now being treated as stimulation, the nett effect in this sense is that removing the grant would depress activity. Yet it has also been claimed that a cost to the government of $200m has blown out property prices by $3b.


Gittens argues the case that the raw appeal of free money has been responsible for a good number of the new housing entrants. His point is that this housing activity has been greatly exacerbated by the psychological effect of touting the grant as a 'limited offer' (which it currently is) of 'free money' - so grab it now. As a result, so many new players at entry level have been driven up the price of an entry-level home by more than the value of the grant. He suggests the best action is to wait for the grant to finish, and buy in when prices fall by more than the grant's value.

Of course, the other side of the coin is the creation of a property bubble that can induce a lot of defaults by people who have over-committed and whose situation then changes (usually through the reduced income of unemployment). This may well coincide with falling house prices once the grant comes off - and higher interest rates kicking in. This potentially risks affecting any economic recovery - making it much weaker and slower, or collapse altogether. Yes, interest rates are at their lowest since 1968. But the average Sydney house price in number of years of average earnings has shot up to nine times average annual income - more than the seven times average of the US and UK when their property bubbles burst (see here). It was three times the average annual earnings from the 1950s through the 1970s, which gives an idea why housing was more affordable for previous generations.

Gittens also gives as example a limited-time offer of $1m superannuation contributions being made tax-free, which induced people to borrow to take advantage of the tax windfall, only to see the investment crash by a far greater amount (than the tax benefit) when the sharemarket crashed. He reports advice - a general truism - not to get so carried away as to buy assets that weren't needed, nor take on more debt than could be handled. In these times of uncertainty, due caution helps.

Iran's election result was doctored

Were the declared results of the Iranian election accurate? Did hardliner Ahmadinejad win resoundingly?

Western governments reacted quite cautiously to the announced results - primarily because they had no information (such as pre-election polls or exit polls) to gauge the fairness. Obama was excoriated by the American right for not speaking out, but as he said, he didn't want America to become the issue, and to have external and internal groupings close ranks simply because of an American pronouncement.

But as heard on BBC World Service radio, an analysis from the UK's Chatham House and St Andrews University has now cast serious doubts on the validity of the declaration. The research was conducted on declared results specifically on a province-by-province basis. Results indicate, inter alia, that:
- in two conservative provinces, a greater than 100% turnout was recorded.
- did an increase in voter turnout swing it? No, because the greatest swing to Ahmadinejad didn't occur in the provinces with greatest increases in turnout.
- For the official results to be true, in a third of the provinces Ahmadinejad would have had to take all previous conservative and centrist votes, all new votes, and 44% of previous reformist votes, which belies continued tensions between reformists and conservatives.
- Ahmadinejad was "markedly unpopular in rural areas", which belies the claim that he triumphed in the more rural provinces.


The BBC's report comprised an interview with one of the researchers, who added several years of recent anecdotal personal experience in Iran, which fleshed out and backed up the analysis of figures.

Further comment was offered that there was an equivalent divide behind the scenes. One aspect of this was that former president Rafsanjani, a reformist, is currently chair of the influential Assembly of Experts.

The Iranian ruling Guardian Council had been assessing some of the results, but this evaluation was of a relatively small number of votes, and didn't look at wider provincial results. They thus reported no major irregularities.

The BBC report also indicated that new (internet-based) media was playing a significant part in information dissemination, so press restrictions are, to some extent at least, not as effective as those in power would like.

The world is watching, yes. But at this point it's hard to see the status quo being overturned: current unrest in Iran is not - yet - at revolutionary pitch. When - if - it all settles, the only lasting effect may be a taint on the legitimacy of Ahmadinejad, and Iran's voice in the world.

Sadly, I can never find web references to the full BBC radio reports, but I found one BBC report on that analysis here; the Christian Science Monitor also has a summary here. Chatham House's full report is here.

Duane Allman - AND band

I'm only a recent convert to the Allman Brothers Band, despite having had several of their albums for some time.

By that I mean, I have appreciated them like I appreciated a lot of music, and the sheer genius of Duane Allman is inescapable. But I have only just come to appreciate the full mastery of the band. At its peak, music rarely gets better.

To convert to Duane Allman, it's enough to listen to him on Boz Scaggs' 1969 Loan Me A Dime.  After that, a wealth of Allmans music awaits. Yet it's easy to overlook the achievements of the band under the shadow of Duane. It takes a close reading of a few tracks from their live At Fillmore East recordings (original album and subsequent releases from those concerts) to properly appreciate what they can do together that nobody else could.

When I first sought out Miles Davis, I stumbled across A Kind Of Blue; without knowing it, I'd come upon what is often acclaimed as one of the best jazz albums ever.

Duane, at the time of the Fillmore East recordings, said: "I've listened to that album [A Kind Of Blue] so many times that for the past couple of years, I haven't hardly listened to anything else."

Now I've been a harsh critic of Miles Davis for the instigation of jazz rock. However, the Allmans introduced the complexities of jazz-like improvisation and timing to rock music in a way that preserved the best of both worlds, rather than the worst. To begin to understand the intricacy of their jamming, it's enough to read appreciations of a couple of the Fillmore tracks: In Memory of Elizabeth Reed and Whipping Post - preferably while listening to the music. Whereas I once thought the Allman Brothers were simply steeped in blues with the number of standards they covered, I now appreciate that they were capable of using practically any song as a starting point for their music: the song itself didn't matter (Mountain Jam derived from a song of Donovan's, of all people) - and indeed, Greg Allman's vocals, although very apt, were really only background to the music as a whole.

Two drummers, two lead guitarists, and it worked. As the other lead guitar, Dicky Betts was doomed to remain in Duane's shadow, but he is so good in his own right that people often mistake his parts for Duane's (seek out 'Duane Allman's best guitar lick ever' on YouTube - comments indicate that it was actually Dicky Betts'). The whole of the band, together, jamming, were simply better than the parts.

An essential part of my kids' musical education.

Damned statistics and climate change

A news item in the local Southern Courier discussed the privately-owned train link to Sydney's airport.

• Botany Bay's Mayor Ron Hoenig: "In reality, it was shown to be cost inefficient, and a disaster."
• In response, "Airport Link chief executive Tim Anderson... said there had been a 27 per cent increase in patronage on the airport line over the past two years."

The context was the exhorbitant charge for that particular stretch of rail ($14.80 from central, one way), and the effect on locals who might otherwise use it.

Put aside other issues, such as whether the patronage increase justifies the usage charge, or whether the increase was from such a low base that any change would look like a win.

The question is over the use of the statistic, and how it can mislead. If Anderson looked at the fluctuating usage figures over the past 9 years since opening, he could pick any two years he liked to make his point. Likewise, Hoenig could pick any other years to justify the opposite perspective. For a reality check, read about Airport Link above.

As with a work of fiction, most people don't stop to question figures presented in a news report. There's just not enough time in the day to analyse everything.


Climate change skeptics are particularly guilty of this. As this article details, Steve Fielding, a key balance-of-power Senator, was persuaded that there is no significant issue because global temperatures are not significantly different from those of ten years ago.

And that is a favourite approach of climate change skeptics - near universally, they use this trick (eg The Great Climate Change Swindle). Pick a year that was slightly out of kilter with its neighbours (in this case, 1998, which had a strong El Nino weather pattern) to prove the case. Take that statistic in isolation, without revealing or analysing the sequence of readings over time. Which in this case show that the past ten years have been the hottest decade on record.

(An extension of this argument is the use of long-range figures to show that Earth's climate has always been changing, and has indeed been hotter. True, but a) significant evolutionary change - including much species extinction - accompanies such changes), and b) we are currently inducing one of the fastest periods of climate change in the planet's history.)


It's devilishly hard to read statistics with a critical eye, if you don't have access to the full data set. The best that can be done is to scan for context. (In the case of Fielding, he's known as a conservative who is not fiercely intelligent, and he went fact-finding to the US, hosted by the Heartland Institute, known as conservative and funded by fossil fuel and tobacco interests, amongst others.) Scanning for context includes a healthy degree of questioning, critical analysis, and absorbing information from a variety of credible sources. But you knew that already, didn't you?

Australia and the complexities of racism

India press has been awash recently with news of racism in Australia, specifically in the context of claims of attacks on Indian students in Sydney and Melbourne.

From Sydney's west comes stories of violence against Indians in Harris Park. A column in the Sydney Morning Herald puts a bit of context on this. Tanveer Ahmed paints a picture of Harris Park as home to successive waves of fresh migrants to Australia, formerly Mediterranean or Lebanese, and most recently Indians. In fact, when I worked close by there a few years ago, I noticed a heavy preponderance of Indian shops, with no particular signs [left] of previous communities maintaining a distinct identity. As always happens, the waves of migrants tend to blend in over time.

The writer positions recent violence in Harris Park specifically in the context of second-generation descendants of original migrants: "the worst racism encountered by the average migrant is usually from other migrants".

I would add a few anecdotal observations to that, having first arrived in this country something over twenty years ago. Coming from a similar culture, I could blend in barely noticed, yet I observed with fresh eyes the attitudes of Australians to those who were different. First, outward manifestations of violence [and racism] tend to come from young males (of course), say about 15 to 25. There was little overt racism towards earlier migrants, but noticeably more so towards recent arrivals. Those that are obviously different in speech and culture were the most likely targets - and, for example, if someone of darker skin spoke perfect english, they were more easily accepted.

But, I noticed at the time, Australians as a whole seemed to reserve their most vituperous ill-feeling to the original inhabitants - aboriginals. Having seen both sides - through both aboriginal friends and being on the receiving end of violence - I know better than to lump everyone into one basket. Not so your average Australian, who had simply not had any day-to-day involvement with any aboriginals, and so absorbed simply what they were exposed to by tabloids and talkback.

So yes, there is racism here, but I very much doubt that its worse than any multicultural country. And yes, where there is racism, it's most likely to be directed at aboriginals or recent migrants - yet the latter receive the press, while aboriginals just suffer day to day.

I would also add that those of the dominant culture are quite blind to the subtleties of racism, and would be quite ill-qualified to put a believable case against the existence of racism.

My personal feeling is such barriers best break down in situations where people are working together and get to know representatives of a variety of cultures. There's nothing like a multicultural workplace.

Current effects of climate change

A couple of recent news items reported on some slow but relentless current effects of climate change - let alone future outcomes.

New Scientist mentioned a report released by the Global Humanitarian Forum (led by ex-UN Secretary General Kofi Annan). Inter alia, it concluded that climate change is already causing 300,000 deaths annually. This is due to "gradual environmental degradation", including droughts, floods, and crop failure.

And the Sydney Morning Herald showed that it's not only those situated in low-lying coastal areas that will see their land disappear. The article is illustrated with a picture of someone whose coastal home is perhaps eight metres above sea level, but which is already being eroded. Both rising seas and more extreme weather will hasten that process.

My home is possibly four metres above sea level, and about 1000 metres inland. I would have thought I would be buffered by the intervening hectares of infrastructure that would need protection first, but current government policy suggests socialising the cost of protection would be far too costly, and future governments may opt for slow strategic retreat. I take cold comfort in the thought that the Sydney Opera House is more precariously positioned than me, right now.

Mission Obama: Middle East

Before Obama's middle east speech, I heard a senior BBC news editor interview him. His responses were very thoughtful and candid - albeit to the more diplomatic end of the scale when asked if Mubarek was a dictator. Afterwards, the editor commented that he saw Netanyahu after his talk with Obama - the discussion which ran twice the scheduled 60 minutes worth - and that Netanyahu looked particularly grim-faced - as if he'd been given a good talking-to.

Obama can achieve without taking action. His middle east speech was masterful in what it says to both sides: two states, settlements out, but the alliance with Israel is powerful. When the BBC canvassed comments on it afterwards from a range of people, it was notably only the Israeli and Palestinian extremists that had anything negative to say about it - all else was praise. A good illustration that Obama was on the right track.

He has already succeeded in wringing concessions out of Netanyahu: not yet on the settlements, but at least on the two states.

And his speech was exquisitely timed - probably intentionally - to have some effect on the Iranian election. In the leadup to that election, there was a degree of political activism in Iran that many commented they hadn't seen since the 1979 revolution.

The outcome - to date - of that election seems to have run counter to everyone's expectations, given the mood on the ground beforehand. Which is probably why many are calling fraud - a vote of over 60% for Ahmadinejad is tantamount to absurd. Situation still unfolding.

Early Le Guinn science fiction

Just finished Ursula Le Guinn's Rocannon's World, which was thrust upon me by a friend.

It was a fairly easy read; I found out afterwards that it was her first, published in 1966. Yet that belies the facility of language that Le Guinn already possessed, and a literacy that was rather less common in science fiction, even up to the 1960s.

Certainly in the 1950s and beyond, science fiction was largely devoid of literary pretensions: it was the novelty of ideas that mattered. To my mind there were more raw ideas presented in 1950s science fiction (my particular interest) than all other genres put together.

Rocannon's World has more of interest in the quotidian prose than the plot. That plot largely consists of a heroic quest to save a world populated with a variety of fabulous beasts and sentient creatures. That could be given as a description of Tolkein's Lord Of The Rings, and that might not be a coincidence. (It should also be noted that the depicted cultures in this book present a somewhat idealised feudal class structure, possibly more pronounced than that of Tolkein, but which Le Guinn undoubtedly drew back from in later work.)

In this case, the epic journey is pretty much the entirety of the book. The denouement is almost an afterthought, consisting of little more than a very late deus ex machina, plus a hurried mission fulfillment.

Yet it is a pleasant read, as much for its slightness as for its language and ideas.


Le Guinn was later to win the two main science fiction awards (Hugo and Nebula) for a 1969 novel, The Left Hand Of Darkness. That book was set in the same universe Le Guinn created in Rocannon's World (and, coincidentally, that was another novel that was thrust upon me - so many years ago that I barely remember it). The stories of that universe, dubbed the Hainish cycle, are an admixture of science fiction and fantasy. By contrast, the Earthsea stories, for which Le Guinn is arguably better remembered, are a more pure fantasy genre.

Climate change and the politics of pseudo-science

In the midst of the absurdity that constitutes current debate on climate change, Steve Fielding, an absurd Australian politician, has illuminated some of the reasons such a debate remains festering long after rationality has won through.

Fielding, a quixotic conservative (who scraped into parliament on preferences and votes from people who didn't realised where his 'Family First' party stood on anything), has latched onto an issue that he doesn't realise has left him all asea.

He had argued that a) debate on climate change had been stifled, and b) global temperature rises are not anthropogenic (human-caused) in origin.

Fielding's views - and the reactions to them - are discussed in this article. In a nutshell, he had based his understanding on a single, selective source: Heaven And Earth, a book by Adelaide geologist Ian Plimer.


Lessons:
1. Don't expect politicians to appreciate that their leadership position behooves them to at least attempt to act wisely.
2. Getting your information from a single source - and then not reading critiques of said source - does not make you wise.
3. As quoted in the above article, a book that is "an opinion of an author who happens to be a scientist" does not necessarily equate to a "work of science".


This last point is the most salient, as it gives some insight into how easily people's understanding gets hijacked if they don't a) don't appreciate how scientific consensus is formulated, and b) don't read much.


11-Jun-09 update: According to a more recent news report, "Senator Fielding's newfound scepticism is a result of his trip to the US to listen to the Heartland Institute of Chicago, an organisation that is funded by the fossil-fuel industry."

I would say that people are responsible for their own reputation, and are entitle to muck it up as they choose. Unfortunately, the ramifications are a little more severe: he is one of several people that hold the balance of power in the Senate, and so is uniquely placed to derail any government initiatives on climate change. Yet to pile irony upon irony, the government's plans are quite sub-optimal, so at this point it is hard for anyone to tell for sure whether Fielding's stumblings will help or hinder the cause.

Gillard's rising star

(Finally opened up my spare keyboard and fixed it, so I can type out a few words.)

I've mentioned before our impressive deputy Prime Minister, Julia Gillard (including here and here). I'm not the only one to have perked up, though.

Peter Hartcher, The Sydney Morning Herald's political editor, gave her a warm writeup a few days ago, which placed her star in greater ascendancy than I could have expected.

Her biggest problem is that she comes from the Victorian left of the ALP, and the left would never have the numbers to get up their choice for leader - especially, Hartcher says, due to specific anomosity from the NSW right wing.

However, by Hartcher's account, she has won everyone over with her competence and intelligence. That would not normally be enough for the right wingers, but apparently she has proven her mettle to them by not being beholden to some on the union left (of particular note: standing up to the CFMEU against some of their shoddy practices in the building industry).

Hartcher characterises Gillard as moving from the left more towards the centre in recent times. Regardless,

Rationality on war

A fascinating interview with a counterinsurgency expert, David Kilcullen - an Australian who advised the Bush administration in its later times.

He's actually quite the opposite to what you'd expect - ex-army, but a doctoral graduate in anthropology, and an ethical expert on war, terrorism, and counterinsurgency.

You can listen to it here.

Victorian Conan Doyle

Japanned box... toque... astrakhan... scurvily... bow-window... post-obits... Every so often, I'm pulled up by words that defeat me, in nuance if not in outright meaning.

Arthur Conan Doyle wrote much more than Sherlock Holmes. And reading through some of the esoterica has been a journey best described as interesting. I have a couple of non-Holmes Doyle volumes: one is along the lines of 'tales of the macabre', but the one I'm currently reading is called 'The Original Illustrated Conan Doyle', published in facsimile by Castle Books, 1980.

I have found little sympathy in late Victorian writing in general. For example, wherever my sympathies lie - and although many doubtless differ -
I had always found in the great science fiction progenitor, Herbert George Wells, a dry, unengaging tone, as is my impression of much Victorian writing.

But what is there so different about Conan Doyle? His style has a particular precision, which for some reason I find less dry than that of the similarly precise Patrick White. For me, he has a greater urgency - and intrigue, perhaps - than either White or Wells.

And, of course, it is so Victorian. And written as only befits someone of a class that would seem to have enough leisure and education to chronicle the times with a particular slant. Upper middle class, perhaps, with a due respect (never mind longing or aspiration) for the titled 'betters'. For example, a character that "was expecting a rather long visit to Bankruptcy Court" in the next breath was reluctantly "ordering my valet to pack my valise". Vicars and gentlemen populate his world, with the occasional (reluctant) doff for the earnt money of, say, the 'club-footed grocer'. A regional relative's "benevolence had been so universal" in his community that it drew "the supposition that he had Parliamentary ambitions".

Enjoyable, despite finding the flow interrupted by the occasional obscure period word.