Wednesday 30 March 2011

The Light of a Billion Suns

Merely a brief post this week to let you all know about the recent discovery of a super-luminous supernova. The description supplied in the article elegantly describes the magnificence of these astronomical marvels:

“At its peak luminosity, it was over 100 billion times brighter than the Sun. It emitted enough energy in one second to satisfy the power needs of the United States for one million times longer than the universe has existed.”

If ever we need to be reminded of the awe with which our ancestors looked upon the stars at moments of such change, we need only look at those stars we now see through the lens of our technology. Our means of watching have changed, as has our understanding, but simple human wonder remains constant.

Wednesday 23 March 2011

The Music of the Spheres

It is popularly known, predominantly courtesy of Holst’s The Planets, that people throughout the course of human civilisation have assigned musical patterns and harmonies to the movements of the stars and planets. This “musica universalis” sees early use in Hebrew mythology, which explains the cosmos as having movements and harmonies that are designed to sing the praises of the creator-deity. In that mysticism, there is an intriguing emphasis upon the interrelatedness of many aspects of the universe, including language, mathematics, music, astrology and the demiurge.

This search for such relationships is not, of course, unique to the Jewish people, as can be easily determined from my earlier blogs – constellations and the ‘study’ of astrology are, if anything, elegant proof of this desire. Of particular interest, however, is the fact that there is actually some validity in this particular belief.

Johannes Kepler, who gave us the laws of planetary motion, was a firm believer in a divinely-designed resonance between the planets, and used his observations and calculations to seek it out. Kepler’s great gift to astronomy was the realisation that planets orbit elliptically, rather than circularly, creating what are called the perihelion (greatest distance from the orbital centre) and the aphelion (shortest distance from the orbital centre). The variation in distance also, however, results in changes in a planet’s angular velocity, as it speeds up while closer to the orbital centre.

In his Harmonices Mundi (The Harmony of the World), he observed that the ratio between a planet’s least and greatest angular velocity relates to a musical harmony. Kepler found that maximum and minimum velocities of Saturn formed an almost perfect ratio of 4:5 (a major third in music). The motions of Jupiter differ by a 5:6 ratio (a minor third). Mars differs 2:3 (a “diapente”); Earth differs 15:16 (a semitone); and Venus differs 24:25 (a “diesis”, which is, intriguingly, the smallest difference considered generally audible to the human ear).

Kepler also discovered that nearly all of the ratios of the maximum and minimum angular velocities of neighbouring planets produce musical harmonies. The orbits of Mars and Jupiter represent the single exception, being a less flattering (or disharmonic) 18:19 ratio – in his defence, however, this dissonance could be explained by the presence of the main asteroid belt, which was not discovered for a further 150 years. Had a visible planet orbited there, it is feasible to believe that this pattern of harmonies could well have continued.

Wednesday 16 March 2011

Lines in the Sand

Much is written of the Nazca and their miraculous, monumental art etched into the arid plains of their Peruvian lands – and, alas, much of it is pseudo-scientific at best, and outright fallacious at worst. These writings range from the feasible attachment of those icons to the constellations (although the sheer mass of lines and figures makes such associations inevitable, rather than necessarily accurate), through to the ludicrously overblown claims that they could not possibly have been made without the assistance of extraterrestrials. Like the crop circles revealed to be hoaxes, rumours of miraculous coincidences and grand feats overwhelm the verifiable facts.

Rather than introduce something miraculous to the works of early civilisations, these theories do little but denigrate our ancient ancestors. As I have discussed on many occasions – and the general purpose of this blog is to continue to do so – I must assert the ingenuity of those who came before us. It is a simple matter, in days when gadgets we can fit into our pockets do much of our work for us, to assume that because we do not need to consider how to achieve such feats that it must have been impossible for people thousands of years earlier. In fact, it is worse than simple: it is an arrogance of modern society.

It is comparable, if you will, to imagine someone a thousand years from now looking upon the Eiffel Tower and, assuming records have been lost, believing that it simply could not have been achieved through the technology available at that time. It was, of course, possible, but required Gustave Eiffel to invent new means of construction; new varieties of crane to hoist the vast pillars of metal into place; it was possible, but accompanied by one of the very greatest of our achievements – which is to say, our incomparable desire to innovate.

The fact of the matter is, of course, that archaeologists have been able to replicate the Nazca designs using tools available to the culture of the era, with few people involved, and in relatively short order. That being said, of course, these symbols are magnificent works – truly remarkable feats of ingenuity and a manifestation of man’s desire to see their imagination and their works wrought large across the flesh of the world, as if in ink.

Wednesday 9 March 2011

Clouds that Give Birth to Stars

Nebulae are relatively widely-known as astronomical figures, but this was not always the case – rather, the term was indistinct, referring to a wide range of celestial objects. In fact, even into the early twentieth century, the term referred to those distant objects that we now know are whole galaxies.

Despite this early confusion, nebulae were always notable as objects to those cultures that paid close attention to the night sky. The earliest records of them as such come from the Maya and the Greeks, who noted that some areas of the sky appeared to glow with a diffuse light, as if many tiny stars were clustered in a small region. It was, however, many centuries before their true nature could be correctly defined.

There are three broad types of nebula, according to their ‘emissions’, which is to say, how they behave in accordance with light. Absorption (or ‘dark’) nebulae are clouds without stars within or nearby, and thus are characterised by their dampening effect on the light from stars beyond. Reflection nebulae have nearby stars whose light illuminates the gases of the nebula. The final, and more interesting kind, are called emission nebulae, and are the birthplaces of stars and planets.

Emission nebulae are regions of space in which matter comes together, forming dense pockets that, following all of the usual laws of gravity, gather other matter into themselves. As these gain further mass, their relative gravity continues to increase, faster and faster with the increase of mass and, thus, gravity. In the fullness of time, these pockets gain so much mass that the gravity holding it in place, condensing matter into such a confined space, results in the ignition of the matter, thus giving birth to a star.

If this were not enough, emission nebulae are also among the most beautiful of all astronomical phenomena – the Orion Nebula and Carina Nebula are worthy of special mention, while the Trifid Nebula is composed of emission, reflection and absorption nebulae, creating its wondrous lobed structure.

Wednesday 2 March 2011

Tales of the Stars

The stars are a common source of myth and legend – possibly the greatest source, if one considers the number of tales about the Sun, let alone the Moon and the other stars, which, combined, must surely dwarf the size of the Bible. Today, I’ll be presenting a few of my personal favourites.

In the mythology of New Zealand’s indigenous Maori, all of the stars, the Sun and the Moon were thrown into the sky by the god Tane, to decorate his father’s cloak. In the beginning, his father (Ranginui, the sky father) and his mother (Papatuanuku, the earth mother) clasped themselves to each other, giving their children little room to move. Tane’s brother, Tumatauenga, argued that they should kill their parents, but Tane, showing the strength of his legs, lay upon his back and forced them apart. Later, as an act of contrition for this, he threw the stars up to decorate his father and to give his mother a beautiful image of the husband she would never again embrace.

In ancient Canaan, Venus, the Morning Star, was called Athtar, and was a particularly ambitious deity. Upon the death of Baal, who sat upon the throne of the gods, Athtar attempted to take his place, but was rebuffed (either by the throne itself, or by the other deities – there are several versions), and thus returned to his place. This myth neatly explains why it is that Venus cannot be seen at midnight – it is the time that Athtar attempts to steal the throne. (The real reason, of course, is that Venus lies closer to the Sun than Earth, and, thus, is below the horizon at midnight.)

In Ukrainian folklore, the Pleiades were once seven maidens who were utterly devoted to the gods. Each day, they would dance and sing to honour the gods, and, as one might expect, the gods took notice of their devotion and their beauty. When they died, the gods made them nymphs, and took them into the sky, where they set the stars to be their new homes. To this day, the seven maidens continue their dancing, which explains why the Pleiades cross the sky as one.

Not forgetting that the sun itself is a star, the Chinese tell a story providing the reason that the cock crows at dawn. In ancient times, the cock had horns and the dragon did not, which was a source of great shame to the dragon as he could not fly without them. The dragon came to the cock and begged for the horns, which it promised to return the next day – obviously, the dragon, resplendent with his new horns, elected to break the deal, and to this day the cock each morning watches the dragon follow the sun across the sky and demands, “Dragon! Give back my horns!”