22-12-2007 Romance in the stars (Article 117)

[Simon Kenny]

Romance in the stars (Article 117)

Since the dawn of civilization, the ways of love have been so important, yet so unpredictable, that every method from the pedestrian to the bizarre has been employed to confirm our hopes or dispel our fears in the tangled and uncertain minefield of romantic affairs.

Not surprisingly, astronomy and astrology were used to predict the opportunities and pitfalls that lay ahead in affairs of the heart. Today, astrology is the only one of this pair that takes on this task, as the horoscopes in modern magazines show.

So what about astronomy — what has it to offer those seeking romantic advice? Well, nothing, actually! True, much of what happens in the sky can now be predicted well in advance, but this has been the result of slow, methodical observation. Complex as the laws are that predict the movements of the stars, they are child’s play compared to the complexities of romantic entanglements. Heisenberg’s Uncertainty Principle may explain complex features of quantum mechanics, but couldn’t cope with the wilder uncertainties in the chemistry of interpersonal relations.

However, astronomy and romance do have one similarity: they are both about attraction, though of very different kinds. Attraction as studied in astronomy is not the hormone fuelled, starry-eyed (pardon the pun and those that follow) version we have all experienced when in love. However, it does explain much of what goes on in our world, our solar system, our galaxy and beyond. The attraction in question is gravity, in whose inescapable embrace everything exists and moves. Size affects gravity, which is why on the Moon, we would weigh only one-sixth of our Earth-weight. Perhaps there is a future for instant weight loss here?

In November 2005 the Japanese space probe ‘Falcon’ lightly kissed the surface of the small asteroid Itokawa, (which exerts very low gravity), took samples of its dust and will return them to Earth in 2010. On a much grander scale, galaxies express their mutual attraction in a gravitationally driven tango surrounded by magnificently streaming arcs of stars that whirl like the costumes of frenzied dancers. Examples of these are NGC 4038/9, ‘The Antennae’ in Corvus, and NGC 4676, ‘The Mice’, in Coma Bernices. Incidentally, ‘NGC’ refers to the New General Catalogue of celestial objects, compiled in the 1880s and cataloguing about 8000 objects, many of them observed by astronomer William Herschel.

And finally, the cosmos also has its ‘fatal attractions’ and it provides them on a grand scale. At the centre of our own galaxy there is a ‘black hole’ thousands of times more massive than our sun, which shreds and swallows anything, including stars that come too close. Its matter has been reduced to a single point by overwhelming force and nothing, not even light, can escape its intense gravity.
Now that’s the ultimate ‘crush’! Clear skies!

In the image two galaxies perform an intricate dance in this new Hubble Space Telescope image. The galaxies, containing a vast number of stars, swing past each other in a graceful performance choreographed by gravity. The pair, known collectively as Arp 87, is one of hundreds of interacting and merging galaxies known in our nearby universe.
Arp 87 is in the constellation Leo, the Lion, approximately 300 million light-years away from Earth. These observations were taken in February 2007 with the Wide Field Planetary Camera 2. Image credit: NASA, ESA, and the Hubble Heritage team (STScI/AURA).