Tuesday, September 22, 2015

Chiral ?

Last week, in researching and featuring poet Jane Hirshfield, I learned a new word from a piece of her poetry/prose:

Left-Handed Sugar - Poem by Jane Hirshfield

In nature, molecules are chiral — they turn in one direction or the other. Naturally then, someone wondered: might sugar, built to mirror itself, be sweet, but pass through the body unnoticed? A dieters' gold mine. I don't know why the experiment failed, or how. I think of the loneliness of that man-made substance, like a ghost in a ‘50s movie you could pass your hand through, or some suitor always rejected despite the sparkle of his cubic zirconia ring. Yet this sugar is real, and somewhere exists. It looks for a left-handed tongue.

Chiral ? Was this word, I wondered, related to Chiron, "wounded healer" and centaur often found in astrology's broader reaches? No, it has no connection to Chiron.
Chirality /kaɪˈrælɪtiː/ is a property of asymmetry important in several branches of science. The word chirality is derived from the Greek, χειρ (kheir), "hand", a familiar chiral object.

An object or a system is chiral if it is distinguishable from its mirror image; that is, it cannot be superposed onto it. Conversely, a mirror image of an achiral object, such as a sphere, cannot be distinguished from the object. A chiral object and its mirror image are called enantiomorphs (Greek opposite forms) or, when referring to molecules, enantiomers. A non-chiral object is called achiral (sometimes also amphichiral) and can be superposed on its mirror image.

The term was first used by Lord Kelvin in 1893 in the second Robert Boyle Lecture at the Oxford University Junior Scientific Club which was published in 1894:
"I call any geometrical figure, or group of points, 'chiral', and say that it has chirality if its image in a plane mirror, ideally realized, cannot be brought to coincide with itself."
Human hands are perhaps the most universally recognized example of chirality: The left hand is a non-superimposable mirror image of the right hand; no matter how the two hands are oriented, it is impossible for all the major features of both hands to coincide across all axes This difference in symmetry becomes obvious if someone attempts to shake the right hand of a person using their left hand, or if a left-handed glove is placed on a right hand. In mathematics chirality is the property of a figure that is not identical to its mirror image.

I live and learn, sometimes on the ecliptic, sometimes elsewhere.

Using hands to explain chirality is the easy part. I shall delve no further into the scientific uses of the term, lest eyes (mine) begin to cross in trying to experiment with the chirality of eyes.


mike said...

Chirality is a complete mystery in physics, as there is no plausible explanation for its existence. It defies the perfection of nature, yet it is part of that perfection as the asymmetry of symmetry! You gave the example of the left vs right hand as chiral. That chirality is a result of the symmetry of the bilateral plane that divides the body into left and right halves. Plants and some animals have rotational symmetry, such as starfish. Light and other waves can exhibit chiral symmetry, too, detected using polarized filters (polarized sunglasses to reduce glare). Polarized filters are used to detect the chirality of chemicals in solution by passing light through the solution and observing through the filter. In physics, chiral symmetry is the clockwise or counter-clockwise energy spin of particles, but those theories diminish when considered from the quantum perspective, and are called chiral anomalies. Quantum physics is constantly indicating that our physical universe is not what it seems.

Twilight said...

mike ~ LOL! Thank you. Well, now my eyes really are crossing!

(Quick O/T
Trans Saturn trine my natal Pluto (which began a few days ago) has brought forth further information on my deceased cousin, via a longtime friend of his. E-mail yesterday throws some light on S's life, and sudden, unexpected death. I'll probably wait until the date that would've been S's birthday, 12 October, to do a post about what I've discovered about him. I'm not optimistic that the lawyers will complete their doings on his estate anytime soon, however. But surprises are the name of my game, it seems so.....)

mike (again) said...

Well, I guess waiting three more weeks won't kill me...LOL. Stephen's story is intriguing, combined with your involvement as heir apparent. The paraphernalia of a good novel to be written. Touches of "Philomena", though I haven't seen the movie.