Through the past darkly

Your trusty editor got sick, stayed at home and then watched light slow to a complete halt under the influence of daytime television. Well, almost.

The Esper machine: Mr. Deckard.Deckard: Yes? The Esper machine: Do you have something against science? Deckard: Not if it works. The Esper machine: And what in your estimation works? Deckard: The umbrella.

(Blade Runner. Original script by Hampton Fancher.)

Last week, sick and off work, I watched what seemed like an eternity of daytime soap operas, home improvement shows, interminable news programs and old black and white films from the middle of the last century.

Finally, bored witless with this dull routine, and in search of something a little more entertaining, I opened up a book of old science fiction stories. There’s something about old science fiction that appeals to me, you know. It’s amusing to look back and see if the authors predicted the future accurately, or if they got it all wrong.

Bob Shaw was a writer who got things right, or pretty close to it. In his 1966 short story, ‘Light of Other Days,’ he came up with the concept of ‘Slow Glass,’ a glass that light takes up to ten years to travel through. When someone looks through a pane of the stuff, he or she views events that took place up to ten years earlier.

In Bob’s story, a man and his wife go to the home of a fellow who sells the ‘slow glass’. Looking through the window of his abode, they notice the man’s wife and child playing together inside. But when they enter the house, it is a deserted dump. Then they realise that the windows of the house are made of the slow glass and that they are looking into the past – the wife and child have been dead for years.

In 1966, this all seemed pretty far-fetched. We all knew that light travelled at 186,282 miles per second and we assumed that the speed of light was a constant. No one dreamed that light could be slowed down, even though Einstein never actually said that it couldn’t.

Fast forward to 1999. And over to the Rowland Institute for Science in Cambridge, MA in the USA. There, a team headed up by the Danish physicist Dr. Lene Vestergaard Hau demonstrated that optical pulses travelling through a gas of sodium atoms cooled to ultracold temperatures propagated twenty million times slower than the speed of light in a vacuum. Since then, this remarkable woman and her team have brought light to a complete stop for one thousandth of a second.

The potential applications for this technology are far reaching. But it seems unlikely, for now at least, that we are likely to see the researchers produce any of Bob’s ‘slow glass’ – unless we’d all like to look through double glazed windows filled with sodium gas cooled to nanokelvin temperatures, that is. I for one am extremely grateful for this. The thought of looking back at last week’s daytime TV again is a chilling thought.

Editor’s note:

If you would like to read Bob Shaw’s story ‘Light Of Other Days,’ it can be found on the web here.

If, on the other hand, you’d like to see how it was really done, check out ‘Light speed reduction to 17 metres per second in an ultracold atomic gas,’ by Dr. Lene Vestergaard Hau and her colleagues. It’s on the web here.