Science: Search Engines: Serendipity A trick of the light

THOMAS Young was one of the most remarkable scientists of the 19th century. His most famous experiment involved shining light at a partition containing two very thin parallel slits. On the other side of the slits, the light fanned out and illuminated a screen with several light and dark stripes. Young was perplexed, because he expected to see just two light stripes, projections of the slits in the partition.

Young conducted much of his research at Emmanuel College, Cambridge, and it is said that he eventually worked out what was happening in his light experiment while wandering around the college duck pond.

The inspiration for his discovery was the sight of two ducks swimming next to each other. Behind them, two sets of ripples fanned out and interacted, creating a whole series of rough and calm patches. If the crest of a wave from one duck met the crest of a wave from the other, the result was an even bigger wave. On the other hand, if the crest from one duck met the trough from the other, they cancelled each other, and the result was a patch of calm.

Young believed that exactly the same thing was happening in his light experiment. He argued that light was a form of wave, and light waves emerging from the two slits were akin to the two sets of ripples from the ducks. If two light peaks coincided, then the result was a bright stripe, and if a light peak met a light trough, then the result was a dark stripe.

Thanks to his encounter with the ducks, Young had made a brilliant discovery. However, in the 20th century Young's experiment has led to a strange paradox. Scientists have repeated it using a light source that is so dim that it emits only one wave of light at a time. The result is another striped pattern, as before, but how can that be? Young's original explanation required two waves to interact simultaneously, and so how can waves travelling one at a time cause the same thing?

This result can only be explained by quantum mechanics, one of the weirdest areas of science. According to one interpretation of quantum mechanics, when the single light wave is confronted by two slits, the universe splits into two. In one universe the light passes through one slit, and in the other universe it passes through the other slit. The two universes then interact to create the final pattern.

This week the Institute of Physics is holding a seminar on the prospect of a quantum computer, a device that attempts to exploit the same effect. It would perform long calculations by entering a multitude of universes and then doing a separate part of the calculation in each one. Quantum computers are currently one of the hottest research topics, even though the idea sounds totally absurd. As the Nobel prize winner Niels Bohr once put it: "Anyone who can contemplate quantum mechanics without getting dizzy hasn't understood it."

Arts and Entertainment
Legendary charm: Clive Owen and Keira Knightley in 2004’s ‘King Arthur’
FilmGuy Ritchie is the latest filmmaker to tackle the legend
Arts and Entertainment
Corporate affair: The sitcom has become a satire of corporate culture in general

TV review

Broadcasting House was preparing for a visit from Prince Charles spoiler alert
Have you tried new the Independent Digital Edition apps?
Arts and Entertainment

ebooksNow available in paperback
Arts and Entertainment

ebooks
Arts and Entertainment
tvReview: There are some impressive performances by Claire Skinner and Lorraine Ashbourne in Inside No. 9, Nana's Party spoiler alert
Arts and Entertainment
Glastonbury's pyramid stage

Glastonbury Michael Eavis reveals final headline act 'most likely' British pair

Arts and Entertainment
Ewan McGregor looks set to play Lumiere in the Beauty and the Beast live action remake

Film Ewan McGregor joins star-studded Beauty and the Beast cast as Lumiere

Arts and Entertainment
Charlie feels the lack of food on The Island with Bear Grylls

TV

The Island with Bear Grylls under fire after male contestants kill and eat rare crocodile
Arts and Entertainment
Aaron Taylor-Johnson as Quicksilver and Elizabeth Olsen as Scarlet Witch, in a scene from Avengers: Age Of Ultron
filmReview: A great cast with truly spectacular special effects - but is Ultron a worthy adversaries for our superheroes? spoiler alert
Arts and Entertainment
Robin Ince performing in 2006
comedy
Arts and Entertainment
Beth (played by Jo Joyner) in BBC1's Ordinary Lies
tvReview: There’s bound to be a second series, but it needs to be braver spoiler alert
Arts and Entertainment
Paul Hollywood and Mary Berry, the presenters of The Great Comic Relief Bake Off 2015

TV
Arts and Entertainment
A still from Harold Ramis' original Groundhog Day film, released in 1993

Theatre
Arts and Entertainment
Christopher Eccleston (centre) plays an ex-policeman in this cliché-riddled thriller

TV review
Arts and Entertainment
Lena Headey looks very serious as Cersei Lannister in Game of Thrones

TV This TV review contains spoilers
Arts and Entertainment

film
Arts and Entertainment
Wiz Khalifa performs on stage during day one of the Wireless Festival at Perry Park in Birmingham

music
Arts and Entertainment
Festival-goers soak up the atmosphere at Glastonbury

music

Arts and Entertainment
Star Wars creator George Lucas

film

Arts and Entertainment

music

Arts and Entertainment
A shot from the forthcoming Fast and Furious 7

film

Arts and Entertainment
The new-look Top of the Pops could see Fearne Cotton returns as a host alongside Dermot O'Leary

TV

Arts and Entertainment
The leader of the Church of Scientology David Miscavige

TV

Arts and Entertainment
No half measures: ‘The Secret Life of the Pub’

Grace Dent on TV The Secret Life of the Pub is sexist, ageist and a breath of fresh air

  • Get to the point
Latest stories from i100
Have you tried new the Independent Digital Edition apps?

ES Rentals

    Independent Dating
    and  

    By clicking 'Search' you
    are agreeing to our
    Terms of Use.

    Not even the 'putrid throat' could stop the Ross Poldark swoon-fest'

    Not even the 'putrid throat' could stop the Ross Poldark swoon-fest'

    How a costume drama became a Sunday night staple
    Miliband promises no stamp duty for first-time buyers as he pushes Tories on housing

    Miliband promises no stamp duty for first-time buyers

    Labour leader pushes Tories on housing
    Aviation history is littered with grand failures - from the the Bristol Brabazon to Concorde - but what went wrong with the SuperJumbo?

    Aviation history is littered with grand failures

    But what went wrong with the SuperJumbo?
    Fear of Putin, Islamists and immigration is giving rise to a new generation of Soviet-style 'iron curtains' right across Europe

    Fortress Europe?

    Fear of Putin, Islamists and immigration is giving rise to a new generation of 'iron curtains'
    Never mind what you're wearing, it's what you're reclining on

    Never mind what you're wearing

    It's what you're reclining on that matters
    General Election 2015: Chuka Umunna on the benefits of immigration, humility – and his leader Ed Miliband

    Chuka Umunna: A virus of racism runs through Ukip

    The shadow business secretary on the benefits of immigration, humility – and his leader Ed Miliband
    Yemen crisis: This exotic war will soon become Europe's problem

    Yemen's exotic war will soon affect Europe

    Terrorism and boatloads of desperate migrants will be the outcome of the Saudi air campaign, says Patrick Cockburn
    Marginal Streets project aims to document voters in the run-up to the General Election

    Marginal Streets project documents voters

    Independent photographers Joseph Fox and Orlando Gili are uploading two portraits of constituents to their website for each day of the campaign
    Game of Thrones: Visit the real-life kingdom of Westeros to see where violent history ends and telly tourism begins

    The real-life kingdom of Westeros

    Is there something a little uncomfortable about Game of Thrones shooting in Northern Ireland?
    How to survive a social-media mauling, by the tough women of Twitter

    How to survive a Twitter mauling

    Mary Beard, Caroline Criado-Perez, Louise Mensch, Bunny La Roche and Courtney Barrasford reveal how to trounce the trolls
    Gallipoli centenary: At dawn, the young remember the young who perished in one of the First World War's bloodiest battles

    At dawn, the young remember the young

    A century ago, soldiers of the Empire – many no more than boys – spilt on to Gallipoli’s beaches. On this 100th Anzac Day, there are personal, poetic tributes to their sacrifice
    Dissent is slowly building against the billions spent on presidential campaigns – even among politicians themselves

    Follow the money as never before

    Dissent is slowly building against the billions spent on presidential campaigns – even among politicians themselves, reports Rupert Cornwell
    Samuel West interview: The actor and director on austerity, unionisation, and not mentioning his famous parents

    Samuel West interview

    The actor and director on austerity, unionisation, and not mentioning his famous parents
    General Election 2015: Imagine if the leading political parties were fashion labels

    Imagine if the leading political parties were fashion labels

    Fashion editor, Alexander Fury, on what the leaders' appearances tell us about them
    Phumzile Mlambo-Ngcuka: Home can be the unsafest place for women

    Phumzile Mlambo-Ngcuka: Home can be the unsafest place for women

    The architect of the HeForShe movement and head of UN Women on the world's failure to combat domestic violence