Horizon
Season 46 Episode 17 - How Long is a Piece of String?
Alan Davies attempts to answer the proverbial question: how long is a piece of string? But what appears to be a simple task soon turns into a mind-bending voyage of discovery where nothing is as it seems. An encounter with leading mathematician Marcus du Sautoy reveals that Alan's short length of string may in fact be infinitely long. When Alan attempts to measure his string at the atomic scale, events take an even stranger turn. Not only do objects appear in many places at once, but reality itself seems to be an illusion. Ultimately, Alan finds that measuring his piece of string could - in theory at least - create a black hole, bringing about the end of the world.
Episodes in Season 46
Why Are Thin People Not Fat?
60 min
Cannabis: The Evil Weed?
60 min
Why Do We Dream?
60 min
Can We Make a Star on Earth?
60 min
The Secret Life of Your Bodyclock
60 min
What's the Problem with Nudity?
60 min
How to Survive a Disaster
60 min
Who Do You Want Your Child to Be?
60 min
Why Can't We Predict Earthquakes?
60 min
Alan and Marcus Go Forth and Multiply
60 min
How Violent Are You?
60 min
Do I Drink Too Much?
60 min
The Secret You
60 min
Fix Me
60 min
Who's Afraid of a Big Black Hole?
60 min
Why Do We Talk?
60 min
How Long is a Piece of String?
60 min
