Paradox: The Nine Greatest Enigmas in Science, By Professor Jim Al-Khalili
The curiousness of the dark in the night time
Why does it get dark at night? It's a simple question, but the answer has taken astronomers half a millennium of groping in the black skies to find. The question is not about the rotation of the Earth but about starlight, and as telescopes expanded, along with theories of the universe, so too did what became known as Olbers' paradox.
The problem is this. Imagine looking at a postage-stamp-size area of the sky. Within that space, the naked eye may see a couple of bright stars, those closest to us. But behind them are thousands of others receding into space, and the further into space you go, the greater the number of stars. While individual stars may not be bright enough to see, the number of them packed into one's sight-line means that the whole postage stamp should be glowing. Why isn't it?
Professor Al-Khalili's new book Paradox looks at some of science's famous conundrums from some interesting modern angles. He begins with the logical paradoxes of Zeno, including the old favourite of Achilles and the Tortoise. But ancient Greek paradoxes that can be solved with Newtonian mathematics are not the real meat of his project. They are useful as the templates for later problems. The best example is Zeno's arrow paradox, in which the philosopher posited that an arrow observed during a moment of flight could also be perceived as static – a paradox which was picked up again by some quantum physicists in the Seventies, trying to explain why a watched radioactive atom would never decay.
To the sci-fi fan, al-Khalili's meditations on the theory of relativity and time travel will be enlightening, and Schrodinger's cat is let out of his box again. Al-Khalili, a master of making the complex simple, concludes his book with the paradox that could potentially emerge if CERN reports this summer that particles travelling faster than the speed of light do indeed exist, challenging Einstein's laws of physics.
With anecdotal explanations and good graphics, it's a well-written and lucid book. And worthy of repetition at dinner parties is the brainteaser which a Scottish physicist put to Al-Khalili: "Every Scotsman who travels south to England raised the average IQ of both countries." As for Olbers' paradox, the simple answer is that one day, a long time hence, the night sky could well be bright. It's just that starlight from galaxies more than 14 billion light years away has yet to reach us.
Ray Davies' Sunny Afternoon scoops the most awardsTheatre
Grace DentChannel 4 show proves there's no app for happiness
Arts & Ents blogs
- 1 Alan Rickman admits editing 'terrible' script with friends in Pizza Hut behind backs of writers on Robin Hood: Prince of Thieves
- 2 Rarest Beanie Baby of them all could be sold for £62,500 on eBay
- 3 Professional big game hunter Ian Gibson crushed to death by elephant during hunt
- 4 Farmer told to tear down mock-Tudor castle after hiding construction behind hay bales
- 5 Rebecca Francis accuses Ricky Gervais of using 'influence' to target female hunters after receiving barrage of death threats
Better Call Saul creator Peter Gould on the creative concerns of a prequel, season 2 and the mind-numbing realities of the small courts
Game of Thrones season 5: Emilia Clarke praises characters who 'accept their femininity'
Britain's Got Talent 2015: RSPCA investigating Marc Metral's miming dog after cruelty complaints
Fifty Shades of Grey movie shows first sex scene 'after 40 minutes'
Glastonbury 2015 tickets: How to make sure you’re successful in Sunday's re-sale
If I’m being racially abused I don’t need a stranger with a saviour complex to rescue me
The only black face in the Ukip manifesto is on the page about overseas aid
Ukip is the only main political party to not address LGBT rights in its manifesto
Food banks: One million Britons will soon be using them, according to Trussell Trust
Religion isn't growing, it is becoming vigorous in its demise, says philosopher AC Grayling
BBC election debate: The one photo that summed up the whole 90-minute leaders debate