13 Things That Don't Make Sense: The Most Intriguing Scientific Mysteries of Our Times by Michael Brooks

The Sunday Times review by Christopher Hart

For all the achievements of science during the 20th century, its great heroic age, there remains a surprising number of absolutely fundamental questions still to be answered. Questions as basic as What Is Life? and Why Do We Die?

In this fascinating, bang-up-to-date report from the outer limits of scientific knowledge today, New Scientist writer Michael Brooks examines 13 of the most urgent scientific mysteries in turn.

One of the great discoveries of 20th-century science was that our universe is expanding. The discovery, however, led straight to another puzzle. The puzzle is, there's nowhere near enough matter to prevent the expanding universe from blowing apart completely into a vast, sterile infinity of lifeless interstellar dust. So how come we live in a lumpy universe, one of the lumps being the planet on which we live? There must be more matter than we can see: the famous dark matter and, to go with it, something even more mysterious - dark energy.

To date, however, there's not a shred of evidence for either, even though teams of scientists have been looking for years. (The UK's search “takes place 1,100m underground, in a potash mine whose tunnels reach out under the seafloor”.) The only alternative to dark matter is to tweak Newton's most fundamental laws of physics and suggest that they don't apply everywhere, all the time, in quite the same way. But physicists are a law-abiding bunch, and detest this idea.

In his next chapter, however, Brooks considers the curious afterlives of the Pioneer spacecraft, which only seem to cast more doubt on the universal truth of Newton's law. Pioneer 10 and 11 are now 8 billion miles away, “far beyond our solar system, drifting silently out into the void”. In 2m years' time, they will crash and burn in the star Aldebaran. Except that neither of them have quite followed the course they were supposed to - every year they veer 8,000 miles farther away from their intended trajectory. “Nasa explicitly planned to use them as a test of Newton's law,” explains Brooks. “The law failed the test; shouldn't we be taking that failure seriously?”

If that weren't enough of a revelation, there's alien intelligence as well. And here we have one of modern science's greatest mysteries: the Wow! signal, so-called because the man who first registered it simply scribbled Wow! on the read-out sheet. It is the only signal ever received from outer space that is utterly inexplicable - unless, as Brooks points out, you grant the existence of alien intelligence.

In 1959, two scientists wrote an article in Nature, describing what an intelligent alien signal would probably sound like. They predicted a radio signal at a steady frequency of 1420Mhz, referring to the most obvious universal constant, the element hydrogen. Nothing in nature would emit such a deliberate signal. And on August 15, 1977, a receiver in Ohio picked up just such a signal. “A few hours later,” notes Brooks dryly, “by coincidence, it should be emphatically noted, Elvis Presley died.” He also reminds us of William of Ockham's famous razor: given a number of possible explanations, the simplest one is always the best. And the simplest explanation for the Wow! signal is alien intelligence.

But surely such an intelligence wouldn't send out just one signal? Well, that's just what we've done ourselves, actually. In 1974, Nasa beamed out a message to star cluster M13, just once: a stream of binary digits that ET and his chums should easily resolve into what Brooks calls “a crappy Atari Pong-style picture of a person”. Arthur C Clarke put it best, though. Either we're alone in the universe or we're not. “In either case the idea is quite staggering.”

Back on earth, points out Brooks, science still can't define what “living” means, as opposed to inanimate, nor can it explain death. Especially since some species, such as Blanding's turtles of North America, don't age. They die from injury or illness, but not from cell death like us. Sex also gives scientists a terrible headache. Why do we do it? In terms of expenditure of time and energy (not to mention income), having to attract a mate is a ridiculously costly way of self-replicating. Many species simply sub-divide, like amoeba, or practise virgin birth, like the solitary Komodo dragon in London Zoo in 2006. She thus passed on 100% of her genes without having to flirt, diet or splash out on Jimmy Choos. But sexual reproduction reproduces only 50% of you, with no guarantee that it'll be the best 50%.

While on the subject of sex, Brooks also explains that scientists remain mystified by the process of courtship. It's a myth that females choose the biggest and flashiest males - hence the peacock's tail, the stag's antlers. In reality, naturalists have often observed a couple of alpha stags bashing away at each other during the rut, while the females, getting bored, slope off to mate with some less well-endowed and less aggressive beta male. The evolutionary biologist John Maynard Smith named these beta males (and this is official) sneaky f*****s.

Some biologists think that sex arose in response to death. Once our evolutionary ancestors, the eukaryotes, started using oxygen as a fuel, they had much more energy, but also suffered a lot more cell damage. Think of rust: it's what happens to iron when oxygen gets to work on it. As Brooks says, there's no such thing as a free lunch. If you start burning oxygen, your metabolism has a powerful source of energy, but it's also going to suffer extensive cell damage due to free radicals. So sex arose as a way of reshuffling your genes along with your partner's, in the hope that the resulting new combination - your offspring - will evade damage.

Freewill is the biggest puzzle in this book. As Brooks points out, human civilisation is built on it: law and order, praise and blame, good and evil. Yet most neuroscientists declare it doesn't exist. “Freewill is a fictional construction,” says Steven Pinker. But this is a puzzle in itself. Why isn't Pinker a passionate opponent of any punishment for crime, in that case? You might as well discipline a great white shark for swallowing a surfer. Do Pinker et al really believe war heroes don't deserve medals, or war criminals prosecution? Or are such “experts” just enjoying saying something wildly controversial, without really believing it themselves, let alone putting it into practice?

The experiments they adduce to disprove human freewill are less than impressive: attaching an electrode to your head and them making you wiggle your fingers involuntarily. More proof than this will be needed. Elsewhere in 13 Things, there are numerous examples of scientists making mistakes, refusing to see the obvious, or simply following the herd. On freewill, I choose to believe that they're wrong.

Like all the best science popularisers, though, Brooks reawakens us to the astonishing fact of our mere existence, the strangeness of the world around us, and the astonishing amount that science has yet to discover. A writer once called South America “a continent of inexhaustible wonders”, which is quite true. But it's true of the rest of the universe as well.