One world is not enough

On inaccessible universes and infinite planets.

Don’t worry, there are other worlds. There have to be. If there aren’t, then we haven’t yet made sense of this one. On 19 June, the celebrated science-fiction writers Terry Pratchett and Stephen Baxter will publish a new book, The Long Earth. It is based on an outlandish premise: that an infinite number of variations on our planet are hidden in inaccessible universes. If it were just science fiction, we could either welcome or dismiss it, according to our taste, as yet another example of the limitless human imagination. The trouble is, the whole thing is based in evidence. Worse, this evidence is now the bedrock of modern science.

First of all, let’s go to the roots of our physical reality. If you fire an atom at a screen containing two openings, the atom will go through both. It’s not just atoms; a molecule composed of 60 or so atoms does the same thing. Anything that follows the laws of quantum theory will do it. The only time this doesn’t happen is when someone is watching.

That we don’t get into a car using all four doors at once tells us that the weirdness disappears once you have a lot more than a few dozen atoms clumped together. No one knows why, and it doesn’t change the fact that the strange behaviour of the building blocks of matter is capable of breaking your mind.

No one knew this better than Hugh Everett, who started his career trying to solve this puzzle and ended up a chain-smoking alcoholic. Everett’s idea is now known as the “many worlds” interpretation of quantum mechanics. According to this, a new universe is created every time a subatomic particle is faced with a choice of things to be or do. The ultimate logical consequence is that the universe is composed of myriad sub-universes, each subtly different from the one that spawned it. In this cornucopia of worlds, many will be utterly different from ours. There is, according to the theory, a world where Elvis Presley is the king, not of rock’n’roll, but of Great Britain and Northern Ireland.

No one accepted the idea, and Everett responded to the pain of rejection by slowly self-destructing. Today, however, physicists take these quantum worlds seriously. And they are not the only strange fruit of modern physics.

Our best theory of how the universe began requires that it went through a ridiculous period of super-fast expansion, increasing in size by a factor of 1,000 billion billion billion in a fraction of a millisecond. If that is the case, the same “inflation” mechanism will cause other universes to blow up from tiny instabilities in the fabric of our universe. They pinch off and float away beyond our reach. And if you believe Everett’s theory, the activity of quantum particles in each of those worlds will spawn ever more worlds nested within them.

Forget reality

It might seem as if the existence of these universes would be unverifiable, but that is a supposition which ignores the ingenuity of scientists. Some have already worked out what imprint a collision with one of the inflated universes would make on the microwave background radiation that fills our universe. Having figured that out, they are now combing the universe for signs that we have touched another world.

It will be harder to verify the existence of the many quantum worlds. Some believe a better explanation for quantum phenomena is that there is no objective reality at all; nothing exists until an experimental observation brings it into being. But clearly, whatever Pratchett and Baxter have come up with, it won’t be as strange or unbelievable as the truth. 

Michael Brooks’s “The Secret Anarchy of Science” is out now in paperback (Profile Books, £8.99)

Michael Brooks holds a PhD in quantum physics. He writes a weekly science column for the New Statesman, and his most recent book is At the Edge of Uncertainty: 11 Discoveries Taking Science by Surprise.

This article first appeared in the 18 June 2012 issue of the New Statesman, Drones: video game warfare

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Haystack in a haystack: travels around the human genome

Siddhartha Mukherjee’s book is a tourist guide to the twenty-first century’s uncharted continent, the human genome.

My favourite quotation from Charles Darwin: “Ignorance more frequently begets confidence than does knowledge.” In that brief sentence, the founder of modern biology unknowingly summarised in advance the history of genetics, from the eugenical ideas of his half-cousin Francis Galton to Bill Clinton’s statement that the human ­genome sequence was “the most important, the most wondrous map ever produced by humankind”.

The eugenics movement led to ­disasters known to everyone. It is not yet dead: Francis Crick once claimed that “no newborn should be declared human until it has passed certain tests regarding its genetic endowment”, and our own government’s decision to deny child support to poor people irresponsible enough to have more than two offspring (the agent of the policy has four) is in the same tradition. As a reminder of our ignorance, the DNA chart looks more like a medieval atlas than a modern map – with geneticists, in unconscious parallel to Swift’s words, the geographers who “in Afric maps/With savage pictures fill their gaps,/And o’er inhabitable downs/Place ­elephants for want of towns”.

Siddhartha Mukherjee’s book is a tourist guide to the new Africa, the human genome. The chart of that continent does indeed have too many metaphorical elephants and a noticeable shortage of productive towns: there are only about 20,000 working genes in the conventional sense, rather than the millions once assumed to exist (and why do tomatoes have more than we do?). They are surrounded by vast numbers of more or less mysterious molecular beasts, some of them parasites that invaded long ago, others the mouldering corpses of once-noble creatures, and yet more – the so-called junk – known more in its anatomy than in what it actually does. Lengthy as this book is (and Mukherjee might have gained from turning to his own account of the genome’s ability to cut out redundant and repetitive sections), it gives a full and lively account of the development of the subject, from its birth in the 19th century to its infancy in the 20th and its uncertain adolescence in the 21st.

Mukherjee begins the book with a melancholy tale of the schizophrenia that attacked two of his uncles and his cousin, and caused his own father to worry that elements of the illness “may be buried, like toxic waste, in himself”. Other family members had blamed the madness of their relatives on the horrors of Partition in India in 1947, which led to millions of deaths. Now, however, it has become clear that a predisposition to the condition, and particularly to the variety known as bipolar disorder (doctors have abandoned the old name “manic ­depression”), has a strong hereditary component, and Mukherjee confesses that part of the impetus for writing The Gene: an Intimate History was a personal concern about his own offspring. In this it resembles his 2011 work on cancer, The Emperor of All Maladies, which he describes as a biography rather than a work of popular science.

The problem with genetics is that it lends itself too readily to anecdote. When teaching, I begin my own first-year course on the subject by telling the students: “I am a geneticist and my job is to make sex boring.” They look somewhat bemused, but after 20 lectures that fight through pedigrees, linkage mapping, population genetics, inbreeding, heritability, mutation and the like, I can tell that they agree heartily – and I’ve not even started to talk about the mechanics of sequencing or the horrors of bioinformatics, which have turned much of biology into computer science. Instead, to leaven the mix, and much as I secretly regret it, I plunge again and again into the Swamp of Storytelling and revel in colourful and often tragic tales of Sex, Age and Death (a phrase I once planned to use as a book title but made the mistake of mentioning to Bob Geldof, who stole it for one of his albums).

Mukherjee does the same, and often succeeds. I did not know that Gregor Mendel twice failed in his attempts to enter teacher training college; that the founder of (and donor to) the notorious “genius” sperm bank of the 1980s, the Nobel prizewinner William Shockley, may well have had autism, another condition with some genetic component; nor that the human genome paper was the longest ever published in Nature. And I learned perhaps more than I needed to know about the sordid disagreements between public and private genome mappers, the latter anxious to make millions, even billions, from the map, and the former who saw it as a public good. The good guys won in the end, though the American molecular diagnostics company Myriad Genetics managed to leap in just in time to patent the two genes that can cause breast cancer when they go wrong.

On his trek across the genetical landscape Mukherjee gives an exhaustive account of the development of the modern science of inheritance. He has talked to many of the main players and gives deep insights into their moments of discovery. He does sometimes fall a little too hard for the latest scientific fashion, the most glittering (or tawdry) of which is epigenetics, the interaction between gene and environment. The term was coined by one of my own teachers at Edinburgh, C H Waddington, a student of fruit fly development. He found that a sudden heat shock to the embryos led to the appearance of a few flies with abnormal wings among the adults. By breeding from these, he could obtain stocks that in time produced such flies with no need for a shock, proof that an environmental stress could uncover hidden genetic variation. Unfortunately, the term has been hijacked and turned into a universal bridge between chemistry and biology. It is even used to revive the discred­ited idea that an organism can pass on characteristics acquired in its own lifetime.

That bridge goes far too far. The idea that genes respond to external stresses can be traced to the first days of molecular genetics, when it became clear that some genes regulate the activity of others when a creature is faced with a shift in food, or temperature, or some other external stress. In part it is a statement of the obvious: go out in the summer sunshine and the average Briton will get a tan, because skin cells respond to an alarm call by a protein that senses cellular damage to summon up dark granules of melanin around the DNA in order to protect it. His or her children, though, will be born pink. Quite why there has been such a fuss about a concept invented 70 years ago is not clear and is made no clearer here.

The book ends where it began, with schizophrenia. That illness is a microcosm of Darwin’s aphorism on ignorance. Freud blamed the condition on “unconscious homosexual impulses”, while others were just as confident that it was brought on by hostile mothers. Then the pendulum swung towards treating it as a genetic disease almost as straightforward as haemophilia. Some cases, like those described in Mukherjee’s opening pages, do indeed run in families, but many more are sporadic and appear among kindred that have no history of the problem. For the latter, the new genetics has revealed hundreds of gene mutations in affected children that are not present in their parents. For the former, the story is not so simple. Certainly, genes that predispose to the condition can be passed on, but various families may inherit different genes yet show similar symptoms, and particular combinations of genes rather than single elements may be responsible for the illness.

As this book puts it, the search for the genes behind mental disorder is not like searching for a needle in a haystack, but for a haystack in a haystack. Even for highly heritable attributes such as height, the quest for genes has been baffling, given that more than a hundred are known to be involved in such variation but altogether do not represent even a tenth of the number needed to explain the similarity of parents and children. Unpalatable as this may be for us mere Mendelians, almost every human gene, in effect, may influence almost every one of our attributes, which will be no fun for tomorrow’s molecular cartographers. Even so, and tangled as it already is, Mukherjee does a good job of cutting away the web of ambiguity and complexity that scientists have woven since the happy days when Mendel counted the ratio of round to wrinkled peas in the garden of Brno’s abbey.

Another Darwin quotation, this one from The Voyage of the Beagle:

There are several other sources of enjoyment in a long voyage . . . The map of the world ceases to be a blank; it becomes a picture full of the most varied and animated figures. Each part assumes its proper dimensions: continents are not looked at in the light of islands, or islands considered as mere specks, which are, in truth, larger than many kingdoms of Europe. Africa, or North and South America, are well-sounding names, and easily pronounced; but it is not until having sailed for weeks along small portions of their shores, that one is thoroughly convinced what vast spaces on our immense world these names imply. 

Very true, but for his genetical descendants the expedition has only just begun. 

Steve Jones is Emeritus Professor of Human Genetics at University College London and the author of “No Need for Geniuses: Revolutionary Science in the Age of the Guillotine” (Little, Brown)

The Gene: an Intimate History by Siddhartha Mukherjee is published by Bodley Head (608pp, £25)

This article first appeared in the 16 June 2016 issue of the New Statesman, Britain on the brink