In search of feral apples and underground men

My village, just outside Barnsley on the A635, used to supply the workers for lots of coal mines: Darfield Main, Grimethorpe, Houghton Main, Dearne Valley Drift, Goldthorpe, Barnburgh, Cortonwood; names of closed pits ringing like bells.

It’s a Sunday evening in late, late November and I’m just about to walk down through the village with my wife to her mother’s for tea. There will be homemade pies and celery sticks in a jug. I’ve got my thick coat on and my lucky Barnsley FC hat, and I’m carrying my carrier bag and my stick. Actually, it’s not really my stick: it was the one my mother had for the last few years before she died, the one she hung on to in the hope she might walk again.

The sky is clear as we set off and the full and insistent moon lights up the field behind the high wall; the herons are there, four of them sitting on the bare earth like constructions, like toys. We stand and watch them not moving, being still. Behind the field the Grimethorpe bypass is lit by passing cars, and the huge ugly Asos warehouse glows beside the hill that used to be the Houghton Main pit stack.

I’m pointing with my stick at the stars. I wish I knew more about the names of the constellations. Maybe I could just make some up: Uncle Frank’s Cap. The Unravelling Muffler. Somebody did it once, after all. Beyond Asos is the RSPB site, the ducks rising and falling from the water to the air and back again beside the double-glazing place.

My village, just outside Barnsley on the A635, used to supply the workers for lots of coal mines: Darfield Main, Grimethorpe, Houghton Main, Dearne Valley Drift, Goldthorpe, Barnburgh, Cortonwood; names of closed pits ringing like bells. Winding gear and slag heaps were slapped on to landscapes that had hardly changed over decades and miners like my father-in-law walked to work down a bridle path that had been there for centuries.

There was a persistent rumour of a mandrake growing in the swampy patches near the river; “When tha pulls ‘em up they scream!” Jim Marsden said one afternoon as we stood together in the drizzle at the top of the hill listening for sounds of the men working in the mines underneath. Jim insisted that some days you could hear them. “Blokes coughing” he’d say, “and blokes swearing.”

I walk this route every morning at the crack of dawn and I tweet about it; I see the most amazing things and I struggle to squeeze them into 140 characters, like the time I saw that man in a camouflage jacket walk by that man in a hi-vis jacket and as they passed they cancelled each other out.

The owner of the big house put a wall up some time in the last century so that he wouldn’t be able to see men like my father-in-law walking to Houghton Main, and now the workers from Asos stroll that way too, a historical continuation with boots and snap bags. I never found the mandrake but there are three or four plum trees down there, grown from spat stones; the jam glows (metaphorically) at the back of my pantry.

Now we’re at the top of the bridle path and I pull the carrier bag out of my pocket and get my stick ready. This is the reason for the stick – the apple tree by the wall, still full of fruit even this late in the year. Us hunters of the feral apple know what a good year 2013 has been: that mini orchard by the roundabout at Junction 37 of the M1, that huge crop of green beauties across from Tesco’s at Stairfoot near the fossil bank that my kids used to dig in, those heavy cookers that fall to the ground beside the fishing tackle shop in Low Valley.

And these: Yeats’s “silver apples of the moon” hanging just out of reach. Potential crumbles that I poke with my stick until they tumble and I catch them in the carrier. Some are as small as marbles but I’ll take them home anyway. Some roll into the road and a car passes and somebody beeps their horn and gestures to me. It’s either a thumbs-up or a raised pair of fingers. You can’t tell round here, in this Barnsley of the mind where layers of history cover the ground like fallen apples. I’ll just keep poking with my mother’s stick.


This season has ssen a bumper crop of British apples. Photo: Nicolo' Minerbi/Luzphoto/Redux

This article first appeared in the 27 November 2013 issue of the New Statesman, The North

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Has this physicist found the key to reality?

Whenever we have ventured into new experimental territory, we’ve discovered that our previous “knowledge” was woefully incomplete. So what to make of Italian physicist Carlo Rovelli?

Albert Einstein knew the truth. “As far as the laws of mathematics refer to reality, they are not certain; and as far as they are certain, they do not refer to reality.” However good we are at maths – or theoretical physics – our efforts to apply it to the real world are always going to mislead. So perhaps we shouldn’t be surprised that reality is not what it seems – even when, like the Italian physicist Carlo Rovelli, you’ve done the maths.

It is a lesson we could certainly learn from the history of science. Whenever we have ventured into new experimental territory, we’ve discovered that our previous “knowledge” was woefully incomplete. With the invention of the telescope, for instance, we found new structures in space; Jupiter’s moons and sunspots were just the beginning. The microscope took us the other way and showed us the fine structure of the biological world – creatures that looked uninteresting to the naked eye turned out to be intricate and delicate, with scales and hooks and other minute features. We also once thought that the atom lacked structure; today’s technology, such as the particle colliders at the Cern research centre in Geneva and Fermilab in the United States, have allowed us to prove just how wrong that idea was. At every technological turn, we have redefined the nature of reality.

Unfortunately, we don’t yet have the technology to take the next step. The present challenge to physicists seeking to discover how things really are is to investigate our environment on a scale known as the “Planck length”. Rovelli tries to convey just how small this is. Imagine, he says, a walnut magnified until it is the size of the universe. If we were to magnify the Planck length by that much, we still couldn’t see it. “Even after having been enormously magnified thus, it would still be a million times smaller than the actual walnut shell was before magnification,” he tells us.

We simply cannot probe the universe at these scales using current methods, because it would require a particle accelerator the size of a small galaxy. So – for now, at least – our search for the nature of reality is in the hands of the mathematicians and theorists. And, as Einstein would tell us, that is far from ideal.

That is also doubly true when theoretical physicists are working with two highly successful, but entirely incompatible, theories of how the universe works. The first is general relativity, developed by Einstein over 100 years ago. This describes the universe on cosmic scales, and utterly undermines our intuition. Rovelli describes Einstein’s work as providing “a phantasmagorical succession of predictions that resemble the delirious ravings of a madman but which have all turned out to be true”.

In relativity, time is a mischievous sprite: there is no such thing as a universe-wide “now”, and movement through space makes once-reliable measures such as length and time intervals stretch and squeeze like putty in Einstein’s hands. Space and time are no longer the plain stage on which our lives play out: they are curved, with a geometry that depends on the mass and energy in any particular region. Worse, this curvature determines our movements. Falling because of gravity is in fact falling because of curves in space and time. Gravity is not so much a force as a geometric state of the universe.

The other troublesome theory is quantum mechanics, which describes the subatomic world. It, too, is a century old, and it has proved just as disorienting as relativity. As Rovelli puts it, quantum mechanics “reveals to us that, the more we look at the detail of the world, the less constant it is. The world is not made up of tiny pebbles, it is a world of vibrations, a continuous fluctuation, a microscopic swarming of fleeting micro-events.”

But here is the most disturbing point. Both of these theories are right, in the sense that their predictions have been borne out in countless experiments. And both must be wrong, too. We know that because they contradict one another, and because each fails to take the other into account when trying to explain how the universe works. “The two pillars of 20th-century physics – general relativity and quantum mechanics – could not be more different from each other,” Rovelli writes. “A university student attending lectures on general relativity in the morning, and others on quantum mechanics in the afternoon, might be forgiven for concluding that his professors are fools, or that they haven’t talked to each other for at least a century.”

Physicists are aware of the embarrassment here. Hence the effort to unite relativity and quantum mechanics in a theory of “quantum gravity” that describes reality at the Planck scale. It is a daunting task that was the undoing of both Einstein and his quantum counterpart Erwin Schrödinger. The two men spent the last years of their working lives trying to solve this problem, but failed to make any headway. Today’s physicists have some new ideas and mathematical intuitions, but they may also be heading towards a dead end. Not that we’ll find out for sure any time soon. If the history of science offers us a second lesson, it is that scientific progress is unbearably slow.

In the first third of his book, Rovelli presents a fascinating dissection of the history of our search for reality. The mathematical cosmology of Ptolemy, in which the Earth stood at the centre of the universe and the other heavenly bodies revolved around it, ruled for a thousand years. It was unfairly deposed: the calculations based on Copernicus’s sun-centred model “did not work much better than those of Ptolemy; in fact, in the end, they turned out to work less well”, the author observes.

It was the telescope that pushed us forward. Johannes Kepler’s painstaking obser­vations opened the door to the novel laws that accurately and succinctly described the planets’ orbits around the sun. “We are now in 1600,” Rovelli tells his readers, “and for the first time, humanity finds out how to do something better than what was done in Alexandria more than a thousand years earlier.”

Not that his version of history is perfect. “Experimental science begins with Galileo,” Rovelli declares – but there are any number of Renaissance and pre-Renaissance figures who would baulk at that claim. In the 12th century the Islamic scholar al-Khazini published a book full of experiments that he had used to test the theories of mechanics. The man who helped Galileo achieve his first academic position, Guidobaldo del Monte, also carried out many experiments, and possibly taught Galileo the craft.

It’s a small misjudgement. More ­irritating is Rovelli’s dismissal of any path towards quantum gravity but his own, a theory known as “loop quantum gravity”. He spends the last third of the book on explaining this idea, which he considers the “most promising” of all the assaults on the true ­nature of reality. He does not mention that he is in a minority here.

Most physicists pursuing quantum gravity give a different approach – string theory – greater chance of success, or at least of bearing useful fruit. String theory suggests that all the forces and particles in nature are the result of strings of energy vibrating in different ways. It is an unproven (and perhaps unprovable) hypothesis, but its mathematical innovations are nonetheless seeding interesting developments in many different areas of physics.

However, Rovelli is not impressed. He summarily dismisses the whole idea, characterising its objectives as “premature, given
current knowledge”. It’s a somewhat unbecoming attitude, especially when we have just spent so many pages celebrating millennia of ambitious attempts to make sense of the universe. He also strikes a jarring note when he seems to revel in the Large Hadron Collider at Cern having found no evidence for “supersymmetry”, an important scaffold for string theory.

As readers of his bestselling Seven Brief Lessons on Physics will know, Rovelli writes with elegance, clarity and charm. This new book, too, is a joy to read, as well as being an intellectual feast. For all its laudable ambition, however, you and I are unlikely ever to learn the truth about quantum gravity. Future generations of scientists and writers will have the privilege of writing the history of this particular subject. With theory ranging so far ahead of experimental support, neither strings nor loops, nor any of our other attempts to define quantum gravity, are likely to be correct. Reality is far more elusive than it seems.

Michael Brooks’s books include “At the Edge of Uncertainty: 11 Discoveries Taking Science by Surprise” (Profile)

Reality Is Not What It Seems: the Journey to Quantum Gravity by Carlo Rovelli. Translated by Simon Carnell and Erica Segre is published by Allen Lane (255pp, £16.99)

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 20 October 2016 issue of the New Statesman, Brothers in blood