The modern world hasn’t stayed evolution’s hand. Comparisons of different genomes show that natural pressures are still doing their thing. The gene for digesting lactose, for example, is slowly spreading from European populations to the rest of humanity. A gene that appears to enhance fertility is also becoming more common across Europe. Disease is still a big driver of human evolution: people with particular genetic arrangements are more likely to survive malaria and HIV, for example. And almost all humans have lost the caspase 12 gene from their genomes, probably because those who have it are more susceptible to bacterial infections. It happens slowly, but we’re still changing.
Physicists searching for the ultimate “theory of everything” have a big problem with time. They have to stitch quantum theory - our description of how very small things behave - together with relativity - the theory behind the way space, time and matter interact. The biggest stumbling block to this is that time works in different ways in these theories.
In relativity, the passage of time is different for people moving relative to one another, so there is no absolute measure of time. In quantum theory, it’s even less well defined: time doesn’t even figure as something that gets measured. Quantum theory might be able to tell you where an electron is, but it can’t tell you how long it’s been there. One radical solution to the problem is to view time as a concept that humans have made up. If it doesn’t play a fundamental, well-defined role in the processes of the universe, maybe our theories can do without it altogether.
Physicists like to know why things are as they are. Which makes it frustrating that some facts about the universe appear inexplicable. There are certain constants of nature - the numbers that determine how strong forces such as gravity are - that seem to be “just so” for no good reason. That wouldn’t be so bad if they weren’t so exquisitely perfect for allowing life to develop in our universe. Naively speaking, it looks as if someone designed the universe. That doesn’t seem like a satisfying explanation to most physicists, so they have come up with a better one: that there are many universes, all with different properties. It is impossible to move from one to another, so we can’t test this idea, but it does take away the “specialness” of the conditions we find ourselves in. Of course the universe is perfect for us: if it were any different we wouldn’t be here to observe it.
Can we flick a switch in our genome that will greatly extend our lifespan? Experiments on worms, mice and fruit flies indicate that stopping certain genes from functioning, or altering others so that they flood the body with particular combinations of chemicals, can dramatically slow the rate at which an organism ages. It can even be done by more low-tech means: changing the chemical environment of the body by altering the diet or by injecting certain hormones can slow ageing, too. It’s an alluring avenue of research, but it is also controversial.
Plenty of biologists still say it’s a mirage because we will never overcome the biological programme whereby cells die after a certain time, or indeed the rigours of wear and tear on the genome. Add that to the dangerous genetic copying errors that occur as cells divide and, for these naysayers, growing old remains an unavoidable future for humanity. Nevertheless, the consensus is that the fight against biological ageing has moved from impossible to enormously difficult, and that is exciting progress.
The next generation of humans — or perhaps the one after that — will face a difficult choice: do they equip their children with “enhancements”? A group of researchers, led by Ray Kurzweil, is suggesting that we are approaching “the Singularity”, where technologies will enhance our mental and physical capabilities to produce a giant leap in what human beings can do. Most of these technologies were initially developed to help those with health problems, but they are now being co-opted for those looking to get past their normal limitations. Drugs developed to help children with ADHD are already in common use in academia as concentration improvers. Retinal implants that help the partially sighted are being developed as bionic eyes. Brain implants, such as those developed to fight neurological problems such as Parkinson’s disease, are paving the way for neural enhancement and plug-in memory upgrades. Genetic diagnosis of IVF embryos has enabled the selection of babies that are equipped to donate to an ill sibling; selecting for other kinds of advantage is not far behind. The big worry is it may leave us with a new enhancement-free underclass. Discuss.
If you had a magic microscope that could see how things work on the tiniest scale in nature, you might get a bit of a surprise. Right at the bottom, holding everything together, is something we think of as abstract: information. The idea that has big thinkers all worked up is that everything in physics is made up of atoms of information. Any experiment or observation can be boiled down to asking a yes/no question, and the answer is a piece of information analogous to the 0 and 1 binary digits (bits) that computers process.
Ultimately, the universe works as a giant computer, with answers to questions such as “Did the photon pass through this point?” providing the digital information to be processed. Constructing the full range of binary answers to questions the universe might pose will take a while, but it might provide an entirely new way to simplify - and thus understand - the fundamentals of how everything works.
How do the few kilos of spongy stuff in our skulls create the experience of being human? A combination of imaging techniques, computer models and an ever-increasing understanding of the biology of the brain means that we are in a good position to get an answer. Even if a good understanding of consciousness is another century away, there will be spin-offs that make the journey worthwhile. The quickest route to understanding the brain is to watch what happens when small bits of it go wrong. Many illnesses, such as depression, schizophrenia, autism and dementia, result from breakdowns in small component parts; researchers looking for clues to the root of consciousness are studying these malfunctions - and hope to learn as much about curing them as they do about consciousness.
Ninety-six per cent of the universe is in a form we can’t fathom. Observations of galaxies show they are rotating too fast to hold all their stellar material in place: the outer stars should be flung out. The only explanation is that there is an extra gravitational pull from something unseen, holding them in place. The unseen stuff is known as dark matter, and accounts for just under a quarter of the mass in the universe. Around three-quarters is “dark energy”, which creates a force that is speeding up the expansion of the universe. Physicists have yet to come up with a plausible explanation for the source of either of these dark entities. Dark matter requires the existence of particles with properties unlike anything else we have discovered. We are looking for what they might be, and the Large Hadron Collider might even create some. Dark energy is even more of a challenge: it comes neither from known particles nor from the empty space between them. Researchers are literally clueless about its source.
Physics is becoming ever more exciting as Cern’s Large Hadron Collider ramps up the energy of its colliding particles. That’s because the collisions might give us a fleeting glimpse of the Higgs boson. This is the final piece of the puzzle in our best theories of particle physics. The Higgs boson creates a field that exerts a drag on certain types of particles. The result of this is that the particles feel mass, the property of matter that responds to gravity. If the Higgs boson does show up, physicists will breathe a sigh of relief, because it is a central pillar of particle physics. If it doesn’t, physicists will have a lot of explaining to do. And not just about the source of mass.
Space agencies are identifying hundreds of planets outside our solar system that could harbour life. Biochemists have a firm grasp on the conditions that make life possible, and the traces that such life would leave in their vicinity. What’s more, our imaging technologies are getting better at detecting the signatures of life in the atmospheres that surround the potential homes of extraterrestrial life. It looks as if people alive today might well hear the news that we have discovered life elsewhere in the universe. It is unlikely to be intelligent life - more likely to be in the form of microbes - but it will still cause a fundamental shift in our view of life on earth. It would show that life has probably evolved more than once, and that the universe is likely to be teeming with other life forms. Scientists, ethicists and philosophers are now rushing to work out what action - if any - we should take if and when we make the discovery.
So far, researchers have found only three genes unique to humans. The likelihood is that, in total, fewer than 20 of our 20,000 or so genes are not found in any other creature. Other primates have brain cells exactly like ours, and our seemingly unique mental capacities are, it turns out, more developed versions of tricks that other animals can pull off. Killer whales and dolphins show distinct cultural groups within their populations. Crows use tools and chimps display morality. Elephants show empathy, and even salamanders and spiders show a range of personalities. Though nothing in the animal kingdom is using what we think of as language, gestures used by bonobos and orang-utans come close. We are top of the class, perhaps, but not in a class of our own.
It takes a lot of effort to be an atheist, and not just because you now have to find new ways to fill Sunday mornings. The human brain evolved to attribute a living cause to every phenomenon - if the rustling of a bush in the forest wasn’t a predator, then it was probably an evil spirit. Those who instinctively assumed something was there were the ones who survived when it actually was a predator. And those people - and they alone - are our ancestors. Neuroscience experiments show that belief in invisible entities interacting with the physical world has become the default state of the human brain.
Covering 70 per cent of the planet, with an average depth of 4km, the ocean is the largest habitat on earth, and it is largely virgin territory. Whenever researchers go into the deep, they almost always discover new species. The oceans are also throwing up new geology, and surprising us about the conditions under which life can thrive, redefining what we think of as habitable zones. As it turns out, we probably know very little about life on earth.
Darwin’s tree of life is evolving. No longer do we think one creature leads to another down an ever-branching path, while at the base of everything stands Luca, the Last Universal Common Ancestor of all living things. Genetic analysis is showing that life is much more complex than that: all kinds of hidden mechanisms have allowed speciation to occur as a wandering from branch to branch. Life is a web, not a tree, which means he future of biology is much more interesting than anyone had dared to hope. Rather than just cataloguing the differences between species and looking for ways in which natural selection has acted, we can explore the plethora of mechanisms and revel in the inventiveness of life.
The ultimate aim of physics is, as one wag put it, to be able to write all the equations of the universe on a T-shirt. This snappy, self-contained final theory will encompass all other explanations of phenomena - the forces of nature, the way particles come together to form atoms, planets and stars - and offer a single, simple explanation. For years, the only game in town was string theory, an attempt to describe the stuff of the universe as arising from the vibrations of loops of energy. Now some serious competitors have turned this into a race.
They have suitably exotic names, such as loop quantum gravity, causal dynamical triangulations and quantum graphity. More important, though, they provide the prospect of testing and elimination through experiment - the acid test of any theory. Biology doesn’t have exclusive rights over
the survival of the fittest.
Not all physics is sexy. There are physicists who work in dingy basements, following electron movements through slivers of metallic crystal or spending hours watching the swirling patterns in vats of liquid helium. These physicists have often looked at their colleagues working on huge, expensive particle accelerators with envy. But not for much longer, perhaps. It turns out that particles in crystals and bubbles in liquid helium follow the same laws as some of the fundamental particles of nature. That makes them excellent ways of simulating much bigger systems, and perhaps even replacing the mega-machines of physics. They can even make artificial black holes. How sexy is that?
A discovery made from pencil lead is promising to change the future of the electronics industry. In 2004, Andre Geim at the University of Manchester made a pencil scrawl on a sheet of paper, then used a length of Sellotape to pull off the graphite deposits. They came off as sheets of carbon atoms linked together in a hexagonal array, rather like microscopic chicken wire. Tests have shown that these “graphene” sheets have extraordinary properties. Graphene is ten times stronger than steel. Where copper wire and semiconductors lose a lot of electrical energy as heat, resulting in the average computer chip wasting 75 per cent of its power, graphene conducts electricity with little loss of energy.
Researchers have now refined the production technique and are busy turning graphene into low-power electronic components such as transistors. It gets better: graphene’s optimum electronic performance comes in the high-frequency range. This has phone manufacturers, eager to squeeze ever more information through their circuits, falling over themselves to get graphene components into handsets. And, as if its future wasn’t bright enough already, graphene is also transparent to visible light. That makes it the ideal material for transferring information between optical fibres and the electronic devices they link. Because of this, graphene-based telecommunications devices are already on the laboratory bench, as are graphene-based TV screens and high-efficiency solar cells. The humble pencil just made good.
We used to think that all human languages arose from brain programming that existed, fully formed and ready for action, at birth. This idea, put forward by Noam Chomsky in the 1960s, is no longer unchallenged. Ethnographic research has thrown up so many exceptions to the “universal” rules of language that some researchers are rejecting Chomsky’s dominance and suggesting that nothing is pre-programmed: instead, different cultures’ ways of thinking and their languages are intertwined. It may even be that the restrictions of a primitive language are a barrier to creating complex thoughts.
First take a few hundred strands of DNA, then chemically alter them so they will bond at various points. Now put them all together and use every technique available to chemistry to get those bonds to stick to each other. If you do it right, you’ll end up with all kinds of tiny shapes. The highlights so far are “toothed gears”, a nanoscale tetrahedron and a lidded box that can be locked or unlocked with a key made of a short strand of DNA. It looks like chemists messing around, but could be the best way to get drug doses delivered into the heart of a cell, and build DNA-based computers and micromachines that work on the same scale as standard biological machinery.