From the nature of the universe (that’s if there is only one) to the purpose of dreams, there are lots of things we still don’t know – but we might do soon. A new book seeks some answers
1 What is the universe made of?
Astronomers face an embarrassing conundrum: they don’t know what 95% of the universe is made of. Atoms, which form everything we see around us, only account for a measly 5%. Over the past 80 years it has become clear that the substantial remainder is comprised of two shadowy entities – dark matter and dark energy. The former, first discovered in 1933, acts as an invisible glue, binding galaxies and galaxy clusters together. Unveiled in 1998, the latter is pushing the universe’s expansion to ever greater speeds. Astronomers are closing in on the true identities of these unseen interlopers.
2 How did life begin?
Four billion years ago, something started stirring in the primordial soup. A few simple chemicals got together and made biology – the first molecules capable of replicating themselves appeared. We humans are linked by evolution to those early biological molecules. But how did the basic chemicals present on early Earth spontaneously arrange themselves into something resembling life? How did we get DNA? What did the first cells look like? More than half a century after the chemist Stanley Miller proposed his “primordial soup” theory, we still can’t agree about what happened. Some say life began in hot pools near volcanoes, others that it was kick-started by meteorites hitting the sea.
3 Are we alone in the universe?
Perhaps not. Astronomers have been scouring the universe for places where water worlds might have given rise to life, from Europa and Mars in our solar system to planets many light years away. Radio telescopes have been eavesdropping on the heavens and in 1977 a signal bearing the potential hallmarks of an alien message was heard. Astronomers are now able to scan the atmospheres of alien worlds for oxygen and water. The next few decades will be an exciting time to be an alien hunter with up to 60bn potentially habitable planets in our Milky Way alone.
4 What makes us human?
Just looking at your DNA won’t tell you – the human genome is 99% identical to a chimpanzee’s and, for that matter, 50% to a banana’s. We do, however, have bigger brains than most animals – not the biggest, but packed with three times as many neurons as a gorilla (86bn to be exact). A lot of the things we once thought distinguishing about us – language, tool-use, recognising yourself in the mirror – are seen in other animals. Perhaps it’s our culture – and its subsequent effect on our genes (and vice versa) – that makes the difference. Scientists think that cooking and our mastery of fire may have helped us gain big brains. But it’s possible that our capacity for co-operation and skills trade is what really makes this a planet of humans and not apes.
5 Why do we dream?
We spend around a third of our lives sleeping. Considering how much time we spend doing it, you might think we’d know everything about it. But scientists are still searching for a complete explanation of why we sleep and dream. Subscribers to Sigmund Freud’s views believed dreams were expressions of unfulfilled wishes – often sexual – while others wonder whether dreams are anything but the random firings of a sleeping brain. Animal studies and advances in brain imaging have led us to a more complex understanding that suggests dreaming could play a role in memory, learning and emotions. Rats, for example, have been shown to replay their waking experiences in dreams, apparently helping them to solve complex tasks such as navigating mazes.
6 How do we get more energy from the sun?
Dwindling supplies of fossil fuels mean we’re in need of a new way to power our planet. Our nearest star offers more than one possible solution. We’re already harnessing the sun’s energy to produce solar power. Another idea is to use the energy in sunlight to split water into its component parts: oxygen, and hydrogen, which could provide a clean fuel for cars of the future. Scientists are also working on an energy solution that depends on recreating the processes going on inside stars themselves – they’re building a nuclear fusion machine. The hope is that these solutions can meet our energy needs
7 How do we beat bacteria?
Antibiotics are one of the miracles of modern medicine. Sir Alexander Fleming’s Nobel prize-winning discovery led to medicines that fought some of the deadliest diseases and made surgery, transplants and chemotherapy possible. Yet this legacy is in danger – in Europe around 25,000 people die each year of multidrug-resistant bacteria. Our drug pipeline has been sputtering for decades and we’ve been making the problem worse through overprescription and misuse of antibiotics – an estimated 80% of US antibiotics goes to boosting farm animal growth. Thankfully, the advent of DNA sequencing is helping us discover antibiotics we never knew bacteria could produce. Alongside innovative, if gross-sounding, methods such as transplanting “good” bacteria from fecal matter, and the search for new bacteria deep in the oceans, we may yet keep abreast in this arms race with organisms 3bn years our senior.
8 Will we ever cure cancer?
The short answer is no. Not a single disease, but a loose group of many hundreds of diseases, cancer has been around since the dinosaurs and, being caused by haywire genes, the risk is hardwired into all of us. The longer we live, the more likely something might go wrong, in any number of ways. For cancer is a living thing – ever-evolving to survive. Yet though incredibly complicated, through genetics we’re learning more and more about what causes it, how it spreads and getting better at treating and preventing it. And know this: up to half of all cancers – 3.7m a year – are preventable; quit smoking, drink and eat moderately, stay active, and avoid prolonged exposure to the midday sun.
9 Is time travel possible?
Time travelers already walk among us. Thanks to Einstein’s theory of special relativity, astronauts orbiting on the International Space Station experience time ticking more slowly. At that speed the effect is minuscule, but ramp up the velocity and the effect means that one day humans might travel thousands of years into the future. Nature seems to be less fond of people going the other way and returning to the past, however some physicists have concocted an elaborate blueprint for a way to do it using wormholes and spaceships. It could even be used to hand yourself a present on Christmas Day, or answer some of the many questions that surround the universe’s great unknowns.
10 Can we live for ever?
We live in an amazing time: we’re starting to think of “ageing” not as a fact of life, but a disease that can be treated and possibly prevented, or at least put off for a very long time. Our knowledge of what causes us to age – and what allows some animals to live longer than others – is expanding rapidly. And though we haven’t quite worked out all the details, the clues we are gathering about DNA damage, the balance of ageing, metabolism and reproductive fitness, plus the genes that regulate this, are filling out a bigger picture, potentially leading to drug treatments. But the real question is not how we’re going to live longer but how we are going to live well longer. And since many diseases, such as diabetes and cancer, are diseases of ageing, treating ageing itself could be the key.