Innholdsfortegnelse for The Big Ideas in Science Explained i The Big Ideas in Science Explained

◼ Take notes and re-read them frequently. Repetition prevents information from being forgotten because it reignites and helps solidify the neural networks that hold memories. Try the Cornell note-taking method (lsc.cornell.edu/notes.html): ◼ Revise for an exam in a room scented with something unusual then put a bit of this scent on your wrist before the exam and sniff it if you are stuck. This is particularly effective if the material has an emotional component: in a 2011 study at Utrecht University, volunteers watched an emotionally engaging film in a room smelling of cassis (a fruity smell similar to blackcurrant). Later re-exposure to the smell triggered strong recollections of what they had seen. ◼ Break information into chunks. For example, turn the sequence 8,3, 2, 4, 9, 0, 1, 9, 8…

We’re always being told what to eat to lose weight, prevent cancer or sleep more soundly. But what if pumpkin seeds and papaya just aren’t doing it for you? Not everybody’s body works the same and the one-size-fits-all dietary recommendations dished up by the media and public health campaigns are starting to look outdated. Instead, some nutrition experts suggest we need to tailor our diets to our DNA. The future of food, they suggest, is in ‘personalised nutrition’. We’ve known for a long time that everyone processes food slightly differently, but this knowledge is now being supplemented by information about our genes, shedding new light on individual food issues and preferences. Many of us, for example, struggle to deal with dairy. “Some people have the ability to metabolise lactose –…

Alcohol is dangerous. Its abuse accounts for around 8,000 deaths in the UK every year, while the societal cost – in terms of the strain on the NHS and the police – is enormous. It costs £3.5bn a year for the NHS to treat alcohol-related illnesses and injuries, while 70 per cent of violent incidents occurring during the evenings, nights and weekends involve alcohol. Many people are, of course, able to enjoy a drink without coming to any harm, or becoming addicted. But many aren’t: it’s estimated that 9 per cent of men and 3 per cent of women in the UK show signs of alcohol dependence. And if you do get hooked, the prospects aren’t great. There are many treatment programmes available, but over 80 per cent of people…

Dinosaurs dominated life on land for more than 160 million years, and the many skeletal remains they left behind are among the most familiar of fossils. But dinosaurs did not leave us with bones alone. Millions of tracks, made by the forefeet and hindfeet of species belonging to all the major dinosaurian groups, are known from rocks worldwide. Fossilised dinosaur tracks have been known to science since the 1850s. By matching toe number and shape, foot proportions, claw shape and track size with skeletal remains, experts have been able to identify tracks to specific dinosaur groups, and sometimes to species. The smallest tracks, made by chicken-sized dinosaurs, are a few centimetres long, while the biggest – made by long-necked, herbivorous sauropods – are 1.8m in length. Sequences of tracks –…

The greatest discovery in the history of science is that there was a day without a yesterday. The Universe has not existed forever. It was born. All matter, energy, space and even time, burst into being in a titanic fireball we call the Big Bang, 13.82 billion years ago. The fireball expanded and, out of the cooling debris, galaxies congealed – great islands of stars; two trillion of them, of which our Milky Way is but one. Whatever way you look at it, the idea of the Universe popping into existence like a rabbit out of a hat is bonkers. For this reason, scientists had to be dragged kicking and screaming to it. The last thing they wanted to answer was the awkward question: what happened before the Big Bang?…

A black hole forms when matter is compressed into so small a volume that its gravity becomes intense enough that nothing, not even light, can escape. This necessarily makes a stellar-mass black hole anywhere in our Galaxy too small for us to see with any Earthbound telescope. However, there are also supermassive ones with masses of up to 50 billion times the mass of the Sun, one of which lurks in the heart of almost every galaxy. But, on account of being very far away, these behemoths are as difficult to image as stellar-mass black holes in our Milky Way neighbourhood. Except in two cases: Sagittarius A*, which is just 27,000 light years away, and its more massive 7 billion-solar-mass cousin in M87, which is at a distance of 56…

1 THE CLASSIC BUT DEADLY EINSTEIN-ROSEN WORMHOLE This is the original wormhole version investigated by Einstein. It seems to offer a shortcut through space and time, and thus the possibility of effectively travelling faster than the speed of light. But the Einstein-Rosen bridge inside the wormhole immediately collapses and traps travellers inside, unless it’s supported by some strange form of material that generates negative energy. 2 THE ENTANGLED WORMHOLE The deadly collapse of the Einstein-Rosen bridge could be prevented if the black holes forming the entrance and exit of the wormhole have a special quantum property called ‘entanglement’. This requires the two black holes to be in direct contact with each other, consuming the radiation that each spews out. But while this keeps the Einstein-Rosen bridge intact, it also means…

1 Tardigrades, also known as water bears or moss piglets, are a group of eight-legged animals. They are about 0.5mm long and can be found around the world in a wide range of environments. 2 Tardigrade means ‘slow paced’. It was originally an adjective applied to tortoises, but since 1800 it has been the name of these microscopic creatures. 3 Tardigrades can cope with extremely high and low temperatures, the kind that would kill other organisms. Some species can survive exposure to -272.15°C. 4 If a tardigrade is dehydrated and loses up to 99 per cent of its water content, its living processes can be near-suspended for several years before being brought back to life. 5 In 2007, dehydrated tardigrades were taken up into orbit and exposed to the vacuum…

Listen to the series Brain Power bbc.in/2Jr3cEZ 1. ATTENTION From broad beam to laser focused, it’s your flexible friend We’ve all experienced that irritating feeling of being distracted from the task at hand. But don’t be too hard on your butterfly mind: our brains have evolved, for good reason, to be distractible. We prize an ability to concentrate, but we need our attention to be flexible. If we focused too tightly we’d miss the creaking floorboard that signifies an intruder, or the whiff of smoke that announces fire. At tent ion has proven to be much more complicated, and weirder, than it seems. If you look closely at something – a photo of a landscape, say – you probably feel that you are noticing everything when, in fact, you’re taking…

Consuming lots of B vitamins (found in whole grains, seeds, nuts and beans) may help. These aid many brain functions, including neurotransmitter production. One study found that high doses of B vitamins halved the rate of brain shrinkage in people with mild memory problems. ◼ Use mnemonics such as rhymes (‘30 days has September’) and acronyms (‘Richard Of York Gave Battle In Vain’) – both tried-and-tested ways of making information more memorable. ◼ Construct a mental picture of a familiar location, such as your home, and place things that you want to recall in its rooms so that you can mentally stroll through and spot unfamiliar items – a bit like Sherlock’s ‘mind palace’. ◼ Write a to-do list each morning and consult it regularly throughout the day, to keep…

Species-wise, you probably identify as human. But based on the number of cells in and on your body, you are actually more microbe, because trillions of them call you home. Scientists exploring our microbial ecosystems (microbiomes) are discovering that the armies of tiny freeloaders our bodies host are quietly controlling us – governing mood, appetite and immune responses, as well as helping to digest and metabolise foods. “I can tell more about someone’s health by getting a detailed screen of their microbes than by screening their genes,” says Prof Tim Spector, who runs a microbiome research unit at King’s College London called the British Gut Project, pointing out that we’re 99.7 per cent genetically similar, whereas “we only share about 20 or 30 per cent of our microbes”. The British…

GENE DRIVES COULD ERADICATE DISEASES LIKE MALARIA, WHICH KILLED 435,000 PEOPLE IN 2017 Natural selection only makes features more common if they help organisms survive or reproduce. But we could get around that restriction by accelerating evolution using something called a ‘gene drive’. Gene drives are bits of DNA that work by breaking the laws of inheritance. Many organisms inherit genes on pairs of chromosomes, one from each parent, so their offspring have a 50/50 chance of inheriting either the maternal or paternal copy of any given gene. But a gene drive can copy-and-paste its DNA sequence from the chromosome carrying it to the other chromosome, ensuring the drive is passed on to 100 per cent of an organism’s offspring. Over multiple generations, the drive rapidly spreads through a population’s…

LSD may have benefits as a tool for therapy. In 2017, a metastudy of LSD research over the past 25 years found that it increased feelings of openness and trust, dampened the fear response and enhanced emotional empathy. It has proved useful in treating anxiety in terminal patients, with as few as two doses causing a reduction in symptoms. KETAMINE was developed in the 1960s as an anaesthetic and is still used medically in that context. Recreational use can cause problems with the liver and urinary tract, but the drug can also be beneficial in treating depression, particularly in those who have proved resistant to other treatments. PSILOCYBIN is the active ingredient in magic mushrooms. They have a similar effect on the brain to LSD, so psilocybin can be similarly…

Humans are the only living species of hominin, a tribe of great apes that also includes our shorter, stockier, stronger – and extinct – cousins, the Neanderthals. These prehistoric relatives originated in Europe, colonised Asia and were successful for almost 250,000 years. But within 10,000 years of ‘anatomically modern humans’ appearing in Eurasia, following our last migration out of Africa over 50,000 years ago, Neanderthals had disappeared. While the cause of extinction remains controversial, many academics believe our ancestors outcompeted Neanderthals by being smarter. Archaeological evidence tells us that we had burial rituals, cave art and tools that surpassed anything created by the Neanderthals – all thanks to an ability to innovate. “We could solve novel problems better,” says Prof Fred Coolidge, a psychologist at the University of Colorado, Colorado…

…It comes down to the fact that, in Einstein’s theory, time is not absolute, ticked off by a universal clock with which everyone agrees, but instead is relative. “I can’t talk to you in terms of time – your time and my time are different,” wrote the English novelist Graham Greene. According to Einstein, the rate at which time flows for someone depends on how fast they’re moving relative to you and the strength of the gravity they’re experiencing. If you can find a way to jump from a region where time flows at one rate to a region where it flows at a slower rate, you can go back in time – you’ll have made a time machine. The recognition that time is not what you think it is…

Back in 1935, Albert Einstein and colleagues hypothesised that quantum theory predicted a remote linkage between particles, called quantum entanglement. Einstein took an instant dislike to the idea, hoping that the existence of quantum entanglement meant that quantum theory, which he wasn’t too keen on to begin with, was somehow flawed, or not yet fully understood. Quantum entanglement is a bizarre offshoot of quantum theory that says certain properties of a pair of particles become linked in such a way that if you measure one of them, then you instantaneously know the state of the other, even if they are separated by vast distances. Sadly for Einstein, quantum entanglement has been demonstrated to be true many times, but so far only on a subatomic level. TOO WEIRD FOR EINSTEIN Quantum…

◼ Make a chart of your life, divided into sections such as work, family, health and so on. Go over it regularly, considering whether anything needs attention in each area. If it does, mark that section until you have done it. Aim to keep the chart clear. By looking broadly at your life, you’ll be able to make sure that you’re not focusing on one area to the detriment of others. ◼ Read, watch or listen to something new every day. The unfamiliar subject matter will stimulate underused brain areas, making these brain cells easier to activate again in future, and helping to increase your overall attention. ◼ Take short breaks from tasks that need prolonged attention. When we’re doing the same thing for a long time, the brain interprets…

◼ Challenge yourself with increasingly complicated problems. Eventually your brain will learn to abandon the fixed-attention strategy it uses for simple problems, and start to look at problems from multiple points of view. ◼ If you’re stuck on a puzzle, shift attention elsewhere and come back to it later. This turns off the neural firing pattern that is locking the brain into an unsuccessful approach, and allows the brain to incubate the problem, casting around unconsciously for knowledge that might be useful. When you return to the puzzle, this new information is likely to be incorporated into the problem-solving attempt. ◼ Combine problem-solving with a low-level activity such as walking or jogging. This helps to reduce focused attention because you need to use some of your conscious resources on the…

1 Scientists design a ‘CRISPR’ made from RNA. It includes a series of letters that matches a unique DNA sequence within an organism’s genome. 2 The CRISPR molecule is attached to ‘Cas9’ (shown here in beige). This is an enzyme that uses its RNA ‘guide’ to recognise the target DNA sequence. 3 The CRISPR-Cas9 tool cuts the strands of the target DNA’s double helix, then the cell’s repair machinery will fix the damage – minus the old DNA sequence. 4 The CRISPR technique can be used to delete unwanted DNA, or to find and replace a sequence by adding genetic material – such as a new gene.…

Sometime around 400 million years ago, the land-living, four-legged vertebrate animals properly called tetrapods evolved from their aquatic fish ancestors. Early, land-going tetrapods – animals like the famous Ichthyostega, a short-snouted aquatic animal discovered as fossils in 360-million-year-old rocks in eastern Greenland – were seemingly slow, clumsy walkers that kept their bodies close to the ground and appeared to lack agility or speed when moving on land. Any analysis of the fossils points to them having a very inefficient gait. But if we look at the enormous variety of land-living tetrapods that evolved later during Earth’s history, including those that live alongside us today, it’s obvious that far greater agility, speed and efficiency eventually evolved. Supposedly, it was only when more modern tetrapods evolved, such as reptiles and the ancestors…

1. MAKE STEM CELLS Viruses or RNA are used to deliver several genes, or ‘reprogramming factors’, into normal human cells (usually skin cells) from a healthy adult, which prompts them to turn into ‘induced pluripotent stem cells’ (iPS cells) after a few weeks. Like embryonic stem cells, iPS cells have the potential to become any tissue in the body. 2. EDIT HUMAN GENES Genomes of a modern human and Neanderthal are compared to identify genes, like NOVA1, that ifluence neural development. The CRISPR/Cas9 gene-editing system then targets a single DNA letter and replaces it with the variant found in Neanderthals, which creates ‘Neanderthalised’ stem cells. 3. DEVELOP NEURONS A cocktail of chemicals is added to a liquid growth solution over several steps, guiding cells to divide and mature, from Neanderthalised…

In 1915 in Berlin, at the height of WWI, Albert Einstein presented a revolutionary new theory of gravity – the General Theory of Relativity. It has since become one of the most successful theories ever, predicting cosmological phenomena such as the Big Bang, black holes and gravitational waves. However, theorists have long known that General Relativity cannot be the last word about gravity. That’s because it fails to incorporate the other cornerstone of modern physics, quantum theory. As well as describing the subatomic world with astonishing precision, quantum theory has been able to account for all the fundamental forces of nature apart from one: gravity. Since the 1950s, theorists have tried to marry the two views of nature to produce one overarching theory. Now, a new theory could rewrite the…

A typical neural network consists of a number of artificial neurons arranged into a series of interconnected layers. When a neural network is tasked with learning something, input neurons receive the data from the outside world that it’s attempting to make sense of. For example, if I wanted my neural network to learn how to read handwriting, I might have a lot of input neurons ‘looking’ at the pixels in images of the handwritten letters. This raw data is then converted into a convenient form and passed on to one or more ‘hidden’ layers, where the processing of the data takes place. Hidden layers are so-called because their outputs are connected to the input of another layer, and so are not visible as a network output. In the handwriting example,…