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The Theory of (nearly) Everything

The Theory of (nearly) Everything

The Theory of (Nearly) Everything 2019

In this special issue, the editors of BBC Science Focus explain the fundamental concepts of science, and reveal the latest cutting-edge research that will change our world. IN THIS ISSUE… - The Universe's history and how it will end - Clear explanations of key scientific concepts - Science facts, stats and expert opinion - Stunning images of life on and off Earth

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Pays:
United Kingdom
Langue:
English
Éditeur:
Immediate Media Company London Limited
Fréquence:
One-off
9,90 €(TVA Incluse)

dans ce numéro

9 min
the composition of stars

The philosopher Auguste Comte wrote, in 1835, that “there is no conceivable means by which we shall one day determine the chemical composition of the stars”. So much for philosophy. By the time Comte died in 1857, astrophysicists were well on the way to finding out what stars are made of. Indeed, spectroscopy, the tool they would use to do it, had already been invented decades before Comte made his pronouncement. In 1802, the British scientist William Hyde Wollaston was studying sunlight by passing it through a slit to make a narrow beam and then through a glass prism to spread the beam into a solar spectrum. By doing so, he noticed that the colours were separated by dark bands – two in the red part of the spectrum, three in…

2 min
gene editing

The most powerful new technique in molecular biology is the CRISPR-Cas9 system – known as ‘CRISPR’. CRISPRs (Clustered Regularly Interspaced Short Palindromic Repeats) are sequences of DNA letters, first discovered in E. coli in 1987. A decade later, researchers revealed that CRISPRs form part of an anti-viral defence system used by bacteria and other microbes: after a virus invades a cell, enzymes cut and paste bits of the viral genome between CRISPR sequences in the cell’s DNA. This leaves a genetic memory for an RNA ‘guide’ that an enzyme called ‘Cas9’ uses to recognise and destroy viral DNA, should an invader return. In 2012, bioengineers showed that the RNA guide could be reprogrammed to target any DNA sequence. One of CRISPR’s most useful applications is gene therapy – to treat or even…

10 min
the structure of dna

The year is 1869 and a young researcher is toiling away in a laboratory in an old castle in Germany, on course to make a remarkable discovery. The lab studies the composition of cells and Friedrich Miescher is analysing white blood cells, which he extracts from the pus in a local clinic’s discarded bandages. Having exhausted his efforts in classifying the cell’s proteins, Miescher turns his attention to another substance in his samples. He finds it odd – an acid that contains phosphorus – and declares he has discovered a completely new type of substance. Nuclein, or DNA as we now call it, has been found. Like any good sceptical scientist, Miescher’s boss Felix Hoppe-Seyler is wary and waits to repeat the experiments before, two years later, allowing publication. But this…

1 min
cast of characters

WILLIAM ASTBURY (1898-1961) was a British molecular biologist and physicist who spent much of his working life in Leeds. His work focused originally on the structure of proteins in textiles but, along with his PhD student Florence Bell, he took the first X-ray photographs of DNA in 1937. FRANCIS CRICK (1916-2004) was born near Northampton to the owner of a shoe factory and became a British biophysicist and molecular biologist. After co-discovering the structure of DNA, he went on to determine how DNA codes for proteins, before venturing into neuroscience. MAURICE WILKINS (1916-2004) was a British physicist and molecular biologist who was born in New Zealand. As well as his DNA research, he worked in fields such as radar and microscopy. He remained at King’s College until his retirement in 1981. ROSALIND FRANKLIN…

1 min
timeline

1803 John Dalton proposes that all matter is made of indestructible atoms; that atoms of different elements are distinguished by their weights and that chemical reactions occur when atoms are rearranged. 1897 Joseph John ‘JJ’ Thomson (above) discovers the electron – a constituent of all atomic elements. Negatively charged, it suggests there must also exist positively charged constituents to neutralise the atom. 1911 Ernest Rutherford discovers the positively charged atomic nucleus following experiments by Hans Geiger and Ernest Marsden. He realises the nucleus is massive and compact, and that an atom is mostly empty space. 1913 Niels Bohr (left) creates a conceptual picture of the atom like a miniature Solar System, where ‘planetary’ electrons orbit a central nuclear ‘Sun’. 1925-28 Erwin Schrödinger produces a quantum theory of electron behaviour in the hydrogen atom in 1925. Three years later, Paul…

1 min
cast of characters

JOHN DALTON (1766-1844) An English chemist and founder of modern atomic theory. Born in Cumberland, he moved to Manchester where he taught mathematics and natural philosophy. He studied the behaviour of gases and the atmosphere, but his most famous insights were with the atomic theory of chemistry, with which his name is associated. DMITRI MENDELEEV (1834-1907) A Russian chemist most famous for his Periodic Table of Elements, which he discovered while writing a textbook on chemistry in 1869. He was twice nominated for the Nobel Prize, in 1906 and 1907, but this was rejected after claims that his discovery was too old. JOSEPH JOHN THOMSON (1856-1940) Better known as JJ Thomson, he was born in Manchester and joined Trinity College, Cambridge, in 1876. He spent the rest of his life there and his work on the properties of…