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Protein shapes

Protein shapes   Reference library

Magic Universe: A Grand Tour of Modern Science

Reference type:
Subject Reference
Current Version:
2009
Subject:
Science and technology, History of Science
Length:
2,241 words

...X-rays from a DESY accelerator to examine a protein from insect muscle. So clean and controllable were the X-rays, compared with those from ordinary machines, that Holmes' pioneering work launched a major scientific industry. Purpose-built synchrotron radiation laboratories appeared all around the world. Materials scientists benefited, as well as the investigators of biological molecules. Motifs for three-dimensional structures In the mid-20th century, X-ray crystallographers in the UK had begun deducing the shapes of biomolecules, using ordinary X-ray...

Black holes

Black holes   Reference library

Magic Universe: A Grand Tour of Modern Science

Reference type:
Subject Reference
Current Version:
2009
Subject:
Science and technology, History of Science
Length:
3,668 words

...a fifth of a light-year across. But the honours for really confirming the black hole theory went to X-ray astronomers. That's not surprising if you consider that, just before matter disappears, it has become so incandescent that it is glowing with X-rays. They are the best form of radiation for probing very close to the black hole. An emission from highly charged iron atoms, fluorescing in the X-ray glare at the heart of an active galaxy, did the trick. Each X-ray particle, or photon, had a characteristic energy of 6400 electron-volts, equal to that of an...

Neutron stars

Neutron stars   Reference library

Magic Universe: A Grand Tour of Modern Science

Reference type:
Subject Reference
Current Version:
2009
Subject:
Science and technology, History of Science
Length:
2,516 words

...Telescope would do. Even Hubble had to stare at the spot for more than an hour to make out the faint Geminga, just 20 kilometres wide. Caraveo made three observations with Hubble, at intervals of six months. They revealed very slight shifts in Geminga's apparent direction as the Earth and Hubble orbited the Sun. These fixed the distance of Geminga at about 500 light-years, and showed the neutron star to be ten times more radiant in gamma rays and X-rays than the Sun is by visible light. And it rushes through the Galaxy at 120 kilometres per second. Caraveo...

Gamma-ray bursts

Gamma-ray bursts  

Magic Universe: A Grand Tour of Modern Science

...Other telescopes could then look for it, and the first to do so was a cluster of other X-ray instruments on BeppoSAX itself—Italian devices with a narrower field of view, able to analyse the X-rays over a wide range of energies. By the time the spacecraft had been manoeuvred for this purpose, eight hours had elapsed since the burst, but the instruments picked up a strong X-ray afterglow from the scene and narrowed down the uncertainty in direction to a 20th of a degree. By a stroke of luck, Jan van Paradijs of the Universiteit van Amsterdam had...

Space weather

Space weather   Reference library

Magic Universe: A Grand Tour of Modern Science

Reference type:
Subject Reference
Current Version:
2009
Subject:
Science and technology, History of Science
Length:
3,814 words

...and the Sun's visible surface is dark. The Earth's own air blocks the solar X-rays, but they were first seen in 1948 , when US scientists used a German V2 rocket to carry a detector briefly into space. By 1973 NASA's manned space station Skylab was obtaining magnificent X-ray images of the Sun, but these were limited in number by the supply of photographic film. Yohkoh's electronic cameras were the first to provide millions of sharp X-ray images, and to monitor changes in activity in the solar atmosphere. A Japanese launcher put the satellite into orbit...

Protein-making

Protein-making  

Magic Universe: A Grand Tour of Modern Science

...had to make crystals of the ribosomes or their modules and analyse them with X-rays. Experts shied away from the monstrous task until Ada Yonath of Israel's Weizmann Institute and Heinz-Günther Wittmann of the Max-Planck-Institut für molekulare Genetik in Berlin led the way. Yonath found out by trial and error how to make stable crystals of the larger 50S module, protect them at low temperatures, and decorate them with clusters of heavy atoms to provide landmarks when she X-rayed the crystals. But when she showed her early results in 1980 , the pictures...

Elements

Elements   Reference library

Magic Universe: A Grand Tour of Modern Science

Reference type:
Subject Reference
Current Version:
2009
Subject:
Science and technology, History of Science
Length:
3,688 words

...At the same institute in Garching, astronomers looked at supernova remnants in closer detail with the German-US-UK X-ray satellite Rosat ( 1990–99 ). Bernd Aschenbach studied, in 1996 , Rosat images of the Vela constellation, where a large and bright supernova remnant spreads across an area of sky 20 times wider than the Moon. It dates from a relatively close stellar explosion about 11,000 years ago, and it is still a strong source of X-rays. Aschenbach wondered what the Vela remnant would look like if he viewed it with only the most energetic rays. He...

Photosynthesis

Photosynthesis   Reference library

Magic Universe: A Grand Tour of Modern Science

Reference type:
Subject Reference
Current Version:
2009
Subject:
Science and technology, History of Science
Length:
2,854 words

...from the blue-green S. elongatus , in 1988 . That opened the possibility of X-ray analysis down to an atomic level. With so formidable a complex as Photosystem I, containing 12 different proteins and about 100 chlorophyll molecules, this was no small matter. Very powerful X-rays, available at the European Synchrotron Radiation Facility in Grenoble, were essential. The crystals had to be frozen at the temperature of liquid nitrogen to reduce damage to the delicate structures by the X-rays themselves. By 2001 the Berliners' analysis of Photosystem I was...

Bits and qubits

Bits and qubits   Reference library

Magic Universe: A Grand Tour of Modern Science

Reference type:
Subject Reference
Current Version:
2009
Subject:
Science and technology, History of Science
Length:
1,881 words

...Shannon saw in simple relays—electric switches under electric control—the potential to make logical decisions. Suppose two relays represent propositions X and Y. If the switch is open, the proposition is false, and if connected it is true. Put the relays in a line, in series, then a current can flow only if X AND Y are true. But branch the circuit so that the switches operate in parallel, then if either X OR Y is true a current flows. And as Shannon pointed out in his eventual dissertation, the false/true dichotomy could equally well represent the digits 0 or...

Meitner, Lise

Meitner, Lise (1878–1968)   Reference library

The Oxford Companion to the History of Modern Science

Reference type:
Subject Reference
Subject:
Science and technology, History of Science
Length:
858 words

...for the inclusion of women into German science. She held no position whatsoever until Planck appointed her his assistant in 1912 . In 1913 she was given a position and salary comparable to Hahn's in the Kaiser-Wilhelm Institute for Chemistry (KWI). After volunteering as an x-ray nurse in the Austrian army during World War I, she returned to the KWI to head her own physics section in 1917 , acquired the title of professor in 1920 , and served as an adjunct professor at the University of Berlin from 1926 until she was dismissed by the Nazi regime in ...

Human genome

Human genome   Reference library

Magic Universe: A Grand Tour of Modern Science

Reference type:
Subject Reference
Current Version:
2009
Subject:
Science and technology, History of Science
Length:
3,502 words

...most of the 20th century the genome had been simply an arm-waving term, used by geneticists to mean the whole shebang. The idea that the human genome could perhaps be decoded in its entirety grew in biologists' minds in the early 1980s. Prompting came from a way of reading sequences of several hundred letters at once, in DNA strands, invented in 1977 by Fred Sanger at the UK's Laboratory of Molecular Biology. Sanger's group used it to produce the first DNA whole-genome sequence of 5000 letters, belonging to a virus that attacks bacteria, phi-X174. Next they...

Genes

Genes   Reference library

Magic Universe: A Grand Tour of Modern Science

Reference type:
Subject Reference
Current Version:
2009
Subject:
Science and technology, History of Science
Length:
3,546 words

...finished up with Nobel Prizes. Lawrence Bragg earned his while still an undergraduate, for pioneering the analysis of crystals by X-rays. Later, as Cavendish professor, Bragg plotted the hijacking of biology by physics. In the prefabs he nurtured and protected a Medical Research Council Unit for the Study of Molecular Structure of Biological Systems. Its small team, led by the Austrian-born Max Perutz, was dedicated to using X-rays to discover the 3-D atomic structures of living matter. In 1950 Perutz was in the midst of a tough task to find the shape of...

High-speed travel

High-speed travel   Reference library

Magic Universe: A Grand Tour of Modern Science

Reference type:
Subject Reference
Current Version:
2009
Subject:
Science and technology, History of Science
Length:
3,092 words

...from a pulsating star orbiting a stellar companion will vary in an irregular manner. That doesn't happen. X-rays are a form of light, and in 1977 Kenneth Brecher of the Massachusetts Institute of Technology applied this reasoning to an X-ray star in a nearby galaxy, the Small Magellanic Cloud. There, the X-ray source SMC X-1 is orbiting at 300 kilometres per second around its companion, yet there is no noticeable funny business in the arrival of the X-rays. So the proposition about the invariance of the speed of light from a moving source is correct to at...

Earth

Earth  

Magic Universe: A Grand Tour of Modern Science

...Smart-1 spacecraft, due there in 2005 , carries an X-ray instrument explicitly to test the impact hypothesis. Chemical elements on the lunar surface glint with X-rays of characteristic energy, and Smart-1 will check whether the relative proportions of the elements—especially of iron versus magnesium and aluminium—are in line with predictions of the theory. ‘Surprisingly, no one has yet made the observations that we plan,’ said Manuel Grande of the UK's Rutherford Appleton Laboratory, team leader for the X-ray instrument. ‘That's why our small instrument on...

Brain images

Brain images   Reference library

Magic Universe: A Grand Tour of Modern Science

Reference type:
Subject Reference
Current Version:
2009
Subject:
Science and technology, History of Science
Length:
2,502 words

...trying to measure what a factory does by measuring the intake of water and the output of sewage. This is only a problem of plumbing.’ What wasn't in doubt was the medical importance of blood flow, which could fail locally in cases of stroke or brain tumours. Patients' heads were X-rayed after being injected with material that made the blood opaque. A turning point in brain research came in the 1960s when David Ingvar in Lund and Niels Lassen in Copenhagen began introducing into the bloodstream a radioactive material, xenon-133. The scientists used a...

Cosmic rays

Cosmic rays   Reference library

Magic Universe: A Grand Tour of Modern Science

Reference type:
Subject Reference
Current Version:
2009
Subject:
Science and technology, History of Science
Length:
2,184 words

...about 20 million years old. Wandering in interstellar space, some of them hit atoms and make radioactive nuclei. Scientists used data on heavy cosmic-ray particles gathered by the European–US Ulysses spacecraft ( 1990–2004 ) to date the survivors, much as archaeologists use radiocarbon to find the ages of objects. Older cosmic rays have presumably leaked out of the Galaxy. One popular hypothesis was that the commonplace cosmic rays came from the remnants of exploded stars, where shock waves might accelerate charged particles to very high energies. X-ray...

Dark matter

Dark matter   Reference library

Magic Universe: A Grand Tour of Modern Science

Reference type:
Subject Reference
Current Version:
2009
Subject:
Science and technology, History of Science
Length:
2,479 words

...of stars, their masses are greatly boosted by attendant dark matter. Gravitational attraction will tend to bunch them. Early in the 20th century, when small smudges were at last recognized as other galaxies, a cluster in the Virgo constellation was immediately obvious. Clustering occurs in a hierarchy of scales. The Milky Way's neighbours are the large Andromeda spiral M31, 2 million light-years away, and a swarm of about 20 small galaxies, including the Clouds of Magellan. Gravity binds this modest Local Group together, and also links it to the Virgo...

Quantum tangles

Quantum tangles   Reference library

Magic Universe: A Grand Tour of Modern Science

Reference type:
Subject Reference
Current Version:
2009
Subject:
Science and technology, History of Science
Length:
3,734 words

...of your view.’ The train of thought began in Louis de Broglie's conversations with his brother Maurice , who was interested in the way X-rays interact with crystals. This phenomenon showed very plainly the dual nature of light-like radiation, as in the quantum theory initiated by Max Planck in Berlin in 1900 and pinned down by Albert Einstein in Bern in 1905 . When scattered by planes of atoms in a crystal, X-rays behave like waves, but when they hit a photographic film they miraculously shrink into individual particles, called photons. The dual...

Galaxies

Galaxies   Reference library

Magic Universe: A Grand Tour of Modern Science

Reference type:
Subject Reference
Current Version:
2009
Subject:
Science and technology, History of Science
Length:
1,667 words

...for a high plateau in the Chilean desert as a joint US-European venture. Its sixty-four 12-metre dishes were expected to detect warm dust made by the very first generation of stars. In space, a succession of infrared telescopes joined in the quest for very young galaxies, while X-ray telescopes sought out primeval black holes that might have antedated the galaxies. Meanwhile the visual evidence mounted, that galaxies grew by mergers of smaller star-swarms, from the very earliest era until now. The elegant spirals of middle-sized galaxies were commoner in...

Sun's interior

Sun's interior  

Magic Universe: A Grand Tour of Modern Science

...In 1938 , in another of the great 20th-century discoveries about the Sun, Hans Bethe of Cornell figured out the source of the Sun's power, in a sequence of fusion reactions that converts hydrogen into helium. The picture of the Sun's interior, which eventually emerged, has the very hot, dense core of the Sun surrounded with a thick layer that rotates like an almost solid ball around the north-south axis. It is called the radiative zone, and here the heat from the core works its way slowly outwards in the form of X-rays. Above the radiative zone lies the...

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