A supernova explosion marks the death of a certain type of star. During the evolution of these stars, nuclear reactions take place at their cores, creating light elements like hydrogen and helium. Heavier elements are produced as the chain reaction proceeds, but iron is the heaviest element that it is energetically favourable for the star […]
Atoms move through the crystal lattice of a solid by a process called diffusion. The atoms migrate by swapping places with ‘point defects’ such as vacancies – empty spaces in the lattice – and ‘interstitial’ atoms, which float between the regularly spaced atoms. In a semiconductor structure, a solid is doped with ‘foreign’ atoms that […]
Read article: Bridging the North-South divide
From the pure beauty of general relativity to modern high technology, physics is a fascinating and worthwhile subject, leading to both vast new industries and far-reaching speculations about the world in which we live. However, physics does not necessarily need advanced equipment or the latest supercomputers for worthwhile research to be carried out. In some […]
Read article: History found in a grain of sand
Hari Seldon, the fictional creator of “psychohistory” in Isaac Asimov’s “Foundation” series of novels, predicts the imminent demise of the First Galactic Empire after a 12 millennium run and establishes the Foundation on a planet at the galaxy’s edge. In doing so, he initiates a chain of events aimed at reducing the duration of the […]
Read article: Liquid hydrogen turns superfluid
Superfluids are among the most peculiar and counterintuitive of all materials. They have no viscosity, which allows an object travelling in a pure superfluid to move without friction. Similarly, they can flow effortlessly through narrow channels and pores that are virtually impermeable to conventional liquids. Superfluids are relatively rare and inaccessible, with only two known […]
Read article: Quintessence
Cosmologists have proposed that a mysterious substance called quintessence can explain why our universe is accelerating. But what is it made of?
Read article: The search for extra dimensions
The idea that the universe is trapped on a membrane in some high-dimensional space-time may explain why gravity is so weak, and could be tested at high-energy particle accelerators
Read article: Not the right stuff
Almost 40 years later, as the International Space Station takes shape, history is repeating itself. Of course, the space station has never been a scientific mission – its main purpose has always been to develop new technologies for space exploration, and latterly (and ironically given their history of competition in space) the United States has […]
Read article: No space like home
Space station commander Bill Shepherd (US), Soyuz commander Yuri Gidzenko and flight engineer Sergei Krikalev have trained for four years in both Russia and the US in preparation for the expedition, which represents the first permanent human occupation of the space station. The crew is expecting a number of visitors over the next few months. […]
Galindo-Uribarri and co-workers chose an isotope of neon with an energy structure that prevents it from emitting protons one at a time. This means that the two protons are certainly ejected simultaneously. The team fired a beam of radioactive fluorine ions at a proton-rich target to produce neon-18, which then decays into oxygen and two […]
