
The social conscience of scientists
Joseph Rotblat says scientists need to accept responsibility for the human and environmental consequences of their research,.
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Joseph Rotblat says scientists need to accept responsibility for the human and environmental consequences of their research,.
What happens when you ask some of the world's leading physicists seven questions about the past, present and future of physics?
The experiment was carried out inside a vacuum chamber filled with a low density nitrogen or argon gas. A wave plate – in the form of a small circular piece of material – was inserted into the beam to reduce the strength of the signal at the centre of the beam. A series of lenses […]
Physicists have tried for years to develop a beam of atoms that could be focused as easily as electrons and photons. The helium atoms are fired at 1 km/s through a micron diameter nozzle past a set of fresnel plates – concentric rings of material of varying thickness. As the beam passes the plates, the […]
The UK government has been trying for some time to incorporate private-sector practices into government-run research centres. AWE Management replaces Hunting-BRAE, who were awarded a seven-year contract to manage the UK nuclear programme in 1993. BNFL is expected to manage waste, decommissioning and “legacy clean-up” operations, Lockheed will control weapons and technology, while Serco will […]
As a water molecule is excited by the laser pulse, it can only drop back to a less excited state by releasing the excess energy. This energy causes the O-H bonds to stretch and vibrate. As the bonds vibrate they knock other water molecules, transferring energy to a different O-H bond. This energy transfer can […]
Almost 400 people took part in the PhysicsWeb poll, each one naming their top-five physicists. The votes for each physicist were added up and weighted according to how they were ranked by individual voters. This meant that Newton received a higher score than Einstein even though more people voted for the twentieth century physicist. In […]
Astronomers have argued about high-velocity clouds for over thirty-five years. Wakker and colleagues detected ionized sulphur in one such cloud using the Hubble Space Telescope. According to their calculations, the abundance of heavy elements in the cloud is only 9% of that found in the Sun. This, says Wakker, strongly suggests that the clouds replenish […]
When charged particles move in a circle they lose energy through synchrotron radiation. However, muons lose much less energy that electrons or positrons because they are 200 times heavier. This reduces the power needed to maintain the beam against energy loss. The muons would be created from the decay of the pions produced when a […]
The number of papers published by Chinese scientists in journals monitored by the US-based Institute for Scientific Information has grown from 3475 in 1983 to 10 033 in 1997. However, the proportion published in Chinese journals has dropped from 43.2% to 17% over the same period. The reason, say Ren and colleagues, is that Chinese […]