Physics and Astronomy

Spot-welds stick sliding metals

Two smooth, cold, metal surfaces are like pieces of tacky Sellotape. They form tiny spot welds that have to be broken apart before they can slide over each other. This, claim two physicists in California 1 , is another reason why metals stick as they slip if they are pressed together and pushed.

Such microscopic causes of friction and wear are increasingly important as the scale of mechanical engineering shrinks to below what&#1

Successful Test Observations With Powerful New Instrument at Paranal

One of the most fundamental tasks of modern astrophysics is the study of the evolution of the Universe. This is a daunting undertaking that requires extensive observations of large samples of objects in order to produce reasonably detailed maps of the distribution of galaxies in the Universe and to perform statistical analysis.

Much effort is now being put into mapping the relatively nearby space and the

Bouncing laser beams could bring quantum strangeness to the everyday world.

The quantum world of atoms and subatomic particles is full of intuition-defying phenomena such as objects existing in two different states at once. We don’t normally have to worry about such weirdness impinging on our everyday macroscopic world. But Italian physicists have worked out how to invest something we can see and touch with quantum strangeness.

Stefano Mancini, of the University of Mila

Surplus of Intergalactic Material May Be Young Supercluster Observations with ESO`s Very Large Telescope (VLT) have enabled an international group of astronomers to study in unprecedented detail the surroundings of a very remote galaxy, almost 12 billion light-years distant. The corresponding light travel time means that it is seen at a moment only about 3 billion years after the Big Bang. This galaxy is designated MS 1512-cB58 and is the brightest known at such a large distance and

Jumps in space-time might explain the curious survival of energetic particles.

Space and time must be grainy, not smooth. Otherwise high-energy particles produced in astrophysical processes would not be detectable on Earth.

So says Richard Lieu of the University of Alabama in Huntsville. Many agree that jumps in space-time occur on scales that are far too small to measure, but the idea has not yet been proved. Lieu now shows that using this hypothesis can explain how highly

Sci-fi experts know that many seemingly impossible technologies materialise years later, but unfortunately this may not to be the case for warp-drive – travelling through space faster than the speed of light. The favourite science fiction theory of space contracting in front of spacecraft, and expanding behind it to form warp-drive is under threat according to new work by a researcher in Portugal published today in the Institute of Physics journal, Classical and Quantum Gravity.

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