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The universe is expanding at an accelerating rate — or is it?

21 October 2016 Astronomy Now

Five years ago, the Nobel Prize in Physics was awarded to three astronomers for their discovery, in the late 1990s, that the universe is expanding at an accelerating pace. Now, a team of scientists led by Professor Subir Sarkar of Oxford University’s Department of Physics has cast doubt on this standard cosmological concept.

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Five-dimensional black hole could ‘break’ general relativity

20 February 2016 Astronomy Now

Researchers from the University of Cambridge and Queen Mary University of London have shown how a bizarrely shaped black hole could cause Einstein’s general theory of relativity, a foundation of modern physics, to break down. However, such an object could only exist in a universe with five or more dimensions.

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New cosmological theory of secondary inflation avoids excess of dark matter

16 January 2016 Astronomy Now

The Big Bang Theory with its early period of exponential growth known as inflation is the prevailing scientific model for our universe, in which the entirety of space and time ballooned out from a very hot, very dense point into a homogeneous and ever-expanding vastness. This theory accounts for many of the physical phenomena we observe, but what if that’s not all there was to it?

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‘Stealth dark matter’ theory may explain universe’s missing mass

25 September 2015 Astronomy Now

A Lawrence Livermore National Laboratory team has combined theoretical and computational physics techniques using the Laboratory’s 2-petaflop Vulcan supercomputer to devise a new model of dark matter. They found that dark matter is “stealthy” today, but would have been easy to detect in the extremely high-temperature plasma conditions that pervaded the early universe.

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The dark matter conspiracy

3 May 2015 Astronomy Now

A new study finds that elliptical galaxies maintain a remarkably constant circular speed out to large distances from their centres, in the same way that spiral galaxies do. In these very different types of galaxies, stars and dark matter somehow conspire to redistribute themselves to produce this effect, or does modified Newtonian dynamics offer an explanation?