Euclid to pinpoint nature of dark energy
The accelerating expansion of the universe, first realised 20 years ago, has been confirmed by numerous observations. Remarkably, whatever the source of the acceleration, it is the primary driver of t...
LHCb brings cosmic collisions down to Earth
In an effort to improve our understanding of cosmic rays, the LHCb collaboration has generated high-energy collisions between protons and helium nuclei similar to those that take place when cosmic ray...
Dark-matter surprise in early universe
New observations using ESO’s Very Large Telescope (VLT) in Chile indicate that massive, star-forming galaxies in the early universe were dominated by normal, baryonic matter. This is in stark contra...
Editor’s note
After 13 years as the Courier’s Astrowatch contributor, astronomer Marc Türler is moving to pastures new. We thank him for his numerous lively columns keeping readers up to date with the la...
Gravitational lens challenges cosmic expansion
Using galaxies as vast gravitational lenses, an international group of astronomers has made an independent measurement of how fast the universe is expanding. The newly measured expansion rate is consi...
WIMP no-show in gamma-ray background
Although the night sky appears dark between the stars and galaxies that we can see, a strong background emission is present in other regions of the electromagnetic spectrum. At millimetre wavelengths,...
Compact star hints at vacuum polarisation
By studying an isolated neutron star, astronomers may have found the first observational indication of a strange quantum effect called vacuum birefringence, which was predicted in the 1930s by Werner ...
The dawn of a new era
One of the greatest scientific discoveries of the century took place on 14 September 2015. At 09.50 UTC on that day, a train of gravitational waves launched by two colliding black holes 1.4 billion li...
General relativity at 100
As in precision electroweak experiments, it is useful to parameterise plausible deviations from general relativity.
Catching a gravitational wave
Gravitational waves alternatively compress and stretch space–time as they propagate, exerting tidal forces on all objects in their path. Detectors such as Advanced LIGO (aLIGO) search for this subtl...
