Read article '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...
Read article '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,...
Read article '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 ...
Read article '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...
Read article 'General relativity at 100'
As in precision electroweak experiments, it is useful to parameterise plausible deviations from general relativity.
Read article '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...
Read article 'Linking waves to particles'
Black holes are arguably humankind’s most intriguing intellectual construction. Featuring a curvature singularity where space–time “ends” and tidal forces are infinite, black-hole interiors ca...
Read article 'n_TOF deepens search for missing cosmic lithium'
An experiment at CERN’s neutron time-of-flight (n_TOF) facility has filled in a missing piece of the cosmological-lithium problem puzzle, according to a report published in Physical Review Letters. ...
Read article 'Hubble misses 90% of distant galaxies'
A team of astronomers has estimated that the number of galaxies in the observable universe is around two trillion (2 × 1012), which is 10 times more than could be observed by the...
Read article 'Testing times for space–time symmetry'
Throughout history, our notion of space and time has undergone a number of dramatic transformations, thanks to figures ranging from Aristotle, Leibniz and Newton to Gauss, Poincaré and Einstein. In o...
