Monday, 27 June 2016

In praise of immigrants

Immigrants in Britain have been suffering abuse and harassment in the days following the notorious Brexit vote. By immigrants I mean anyone who the psychotic xenophobic shit-heads have decided does not belong in the UK. Which means: unless you have pasty white skin that goes blistering red after fifteen minutes in the feeble English sun, you are at risk of being identified as “an immigrant”. But the waves of intolerance and hatred extend well beyond those whose bodies reflect light at unwelcome wavelengths. Anyone who is an actual immigrant feels suddenly unwelcome, too. It doesn’t matter whether you are poor with no skills beyond ambition and tenacity, or well-off and well-educated and propping up local deficiencies. It doesn’t matter whether you are at risk of being evicted post-Brexit, or are legally allowed to remain. It doesn’t matter whether your family arrived one generation ago, or you arrived last week and were only expecting to be here for two years. Whatever the case: you do not feel welcome. 

Monday, 20 June 2016

Rumours, secrets, and other sounds of gravitational waves

Last Wednesday LIGO announced another detection of a binary-black-hole merger. Four months passed between the first announcement (in February, of a detection the previous September) and the second (a detection from late December). Which begs the question: are more on the way?

Wednesday, 15 June 2016

Black holes rule!

Finally, the news is out. LIGO conclusively observed a second pair of black holes spiralling into each other. For the record, that's a total of six black holes observed with LIGO in its first four months of operation: for every binary merger, two black holes go in, and one comes out. Not bad for a machine that many grouchy astronomers claimed would never see anything [1].

The black holes in the latest binary were less massive than those in the first detection, and the signal was weaker. This time the signal was not clearly visible in the data — the fancy search algorithms and waveform models that we have spent so many years working on were absolutely essential to the observation [2].

So: what does all this mean? And do we have any more secrets up our sleeves?

Tuesday, 7 June 2016

A spacetime operetta

Review of Janna Levin's "Black Hole Blues and Other Songs from Outer Space," published in the June 2016 issue of Physics World.


In February, gravitational waves flooded the global public consciousness, thanks to the announcement that the Advanced LIGO detectors -- two supersensitive space-time microphones – had picked up the distortions in space and time produced when two black holes collided over a billion years ago. This marked the first direct detection of gravitational waves, just under 100 years since Einstein predicted their existence. For all but a handful of experts and onlookers, this announcement must have come out of nowhere. In reality, the LIGO experiment was conceived 40 years ago, and as we learn in Janna Levin’s Black Hole Blues, its subsequent history was often tortuous, with grand dreams, deep science, and enough cursing-and-spitting drama to sustain the very worst of daytime soaps.