Science,People&Politics issn:1751598x. Issue three 2017.

Quantum fluctuations of the gravitational field in the early Universe, amplified by inflation,
produce a primordial gravitational-wave background across a broad frequency band.

Gravitational-wave Cosmology across 29 decades in frequency. P.D.Laky et al.
Phys. Rev. X6 011035 (2016), arXiv: 1511.05994 [astro-ph.c0]

It is against this primordial background that Grvitational Wave astronomers make experimental
observations of phenomena such as the coalescing binary stars reported here.

run ends at the end of August. The era of gravitational-wave astronomy is moving in to full swing. A whole new spectrum - the gravitational spectrum - from which to tease knowledge of our Universe is now accessible.

Mysteries to be solved include: clarifying the nature of the missing 95 percent of the Universe, known to exist, but of unknown nature; exploring general relativity - a theory which has always had some mathematical challengers; finding the math and a physical understanding to reconcile special and general relativity and quantum mechanics.

On the British Radio Programme, "The Infinite Monkey cage", physicist Catherine Heymans, who has a chair in astrophysics at the University of Edinburgh, told listeners that we may be on the brink of a completely new understanding of physics. LIGO and VIRGO should help that tran-sition in knowledge. Such changes bring with them revolutions in societal structures and inter-national relationships.

In Gravitational Wave astronomy, the new breed of astronomers and physicists are responding to massless gravitons, representative of the gravitational wavelengths arriving at Earth. This is very different from collecting and analysing massless photons of radio, visible and other electro-magnetic wavelengths.

All gravitational waves are very long, some of cosmological length. Those detected on 4th January, 2017 are analysed currently as being 1.5-trillion kilometres from peak to peak. From measurements of the two binary coalescences which were detected in 2015, combined with this year's observation, physicists have calculated a combined value yielding a hypothetical gravitational wavelength of 1.6-trillion kilometres, and corresponding to a graviton having a mass of less than or equal to 7.7 time10-23 electron volts, divided by the speed of light squared. The speed of light is 299,792, 458 metres per second - just under 300,000 kilometres per second. In one year, light can travel 300,000 x 300,000 x 24 x 365.25 kilometres, or, approxi-mately 9.5 trillion kilometres. So, in one year the 0.000000000000000000000077 electron volts of a graviton could be spread over 9.5 trillion, trillion square kilometres, which would be a vanishingly small amount of energy (and so a vanishingly small mass).

These are highly technical results, having highly technical consequences, which are also highly theoretical, and I think it is difficult for the non-specialist to claim with any confidence that they (...continued on page 5)

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