May the force not be with you: Sandra Bullock goes for a spacewalk in Gravity. Photo: Warner Bros
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In search of the notorious Big G: why we still know so little about gravity

Gravity is pathetic and so is our understanding of it.

Gravity is pathetic. The Oscar statuette, for instance, has a mass of 3.85 kilograms but it is pulled down to earth by a force so weak that you can buy a £2.99 fridge magnet that can beat it. It’s shameful that the gravitational pull of the entire earth can be overcome by a cheap piece of magnetised steel.

Gravity is by far the weakest of the fundamental forces of nature (the fridge magnet puts the far stronger electromagnetic force to work). It is so weak that its strength is proving difficult to measure accurately. In late February, while Alfonso Cuarón, the director of the sci-fi film Gravity, was on tenterhooks waiting for the Oscars result, the world’s experts on gravity assembled just outside Milton Keynes in an attempt to sort out this most embarrassing problem.

Numbers such as the strength of gravity, the speed of light and the charge on an electron are known to physicists as the “fundamental constants”. They are in some ways the sticking plaster of physics. We can explain the origin of most things but we know the values of the fundamental constants only by measuring them – there is no way to work them out from a theory.

These days, most are very well defined – but not gravity. It is the only fundamental constant for which our uncertainty over its value has got worse over the years.

The gravitational constant is sometimes known as “Big G”. This differentiates it from “little g”, which describes how fast things accelerate towards Planet Earth when free to fall. The first accurate measurement of Big G was made in 1798. Henry Cavendish used a torsion balance, a device in which two lead weights are attached to the ends of a metal bar. The bar hangs horizontally by a metal wire attached to its midpoint. Cavendish then brought other weights close to one of the lead weights and measured how much the gravitational attraction between the weights twisted the wire. From that measurement, he calculated the strength of gravity.

Cavendish’s accuracy was five parts in 1,000. Over 200 years later, our accuracy stands at roughly one part in 10,000. Given that modern measurements use lasers and electronic devices and Cavendish used a mirror and a candle, it hardly counts as a great improvement.

What’s worse is that our measurements of Big G are getting less accurate. The latest measurement, reported at the end of last year, reduced the overall value by 66 parts per million but the uncertainty
of the value increased from 100 parts per million to 120 parts per million.

The measurement was taken by Terry Quinn, emeritus director of the International Bureau of Weights and Measures in Paris. At its meeting in February, he argued that it was time researchers admitted that everyone must be making some basic errors in their method and that they should give up on making any more unilateral measurements.

The experts now agree that future experiments seeking the value of Big G will be done in big collaborations, with the proposals for equipment and methodology being scrutinised by everyone in advance to minimise the chance of further embarrassment.

It will, they say, mimic the way that researchers worked together to find the Higgs boson. That gave us the secret of mass: the hope is that if the physicists all pull together, they can finally work out exactly what size of force brings that mass down to earth.

Michael Brooks holds a PhD in quantum physics. He writes a weekly science column for the New Statesman, and his most recent book is At the Edge of Uncertainty: 11 Discoveries Taking Science by Surprise.

This article first appeared in the 05 March 2014 issue of the New Statesman, Putin's power game

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Why have men become so lonely – and how does it affect their health?

New findings show the consequences of having a lonely heart.

Go out and get some friends. No, seriously. Hop on the Tube and act faux-interested in the crap-looking book your fellow commuter is reading, even if it's on their Kindle. Chances are it's better than the one in your bag, and they're probably a decent human being and just as lonely, like you and me.

A new slate of facts and figures are showing just how widespread loneliness, is while simultaneously being amazingly terrible for your health.

Research led by Steven Cole from the medicine department at University of California, Los Angeles is showing the cellular mechanisms behind the long known pitfalls of loneliness. Perceived social isolation (PSI) – the scientific term for loneliness –increases the exposure to chronic diseases and even mortality for individuals across the world.

The authors examined the effects of loneliness on leukocytes, also known as white blood cells, which are produced from stem cells in the bone marrow and are critical to the immune system and defending the body against bacteria and viruses. The results showed loneliness increases signalling in the sympathetic nervous system, which is responsible for controlling our fight-or-flight responses, and also affects the production of white blood cells.

Recently, the Movember Foundation, which focuses on men's health and wellbeing, carried out a survey with the help of YouGov investigating friendship and loneliness amongst men. The results are alarming, with only 11 per cent of single men across the spectrum in their early 20s to late-middle age saying they had a friend to turn to in a time of crisis, the number rising to 15 per cent for married men.

Friendship has shown not only to be important to a person's overall wellbeing, but can even add to a person's earnings. A previous study involving 10,000 US citizens over 35 years showed people earned 2 per cent more for each friend they had.

The Movember Foundation survey comes soon after the Office for National Statistics (ONS) showed that men in Britain make up 58 per cent of the 2.47m people living alone between the ages of 45 and 64. The reasons behind this figure include marrying later in life and failed marriages, which usually result in children living with the mother. Women still make up the majority of the 7.7m single-occupant households across all ages in the country, at approximately 54 per cent.

Chronic loneliness seems to have slowly become a persistent problem for the country despite our hyper-connected world. It's an issue that has made even Jeremy Hunt say sensible things, such as "the busy, atomised lives we increasingly lead mean that too often we have become so distant from blood relatives" about this hidden crisis. He's previously called for British families to adopt the approach of many Asian families of having grandparents live under the same roof as children and grandchildren, and view care homes as a last, not first, option.

The number of single-person households has continued to increase over the years. While studies such as this add to the list of reasons why being alone is terrible for you, researchers are stumped as to how we can tackle this major social issue. Here's my suggestion: turn off whatever screen you're reading this from and strike up a conversation with someone who looks approachable. They could end up becoming your new best friend.