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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The one where she turns into a USB stick: the worst uses of tech in films

The new film Worst Tinder Date Ever will join a long tradition of poorly-thought-through tech storylines.

News just in from Hollywood: someone is making a film about Tinder. What will they call it? Swipe Right, perhaps? I Super Like You? Some subtle allusion to the app’s small role in the plotline? Nope – according to Hollywood Reporterthe film has been christened Worst Tinder Date Ever.

With the exception of its heavily branded title (You’ve Got Gmail, anyone?), Worst Tinder Date Ever follows neatly in the tradition of writers manhandling tech into storylines. Because really, why does it matter if it was a Tinder date? This “rom com with action elements” reportedly focuses on the couple’s exploits after they meet on the app, so the dogged focus on it is presumably just a ploy to get millennial bums on cinema seats.  

Like the films on this list, it sounds like the tech in Worst Tinder Date Ever is just a byword for “modern and cool” – even as it demonstrates that the script is anything but.

Warning: spoilers ahead.

Lucy (2014)

Scarlett Johansson plays Lucy, a young woman who accidentally ingests large quantities of a new drug which promises to evolve your brain beyond normal human limits.

She evolves and evolves, gaining superhuman powers, until she hits peak human, and turns into first a supercomputer, and then a very long USB stick. USB-Lucy then texts Morgan Freeman's character on his fliphone to prove that: “I am everywhere.”

Beyond the obvious holes in this plotline (this wouldn’t happen if someone’s brain evolved; texting a phone is not a sign of omnipotence), USB sticks aren’t even that good – as Business Insider points out: “Flash drives are losing relevance because they can’t compete in speed and flexibility with cloud computing services . . . Flashdrives also can’t carry that much information.”

Star Wars: The Force Awakens (2015)

If you stare at it hard enough, the plotline in the latest Star Wars film boils down to the following: a gaggle of people travels across space in order to find a map showing Luke Skywalker’s location, held on a memory stick in a drawer in a spherical robot. Yep, those pesky flash drives again.

It later turns out that the map is incomplete, and the rest of it is in the hands of another robot, R2-D2, who won’t wake up for most of the film in order to spit out the missing fragment. Between them, creator George Lucas and writer and director JJ Abrams have dreamed up a dark vision of the future in which robots can talk and make decisions, but can’t email you a map.

Willy Wonka and the Chocolate Factory (1971)

In which a scientist uses a computer to find the “precise location of the three remaining golden tickets sent out into the world by Willy Wonka. When he asks it to spill the beans, it announces: “I won’t tell, that would be cheating.


Image: Paramount Pictures. 

The film inhabits a world where artificial intelligence has been achieved, but no one has thought to pull Charlie's poor grandparents out of extreme poverty, or design a computer with more than three buttons.

Independence Day (1996)

When an alien invasion threatens Earth, David Levinson (Jeff Goldblum) manages to stop it by hacking the alien spaceship and installing a virus. Using his Mac. Amazing, really, that aliens from across the universe would somehow use computing systems so similar to our own. 

Skyfall (2012)

In the Daniel Craig reboot of the series, MI6’s “Q” character (played by Ben Whishaw) becomes a computer expert, rather than just a gadget wizard. Unfortunately, this heralded some truly cringeworthy moments of “hacking” and “coding” in both Skyfall and Spectre (2014).

In the former, Bond and Q puzzle over a screen filled with a large, complex, web shape. They eventually realise it’s a map of subterranean London, but then the words security breach flash up, along with a skull. File under “films which make up their own operating systems because a command prompt box on a Windows desktop looks too boring”.

An honourable mention: Nelly and Kelly Rowland’s “Dilemma” (2009)

Not a movie, but how could we leave out a music video in which Kelly Rowland texts Nelly on a Microsoft Excel spreadsheet on a weird Nokia palm pilot?


Image: Vevo.

You’ll be waiting a long time for that response, Kelly. Try Tinder instead.

Barbara Speed is a technology and digital culture writer at the New Statesman and a staff writer at CityMetric.