Does dark matter exist?

After 80 years of agreement about the dark stuff, opinions may be changing.

The peasants are revolting. Last night the Flamsteed Astronomical Society met at the National Maritime Museum to hear a debate on the existence (or not) of dark matter. In a vote at the end, the audience decided it probably doesn’t exist.

The idea of dark matter has been around since 1933, when a Swiss astronomer called Fritz Zwicky found that centrifugal forces should have been tearing spinning galaxy clusters apart – but weren’t. The answer, he suggested, was that there was extra stuff in there, whose gravitational pull was holding everything together.
 
Astronomers now believe this stuff makes up around a quarter of the universe, if you take into account all the mass and energy in the cosmos. Ignore the pure energy, and dark matter accounts for 80 per cent of the universe’s mass. Which makes it a little embarrassing that we have never seen any.

Neither do we know what it looks like. We’ve been groping around for dark matter since about 1970. Various predictions have been made: in 1980, astronomer Vera Rubin said it would be found within 10 years. In 1990, astronomer royal Martin Rees said the dark matter mystery would be solved by the turn of the century. In 1999 Rees was aware he had been too hasty, and said we would know what dark matter is by 2004. Last January, CERN theoretical physicist and Gandalf lookalike John Ellis gave the physicists another decade.
 
But patience is starting to wear thin. At last night’s debate, Oxford physicist and co-presenter of The Sky at Night Chris Lintott made the case for dark matter; astronomy writer Stuart Clark argued that a modification to the laws of gravity, which are dictated by Einstein’s general relativity theory, held more promise for explaining the (apparently) missing mass. At the end of the evening, the audience sided with Clark and modifying gravity.
 
That’s not going to have dark matter astronomers quaking in their boots. But it is nonetheless indicative of a change of mood. Take what went on at the Cosmic Variance blog last week. Sean Carroll, the blog’s host, has always been bullishly pro dark matter. But it seems he has started to hedge a bit.
 
In a fascinating post, he published the trialogue he had been conducting with astronomer Stacey McGaugh, the original proponent of the modified gravity idea (it’s called MOND: modified Newtonian Dynamics) and German astrophysicist Rainer Plaga. Right at the top, Carroll concedes that “it may very well turn out that the behavior of gravity on large scales does not precisely match the prediction of ordinary general relativity”. In other words, he is saying, we might well have to modify gravity.
 
It’s worth pointing out a couple more reasons it’s OK to harbour doubts about the dark stuff. Last September, Durham astronomer Carlos Frenk admitted he was “losing sleep” over the results of his own computer simulations. His work had showed that the way simulated dwarf galaxies – mainly composed of dark matter – form in a halo around our own galaxy doesn’t tally with what we observe. His conclusion was that the standard theory of dark matter is almost certainly wrong, adding that searches for the stuff at the LHC in Geneva would therefore prove fruitless.
 
Then last month two groups of astronomers announced that dark matter wasn’t where it should be. The sun is meant to be surrounded by a halo of dark matter, and it isn’t.
 
If there really is no dark matter, that won’t be a mainstream view for decades to come. Once it’s got some momentum, it takes a lot of effort to change direction in science. But it does seem that, after 80 years, someone’s found the handbrake on the dark matter juggernaut.
 

Images of giant galaxy clusters, said to be mainly made up of dark matter. Photograph: Nasa/Getty Images

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.

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New Times: David Runciman on networks and the digital revolution

The digital revolution has had two profound effects on how power is distributed – both of which squeeze the state's power.

Left-wing political parties exist to use the power of the state to rectify unjust distributions of power in society. What has gone wrong with this project? First, the political parties bit. Established parties everywhere are struggling to seem relevant to most people’s everyday concerns: they look increasingly like the tired relics of a more hierarchical age. The exception, of course, is the current Labour Party, which has opened itself up to become the biggest mass-membership party in Europe. But the trade-off has been to move away from seeing the acquisition of power as its primary purpose. These days parties can only really draw people in by offering to be vehicles for the expression of political resentment and disenchantment. But that is no way to rectify the causes of their resentment; neglecting the challenge of power usually ends up making things worse.

However, this is just a symptom of the wider problem, which is the changing nature of power. Technology lies at the heart of it. The digital revolution has had two profound effects on how power is distributed. First, it has empowered individuals, by providing them with unprecedented access to information, tools of communication and the means of expression. This is power exercised as choice: we all now have multiple ways of registering our likes and dislikes that never existed before.

Second, the digital revolution has empowered networks, creating vast new webs that span the globe. Some of them, such as Facebook, are close to being monopolies. We end up joining the networks that other people have joined, because that’s where the action is. This gives a small number of networks an awful lot of power.

Both of these developments are deeply problematic for the power of the state. The proliferation of choice makes citizens much harder to satisfy. Many of us have got used to micromanaging our lives in ways that leaves government looking flat-footed and unresponsive, no matter how hard it tries. At the same time, states face global networks that they have no idea how to control. International finance is one of these: money is information and information now has too many different ways to flow. States are getting squeezed.

The paradox is that the same forces that are squeezing the state are also giving impetus to left-wing politics. There are huge imbalances of power being created in networked societies. The monopolists are hoovering up money and influence. Personal connections count for more than ever, now that networked connections have become ubiquitous. Education is turning into a way of pulling up the drawbridge rather than moving up the ladder. One temptation for the left is to assume that the evidence of injustice will sooner or later outweigh the disabling effects of these social forces on the state. That is part of the Corbyn gamble: hang around until people are sufficiently pissed off to start demanding social-democratic solutions to their problems.

I don’t think this is going to happen. There is nothing to suggest that popular dissatisfaction will find its way back to the state as its best outlet. It will be channelled through the networks that are making the life of the state increasingly difficult.

The other temptation is to think that the left can achieve its goals by bypassing conventional social democracy and channelling its own ambitions into network politics. This is the other side of the Corbyn gamble, or at least the view of some of the people who have attached themselves to him: a new politics is coming that uses digital technology to mobilise fleet-footed networks of activists who can generate change without going through the cumbersome and time-consuming process of winning general elections. That also looks pretty wishful to me. These networks are just another vehicle for expressing personal preferences. They don’t have any means of changing the preferences of people who think differently. You need to win power to do that.

The state’s power is being squeezed by networks of empowered individuals, but these networks don’t have the kind of power necessary to do the redistributive work of the state. What is the left to do? It needs to try to find value in the fact that the state is not just another network. The right does this instinctively, by talking up the state’s security functions and championing ideas of sovereignty and national identity. But that does nothing to address the deleterious effects of living in a modern networked society, where we are swamped by personal choice but impotent in the face of corporate and financial power.

Rather than trying to harness the power of networks, the left should stand up for people against the dehumanising power of Big Data. The state isn’t Google and should not try to pretend to be. We don’t need more choice. We don’t need more efficiency of the kind that digital technology is endlessly supplying. We need protection from the mindless bureaucratic demands of the new machine age: the relentless pursuit of information, regardless of the human cost. There are limits to what the state can do but it retains some real power. It still employs real human beings; it educates them and provides them with welfare. It should do what is in its power to make the work tolerable and the education meaningful, to provide welfare in ways that don’t leave people at the mercy of faceless systems. The left needs to humanise the state.

At the moment, too much energy is being spent trying to humanise the party. We are told that people are tired of robotic, careerist politicians; they want unspun versions of people like themselves. But robotic politicians aren’t the problem; the coming age of robots is. While the party tries to feel more comfortable with itself, the effects of a networked society are running rampant. Acquiring the power of the state is still the best way to fight back. It doesn’t matter if that has to be done in an ugly, mechanised, artificial way, by careerist politicians with whom we wouldn’t choose to spend our personal time. Better an ugly, artificial politics than an ugly, artificial world. 

David Runciman is a professor of politics and the head of the department of politics and international studies at Cambridge

This article is part of a New Times collection of the future of the left. Read the other pieces here.

 

This article first appeared in the 22 September 2016 issue of the New Statesman, The New Times