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.

YouTube screengrab
Show Hide image

Why I’m sick of fake theorists lamenting the “millennial problem”

Wise Thinkers lament smartphones, social media, and self-entitlement – ignoring how badly off this generation is thanks to its predecessors.

There is a certain sort of Wise Thinker who loves nothing more than to offer advice on the “problem” of “millennials”. Oh, Wise Thinker, where has this mysterious generation of lazy, entitled narcissists come from, and how am I supposed to deal with the ones who keep showing up in my office?

The answer, we’re told, is a massive failure in parenting that started in the 1980s – suddenly children were told they were special, that they could do anything they wanted to. Worse, they were shown they didn’t have to work for it – they were given participation medals just for showing up, and any time they did badly at school, they didn’t need to improve; their parents just complained to get them better marks!

No evidence that any of this is substantially true (or caused the claimed effects) need be offered: that can be left as an exercise to the reader’s own preconceptions.

(They’ve given out participation medals in the modern Olympics since it started in 1896, by the way. No one ever seems to mention that.)

A particularly refined example of this sort of thing has been doing the rounds of social media recently – a video clip in which motivational speaker and TED talkist Simon Sinek rehearses the familiar lines but then makes a rather bolder claim: millennials are losing the capacity for joy (and some of them are even killing themselves), and it’s all because of mobile phones.

Their use of mobile phones and social media is addictive, Sinek says, in exactly the same way as drugs and alcohol. He refers to the brain chemical dopamine, which immediately turns his every utterance into rigorous neuroscience – regardless of the quantity and quality of the evidence available to support it.

That every millennial is suffering from this terrible addiction is taken as read, as much as everyone who’s ever had a glass of wine is a raging alcoholic. Non-millennials, we all know, completely eschew the mobile phone and have never been seen on Facebook.

But this is only part of the broader millennial addiction to instant gratification – same-day delivery, movies-on-demand, even getting a date is now as simple as swiping right, as anyone who’s never actually tried online dating will surely agree!

It seems all millennials can have everything they want, whenever they want it, so they will never learn the hard lessons that the Wise Thinkers learned in the old times: how to be patient, how to have self-restraint, how to work hard for something.

This can surely be the first time in history in which the old have considered the young to be impatient and lazy.

Worst-case scenario? Sinek points to a rise in depression and suicide, and lets us draw arbitrary lines as we please. His best-case scenario: the millennial will never learn how to find joy, unless, apparently, their benevolent employer helps them with such innovative solutions as banning phones in meetings. Sure.

There is of course nothing wrong with some scepticism towards new technology and the effect it can have on the fragile human mind. If only we had heeded the scientist Conrad Gessner’s dire warning of a powerful new invention that would overwhelm, confuse and ultimately harm us with its unstoppable flood of information. That invention? The book. Gessner lived through the invention of the printing press in the sixteenth century. History doesn’t record whether or not he wore stupid glasses.

But maybe Sinek is right – maybe only by abandoning the embrace of Siri will you know true love, millennials, some of you who are actually in your mid-thirties these days and have probably already started tutting at those younger than you who never learned “real” patience by sending texts on a Nokia 3310.

It must be a lot of fun, theorising about the possible origins of the “millennial problem”, and coming up with brilliant outside-the-box solutions to it. Weird, though, that all these Wise Thinkers never seem to talk about how many millennials started their careers in the midst (or the aftermath) of an uncertain job market caused by the 2008 financial crisis. Or how many of them had to start their careers with unpaid internships. Or, more fundamentally, that they’re the first generation for decades to earn lower wages than their predecessors.

Perhaps, for some strange reason, managers so supposedly desperate to understand millennial employees are not quite as interested in paying motivational speakers to tell them about things like that.