One world is not enough

On inaccessible universes and infinite planets.

Don’t worry, there are other worlds. There have to be. If there aren’t, then we haven’t yet made sense of this one. On 19 June, the celebrated science-fiction writers Terry Pratchett and Stephen Baxter will publish a new book, The Long Earth. It is based on an outlandish premise: that an infinite number of variations on our planet are hidden in inaccessible universes. If it were just science fiction, we could either welcome or dismiss it, according to our taste, as yet another example of the limitless human imagination. The trouble is, the whole thing is based in evidence. Worse, this evidence is now the bedrock of modern science.

First of all, let’s go to the roots of our physical reality. If you fire an atom at a screen containing two openings, the atom will go through both. It’s not just atoms; a molecule composed of 60 or so atoms does the same thing. Anything that follows the laws of quantum theory will do it. The only time this doesn’t happen is when someone is watching.

That we don’t get into a car using all four doors at once tells us that the weirdness disappears once you have a lot more than a few dozen atoms clumped together. No one knows why, and it doesn’t change the fact that the strange behaviour of the building blocks of matter is capable of breaking your mind.

No one knew this better than Hugh Everett, who started his career trying to solve this puzzle and ended up a chain-smoking alcoholic. Everett’s idea is now known as the “many worlds” interpretation of quantum mechanics. According to this, a new universe is created every time a subatomic particle is faced with a choice of things to be or do. The ultimate logical consequence is that the universe is composed of myriad sub-universes, each subtly different from the one that spawned it. In this cornucopia of worlds, many will be utterly different from ours. There is, according to the theory, a world where Elvis Presley is the king, not of rock’n’roll, but of Great Britain and Northern Ireland.

No one accepted the idea, and Everett responded to the pain of rejection by slowly self-destructing. Today, however, physicists take these quantum worlds seriously. And they are not the only strange fruit of modern physics.

Our best theory of how the universe began requires that it went through a ridiculous period of super-fast expansion, increasing in size by a factor of 1,000 billion billion billion in a fraction of a millisecond. If that is the case, the same “inflation” mechanism will cause other universes to blow up from tiny instabilities in the fabric of our universe. They pinch off and float away beyond our reach. And if you believe Everett’s theory, the activity of quantum particles in each of those worlds will spawn ever more worlds nested within them.

Forget reality

It might seem as if the existence of these universes would be unverifiable, but that is a supposition which ignores the ingenuity of scientists. Some have already worked out what imprint a collision with one of the inflated universes would make on the microwave background radiation that fills our universe. Having figured that out, they are now combing the universe for signs that we have touched another world.

It will be harder to verify the existence of the many quantum worlds. Some believe a better explanation for quantum phenomena is that there is no objective reality at all; nothing exists until an experimental observation brings it into being. But clearly, whatever Pratchett and Baxter have come up with, it won’t be as strange or unbelievable as the truth. 

Michael Brooks’s “The Secret Anarchy of Science” is out now in paperback (Profile Books, £8.99)

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 18 June 2012 issue of the New Statesman, Drones: video game warfare

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“A cursed project”: a short history of the Facebook “like” button

Mark Zuckerberg didn't like it, it used to be called the “awesome button”, and FriendFeed got there first. 

The "like" button is perhaps the simplest of the website's features, but it's also come to define it. Companies vie for your thumbs up. Articles online contain little blue portals which send your likes back to Facebook. The action of "liking" something is seen to have such power that in 2010, a class action lawsuit was filed against Facebook claiming teenagers should not be able to "like" ads without parental consent. 

And today, Facebook begins trials of six new emoji reaction buttons which join the like button at the bottom of posts, multiplying its potential meanings by seven: 

All this makes it a little surprising that Facebook CEO Mark Zuckerberg spent a good portion of the noughties giving the like button a thumbs down. According to Andrew Bosworth, Vice President of Advertising and Pages at Facebook (and known simply as "Boz") it took nearly two years to get the concept of an approval button for posts off the ground.

In a fascinating Quora thread, Boz explains that the idea of a star, plus sign or thumbs up for posts first came up in July 2007, three years after "TheFacebook" launched in 2004. Throughout these initial discussions, the proposed bursts of positivity was referred to as an "awesome button". A few months later someone floated the word "like" as a replacement, but, according to Boz, it received a "lukewarm" reception. 

The team who ran the site's News Feed feature were keen, as it would help rank posts based on popularity. The ad team, meanwhile, thought "likes" could improve clickthrough rates on advertisements. But in November 2007, the engineering team presented the new feature to Mark Zuckerberg, and, according to Boz, the final review "[didn't] go well". The CEO was concerned about overshadowing the Facebook "share" and comment features - perhaps people would just "awesome" something, rather than re-posting the content or writing a message. He also wanted more clarification on whether others would see your feedback or not. After this meeting, Boz writes, "Feature development as originally envisioned basically stops". 

The teams who wanted the button forged ahead with slightly different features. If you were an early user, you might remember that News Feed items and ads collected positive or negative feedback from you, but this wasn't then displayed to other users. This feature was "ineffective", Boz writes, and was eventually shut down. 

So when Jonathan Piles, Jaren Morgenstern and designer Soleio took on the like button again in December 2008, many were skeptical: this was a "cursed project", and would never make it past a sceptical Zuckerberg. Their secret weapon, however was data scientist Itamar Rosenn, who provided data to show that a like button wouldn't reduce the number of comments on a post. - that, in fact, it increased the number of comments, as likes would boost a popular post up through the News Feed. Zuckerberg's fears that a lower-impact feedback style would discourage higher value interactions like reposting or commenting were shown to be unfounded. 

A bigger problem was that FriendFeed, a social aggregator site which shut down in April 2015, launched a "like" feature in October 2007, a fact which yielded some uncomfortable media coverage when Facebook's "like" finally launched. Yet Boz claims that no one at Facebook clocked onto FriendFeed's new feature: "As far as I can tell from my email archives, nobody at FB noticed. =/". 

Finally, on 9 February 2009, "like" launched with a blogpost, "I like this", from project manager Leah Pearlman who was there for the first "awesome button" discussions back in 2007. Her description of the button's purpose is a little curious, because it frames the feature as a kind of review: 

This is similar to how you might rate a restaurant on a reviews site. If you go to the restaurant and have a great time, you may want to rate it 5 stars. But if you had a particularly delicious dish there and want to rave about it, you can write a review detailing what you liked about the restaurant. We think of the new "Like" feature to be the stars, and the comments to be the review.

Yet as we all know, there's no room for negative reviews on Facebook - there is no dislike button, and there likely never will be. Even in the preliminary announcements about the new emoji reactions feature, Zuckerberg has repeatedly made clear that "dislike" is not a Facebook-worthy emotion: "We didn’t want to just build a Dislike button because we don’t want to turn Facebook into a forum where people are voting up or down on people’s posts. That doesn’t seem like the kind of community we want to create."

Thanks to the new buttons, you can be angry, excited, or in love with other people's content, but the one thing you can't do is disapprove of its existence. Championing positivity is all well and good, but Zuckerberg's love of the "like" has more to do with his users' psychology than it does a desire to make the world a happier place. Negative feedback drives users away, and thumbs-down discourages posting. A "dislike" button could slow the never-ending stream of News Feed content down to a trickle - and that, after all, is Facebook's worst nightmare. 

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