Relax, the big bang theory has not been debunked. Far from it, in fact

In 2011, an experiment at the European Organization for Nuclear Research, known as CERN, thought that it had detected particles traveling faster than light. This came as a surprise because an absolutely fundamental law of modern physics is that nothing can travel faster than the speed of light in a vacuum. Getting even a single massive particle up to lightspeed would take infinite energy.

But there it was, a finding that some neutrinos had traveled between the particle accelerator in Geneva and the detector in Italy 60 billionths of a second faster than a beam of light would have. It looked, statistically, extremely robust: you’d only see results as unexpected as that one time in every five million, if it were down to chance alone. If it was true, it would probably have been the biggest physics story of the century.

Before even reading the paper, most physicists would have told you it was false. And then they’d have sat back and waited to find out why.

If you ever read a headline saying “Huge, famous, well-supported scientific theory has been proved wrong”, your first assumption should be “No, it hasn’t.” The theory of evolution has been “debunked” thousands of times, but still, humans are descended from apes and traits that help reproduction tend to spread through populations. Any “perpetual motion machine” paper you read will have made an error somewhere in its needlessly complex mathematics.

This week, there’s been a certain amount of online excitement over the James Webb Space Telescope (JWST). Apparently images from it have “debunked” the big bang theory. A physics blogger first raised the issue, a little-known site ran with it, and MSN.com, a relatively well-respected news source, syndicated it to their much larger audience. Then some big names – including the Dilbert cartoonist Scott Adams – tweeted it out. It cited one astrophysicist saying: “I find myself lying awake at three in the morning, wondering if everything I’ve ever done is wrong.”

We can be pretty sure it’s nonsense, and here’s why. The big bang theory isn’t one thing. It’s not that there’s one study someone did in the mid-1950s: there are thousands of studies, and two major lines of evidence.

One is that all the galaxies in the universe are moving away from each other, suggesting that if you rewound the tape, you’d see that they all come from one spot. Another is that the “echoes” of the big bang can still be detected: low-level microwave radiation left over from the initial expansion, just as the theory predicted.

It may well not be the whole picture: scientists have suggested that our “big bang” was just one local expansion in an infinite universe, a sort of “bubble” in an eternal cosmic “foam”.

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But the basic idea, that about 13.8 billion years ago all the matter in the observable universe was concentrated in one infinitesimal point, is unlikely to be overturned. If it ever is, it will be the product of a huge theoretical reimagining of physics; but the safe bet is that it won’t be.

If you follow the links in the story, inevitably, it turns out that the big bang theory hasn’t been debunked. What’s happened is that the JWST found many more disc-shaped galaxies in the very early universe than current theories predict, suggesting that galaxies form more quickly than we think.

It may be that physicists’ models of galaxy formation need updating. But not our understanding of the birth of the universe. The physicist who said she was worried that everything she ‘d ever done was wrong was talking about her work her on how galaxies and stars evolve; she didn’t mean that she was worried that the big bang hadn’t happened.

So perhaps the JWST findings will mean we need to rethink some details of galaxy evolution. But it may not. Remember those faster-than-light neutrinos? Upon investigation, it turned out that a fiber-optic cable connecting a GPS receiver to an atomic clock was slightly loose. That meant that a crucial signal was very slightly delayed, by 73 billionths of a second. That tiny delay was enough to make it seem as though the neutrinos had outpaced light itself.

The thing to remember is: when someone says that some hugely important theory has been overturned, what they’re offering is two hypotheses. One of them is “Everything we know about physics or biology or whatever is wrong.” The other is “Someone made a mistake or is lying to you.” Most of the time – not every time, perhaps, but close enough that you can be pretty confident – ​​the latter is the more likely option.

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