NASA, ESA, CFHT, CXO, M.J. Jee (University of California, Davis), and A. Mahdavi (San Francisco State University)
A few years ago, the internet caught alight with talk of a “vibe shift” in what counts as cool. Skinny jeans and minimalism were out; baggy trousers and messy hair were in. Cue a minor panic for ageing millennials everywhere as it dawned on them that they were suddenly out of touch.
Now, something similar is happening in cosmology. For years, physicists thought they had a neat understanding of how the universe works, a simple and elegant framework called the standard model of cosmology that gave an excellent account of how it began and evolved. At the heart of the model is dark energy, a force we admittedly can’t identify but behaves predictably to force the universe to expand.
Then, last year, explosive results from a telescope survey seemed to show the unthinkable: dark energy has been getting weaker over the history of the universe. If that is true, then the standard model of cosmology will need to be rewritten. In a package of three special features, we delve into the beauty of the standard model, reveal how endangered it really is and explore what might replace it.
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Where the attachment to the old model is motivated by fear or nostalgia, that won’t do
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It must be said, though, that many physicists are still reluctant to abandon their cherished model. To some extent, this is fair enough. As with so many apparently convincing results in modern physics, the dark energy findings may not stand the test of time. But where the attachment to the old model is motivated by fear of the unknown or nostalgia for simpler times, that won’t do.
Scientists tend not to talk of vibe shifts, but of paradigm shifts – periods when our lens of understanding fundamentally changes. History teaches us that paradigm shifts are a good thing. They are discombobulating, no question, but allow us to see reality more clearly. We aren’t yet sure if the challenge to dark energy really will amount to a paradigm shift akin to the quantum or Copernican revolutions – but if it does, we will look back on this period of cosmology as a thrilling time to be alive. Bring on the new vibe.