New scientific accounts of the universe are expected to fit with observation and predicted results from established theories. But at the heart of modern physics there's reason to think this is not the case. Thirty years ago, we observed the universe was not only expanding but accelerating away from us. To stop this undermining the theory of the Big Bang we invented a force called 'dark energy,' seen as the energy of empty space or vacuum energy, pushing the universe apart. But there was a problem. The predicted value of this energy was 120 orders of magnitude out. That's worse than predicting an atom is the size of the universe. Unsurprisingly, it has been described as the 'worst prediction in the history of physics'. Yet the majority of physicists still accept dark energy as a credible theory.
Should we accept that scientific theories ignore observation and prediction if it is convenient? Is there something necessarily wrong with dark energy and our current cosmological story? Or can we fix the problem and find the right answer, or is science a model and not a description of reality at all?