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A team of astrophysicists say that we may have misinterpreted the cosmic microwave background, the historically decisive evidence for the Big Bang theory. And what they say is frighteningly plausible. I have a feeling that this paper is going to cause some people sleepless nights. The cosmic microwave background, CMBB for short, is, as the name suggests, radiation in the microwave range of the electromagnetic spectrum. It's all around us at an extremely steady temperature of about 2.7 Kelvin. Just for context, that's approximately what my husband thinks of as cozy. In the Big Bang theory, the CMBB comes from the hot nuclear plasma that filled the early universe. In that plasma, there's a lot of radiation. And once the particles combine to atoms, the radiation can travel pretty much freely. The wavelength of this leftover radiation then stretches with the expansion of the universe. This means the wavelength gets larger and the frequency is smaller and so the average energy gets smaller. The light gets redshifted as physicists say. This is why the CMBB today is so cold. It's cooled for 13 billion years. But while the temperature of the CMBB is almost exactly the same in all directions, this isn't perfectly so. It has patches that are a tiny little bit warmer or colder by a few parts in 100,000. These are the temperature fluctuations in the CMBB. They come from density fluctuations in the plasma in the early universe, or so we thought. This brings me to the new paper. The authors draw conclusions from data that the James Web Space Telescope has delivered. The telescope has found that galaxies form much earlier and grow big much faster than expected. We've talked about this previously because this is in conflict with the predictions from dark matter. But the new paper draws a much more general conclusion that's even more stunning. They say that whatever the reason for why these galaxies grew large and bright so quickly, evidently they do. And the light from these galaxies would heat up dust of which there was around a lot at the time. This makes the light from the early galaxies very diffuse and thermalizes it. Then the light again becomes stretched with the expansion of the universe. And here's the amazing part. The authors calculate that the temperature of this light today would plausibly be in the range where we measure the cosmic microwave background. They write that even in our most conservative estimates, massive early type galaxies account for 1.4% up to the full present-day CMBB energy density. Let that sink in. Their most conservative estimate challenges the entire foundation of modern cosmology. you know just casually this creates a big problem for the currently accepted standard model of cosmology also known as lambda CDM that's the model with dark energy and dark matter this is because it relies on analyzing CMBB data to extract key parameters and that assumes that the CMB did come from that hot plasma if it didn't come from the plasma but from the early galaxies then this means that most of the other parameters are likely wrong, too, because the analyses are highly interdependent. I expect there'll soon be some criticism of this result, but I think it won't be easy to get rid of. It's worth mentioning that Pavle Krup, one of the authors of the paper, is a very vocal supporter of modified Newtonian gravity. But this isn't what the paper's about. It's rather just saying, "Look, we better think about this. Things aren't adding up. By the way, this video comes with a quiz that lets you check how much you understood. If what they say is correct, what does it mean for the Big Bang theory? Well, that depends on what you mean by big bang. Personally, I take the word big bang to refer to the beginning of the universe, the first moment in our extrapolation into the past. Some science communicators have instead been using it to refer to the idea that the universe expands. Then again, others have used it to refer to the idea that the universe expands in the exact way as predicted by lambda CDM. This new finding doesn't tell us anything about the first moment of the universe because these early galaxies were still born some 100 million years or so after that. So the new paper doesn't change anything about this notion of big bang. It also doesn't change anything about the fact that the universe expands. There is just too much evidence supporting this. Not just the cosmic microwave background, but red shift itself or structure formation. So what this new finding pokes a hole into is the particular standard theory with dark energy and dark matter that's sometimes referred to as the big bang theory. Cosmology used to be about answering the big questions. Now it's mostly about realizing we were asking the wrong questions. To me, science is more than a profession. It's a way to understand the world and how to solve problems. This is why I'm happy to work together with Brilliant, whose mission is to help you learn science in the easiest and most engaging way possible. Brilliant offers courses on a large variety of topics in science, computer science, and mathematics. All their courses have interactive visualizations and come with follow-up questions. Whether you want to learn to think like an engineer, brush up your knowledge of algebra or want to learn coding and Python, Brilliant has you covered. 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