Siegel: “It is time to take seriously the idea that dark energy might simply be a property inherent to the very fabric of space. Until we learn how to calculate the zero-point energy of empty space itself, or gain some bizarre, surprising, and unanticipated evidence, this will remain one of the biggest existential questions in all the universe.” So this is existentialism for physicists, right? Even Sabine Hossenfelder sounds sort of existential on this one.
Sheldon: Translating, Ethan is saying that the old 20th century materialism that says “entropy” or “information” emerges from the particles is being replaced by a 21st century view that “entropy” or “information” is fundamental and the material particles emerge from the immaterial field.
Siegel: In the near future, observatories like the ESA’s Euclid, the NSF’s Vera Rubin Observatory, and NASA’s Nancy Roman Observatory will improve that uncertainty so that if dark energy departs from a constant by as little as ~1-2%, we’ll be able to detect it. If it strengthens or weakens over time, or varies in different directions, it would be a revolutionary new indicator that dark energy is even more exotic than we currently think.
The Big Bang has been very unpopular. It reeks of purpose and is an incitement to theism. And Siegel tells us that it survives only because the evidence rules out all alternatives.
But wait. If it was truly empty, it would not exist, right? What we mean by the “universe” is everything that exists. So, if it’s “empty,” nothing exists. Of course, it could always exist as an abstract idea but then it must be the abstract idea of a Being in another dimension.
Essentially, if we don’t know whether the structures are real or not, why are we worrying about whether they “defy our present cosmic understanding”? First things first.
Siegel offers an inside look at the details. While the finding is doubtless a success for the scientific method, it must be frustrating for those physicists who need dark matter to exist in order to make cosmology understandable — but can’t find any.
Siegel: “… if the theory of inflation is a good one, and the data says it is, a multiverse is all but inevitable.” Our physics color commentator Rob Sheldon writes to offer a response.
Siegel thinks that a rocky planet of more than 30% greater radius than Earth stands a good change of becoming a gas giant in consequence of its size. Earth is the right size to avoid that.
If we leave physical constraints behind, we are certainly not operating in the only universe we know. But thanks to Ethan for an entertaining close to the evening.
Ethan Siegel looks at the limitations: But we’re still a long way away from determining exactly where that information goes, and how it gets out of a black hole. Theorists disagree over the validity and soundness of many of the methods that are currently being employed to do these calculations, and no one has even a theoretical prediction for how this information should be encoded by an evaporating black hole, much less how to measure it.
Sheldon: The politicization of science evidently started before Ethan’s graduate schooling, as Hoyle and his post-doc Chandra Wickramasinghe tell in their biographical writings.
Siegel: “It is a fundamentally misinformative act to present multiple sides of a controversial issue equally when the scientific consensus overwhelmingly favors one perspective.” Actually, consensus is achieved in many ways, including some that contribute to the likelihood that the consensus will be wrong, no matter how many experts believe it. In fact, the surest way to often be wrong is to adopt the very attitude Siegel displays here.
Make no mistake, the Big Bang is unpopular in many quarters and an exterminator has long been sought. Here’s the problem: The explanation for an event may be outside the event. In that case, one can’t derive an explanation from within the event.
Siegel: It’s the ultimate nightmare of astrobiologists: that there’s a fascinating history of life to uncover on another world, but we’ll contaminate it with our own organisms before we ever learn the true history of life on that world.