Cosmologic philosophy: only the Big Bang fits an origin (Introduction)

by David Turell , Saturday, October 01, 2022, 19:36 (784 days ago) @ David Turell

Ethan Siegel shows why:

https://bigthink.com/starts-with-a-bang/cmb-prove-big-bang/?utm_source=mailchimp&ut...

"Since time immemorial, humans have wondered what the Universe is, where it came from, and how it got to be the way it is today. Once a question far beyond the realm of knowledge, science was finally able to settle many of these puzzles in the 20th century, with the cosmic microwave background providing the critical evidence. There's a set of compelling reasons why the hot Big Bang is now our undisputed cosmic origin story, and this leftover radiation is what decided the issue. Here's how.

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"The Universe, as it is today, isn’t just expanding but is also cooling, as the radiation within it is getting stretched to longer wavelengths (and lower energies) by the expansion of space. That means, in the past, the Universe must have been smaller, hotter, and denser than it is today.

"1. Because gravitation is a cumulative process — larger masses exert a greater amount of gravitational attraction across larger distances than smaller masses do — it makes sense that the structures in the Universe today, like galaxies and galaxy clusters, grew up from smaller, lower-magnitude seeds.

"2. Because the Universe was hotter in the past, you can imagine a time, early on, when the radiation within it was so energetic that neutral atoms couldn’t have stably formed. The instant an electron tried to bind to an atomic nucleus, an energetic photon would come along and ionize that atom, creating a plasma state. Therefore, as the Universe expanded and cooled, neutral atoms stably formed for the first time, “releasing” a bath of photons (that would have previously scattered off of free electrons) in the process.

"3. And at even earlier times and hotter temperatures, you can imagine that not even atomic nuclei could’ve formed, as the hot radiation would have simply created a sea of protons and neutrons, blasting any heavier nuclei apart. Only when the Universe cooled through that threshold could heavier nuclei have formed, leading to a set of physical conditions that would have formed a primitive set of heavy elements through nuclear fusion occurring in the aftermath of the Big Bang itself.

"These three predictions, along with the already-measured expansion of the Universe, now form the four modern cornerstones of the Big Bang.

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"Today, billions of years later, we’d expect:
that leftover bath of radiation should still persist, it should be the same temperature in all directions and at all locations, there should be somewhere around hundreds of photons in every cubic centimeter of space, it should only be a few degrees above absolute zero, shifted into the microwave region of the electromagnetic spectrum, and, perhaps most importantly, it should still maintain that “perfect blackbody nature” to its spectrum.

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"And although we had evidence for a blackbody spectrum that improved greatly throughout the 1960s and 1970s, the biggest advance came in the early 1990s, when the COBE satellite — short for COsmic Background Explorer — measured the spectrum of the Big Bang’s leftover glow to greater precision than ever. Not only is the CMB a perfect blackbody, it’s the most perfect blackbody ever measured in the entire Universe.

***

"Throughout the 1990s, 2000s, the 2010s, and now into the 2020s, we’ve measured the light from the CMB to greater and greater precision. We’ve now measured temperature fluctuations down to about 1-part-per-million, discovering the primordial imperfections imprinted from the inflationary stage that preceded the hot Big Bang. We’ve measured not just the temperature of the CMB’s light, but also its polarization properties. We’ve begun to correlate this light with the foreground cosmic structures that have formed subsequently, quantifying the latter’s effects. And, along with the CMB evidence, we now have confirmation of the other two cornerstones of the Big Bang as well: structure formation and the primordial abundance of the light elements.

"It’s true that the CMB provides incredibly strong evidence in support of the hot Big Bang, and many alternative explanations for it fail spectacularly. There isn’t just a uniform bath of omnidirectional light coming toward us at 2.7255 K above absolute zero, it also has a blackbody spectrum: the most perfect blackbody in the Universe. Until an alternative can not only account for this evidence, but also the other three cornerstones of the Big Bang, we can safely conclude there are no serious competitors to our standard cosmological picture of reality.:

Comment: The BB still looks like 'something for nothing'; a true creation. Support for God in action.