Forbes | Ultimately, science moved on while the contrarians became more and more irrelevant, with their trivially incorrect work fading into obscurity and their research programme eventually ceasing upon their deaths.
In the meantime, from the 1960s up through the 2000s, the sciences of astronomy and astrophysics — and particularly the sub-field of cosmology, which focuses on the history, growth, evolution, and fate of the Universe — grew spectacularly.
- We mapped out the large-scale structure of the Universe, discovering a great cosmic web.
- We discovered how galaxies grew and evolved, and how their stellar populations inside changed with time.
- We learned that all the known forms of matter and energy in the Universe were insufficient to explain everything we observe: some form of dark matter and some form of dark energy are required.
And we were able to further verify additional predictions of the Big Bang, such as the predicted abundances of the light elements, the presence of a population of primordial neutrinos, and the discovery of density imperfections of exactly the necessary type to grow into the large-scale structure of the Universe we observe today.
At the same time, there were observations that were no doubt true, but that the Big Bang had no predictive power to explain. The Universe allegedly reached these arbitrarily high temperatures and high energies at the earliest times, and yet there are no exotic leftover relics that we can see today: no magnetic monopoles, no particles from grand unification, no topological defects, etc. Theoretically, something else beyond what is known must be out there to explain the Universe we see, but if they ever existed, they’ve been hidden from us.
The Universe, in order to exist with the properties we see, must have been born with a very specific expansion rate: one that balanced the total energy density exactly, to more than 50 significant digits. The Big Bang has no explanation for why this should be the case.
And the only way different regions of space would have the same exact temperature is if they’re in thermal equilibrium: if they have time to interact and exchange energy. Yet the Universe is too big and has expanded in such a way that we have many causally disconnected regions. Even at the speed of light, those interactions couldn’t have taken place.
Unfortunately, Nobel Laureate Roger Penrose, although his work on General Relativity, black holes, and singularities in the 1960s and 1970s was absolutely Nobel-worthy, has spent a large amount of his efforts in recent years on a crusade to overthrow inflation: by promoting a vastly scientifically inferior alternative, his pet idea of a Conformal Cyclic Cosmology, or CCC.
The biggest predictive difference is that the CCC pretty much requires that an imprint of “the Universe before the Big Bang” show itself in both the Universe’s large-scale structure and in the cosmic microwave background: the Big Bang’s leftover glow. Contrariwise, inflation demands that anywhere where inflation ends and a hot Big Bang arises must be causally disconnected from, and cannot interact with, any prior, current, or future such region. Our Universe exists with properties that are independent of any other.
The observations — first from COBE and WMAP, and more recently, from Planck — definitively place enormously tight constraints (to the limits of the data that exists) on any such structures. There are no bruises on our Universe; no repeating patterns; no concentric circles of irregular fluctuations; no Hawking points. When one analyzes the data properly, it is overwhelmingly clear that inflation is consistent with the data, and the CCC is quite clearly not.
0 comments:
Post a Comment