Big Bang
This Natural Philosophy wiki page disputes content found on Wikipedia page wikipedia:Big Bang
| Scientific Theory | |
|---|---|
| Name | Big Bang |
| Type | Cosmological model of the origin and evolution of the universe |
| Author(s) | Georges Lemaître (1927); developed by George Gamow, Ralph Alpher, and others |
| Keywords | Cosmology, expanding universe, red shift, Hubble's law, cosmic microwave background, nucleosynthesis, singularity, inflation, dark matter, dark energy |
| Year | 1927 |
Big Bang is the prevailing mainstream cosmological model for the origin and evolution of the observable universe. In its standard form it holds that the universe began roughly 13.8 billion years ago in an extremely hot, dense state and has been expanding and cooling ever since, with galaxies, stars, and atoms forming as it evolved. In mainstream physics and astronomy the model is regarded as well supported by several independent lines of observation; this wiki documents a substantial body of work that disputes it, collected in the criticisms section below.
Overview
The core claim of the standard model is that the universe is not static but is expanding, so that in the past it was smaller, hotter, and denser. Extrapolating the observed expansion backward in time leads to a state of enormous density and temperature — often described as an initial singularity — from which space, time, matter, and energy are said to have emerged. As the universe expanded it cooled, passing through a sequence of epochs in which the fundamental forces separated, subatomic particles formed, the lightest atomic nuclei were synthesized, neutral atoms appeared, and matter gradually clumped under gravity into the large-scale structure of galaxies and galaxy clusters seen today.
In its modern form the model is usually stated as the Lambda-CDM ("concordance") model, which supplements the expanding universe with two additional ingredients invoked to fit the data: cold dark matter, an unseen form of matter said to dominate the mass of galaxies, and dark energy (the cosmological constant, Λ), a repulsive component invoked to explain an apparent acceleration of the expansion.
History
The idea grew out of the discovery, in the first decades of the twentieth century, that light from distant galaxies is systematically red shifted. Working from Einstein's general relativity, the Belgian priest and physicist Georges Lemaître proposed in 1927 that the universe is expanding and suggested it had begun from a primeval "atom." In 1929 Edwin Hubble published the observed relationship between the distances of galaxies and their redshifts, now known as Hubble's law, which was widely interpreted as evidence of expansion.
In the 1940s George Gamow, Ralph Alpher, and Robert Herman developed the physics of a hot early universe, arguing that the light elements were forged in the first minutes (Big Bang nucleosynthesis) and predicting that a relic bath of radiation should survive as a faint microwave glow. The name "Big Bang" was coined — dismissively — by Fred Hoyle, a proponent of the rival Steady State cosmology. In 1965 Arno Penzias and Robert Wilson detected a uniform microwave background, which was interpreted as this relic radiation and led most astronomers to favor the Big Bang over the Steady State. In 1980 Alan Guth proposed cosmic inflation, a brief burst of exponential expansion added to the model to address several difficulties. Precision measurements of the microwave background and of large-scale structure over the following decades were assembled into the present Lambda-CDM concordance model.
Observational pillars
Mainstream cosmology rests the case for the Big Bang chiefly on four observations:
- The expansion of the universe (Hubble's law) — the linear relation between galaxy distance and redshift, read as recession velocity increasing with distance.
- The cosmic microwave background (CMB) — a highly uniform ~2.7 K thermal radiation filling the sky, interpreted as light released when the universe first became transparent about 380,000 years after the beginning.
- Primordial abundances of the light elements — the observed proportions of hydrogen, helium, and lithium, interpreted as the yield of Big Bang nucleosynthesis.
- Large-scale structure and galaxy evolution — the distribution of galaxies and the apparent change in galaxy populations with distance (and therefore look-back time).
Chronology
In the standard account the universe passes through a series of epochs: an initial Planck era and (in most versions) a period of inflation; the formation of subatomic particles; nucleosynthesis of the light nuclei in the first few minutes; "recombination" into neutral atoms and the release of the microwave background; a "dark age" before the first stars; and the subsequent gravitational assembly of stars, galaxies, and clusters. The total age of the universe in the concordance model is about 13.8 billion years.
Criticisms of the Big Bang on this wiki
The community of the John Chappell Natural Philosophy Society, which maintains this wiki, has produced an extensive literature challenging the Big Bang. The arguments summarized below are drawn from works catalogued here and are attributed to their authors where known; they run contrary to the mainstream scientific consensus. Many more are indexed under Category:Cosmology. A recurring theme is that the model has repeatedly been rescued from conflict with observation by adding unobserved ingredients — inflation, dark matter, and dark energy — and that its central assumption, that redshift measures recession, may simply be wrong.
Systematic catalogues of problems
Several works attempt to enumerate the model's difficulties comprehensively. In The Top 30 Problems with the Big Bang and its expanded successor The Top 50 Problems with the Big Bang, Tom Van Flandern lists observations he argues the standard model either failed to predict or accommodates only by adding free parameters after the fact. Related surveys on this wiki include Some Critiques of the Big Bang Cosmology, Contradictions in Big Bang Theory, and Cosmology: "Contradictions Between Theory and Observations".
Alternative explanations of redshift
The interpretive foundation of the model — that cosmological redshift is a Doppler-like signature of recession — is the most frequently disputed point. A number of authors argue that redshift can arise without any expansion of space. "Tired light" proposals, in which photons lose energy gradually as they travel, are revisited in On Reviving Tired Light and tested against supernova data in Tired Light and Type Ia Supernovae Observations. Other papers develop static-universe or gravitational mechanisms, including An Explanation of Redshifts In a Static Universe, Explaining the Red Shift in a Non-Expanding Universe, Another Explanation of the Cosmological Redshift, and The Cosmological Red Shift as a Gravitational Interaction of Photons with Masses in Space. The Doppler interpretation itself is challenged directly in Questioning the Doppler Interpretation of Cosmological Red Shifts and Questioning the Cosmological Doppler Red-Shift.
Quantized and intrinsic redshift
A distinct line of work, associated on this wiki with the astronomer Halton Arp, holds that redshifts are partly intrinsic to objects rather than purely a distance indicator, citing physically associated galaxies and quasars with very different redshifts. This case is argued at book length in Seeing Red: Redshifts, Cosmology and Academic Science. Related papers report apparent periodicity or quantization in redshifts — The Karlsson Peaks in the Quasar's Redshift Distribution as an Indication for Circling Light in a Non-Expanding Universe and Testing the Hypothesis of Redshift Quantization in Iwanowska Galaxy Lines Connected with our Galaxy and M31 — and reinterpret high-redshift objects, as in High Redshift Galaxies May be Clusters of Galaxies and Cosmological and Intrinsic Redshifts. If redshift is not a clean measure of recession, the empirical basis for expansion is undermined.
Is the universe expanding at all?
Some authors go further and argue that the expansion itself is not real. Works in this vein include Rigorous Evidence for a Nonexpanding Universe, The Expansion of the Universe Debunked, and Are the Galaxies Really Receding?. The supernova evidence usually cited for expansion (and acceleration) is contested in Supernovae Ia Light Curves Show a Static Universe, and the historical dispute over whether the expansion was ever established is revisited in Sandage Versus Hubble on the Reality of the Expanding Universe and Adriaan van Maanen's Challenge to the Expanding Universe.
The cosmic microwave background
The status of the microwave background as a relic of a hot beginning is questioned in Does The Microwave Background Radiation Support The Big Bang Theory?, which argues the radiation is equally or better explained by other means. The 2.7K Cosmic Background Radiation Within an Expanding Universe examines whether the observed temperature is actually a prediction of the model or a value fitted to it.
The singularity, inflation, and fine-tuning
Critics single out the initial singularity and the inflationary "patch" as especially problematic. Better Big Bang or A more Believable Singularity addresses the incoherence of a beginning from a point of infinite density, while A Bang into Nowhere: Comments on the Universe Expansion Theory presses the conceptual difficulty of the universe "expanding" without anything to expand into. Inflation in particular is argued to be undercut by data in 2013 Planck data reveals non-Copernican universe: nullifies Big Bang inflation theory.
Age and timeline paradoxes
Observations of apparently old or highly evolved objects at large distances are presented as evidence that structures existed too early, or that the universe is older than the model allows — the difficulty raised in A Universe Older Than Itself?. The reliance of nucleosynthesis arguments on unobserved quantities is challenged in No Neutrinos, No Big Bang.
Plasma and electric-universe cosmology
An alternative research program replaces gravity-dominated cosmology with the physics of electrically conducting plasma. Its best-known statement is Eric J Lerner's book The Big Bang Never Happened: A Startling Refutation of the Dominant Theory of the Origin of the Universe, which argues that plasma processes — not a primordial explosion — shape the universe and account for the microwave background and light-element abundances. The broader plasma-cosmology literature catalogued here includes Plasma Universe: Beyond the Big Bang, Plasma Astrophysics and Cosmology, Cosmology: Gravitational or Plasma Physics or Both, and Plasma Theory of Hubble Redshift of Galaxies, with foundational contributions from Anthony L Peratt.
Book-length refutations and alternatives
Beyond individual papers, this wiki catalogues several book-length critiques and replacement cosmologies, including The Big Bang Never Happened: A Startling Refutation of the Dominant Theory of the Origin of the Universe, Seeing Red: Redshifts, Cosmology and Academic Science, and Bye Bye Big Bang, Hello Reality. Shorter polemical statements of the dissenting position include Why the Big Bang is Wrong, Dismantling the Big Bang, The Big Bang Theory is Dead, and The Cult of the Big Bang: Was There a Bang?. Many of these authors favor an Eternal Universe — infinite, unbounded, and without a moment of creation — as the alternative to the Big Bang.