The theory for the entire cosmos involves not just a little physics, but all of physics both what we know today and what we are still learning.
Many people, including most of my friends (outside this forum), don't really bother learning a great deal about the theory or its history, hence some, perhaps a majority, assume it is not that solid a theory. When you combine the metaphysics of a multiverse concept to explain our universe and its incredibly fine-tuned features, then the general view becomes even more cloudy as to the veracity of BBT.
But since its beginning, BBT (originally the "Primeval Atom" theory) has grown into a very substantially supported theory. The original paper was published in 1927 (Georges Lemaitre). We are less than 6 years away from its 100th anniversary.
Ten decades has brought a great deal more discovery. These discoveries were often sought as a way to falsify the claims within BBT. No theory can be a theory without making testable claims, and any theory of the entire cosmos will come with a great many testable claims. [In contrast, any multiverse "theory" does not qualify as a theory until they can produce a claim that can be tested.]
It's also helpful to understand that no theory can be proven; they can only be falsified. The 2000 year-old Aristotle theory -- advanced by Ptolemy and Thomas Aquinas -- was never proven to be true but, thanks to Galileo and his little telescope, he was able to produce direct evidence that falsified it. [The Jesuits quickly accepted his results as they too used one of his scopes to verify this falsifiation (phases of Venus). At that time, they switched to the Tychonic model for an alternative Geocentric universe.]
IMO, each theory has a degree of strength regarding the claims that come from it. Some theories look strong but fail later. It's not uncommon for a theory to be considered very weak initially. Indeed, Einstein called Lemaitre's theory "abomniable", though he liked the math. Each theory should be understood for its relative strength or strengths. Engineers must have reliable science to build things like bridges and rockets.
So, here are some Big Bang Bullets demonstrating a great deal of direct, and some indirect, evidence supporting it. These many independent lines of evidence produce an amazing confluence of support for the theory.
....> Hubble Constant (redshift) More (http://hyperphysics.phy-astr.gsu.edu/hbase/astro/hubble.html)
....> Einstein's field equations (1916) predicted an expanding (or contracting) universe
....> Time Dilation of Supernova More1 (http://www.berkeley.edu/news/media/releases/99legacy/1-7-1999.html)also More2 (http://www-supernova.lbl.gov/public/)
....> Gamma Ray Bursts
....> The CMBR - Cosmic Microwave Background Radiation. More (http://hyperphysics.phy-astr.gsu.edu/hbase/bkg3k.html)
........> The wavelength (microwave)
........> The Temperature (2.73K). More (http://hypertextbook.com/facts/1997/SilinYang.shtml)
........> The Blackbody Results.
........> The "smoothness" (isotropy)
........> The very small "roughness" (anisotropy) in this radiation. WMAP (http://map.gsfc.nasa.gov/m_mm.html)
........> The angular size of the "hot" spots matching predictions.
........> The power spectrum
....> Distant Cloud temperatures
....> The Element Abundances from Nucleosynthesis.
....> Helium (25%)
....> Deuterium, its relative abundance.
....> The observed Differences in Galaxies between today's and earlier ones.
........> Paucity of distant Barred Spirals.
........> Less organized distant Spirals.
........> No local Quasars.
....> The Age of the Universe in relation to Stellar Compositions.
....> Olber's Paradox resolved. More (http://math.ucr.edu/home/baez/physics/Relativity/GR/olbers.html)
....> Entropy - "The universe is dying" (Helmholtz & 2nd Law).
....> Galactic Superstructure of Super Clusters and Galactic Strands
....> No Ancient Objects older than 15 billion years.
....> The anisotropy found in background neutrino maping, probably.
....> The Lyman Forest morphology
Many people, including most of my friends (outside this forum), don't really bother learning a great deal about the theory or its history, hence some, perhaps a majority, assume it is not that solid a theory. When you combine the metaphysics of a multiverse concept to explain our universe and its incredibly fine-tuned features, then the general view becomes even more cloudy as to the veracity of BBT.
But since its beginning, BBT (originally the "Primeval Atom" theory) has grown into a very substantially supported theory. The original paper was published in 1927 (Georges Lemaitre). We are less than 6 years away from its 100th anniversary.
Ten decades has brought a great deal more discovery. These discoveries were often sought as a way to falsify the claims within BBT. No theory can be a theory without making testable claims, and any theory of the entire cosmos will come with a great many testable claims. [In contrast, any multiverse "theory" does not qualify as a theory until they can produce a claim that can be tested.]
It's also helpful to understand that no theory can be proven; they can only be falsified. The 2000 year-old Aristotle theory -- advanced by Ptolemy and Thomas Aquinas -- was never proven to be true but, thanks to Galileo and his little telescope, he was able to produce direct evidence that falsified it. [The Jesuits quickly accepted his results as they too used one of his scopes to verify this falsifiation (phases of Venus). At that time, they switched to the Tychonic model for an alternative Geocentric universe.]
IMO, each theory has a degree of strength regarding the claims that come from it. Some theories look strong but fail later. It's not uncommon for a theory to be considered very weak initially. Indeed, Einstein called Lemaitre's theory "abomniable", though he liked the math. Each theory should be understood for its relative strength or strengths. Engineers must have reliable science to build things like bridges and rockets.
So, here are some Big Bang Bullets demonstrating a great deal of direct, and some indirect, evidence supporting it. These many independent lines of evidence produce an amazing confluence of support for the theory.
....> Hubble Constant (redshift) More (http://hyperphysics.phy-astr.gsu.edu/hbase/astro/hubble.html)
....> Einstein's field equations (1916) predicted an expanding (or contracting) universe
....> Time Dilation of Supernova More1 (http://www.berkeley.edu/news/media/releases/99legacy/1-7-1999.html)also More2 (http://www-supernova.lbl.gov/public/)
....> Gamma Ray Bursts
....> The CMBR - Cosmic Microwave Background Radiation. More (http://hyperphysics.phy-astr.gsu.edu/hbase/bkg3k.html)
........> The wavelength (microwave)
........> The Temperature (2.73K). More (http://hypertextbook.com/facts/1997/SilinYang.shtml)
........> The Blackbody Results.
........> The "smoothness" (isotropy)
........> The very small "roughness" (anisotropy) in this radiation. WMAP (http://map.gsfc.nasa.gov/m_mm.html)
........> The angular size of the "hot" spots matching predictions.
........> The power spectrum
....> Distant Cloud temperatures
....> The Element Abundances from Nucleosynthesis.
....> Helium (25%)
....> Deuterium, its relative abundance.
....> The observed Differences in Galaxies between today's and earlier ones.
........> Paucity of distant Barred Spirals.
........> Less organized distant Spirals.
........> No local Quasars.
....> The Age of the Universe in relation to Stellar Compositions.
....> Olber's Paradox resolved. More (http://math.ucr.edu/home/baez/physics/Relativity/GR/olbers.html)
....> Entropy - "The universe is dying" (Helmholtz & 2nd Law).
....> Galactic Superstructure of Super Clusters and Galactic Strands
....> No Ancient Objects older than 15 billion years.
....> The anisotropy found in background neutrino maping, probably.
....> The Lyman Forest morphology
Last edited: