What was the big bang
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Understanding the Big Bang: Origins and Quantum Nature
The Origin of the Big Bang Concept
Naming the Big Bang
The term "Big Bang" was coined by Fred Hoyle in 1949, and it refers to the initial state of the universe approximately fourteen billion years ago. Despite its current widespread use, the term did not gain immediate acceptance within the scientific community. It took over two decades for "Big Bang" to become a common term among physicists and astronomers, and even then, it was often used with varying connotations1. Initially, the term was more prevalent in popular contexts rather than scientific literature, and it was not always associated directly with cosmology. The history of the term "Big Bang" is richer and more complex than commonly assumed, reflecting a gradual shift in the scientific community's understanding and acceptance of the concept1.
Quantum Nature of the Big Bang
Loop Quantum Cosmology and the Big Bang
Recent advancements in loop quantum cosmology have provided significant insights into the quantum nature of the Big Bang. Traditional cosmological models faced challenges with the singularity at the beginning of the universe, where physical laws break down. However, loop quantum cosmology offers a resolution to this issue by replacing the Big Bang singularity with a "big bounce"2 3.
Key Findings in Quantum Cosmology
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Emergent Time Concept: In the context of homogeneous isotropic models with a scalar field, the scalar field acts as an internal clock, providing a detailed realization of the "emergent time" idea. This concept helps in understanding the evolution of the universe in quantum terms2 3.
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Deterministic Quantum Evolution: Unlike other approaches, loop quantum cosmology employs nonperturbative, background-independent methods, ensuring that quantum evolution remains deterministic even across the deep Planck regime. This means that the universe's evolution can be predicted accurately through the quantum bounce, avoiding the singularity problem2 3.
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Construction of Physical Framework: Researchers have rigorously constructed the physical Hilbert space, Dirac observables, and semiclassical states. These constructions provide a robust framework for analyzing the quantum aspects of the universe's early moments and offer tools for exploring more general models within loop quantum cosmology2 3.
Conclusion
The Big Bang theory, from its initial naming by Fred Hoyle to its modern interpretations in quantum cosmology, represents a significant evolution in our understanding of the universe's origins. While the term "Big Bang" took time to gain acceptance, it now stands as a cornerstone of cosmological science. Advances in loop quantum cosmology have further enriched this concept by resolving the singularity issue and providing a deterministic framework for the universe's quantum evolution. These insights not only deepen our understanding of the universe's beginnings but also pave the way for future explorations in cosmology.
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Naming the Big Bang
The name Big Bang has a richer and more surprising history than commonly assumed, and its etymological approach provides insights into the historical understanding of the emergence of modern cosmology.
Quantum nature of the big bang.
The big bang is replaced by a big bounce in homogeneous isotropic models with a scalar field, allowing for a detailed realization of the "emergent time" idea and ensuring deterministic quantum evolution across the deep Planck regime.
Highly CitedQuantum nature of the big bang: An analytical and numerical investigation
The big bang is replaced by a big bounce in loop quantum cosmology, with the scalar field acting as an internal clock and providing a detailed understanding of the 'emergent time' idea.
Highly CitedMisconceptions about the big bang.
The big bang theory is based on the expansion of space, not an explosion in space, and the universe does not expand at a single speed.
THE BIG BANG NEVER HAPPENED
The big bang theory is challenged by a plasma universe, which is too large to have been created from a single explosion 20 billion years ago, and instead grows slowly in giant strands connecting the smallest particles of matter to an infinity of different cosmic systems.
Highly CitedThe Ekpyrotic universe: Colliding branes and the origin of the hot big bang
The hot big bang universe is produced by the collision of a brane with a bounding orbifold plane, addressing cosmological horizon, flatness, and monopole problems without invoking superluminal expansion.
Highly CitedWhat's in a Name: History and Meanings of the Term 'Big Bang'
The term 'big bang' has a richer and more surprising history than commonly assumed, and the literature on modern cosmology often makes common mistakes and errors.
Was there a Big Bang?
The Inflation theory suggests that the Big Bang was not the beginning of the Universe, but rather a phase transition from cold inflation to the hot phase, with the Big Bang being just a transition from cold inflation to the hot phase.
Laser interferometry for the Big Bang Observer
The Big Bang Observer's laser interferometry between three spacecraft can potentially detect gravitational waves from the early universe.
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