0_Wizard
Stephen Hawking was an amazing scientist. He was the first person to explain cosmology with a combination of the relativity and quantum mechanics.
Hawking was the first to set out a theory of cosmology explained by a union of the general theory of relativity and quantum mechanics.
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Stephen Hawking
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Stephen Hawking
Stephen William Hawking, ( born 8 January 1942) is an English theoretical physicist, cosmologist, author and Director of Research at the Centre for Theoretical Cosmology within the University of Cambridge. His scientific works include a collaboration with Roger Penrose on gravitational singularity theorems in the framework of general relativity and the theoretical prediction that black holes emit radiation, often called Hawking radiation. Hawking was the first to set out a theory of cosmology explained by a union of the general theory of relativity and quantum mechanics. He is a vigorous supporter of the many-worlds interpretation of quantum mechanics.
Quantum mechanics
Quantum mechanics (QM; also known as quantum physics or quantum theory), including quantum field theory, is a fundamental theory in physics which describes nature at the smallest scales of energy levels of atoms and subatomic particles. Classical physics (the physics existing before quantum mechanics) is a set of fundamental theories which describes nature at ordinary (macroscopic) scale. Most theories in classical physics can be derived from quantum mechanics as an approximation valid at large (macroscopic) scale. Quantum mechanics differs from classical physics in that: energy, momentum and other quantities of a system may be restricted to discrete values (quantization), objects have characteristics of both particles and waves (wave-particle duality), and there are limits to the precision with which quantities can be known (uncertainty principle).
Loop quantum gravity
Loop quantum gravity (LQG) is a theory of quantum gravity, merging quantum mechanics and general relativity. It is an effort to unify gravity in a common theoretical framework with the other three fundamental forces of nature. It is the leading competitor to string theory. LQG begins with relativity and tries to add quantum features, while string theory, conversely, begins with quantum field theory and tries to add gravity. From the point of view of Albert Einstein's theory, it comes as no surprise that all attempts to treat gravity simply like one more quantum force (on par with electromagnetism and the nuclear forces) have failed.
String theory
In physics, string theory is a theoretical framework in which the point-like particles of particle physics are replaced by one-dimensional objects called strings. It describes how these strings propagate through space and interact with each other. On distance scales larger than the string scale, a string looks just like an ordinary particle, with its mass, charge, and other properties determined by the vibrational state of the string. In string theory, one of the many vibrational states of the string corresponds to the graviton, a quantum mechanical particle that carries gravitational force. Thus string theory is a theory of quantum gravity.
A Brief History of Time
A Brief History of Time: From the Big Bang to Black Holes is a popular-science book on cosmology (the study of the universe) by British physicist Stephen Hawking. It was first published in 1988. Hawking wrote the book for nonspecialist readers with no prior knowledge of scientific theories. In "A Brief History of Time", Hawking writes in non-technical terms about the structure, origin, development and eventual fate of the universe, which is the object of study of astronomy and modern physics. He talks about basic concepts like space and time, basic building blocks that make up the universe (such as quarks) and the fundamental forces that govern it (such as gravity).
Many-worlds interpretation
The many-worlds interpretation is an interpretation of quantum mechanics that asserts the objective reality of the universal wavefunction and denies the actuality of wavefunction collapse. Many-worlds implies that all possible alternate histories and futures are real, each representing an actual "world" (or "universe"). In layman's terms, the hypothesis states there is a very large—perhaps infinite—number of universes, and everything that could possibly have happened in our past, but did not, has occurred in the past of some other universe or universes. The theory is also referred to as MWI, the relative state formulation, the Everett interpretation, the theory of the universal wavefunction, many-universes interpretation, multi-history or just many-worlds.
History of physics
Physics (from the Ancient Greek φύσις "physis" meaning "nature") is the fundamental branch of science that developed out of the study of nature and philosophy known, until around the end of the 19th century, as "natural philosophy". Today, physics is ultimately defined as the study of matter, energy and the relationships between them. Physics is, in some senses, the oldest and most basic pure science; its discoveries find applications throughout the natural sciences, since matter and energy are the basic constituents of the natural world. The other sciences are generally more limited in their scope and may be considered branches that have split off from physics to become sciences in their own right.