Category: Index
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Andromeda Galaxy
Introduction The Andromeda Galaxy, also known as Messier 31 (M31), is a spiral galaxy approximately 2.537 million light-years away from Earth in the Andromeda constellation. It is the nearest spiral galaxy to the Milky Way, our galaxy, and is on a collision course with our galaxy, expected to occur in about 4.5 billion years. Characteristics…
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Sagnac Effect
Introduction The Sagnac effect, named after French physicist Georges Sagnac, is a phenomenon in the field of interferometry that manifests itself as a phase shift between two light beams traveling in opposite directions around a rotating platform. This effect is significant in areas like geophysics, navigation, and technology associated with light propagation and rotation. The…
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Ultraviolet Catastrophe
Introduction The Ultraviolet Catastrophe refers to a historical paradox in the theory of radiation of heated objects. This paradox resulted from the contradiction between the classical physics laws and experimental observations related to black body radiation at the end of the 19th century. Classical Predictions and the Problem According to the classical theory of electromagnetic…
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X-Ray Astronomy
Introduction X-ray astronomy is a subfield of observational astronomy that deals with the detection and study of X-ray emission from celestial objects. X-ray radiation is absorbed by the Earth’s atmosphere, so instruments to detect X-rays must be taken to high altitude by balloons, sounding rockets, and satellites. Basics of X-ray Astronomy X-ray radiation from space…
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Ionization Energy
Introduction Ionization energy is a fundamental property of atoms and molecules in the field of atomic and molecular physics. It refers to the minimum energy required to remove an electron from an atom or a molecular entity in its gaseous state. It’s usually measured in electron volts (eV) or joules (J). First Ionization Energy The…
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Quantum Chromodynamics (QCD)
Introduction Quantum Chromodynamics (QCD) is a theory in theoretical physics t hat describes the interactions of quarks and gluons, the fundamental particles that make up protons, neutrons, and other particles. The term “chromodynamics” comes from the Greek word “chroma,” meaning color, as quarks carry a type of charge known as “color charge.” Fundamental Concepts and…
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Ferroelectricity
Introduction Ferroelectricity refers to a phenomenon in certain materials characterized by the appearance of spontaneous electric polarization that can be reversed by the application of an external electric field. The name comes from the similarity to ferromagnetism, where a material exhibits a permanent magnetic moment. Ferroelectric materials can have applications in many areas, such as…
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Klein-Nishina Formula
Introduction The Klein-Nishina formula is an essential result in quantum electrodynamics that describes the angular distribution of photons scattered off a single, free electron. Named after Oskar Klein and Yoshio Nishina, who derived the formula in 1928, it takes into account the relativistic and quantum mechanical effects of the scattering process, particularly in the case…
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Liouville’s Theorem
Introduction Liouville’s Theorem is a crucial principle in both statistical and Hamiltonian mechanics. Named after the French mathematician Joseph Liouville, the theorem asserts that the phase space volume occupied by a closed system remains constant throughout its evolution. Phase space, a key concept in physics, is an abstract space where all possible states of a…
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Ostwald Ripening
Introduction Ostwald Ripening is a phenomenon in physical chemistry named after the German chemist Friedrich Wilhelm Ostwald. It describes the process where smaller particles within a solution dissolve, and the material re-deposits onto larger particles. The process leads to the growth of large particles at the expense of small ones, which results in an increase…