Tag: Astrophysics
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Tycho Brahe’s Observations
Introduction Tycho Brahe (1546-1601) was a Danish nobleman and one of the most important astronomers of the late 16th century. Known for his comprehensive and accurate observations of the heavens, his data paved the way for Johannes Kepler to formulate his laws of planetary motion. Brahe’s Observational Equipment Brahe’s observations were carried out with naked-eye…
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Zwicky’s Dark Matter Hypothesis
Introduction The concept of dark matter was first proposed by Swiss astrophysicist Fritz Zwicky in 1933. Observing the Coma galaxy cluster, Zwicky noted that the visible mass of the galaxies within the cluster was insufficient to account for the cluster’s observed dynamics. He suggested that much of the mass must be in some unseen form,…
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Luminosity
Introduction Luminosity is a measure of the total amount of energy emitted by an object per unit of time. It is a fundamental quantity in many fields of science, including astrophysics and particle physics. In the context of astrophysics, luminosity is often used to describe the energy output of stars and galaxies. Luminosity in Astrophysics…
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Kuiper Belt
Introduction The Kuiper Belt is a region of our solar system beyond the orbit of Neptune, populated by a multitude of icy bodies known as Kuiper Belt Objects (KBOs). Named after astronomer Gerard Kuiper, the Kuiper Belt is of significant interest to astronomers due to its status as a preserved remnant of the primordial solar…
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Bremsstrahlung
Introduction Bremsstrahlung, German for “braking radiation,” is the electromagnetic radiation produced when a charged particle, such as an electron, is decelerated or deflected by another charged particle, such as an atomic nucleus. This phenomenon is a fundamental aspect of interactions between charged particles and is prevalent in fields such as nuclear physics, radiation therapy, and…
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Van Allen Radiation Belt
Introduction The Van Allen Radiation Belts are zones of energetic charged particles, most of which originate from the solar wind and become trapped by the Earth’s magnetic field. Named after the discoverer, James Van Allen, these belts pose potential risks to satellites and astronauts, while also serving as a natural laboratory for the study of…
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Parsec
Introduction The parsec is a unit of length used in astronomy and astrophysics to measure astronomical distances. Due to the vast scale of the universe, conventional units like meters or kilometers are inconvenient for astronomical distances, so larger units like the parsec are used instead. Definition The parsec (pc) is defined as the distance at…
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De Sitter Universe
Introduction The de Sitter universe is a solution to Einstein’s field equations of general relativity, representing a cosmological model. Named after the Dutch astronomer Willem de Sitter, it describes an empty universe with a positive cosmological constant, implying a constant positive curvature of space. This universe exhibits exponential expansion, a concept that is key to…
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Airy Disk
Introduction The Airy disk is the bright spot at the center of a pattern that is produced when a plane wave of light is diffracted by a circular aperture. It is named after the British astronomer Sir George Biddell Airy. The pattern consists of a bright central region, or disk, surrounded by a series of…
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Neutrinos
Introduction Neutrinos are one of the fundamental particles which make up the universe. They are also one of the least understood. Neutrinos are unique among the elementary particles because they interact only via the weak nuclear force, making them incredibly difficult to detect. Properties of Neutrinos Neutrinos are electrically neutral and have a very small,…