astrophobiaRelated word or term.spaceRelated word or term.
SpacetimeIn physics, spacetime, or the space-time continuum, is a mathematical model that fuses the three dimensions of space and the one dimension of time into a single four-dimensional continuum. Spacetime diagrams are useful in visualizing and understanding relativistic effects, such as how different observers perceive where and when events occur. Until the turn of the 20th century, the assumption had been that the three-dimensional geometry of the universe (its description in terms of locations, shapes, distances, an...
Position (geometry)In geometry, a position or position vector, also known as location vector or radius vector, is a Euclidean vector that represents a point P in space. Its length represents the distance in relation to an arbitrary reference origin O, and its direction represents the angular orientation with respect to given reference axes. Usually denoted x, r, or s, it corresponds to the straight line segment from O to P. In other words, it is the displacement or translation that maps the origin to P: r = O P → . {\displaystyl...
TimeTime is the continuous progression of existence that occurs in an apparently irreversible succession from the past, through the present, and into the future. Time dictates all forms of action, age, and causality, being a component quantity of various measurements used to sequence events, to compare the duration of events or the intervals between them, and to quantify rates of change of quantities in material reality or in conscious experience. Time is often referred to as the fourth dimension and the temporal di...
UniverseEverything in space and time UniverseThe Hubble Ultra-Deep Field image shows some of the most remote galaxies visible to present technology (diagonal is ~1/10 apparent Moon diameter)Age13.787 ± 0.020 billion yearsObservable diameter8.8×1026 m (28.5 Gpc or 93 Gly)Average density (with energy)9.9×10−27 kg/m3Average temperature2.72548 K(−270.4 °C, −454.8 °F)Main contentsOrdinary (baryonic) matter (4.9%)Dark matter (26.8%)Dark energy (68.3%)ShapeFlat with 0.4% error margin Part of a series onPhysical cosm...
Three-dimensional spaceIn geometry, a three-dimensional (3D) space is a mathematical space in which three values (termed coordinates) are required to determine the position of a point. Alternatively, it can be referred to as 3-space or, rarely, tri-dimensional space. Most commonly, it means the three-dimensional Euclidean space, that is, the Euclidean space of dimension three, which models physical space. More general three-dimensional spaces are called 3-manifolds. The term may refer colloquially to a subset of space, a three-dimensi...
Classical physicsClassical physics consists of scientific theories in the field of physics that are non-quantum or both non-quantum and non-relativistic, depending on the context. In historical discussions, classical physics refers to pre-1900 physics, while modern physics refers to post-1900 physics, which incorporates elements of quantum mechanics and the theory of relativity. However, relativity is based on classical field theory rather than quantum field theory, and is often categorized as a part of "classical physics". Over...
DimensionProperty of a mathematical space From left to right: a square, a cube and a tesseract. The square is two-dimensional (2D) and bounded by one-dimensional line segments; the cube is three-dimensional (3D) and bounded by two-dimensional squares; the tesseract is four-dimensional (4D) and bounded by three-dimensional cubes. The first four spatial dimensions, represented in a two-dimensional picture. Two points can be connected to create a line segment.Two parallel line segments can be connected to form a square.Two ...
Direction (geometry)In geometry, direction, also known as spatial direction, vector direction or relative direction, is the common characteristic of all rays which coincide when translated to share a common endpoint; equivalently, it is the common characteristic of vectors (such as the relative position between a pair of points) which can be made equal by scaling (by some positive scalar multiplier). Two vectors sharing the same direction are said to be codirectional or equidirectional. All codirectional line segments sharing the s...
Four-dimensional spaceGeometric space with four dimensions The 4D equivalent of a cube is known as a tesseract, seen rotating here in four-dimensional space, yet projected into two dimensions for display.1AnimatedStatic GeometryProjecting a sphere to a plane Branches Euclidean Non-Euclidean Elliptic Spherical Hyperbolic Non-Archimedean geometry Projective Affine Synthetic Analytic Algebraic Arithmetic Diophantine Differential Riemannian Symplectic Discrete differential Complex Finite Discrete/Combinatorial Digital Convex Computationa...
Conceptual frameworkA conceptual framework is an analytical tool with several variations and contexts. It can be applied in different categories of work where an overall picture is needed. It is used to make conceptual distinctions and organize ideas. Strong conceptual frameworks capture something real and do this in a way that is easy to remember and apply. ExamplesIsaiah Berlin used the metaphor of a "fox" and a "hedgehog" to make conceptual distinctions in how important philosophers and authors view the world. Berlin describes h...
Modern physicsModern physics is a branch of physics that developed in the early 20th century and onward or branches greatly influenced by early 20th century physics. Notable branches of modern physics include quantum mechanics, special relativity, and general relativity. Classical physics is typically concerned with everyday conditions: speeds are much lower than the speed of light, sizes are much greater than that of atoms, and energies are relatively small. Modern physics, however, is concerned with more extreme conditions,...
PhilosophyPhilosophy (from Ancient Greek philosophía, lit. 'love of wisdom') is a systematic study of general and fundamental questions concerning topics like existence, knowledge, mind, reason, language, and value. It is a rational and critical inquiry that reflects on its methods and assumptions. Historically, many of the individual sciences, such as physics and psychology, formed part of philosophy. However, they are considered separate academic disciplines in the modern sense of the term. Influential traditions in th...
Continuum (measurement)Continuum (pl.: continua or continuums) theories or models explain variation as involving gradual quantitative transitions without abrupt changes or discontinuities. In contrast, categorical theories or models explain variation using qualitatively different states. In physicsIn physics, for example, the space-time continuum model describes space and time as part of the same continuum rather than as separate entities. A spectrum in physics, such as the electromagnetic spectrum, is often termed as either continuou...*As an Amazon Associate I earn from qualifying purchases.