http://en.wikipedia.org/wiki/Gravitation
High-energy astronomy High energy astronomy is the study of astronomical objects that release EM radiation of highly energetic wavelengths. It includes X-ray astronomy, gamma-ray astronomy, and extreme UV astronomy, as well as studies of neutrinos and cosmic rays. The physical study of these phenomena is referred to as high-energy astrophysics.[1] Astronomical objects commonly studied in this field may include black holes, neutron stars, active galactic nuclei, supernovae, supernova remnants, and Gamma ray bursts. Missions[edit]
Solar and Terrestrial Radiation Equation (1) Problem Set (#7)Opaque materials transmit no incident radiationTransparent material have little or no absorption and scattering E.g.,clear glass - high transmission, low reflection and absorptionfresh snow - high reflectance, low transmission and absorptionfresh asphalt - high absorption, minimum transmission and reflection Gravitational wave In physics, gravitational waves are ripples in the curvature of spacetime that propagate as a wave, travelling outward from the source. Predicted in 1916 by Albert Einstein to exist[1] on the basis of his theory of general relativity,[2] gravitational waves theoretically transport energy as gravitational radiation. Sources of detectable gravitational waves could possibly include binary star systems composed of white dwarfs, neutron stars, or black holes.
Light A triangular prism dispersing a beam of white light. The longer wavelengths (red) and the shorter wavelengths (blue) get separated Light is electromagnetic radiation within a certain portion of the electromagnetic spectrum. The word usually refers to visible light, which is visible to the human eye and is responsible for the sense of sight.[1] Visible light is usually defined as having a wavelength in the range of 400 nanometres (nm), or 400×10−9 m, to 700 nanometres – between the infrared (with longer wavelengths) and the ultraviolet (with shorter wavelengths).[2][3] Often, infrared and ultraviolet are also called light. The main source of light on Earth is the Sun. Strong interaction In particle physics, the strong interaction (also called the strong force, strong nuclear force, nuclear strong force or color force) is one of the four fundamental interactions of nature, the others being electromagnetism, the weak interaction and gravitation. At atomic scale, it is about 100 times stronger than electromagnetism, which in turn is orders of magnitude stronger than the weak force interaction and gravitation. It ensures the stability of ordinary matter, in confining the elementary particles quarks into hadrons such as the proton and neutron, the largest components of the mass of ordinary matter. Furthermore, most of the mass-energy of a common proton or neutron is in the form of the strong force field energy; the individual quarks provide only about 1% of the mass-energy of a proton[citation needed]. In the context of binding protons and neutrons together to form atoms, the strong interaction is called the nuclear force (or residual strong force). History[edit]
Physical cosmology Physical cosmology is the study of the largest-scale structures and dynamics of the Universe and is concerned with fundamental questions about its formation, evolution, and ultimate fate.[1] For most of human history, it was a branch of metaphysics and religion. Cosmology as a science originated with the Copernican principle, which implies that celestial bodies obey identical physical laws to those on Earth, and Newtonian mechanics, which first allowed us to understand those physical laws. Physical cosmology, as it is now understood, began with the development in 1915 of Albert Einstein's general theory of relativity, followed by major observational discoveries in the 1920s: first, Edwin Hubble discovered that the Universe contains a huge number of external galaxies beyond our own Milky Way; then, work by Vesto Slipher and others showed that the universe is expanding.
VY Canis Majoris VY Canis Majoris (VY CMa) is a red hypergiant in the constellation Canis Major. It is one of the largest known stars by radius and also one of the most luminous of its type. It is approximately 1,420 ± 120 solar radii[8] (equal to 6.6 astronomical units, thus a diameter about 1,975,000,000 kilometres (1.227×109 mi)), and about 1.2 kiloparsecs (3,900 light-years) distant from Earth. VY CMa is a single star categorized as a semiregular variable and has an estimated period of 2,000 days. Galaxy Galaxies contain varying numbers of planets, star systems, star clusters and types of interstellar clouds. In between these objects is a sparse interstellar medium of gas, dust, and cosmic rays. Supermassive black holes reside at the center of most galaxies. They are thought to be the primary driver of active galactic nuclei found at the core of some galaxies. The Milky Way galaxy is known to harbor at least one such object.[5] Galaxies have been historically categorized according to their apparent shape, usually referred to as their visual morphology.
Physical system Complexity in physical systems[edit] The complexity of a physical system is equal to the probability of it being in a particular state vector. If one considers a classical Newtonian ball situation with a number of perfectly moving physical bodies bouncing off the walls of a container, the system-state probability does not change over time. Weak interaction In particle physics, the weak interaction is the mechanism responsible for the weak force or weak nuclear force, one of the four fundamental interactions of nature, alongside the strong interaction, electromagnetism, and gravitation. The weak interaction is responsible for both the radioactive decay and nuclear fusion of subatomic particles. The theory of the weak interaction is sometimes called quantum flavordynamics (QFD), in analogy with the terms QCD and QED, but in practice the term is rarely used because the weak force is best understood in terms of electro-weak theory (EWT).[1] During the quark epoch, the electroweak force split into the electromagnetic and weak force.
Planetary science Planetary science (rarely planetology) is the scientific study of planets (including Earth), moons, and planetary systems, in particular those of the Solar System and the processes that form them. It studies objects ranging in size from micrometeoroids to gas giants, aiming to determine their composition, dynamics, formation, interrelations and history. It is a strongly interdisciplinary field, originally growing from astronomy and earth science,[1] but which now incorporates many disciplines, including planetary astronomy, planetary geology (together with geochemistry and geophysics), atmospheric science, oceanography, hydrology, theoretical planetary science, glaciology, and exoplanetology.[1] Allied disciplines include space physics, when concerned with the effects of the Sun on the bodies of the Solar System, and astrobiology. There are interrelated observational and theoretical branches of planetary science. History[edit] Disciplines[edit]
Stellar classification Spectral type Most stars are currently classified under the Morgan–Keenan (MKK) system using the letters O, B, A, F, G, K, M, L, T and Y a sequence from the hottest (O type) to the coolest (Y type). The types R and N are carbon-based stars, the type S is zirconium-monoxide-based stars. Each letter class is then subdivided using a numeric digit with 0 being hottest and 9 being coolest (e.g. A8, A9, F0, F1) form a sequence from hotter to cooler. Gravitational singularity A gravitational singularity or spacetime singularity is a location where the quantities that are used to measure the gravitational field become infinite in a way that does not depend on the coordinate system. These quantities are the scalar invariant curvatures of spacetime, which includes a measure of the density of matter. The two most important types of spacetime singularities are curvature singularities and conical singularities.[2] Singularities can also be divided according to whether they are covered by an event horizon or not (naked singularities).[3] According to general relativity, the initial state of the universe, at the beginning of the Big Bang, was a singularity. Interpretation[edit] Many theories in physics have mathematical singularities of one kind or another. Equations for these physical theories predict that the ball of mass of some quantity becomes infinite or increases without limit.
Observation Observation is the active acquisition of information from a primary source. In living beings, observation employs the senses. In science, observation can also involve the recording of data via the use of instruments.