Supernova A supernova (abbreviated SN, plural SNe after "supernovae") is a stellar explosion that is more energetic than a nova. It is pronounced /ˌsuːpəˈnoʊvə/ with the plural supernovae /ˌsuːpəˈnoʊviː/ or supernovas. Supernovae are extremely luminous and cause a burst of radiation that often briefly outshines an entire galaxy, before fading from view over several weeks or months. During this interval a supernova can radiate as much energy as the Sun is expected to emit over its entire life span.[1] The explosion expels much or all of a star's material[2] at a velocity of up to 30,000 km/s (10% of the speed of light), driving a shock wave[3] into the surrounding interstellar medium. This shock wave sweeps up an expanding shell of gas and dust called a supernova remnant. Nova means "new" in Latin, referring to what appears to be a very bright new star shining in the celestial sphere; the prefix "super-" distinguishes supernovae from ordinary novae which are far less luminous. Discovery[edit]
Subatomic particle In the physical sciences, subatomic particles are particles smaller than atoms.[1] (although some subatomic particles have mass greater than some atoms). There are two types of subatomic particles: elementary particles, which according to current theories are not made of other particles; and composite particles.[2] Particle physics and nuclear physics study these particles and how they interact.[3] In particle physics, the concept of a particle is one of several concepts inherited from classical physics. Interactions of particles in the framework of quantum field theory are understood as creation and annihilation of quanta of corresponding fundamental interactions. Classification[edit] By statistics[edit] By composition[edit] The elementary particles of the Standard Model include:[5] Various extensions of the Standard Model predict the existence of an elementary graviton particle and many other elementary particles. By mass[edit] All composite particles are massive. Other properties[edit]
Electromagnetic spectrum The electromagnetic spectrum is the range of all possible frequencies of electromagnetic radiation.[4] The "electromagnetic spectrum" of an object has a different meaning, and is instead the characteristic distribution of electromagnetic radiation emitted or absorbed by that particular object. Most parts of the electromagnetic spectrum are used in science for spectroscopic and other probing interactions, as ways to study and characterize matter.[6] In addition, radiation from various parts of the spectrum has found many other uses for communications and manufacturing (see electromagnetic radiation for more applications). History of electromagnetic spectrum discovery The first discovery of electromagnetic radiation other than visible light came in 1800, when William Herschel discovered infrared radiation.[7] He was studying the temperature of different colors by moving a thermometer through light split by a prism. He noticed that the highest temperature was beyond red. where: Boundaries
Gamma-ray burst Artist's illustration showing the life of a massive star as nuclear fusion converts lighter elements into heavier ones. When fusion no longer generates enough pressure to counteract gravity, the star rapidly collapses to form a black hole. Theoretically, energy may be released during the collapse along the axis of rotation to form a gamma-ray burst. Gamma-ray bursts (GRBs) are flashes of gamma rays associated with extremely energetic explosions that have been observed in distant galaxies. They are the brightest electromagnetic events known to occur in the universe.[1] Bursts can last from ten milliseconds to several minutes. Most observed GRBs are believed to consist of a narrow beam of intense radiation released during a supernova or hypernova as a rapidly rotating, high-mass star collapses to form a neutron star, quark star, or black hole. History[edit] Positions on the sky of all gamma-ray bursts detected during the BATSE mission. Counterpart objects as candidate sources[edit]
Fundamental interaction Fundamental interactions, also called fundamental forces or interactive forces, are modeled in fundamental physics as patterns of relations in physical systems, evolving over time, that appear not reducible to relations among entities more basic. Four fundamental interactions are conventionally recognized: gravitational, electromagnetic, strong nuclear, and weak nuclear. Everyday phenomena of human experience are mediated via gravitation and electromagnetism. The strong interaction, synthesizing chemical elements via nuclear fusion within stars, holds together the atom's nucleus, and is released during an atomic bomb's detonation. The weak interaction is involved in radioactive decay. (Speculations of a fifth force—perhaps an added gravitational effect—remain widely disputed.) In modern physics, gravitation is the only fundamental interaction still modeled as classical/continuous (versus quantum/discrete). Overview of the fundamental Interaction[edit] The interactions[edit]
"Living" Crystal Colonies A bacterium will group together with its neighbors to form a living colony, but what about non-living things? Researchers recently discovered crystals that form similar colonies when illuminated with a specific spotlight. But when this light goes off, the colony breaks apart!1 IT'S ALIVE! Self-Assembled Crystals New York University scientists and a student from Brandeis University doing a summer research project2 recently uncovered this odd crystal behavior that mimics living creatures. A colloidal particle is a particle that does not make a chemical bond with other particles. The colloidal particles used were made of two types of material: a polymer sphere made of 3-methacryloxyporpyl trimethoxysilane (TPM), that encapsulates most of an antiferromagnetic hematite cube.1 Under regular lighting or in the dark, these particles undergo the typically random motion caused by bombarding atoms and molecules in a fluid (gas or liquid). For example, consider a dust particle in air. 2. 3.
Hypernova Eta Carinae, in the constellation of Carina, one of the nearer candidates for a future hypernova A hypernova (pl. hypernovae) is a type of supernova explosion with an energy substantially higher than that of standard supernovae. An alternative term for most hypernovae is "superluminous supernovae" (SLSNe). Such explosions are believed to be the origin of long-duration gamma-ray bursts.[1] Just like supernovae in general, hypernovae are produced by several different types of stellar explosion: some well modelled and observed in recent years, some still tentatively suggested for observed hypernovae, and some entirely theoretical. The word collapsar, short for collapsed star, was formerly used to refer to the end product of stellar gravitational collapse, a stellar-mass black hole. History of the term[edit] Before the 1990s, the term "hypernova" was used sporadically to describe the theoretical extremely energetic explosions of extremely massive population III stars. Gamma-ray bursts[edit]
Flavour (particle physics) In particle physics, flavour or flavor refers to a species of an elementary particle. The Standard Model counts six flavours of quarks and six flavours of leptons. They are conventionally parameterized with flavour quantum numbers that are assigned to all subatomic particles, including composite ones. For hadrons, these quantum numbers depend on the numbers of constituent quarks of each particular flavour. In atomic physics the principal quantum number of an electron specifies the electron shell in which it resides, which determines the energy level of the whole atom. In an analogous way, the five flavour quantum numbers of a quark specify which of six flavours (u, d, s, c, b, t) it has, and when these quarks are combined this results in different types of baryons and mesons with different masses, electric charges, and decay modes. If there are two or more particles which have identical interactions, then they may be interchanged without affecting the physics. Jump up ^ See table in S.
Shattering Science and Glass Physics From windshields to coffee tables to high-rise office buildings, we are surrounded by glass. But as any action movie stunt double will tell you, glass will break when you slam into it with enough force. Sometimes it breaks with devastating consequences, creating jagged shards that spray out in all directions. This can make a bad situation, like an automobile collision, much worse. High-risk applications like car windshields require a balance: glass that not only resists scratching and breaking but also breaks safely under an overwhelming force. Glass is strong but shows potential to be stronger, according to theoretical work by researchers at Rice University. How strong can glass get? In a recent theoretical study at Rice University, Peter Wolynes and his graduate student Apiwat Wisitsorasak explored the physical limit of the strength of glass. The study was based on a mathematical model of how glass forms that Wolynes developed more than twenty years ago. Shattering Safely —Kendra Redmond
White dwarf Artist's concept of white dwarf aging. A white dwarf, also called a degenerate dwarf, is a stellar remnant composed mostly of electron-degenerate matter. They are very dense; a white dwarf's mass is comparable to that of the Sun, and its volume is comparable to that of the Earth. White dwarfs are thought to be the final evolutionary state of all stars whose mass is not high enough to become a neutron star—over 97% of the stars in the Milky Way.[5], §1. The material in a white dwarf no longer undergoes fusion reactions, so the star has no source of energy, nor is it supported by the heat generated by fusion against gravitational collapse. A white dwarf is very hot when it is formed, but since it has no source of energy, it will gradually radiate away its energy and cool. Discovery[edit] I was visiting my friend and generous benefactor, Prof. The spectral type of 40 Eridani B was officially described in 1914 by Walter Adams.[14] The companion of Sirius, Sirius B, was next to be discovered.
Elementary particle In particle physics, an elementary particle or fundamental particle is a particle whose substructure is unknown, thus it is unknown whether it is composed of other particles.[1] Known elementary particles include the fundamental fermions (quarks, leptons, antiquarks, and antileptons), which generally are "matter particles" and "antimatter particles", as well as the fundamental bosons (gauge bosons and Higgs boson), which generally are "force particles" that mediate interactions among fermions.[1] A particle containing two or more elementary particles is a composite particle. Everyday matter is composed of atoms, once presumed to be matter's elementary particles—atom meaning "indivisible" in Greek—although the atom's existence remained controversial until about 1910, as some leading physicists regarded molecules as mathematical illusions, and matter as ultimately composed of energy.[1][2] Soon, subatomic constituents of the atom were identified. Overview[edit] Main article: Standard Model
The sound of silence Neutron star Neutron stars contain 500,000 times the mass of the Earth in a sphere with a diameter no larger than that of Brooklyn, United States A neutron star is a type of stellar remnant that can result from the gravitational collapse of a massive star during a Type II, Type Ib or Type Ic supernova event. Neutron stars are the densest and tiniest stars known to exist in the universe; although having only the diameter of about 10 km (6 mi), they may have a mass of several times that of the Sun. Neutron stars probably appear white to the naked eye. Neutron stars are the end points of stars whose inert core's mass after nuclear burning is greater than the Chandrasekhar limit for white dwarfs, but whose mass is not great enough to overcome the neutron degeneracy pressure to become black holes. The discovery of pulsars in 1967 suggested that neutron stars exist. Neutron star collision Formation[edit] Properties[edit] Gravitational light deflection at a neutron star. Given current values Structure[edit]
Color confinement The color force favors confinement because at a certain range it is more energetically favorable to create a quark-antiquark pair than to continue to elongate the color flux tube. This is analoguous to the behavior of an elongated rubber-band. An animation of color confinement. Energy is supplied to the quarks, and the gluon tube elongates until it reaches a point where it "snaps" and forms a quark-antiquark pair. Color confinement, often simply called confinement, is the phenomenon that color charged particles (such as quarks) cannot be isolated singularly, and therefore cannot be directly observed.[1] Quarks, by default, clump together to form groups, or hadrons. The two types of hadrons are the mesons (one quark, one antiquark) and the baryons (three quarks). Origin[edit] The reasons for quark confinement are somewhat complicated; no analytic proof exists that quantum chromodynamics should be confining. Models exhibiting confinement[edit] Models of fully screened quarks[edit] Quarks