Bullet Cluster Two colliding clusters of galaxies in constellation Carina The object is of a particular note for astrophysicists, because gravitational lensing studies of the Bullet Cluster are claimed to provide the best evidence to date for the existence of dark matter.[3][4] Observations of other galaxy cluster collisions, such as MACS J0025.4-1222, similarly support the existence of dark matter. Overview[edit] The major components of the cluster pair—stars, gas and the putative dark matter—behave differently during collision, allowing them to be studied separately. The third component, the dark matter, was detected indirectly by the gravitational lensing of background objects. The Bullet Cluster is one of the hottest-known clusters of galaxies. Significance to dark matter[edit] According to Greg Madejski: Particularly compelling results were inferred from the Chandra observations of the 'bullet cluster' (1E0657-56; Fig. 2) by Markevitch et al. (2004) and Clowe et al. (2004). According to Eric Hayashi:
Theory of relativity The theory of relativity, or simply relativity in physics, usually encompasses two theories by Albert Einstein: special relativity and general relativity.[1] Concepts introduced by the theories of relativity include: Measurements of various quantities are relative to the velocities of observers. In particular, space contracts and time dilates.Spacetime: space and time should be considered together and in relation to each other.The speed of light is nonetheless invariant, the same for all observers. The term "theory of relativity" was based on the expression "relative theory" (German: Relativtheorie) used in 1906 by Max Planck, who emphasized how the theory uses the principle of relativity. In the discussion section of the same paper Alfred Bucherer used for the first time the expression "theory of relativity" (German: Relativitätstheorie).[2][3] Scope[edit] The theory of relativity transformed theoretical physics and astronomy during the 20th century. Two-theory view[edit] History[edit]
Shooter, Very Cool Gun-Type Fire Extinguisher Concept Email Have you ever imagined to put the fire off in a cool way? Well, this fire extinguisher design is submitted by Eun Jung Kim might answer your question. From the designers : The bullet has a flexible material surface, when it hits the wall, the “cap” separates from the ‘bullet’ so it can reduce the danger. Designer : Eunjung Kim, Yangwoo Kim, Junyi Heo, and Ha Young Song Einasto profile From Wikipedia, the free encyclopedia The Einasto profile (or Einasto model) is a mathematical function that describes how the density of a spherical stellar system varies with distance from its center. Jaan Einasto introduced his model at a 1963 conference in Alma-Ata, Kazakhstan.[1] The Einasto profile possesses a power law logarithmic slope of the form: which can be rearranged to give The parameter controls the degree of curvature of the profile. The larger , the more rapidly the slope varies with radius (see figure). , which has a constant slope on a log-log plot. Einasto's model has the same mathematical form as Sersic's law, which is used to describe the surface brightness (i.e. projected density) profile of galaxies. Einasto's model has been used to describe many types of system, including galaxies,[2] and dark matter halos.[3] See also[edit] NFW profile References[edit] External links[edit] Spherical galaxy models with power-law logarithmic slope.
Biocentrism (cosmology) Biocentric universe (from Greek: βίος, bios, "life"; and κέντρον, kentron, "center") — also known as biocentrism — is a concept proposed in 2007 by American doctor of medicine Robert Lanza, a scientist in the fields of regenerative medicine and biology,[1][2][3] which sees biology as the central driving science in the universe, and an understanding of the other sciences as reliant on a deeper understanding of biology. Biocentrism states that life and biology are central to being, reality, and the cosmos — life creates the universe rather than the other way around. It asserts that current theories of the physical world do not work, and can never be made to work, until they fully account for life and consciousness. Critics have questioned whether the theory is falsifiable. Hypothesis[edit] Lanza has said that he intends to publish aspects of biocentrism in peer-reviewed scientific journals.[17] Synopsis of Lanza's book Biocentrism[edit] Reception[edit] See also[edit] References[edit]
Aircraft engine controls Basic Controls and Indicators[edit] Master Switch - Most often actually two separate switches, the Battery Master and the Alternator Master. The Battery Master activates a relay (sometimes called the battery contactor) which connects the battery to the aircraft's main electrical bus. The alternator master activates the alternator by applying power to the alternator field circuit. These two switches provide electrical power to all the systems in the aircraft.Throttle - Sets the desired power level. The throttle controls the mass flow-rate of air (in fuel-injected engines) or air/fuel mixture (in carburetted engines) delivered to the cylinders.Propeller Control - Adjusts the Constant Speed Unit, which in turn adjusts the propeller pitch and regulates the engine load as necessary to maintain the set R.P.M.Mixture Control - Sets the amount of fuel added to the intake airflow. Fuel[edit] If the aircraft is equipped with a fuel pump: Propeller[edit] Cowl[edit] Front view of open cowl flaps
Dark-energy star Hypothetical object that potentially explains accelerating universal expansion A dark-energy star is a hypothetical compact astrophysical object, which a minority of physicists think might constitute an alternative explanation for observations of astronomical black hole candidates. The concept was proposed by physicist George Chapline. The theory states that infalling matter is converted into vacuum energy or dark energy, as the matter falls through the event horizon. The space within the event horizon would end up with a large value for the cosmological constant and have negative pressure to exert against gravity. There would be no information-destroying singularity.[1] Theory[edit] In March 2005, physicist George Chapline claimed that quantum mechanics makes it a "near certainty" that black holes do not exist and are instead dark-energy stars. In the dark-energy star hypothesis, infalling matter approaching the event horizon decays into successively lighter particles. See also[edit]
10 Awesome Online Classes You Can Take For Free Cool, but you need iTunes for nearly everything, and that gets an 'F.' Are there really no other places to get these lessons? I was sure there are some on Academic Earth. Flagged 1. 7 of them are available via YouTube. 2. iTunes is free. 1. 2. Don't worry, we're looking out for you! While I have no personal beef with iTunes, I know that many people share your sentiments — so I actually made a concerted effort to include relevant youtube links when possible.
Black body As the temperature of a black body decreases, its intensity also decreases and its peak moves to longer wavelengths. Shown for comparison is the classical Rayleigh–Jeans law and its ultraviolet catastrophe. A black body is an idealized physical body that absorbs all incident electromagnetic radiation, regardless of frequency or angle of incidence. A black body in thermal equilibrium (that is, at a constant temperature) emits electromagnetic radiation called black-body radiation. The radiation is emitted according to Planck's law, meaning that it has a spectrum that is determined by the temperature alone (see figure at right), not by the body's shape or composition. A black body in thermal equilibrium has two notable properties:[1] It is an ideal emitter: it emits as much or more energy at every frequency than any other body at the same temperature.It is a diffuse emitter: the energy is radiated isotropically, independent of direction. Definition[edit] Idealizations[edit] Realizations[edit]
Mészáros effect From Wikipedia, the free encyclopedia Evolution of Cold Dark Matter perturbations The Mészáros effect "is the main physical process that alters the shape of the initial power spectrum of fluctuations in the cold dark matter theory of cosmological structure formation".[1] It was introduced in 1974 by Péter Mészáros[2] considering the behavior of dark matter perturbations in the range around the radiation-matter equilibrium redshift and up to the radiation decoupling redshift . an additional distinct growth period which alters the initial fluctuation power spectrum, and allows sufficient time for the fluctuations to grow into galaxies and galaxy clusters by the present epoch. in which , the variable , and is the length scale parametrizing the expansion of the Universe. .
Signs of ageing halted in the lab 2 November 2011Last updated at 18:01 By James Gallagher Health reporter, BBC News Will it one day be possible to stop ageing? The onset of wrinkles, muscle wasting and cataracts has been delayed and even eliminated in mice, say researchers in the US. It was done by "flushing out" retired cells that had stopped dividing. The scientists believe their findings could eventually "really have an impact" in the care of the elderly. Experts said the results were "fascinating", but should be taken with a bit of caution. The study, published in Nature, focused on what are known as "senescent cells". These cells are cleared out by the immune system, but their numbers build up with time. Cleanup Scientists at the Mayo Clinic, in the US, devised a way to kill all senescent cells in genetically engineered mice. The animals would age far more quickly than normal, and when they were given a drug, the senescent cells would die. Eternal youth?
'Water-Trapped' Worlds: Life Around a Cool Star A new study takes a deeper look into the fate of life-permitting water on Earth-like planets around red dwarf stars, the most common stars in the universe. Many of these exoplanets quickly become "tidally locked," with one side always facing their reddish star while the other side freezes in permanent night. The new research suggests that terrestrial, red dwarf-orbiting exoplanets with significantly less water than Earth might end up with almost all of their water "trapped" on the planet's night side, possibly hurting chances of supporting life in the planet's temperate regions. [See Photos of the Strangest Alien Planets] On the other hand, this water-trapping phenomenon might boost an exoplanet's odds for life by keeping at bay a super-heating, runaway greenhouse effect that would otherwise eventually dry a planet out and doom extraterrestrial life. Red suns and 'eyeball Earths' As many as three out of four stars in the Milky Way and other galaxies are red dwarfs. Whither the water?