Dark Energy (Wikipedia) Adding the cosmological constant to cosmology's standard FLRW metric leads to the Lambda-CDM model, which has been referred to as the "standard model" of cosmology because of its precise agreement with observations. Dark energy has been used as a crucial ingredient in a recent attempt to formulate a cyclic model for the universe.[8] Nature of dark energy[edit] Many things about the nature of dark energy remain matters of speculation. The evidence for dark energy is indirect but comes from three independent sources: Distance measurements and their relation to redshift, which suggest the universe has expanded more in the last half of its life.[9]The theoretical need for a type of additional energy that is not matter or dark matter to form our observationally flat universe (absence of any detectable global curvature).It can be inferred from measures of large scale wave-patterns of mass density in the universe. Effect of dark energy: a small constant negative pressure of vacuum[edit] .
Grave Encounters Bloxes: Modular Cardboard Adult-Sized Building Blocks Inflation (Wikipedia) Theory of rapid universe expansion In physical cosmology, cosmic inflation, cosmological inflation, or just inflation, is a theory of exponential expansion of space in the very early universe. Following the inflationary period, the universe continued to expand, but at a slower rate. The re-acceleration of this slowing expansion due to dark energy began after the universe was already over 7.7 billion years old (5.4 billion years ago).[1] Inflation theory was developed in the late 1970s and early 1980s, with notable contributions by several theoretical physicists, including Alexei Starobinsky at Landau Institute for Theoretical Physics, Alan Guth at Cornell University, and Andrei Linde at Lebedev Physical Institute. Cosmic inflation is the hypothesis that the very early universe expanded exponentially fast. Structure formation [edit] Magnetic-monopole problem While solving the monopole problem motivated the original hypothesis, not every cosmologist was impressed. Few inhomogeneities remain
Sinister How To Be A Little Gauss Return to my mathematics pages Go to my home page © Copyright 1997, Jim Loy [Imagine that you are in the audience at this lecture] There is a story about Carl Friedrich Gauss. Some people find that story hard to believe, even impossible. I think that you people can duplicate little Gauss's [2 feet tall] trick [doubt in the audience] . Nobody use your calculators, or even paper and pencil for a while. Here's the problem: We want to find X. What if we start at the other end: Do we get the same answer? That was your first hint, "Associative Law." Let's see, 100+99=199, +98=297, +. What if we add up the even numbers (that's 49 additions), then add up the odd numbers (that's 49 additions), and then add up the two totals? When we finally total them up, we get the same answer, right? How about: Does that help? [A couple people in the audience say that the columns all add up to 101] . [There is general agreement] . Right. How many 101s do we have? 50 x 101 [Some people say "5050"] . Addendum:
Black Hole (Wikipedia) A black hole is defined as a region of spacetime from which gravity prevents anything, including light, from escaping.[1] The theory of general relativity predicts that a sufficiently compact mass will deform spacetime to form a black hole.[2] Around a black hole, there is a mathematically defined surface called an event horizon that marks the point of no return. The hole is called "black" because it absorbs all the light that hits the horizon, reflecting nothing, just like a perfect black body in thermodynamics.[3][4] Quantum field theory in curved spacetime predicts that event horizons emit radiation like a black body with a finite temperature. This temperature is inversely proportional to the mass of the black hole, making it difficult to observe this radiation for black holes of stellar mass or greater. Objects whose gravity fields are too strong for light to escape were first considered in the 18th century by John Michell and Pierre-Simon Laplace. History General relativity
Grave Encounters 2 Human-powered aircraft MIT Light Eagle human-powered aircraft, predecessor to the MIT Daedalus aircraft Early attempts at human-powered flight were unsuccessful because of the difficulty of achieving the high power-to-weight ratio. Prototypes often used ornithopter principles which were not only too heavy to meet this requirement but aerodynamically unsatisfactory. As of 2008, human-powered aircraft have been successfully flown over considerable distances. The Royal Aeronautical Society Human Powered Flight Group[edit] The Royal Aeronautical Society's "Man Powered Aircraft Group" was formed in 1959 by the members of the Man Powered Group of the College of Aeronautics at Cranfield when they were invited to join the Society. Under the auspices of the Society, in 1959 the industrialist Henry Kremer offered the first Kremer Prizes of £5,000 for the first human-powered aircraft to fly a figure-of-eight course round two markers half-a-mile apart. First attempts[edit] First flights[edit] Passenger aircraft[edit]
Neutron Star (Wikipedia) 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]
AVP: Alien vs. Predator Webstock: Aza Raskin, Design is the Beauty of Turning Constraints Into Advantages | danielbachhuber This week I’m at Webstock, a lovely conference in New Zealand. I’m doing my best to write little blog posts about the amazing presentations. Please forgive any typos, etc. If you’re here too, come write a haiku at Automattic’s booth. For the last couple of years, Aza Raskin (@aza) has been working on helping bring design to solving health challenges. In 1959, Henry Kramer had a dream that people should be able to fly under their own power. Paul Maccready in 1977 said that most participants were trying to solve the wrong problem. “Science is in the business of embracing failure because it’s only through failure that we learn.” It’s not about thinking outside the box, because that means there are no constraints. The origin of the 140 character limit for text messages is also one of constraints. Creativity comes from constraint, and asking the right question is the most important part of design.