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Dark energy

Dark energy
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] .

Related:  Astronomispacetime

Antimatter In particle physics, antimatter is material composed of antiparticles, which have the same mass as particles of ordinary matter but opposite charges, as well as other particle properties such as lepton and baryon numbers and quantum spin. Collisions between particles and antiparticles lead to the annihilation of both, giving rise to variable proportions of intense photons (gamma rays), neutrinos, and less massive particle–antiparticle pairs. The total consequence of annihilation is a release of energy available for work, proportional to the total matter and antimatter mass, in accord with the mass–energy equivalence equation, E = mc2.[1]

Gravitational lens A gravitational lens refers to a distribution of matter (such as a cluster of galaxies) between a distant source and an observer, that is capable of bending the light from the source, as it travels towards the observer. This effect is known as gravitational lensing and the amount of bending is one of the predictions of Albert Einstein's general theory of relativity.[1] (Classical physics also predicts bending of light, but only half that of general relativity's.[2]) Although Orest Chwolson (1924) or Frantisek Klin (1936) are sometimes credited as being the first ones to discuss the effect in print, the effect is more commonly associated with Einstein, who published a more famous article on the subject in 1936.

Giant Simulation Could Solve Mystery Of 'Dark Matter' The search for a mysterious substance which makes up most of the Universe could soon be at an end, according to new research. Dark matter is believed to account for 85 per cent of the Universe's mass but has remained invisible to telescopes since scientists inferred its existence from its gravitational effects more than 75 years ago. Now the international Virgo Consortium, a team of scientists including cosmologists at Durham University, has used a massive computer simulation showing the evolution of a galaxy like the Milky Way to "see" gamma-rays given off by dark matter. Inflation (Wikipedia) In physical cosmology, cosmic inflation, cosmological inflation, or just inflation is a theory of exponential expansion of space in the early universe. The inflationary epoch lasted from 10−36 seconds after the Big Bang to sometime between 10−33 and 10−32 seconds. Following the inflationary period, the Universe continues to expand, but at a less rapid rate.[1] Inflation was developed in the early 1980s. It explains the origin of the large-scale structure of the cosmos. Quantum fluctuations in the microscopic inflationary region, magnified to cosmic size, become the seeds for the growth of structure in the Universe (see galaxy formation and evolution and structure formation).[2] Many physicists also believe that inflation explains why the Universe appears to be the same in all directions (isotropic), why the cosmic microwave background radiation is distributed evenly, why the Universe is flat, and why no magnetic monopoles have been observed.

“Red Nugget” Galaxies Were Hiding in Plain Sight In 2005 the Hubble Space Telescope spotted unusually small galaxies densely packed with red stars in the distant, young universe. They were nicknamed “red nuggets,” not only because they are small and red but also their existence challenged current theories of galaxy formation, making them precious in astronomers’ eyes. Since no “red nuggets” were seen nearby, astronomers wondered why they had disappeared over time. Hypercube An n-dimensional hypercube is also called an n-cube or an n-dimensional cube. The term "measure polytope" is also used, notably in the work of H. S. M. Coxeter (originally from Elte, 1912),[1] but it has now been superseded. Large Hadron Collider The Large Hadron Collider (LHC) is the world's largest and most powerful particle collider, most complex experimental facility ever built, and the largest single machine in the world.[1] It was built by the European Organization for Nuclear Research (CERN) between 1998 and 2008 in collaboration with over 10,000 scientists and engineers from over 100 countries, as well as hundreds of universities and laboratories.[2] It lies in a tunnel 27 kilometres (17 mi) in circumference, as deep as 175 metres (574 ft) beneath the France–Switzerland border near Geneva, Switzerland. Its first research run took place from March 2010 to early 2013 at an energy of 3.5 to 4 teraelectronvolts (TeV) per beam (7 to 8 TeV total), about 4 times the previous world record for a collider,[3][4] Afterwards, the accelerator was upgraded for two years. It was restarted in early 2015 for its second research run, reaching 6.5 TeV per beam (13 TeV total, the current world record).[5][6][7][8] Background[edit]

Dark Matter (Wikipedia) Dark matter is invisible. Based on the effect of gravitational lensing, a ring of dark matter has been detected in this image of a galaxy cluster (CL0024+17) and has been represented in blue.[1] Dark matter is a hypothetical kind of matter that cannot be seen with telescopes but accounts for most of the matter in the universe. The existence and properties of dark matter are inferred from its gravitational effects on visible matter, radiation, and the large-scale structure of the universe.