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Expansion Of The Universe
The expansion of the universe is the increase in proper length, distance between Gravitational binding energy, gravitationally unbound parts of the observable universe with time. It is an intrinsic and extrinsic properties (philosophy), intrinsic expansion, so it does not mean that the universe expands "into" anything or that space exists "outside" it. To any observer in the universe, it appears that all but Local Group, the nearest galaxies (which are bound to each other by gravity) move away at Hubble's law, speeds that are proportional to their distance from the observer, on average. While objects cannot move Faster-than-light, faster than light, this limitation applies only with respect to Principle of locality, local reference frames and does not limit the recession rates of cosmologically distant objects. Cosmic expansion is a key feature of Big Bang cosmology. It can be modeled mathematically with the Friedmann–Lemaître–Robertson–Walker metric (FLRW), where it corr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
CMB Timeline300 No WMAP
The cosmic microwave background (CMB, CMBR), or relic radiation, is microwave radiation that fills all space in the observable universe. With a standard optical telescope, the background space between stars and galaxies is almost completely dark. However, a sufficiently sensitive radio telescope detects a faint background glow that is almost isotropic, uniform and is not associated with any star, galaxy, or other astronomical object, object. This glow is strongest in the microwave region of the electromagnetic spectrum. The accidental Discovery of cosmic microwave background radiation, discovery of the CMB in 1965 by American radio astronomers Arno Allan Penzias and Robert Woodrow Wilson was the culmination of work initiated in the 1940s. The CMB is landmark evidence of the Big Bang scientific theory, theory for the origin of the universe. In the Big Bang cosmological models, during the earliest periods, the universe was filled with an Opacity (optics), opaque fog of dense, hot ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Geraint F
Geraint ( ) is a character from Welsh folklore and Arthurian legend, a valiant warrior possibly related to the historical Geraint, an early 8th-century king of Dumnonia. It is also the name of a 6th-century Dumnonian saint king from Briton hagiographies, who may have lived during or shortly prior to the reign of the historical Arthur. The name Geraint is a Welsh form of the Latin Gerontius, meaning "old man". Early sources A "Geraint of the South" appears at the Battle of Catraeth (circa 600) in the poem ''Y Gododdin'', attributed to Aneirin. This is conceivably a reference to Geraint mab Erbin, son of the 5th-century king Erbin of Dumnonia. Geraint is also mentioned as one of the "Three Seafarers of the Isle of Britain" in the Welsh Triads. Geraint's deeds at the Battle of Llongborth are celebrated in the poem " Geraint son of Erbin", which was written probably in the 10th or 11th century and traditionally attributed to Llywarch Hen. However, Derek Bryce, following ot ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Redshift
In physics, a redshift is an increase in the wavelength, and corresponding decrease in the frequency and photon energy, of electromagnetic radiation (such as light). The opposite change, a decrease in wavelength and increase in frequency and energy, is known as a #Blueshift, blueshift. The terms derive from the colours red and blue which form the extremes of the Visible spectrum, visible light spectrum. Three forms of redshift occur in astronomy and cosmology: Doppler effect, Doppler redshifts due to the relative motions of radiation sources, gravitational redshift as radiation escapes from gravitational potentials, and cosmological redshifts of all light sources proportional to their distances from Earth, a fact known as Hubble's law that implies the expansion of the universe, universe is expanding. All redshifts can be understood under the umbrella of Frame of reference, frame transformation laws. Gravitational waves, which also travel at Speed of light, the speed of light, a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Vesto Slipher
Vesto Melvin Slipher (; November 11, 1875 – November 8, 1969) was an American astronomer who performed the first measurements of radial velocities for galaxies. He was the first to discover that distant galaxies are redshifted, thus providing the first empirical basis for the expansion of the universe. He was also the first to relate these redshifts to velocity. Early life and education Vesto Melvin Slipher was born in Mulberry, Indiana, to Daniel Clark and Hannah App Slipher. He spent his early years working on his family farm in Mulberry. Vesto had a younger brother, Earl C. Slipher, who was also an astronomer at Lowell Observatory. Slipher went to high school in Frankfort, Indiana. He then attended Indiana University Bloomington and earned his Bachelor's Degree in Mechanics and Astronomy in June 1901. Two years later, Slipher earned his Master's Degree in the same program. At the age of 33, Vesto graduated with his Ph.D. in Mechanics and Astronomy from Indiana Universi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lambda-CDM Model
The Lambda-CDM, Lambda cold dark matter, or ΛCDM model is a mathematical model of the Big Bang theory with three major components: # a cosmological constant, denoted by lambda (Λ), associated with dark energy; # the postulated cold dark matter, denoted by CDM; # ordinary matter. It is the current ''standard model'' of Big Bang cosmology, as it is the simplest model that provides a reasonably good account of: * the existence and structure of the cosmic microwave background; * the large-scale structure in the distribution of galaxies; * the observed abundances of hydrogen (including deuterium), helium, and lithium; * the accelerating expansion of the universe observed in the light from distant galaxies and supernovae. The model assumes that general relativity is the correct theory of gravity on cosmological scales. It emerged in the late 1990s as a concordance cosmology, after a period when disparate observed properties of the universe appeared mutually inconsistent, and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cosmological Constant
In cosmology, the cosmological constant (usually denoted by the Greek capital letter lambda: ), alternatively called Einstein's cosmological constant, is a coefficient that Albert Einstein initially added to his field equations of general relativity. He later removed it; however, much later it was revived to express the energy density of space, or vacuum energy, that arises in quantum mechanics. It is closely associated with the concept of dark energy. Einstein introduced the constant in 1917. to counterbalance the effect of gravity and achieve a static universe, which was then assumed. Einstein's cosmological constant was abandoned after Edwin Hubble confirmed that the universe was expanding. From the 1930s until the late 1990s, most physicists agreed with Einstein's choice of setting the cosmological constant to zero. That changed with the discovery in 1998 that the expansion of the universe is accelerating, implying that the cosmological constant may have a positive valu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dark Energy
In physical cosmology and astronomy, dark energy is a proposed form of energy that affects the universe on the largest scales. Its primary effect is to drive the accelerating expansion of the universe. It also slows the rate of structure formation. Assuming that the lambda-CDM model of cosmology is correct, dark energy dominates the universe, contributing 68% of the total energy in the present-day observable universe while dark matter and Baryon#Baryonic matter, ordinary (baryonic) matter contribute 27% and 5%, respectively, and other components such as neutrinos and photons are nearly negligible.Sean Carroll, Ph.D., Caltech, 2007, The Teaching Company, ''Dark Matter, Dark Energy: The Dark Side of the Universe'', Guidebook Part 2. p. 46. Retrieved 7 October 2013, "...dark energy: A smooth, persistent component of invisible energy, thought to make up about 70 percent of the energy density of the universe. Dark energy is smooth because it doesn't accumulate preferentially in galaxi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Light-years
A light-year, alternatively spelled light year (ly or lyr), is a unit of length used to express astronomical distances and is equal to exactly , which is approximately 9.46 trillion km or 5.88 trillion mi. As defined by the International Astronomical Union (IAU), a light-year is the distance that light travels in vacuum in one Julian year (365.25 days). Despite its inclusion of the word "year", the term should not be misinterpreted as a unit of time. The ''light-year'' is most often used when expressing distances to stars and other distances on a galactic scale, especially in non-specialist contexts and popular science publications. The unit most commonly used in professional astronomy is the parsec (symbol: pc, about 3.26 light-years). Definitions As defined by the International Astronomical Union (IAU), the light-year is the product of the Julian year (365.25 days, as opposed to the 365.2425-day Gregorian year or the 365.24219-day Tropical year that both approximate) ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Molecule
A molecule is a group of two or more atoms that are held together by Force, attractive forces known as chemical bonds; depending on context, the term may or may not include ions that satisfy this criterion. In quantum physics, organic chemistry, and biochemistry, the distinction from ions is dropped and ''molecule'' is often used when referring to polyatomic ions. A molecule may be homonuclear, that is, it consists of atoms of one chemical element, e.g. two atoms in the oxygen molecule (O2); or it may be heteronuclear, a chemical compound composed of more than one element, e.g. water (molecule), water (two hydrogen atoms and one oxygen atom; H2O). In the kinetic theory of gases, the term ''molecule'' is often used for any gaseous particle regardless of its composition. This relaxes the requirement that a molecule contains two or more atoms, since the noble gases are individual atoms. Atoms and complexes connected by non-covalent interactions, such as hydrogen bonds or ionic ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nanometer
330px, Different lengths as in respect to the Molecule">molecular scale. The nanometre (international spelling as used by the International Bureau of Weights and Measures; SI symbol: nm), or nanometer (American spelling Despite the various list of dialects of English, English dialects spoken from country to country and within different regions of the same country, there are only slight regional variations in English orthography, the two most notable variati ...), is a units of measurement, unit of length in the International System of Units (SI), equal to one billionth (short scale) or one thousand million (long scale) of a metre, meter (0.000000001 m) and to 1000 picometres. One nanometre can be expressed in scientific notation as 1 × 10−9 m and as m. History The nanometre was formerly known as the "''millimicrometre''" – or, more commonly, the "''millimicron''" for short – since it is of a micrometre, micrometer. It was often de ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Inflationary Epoch
__NOTOC__ In physical cosmology, the inflationary epoch was the period in the evolution of the early universe when, according to inflation theory, the universe underwent an extremely rapid exponential expansion. This rapid expansion increased the linear dimensions of the early universe by a factor of at least 1026 (and possibly a much larger factor), and so increased its volume by a factor of at least 1078. Expansion by a factor of 1026 is equivalent to expanding an object 1 nanometer (10−9 m, about half the width of a molecule of DNA) in length to one approximately 10.6 light years (about 62 trillion miles). Description Vacuum state is a configuration of quantum fields representing a local minimum (but not necessarily a global minimum) of energy. Inflationary models propose that at approximately 10−36 seconds after the Big Bang, the vacuum state of the Universe was different from the one seen at the present time: the inflationary vacuum had a much higher energy density. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
