Hello readers, I am back. For the past few months I am very busy coping with my studies and thus I finally found time to update my blog and I hope you guys are happy again.
Thanks to imperfection, you and me exist .
The Big Bang theory is the prevailing cosmological model for the early development of the Universe. According to the theory, the Big Bang occurred approximately 13.798 ± 0.037 billion years ago, which is thus considered the age of the universe. At this time, the Universe was in an extremely hot and dense state and began expanding rapidly. After the initial expansion, the Universe cooled sufficiently to allow energy to be converted into various subatomic particles, including protons,neutrons, and electrons. Though simple atomic nuclei formed within the first three minutes after the Big Bang, thousands of years passed before the first electrically neutral atoms formed. The majority of atoms that were produced by the Big Bang are hydrogen, along with helium and traces of lithium. Giant clouds of these primordial elements later coalesced through gravity to form stars and galaxies, and the heavier elements were synthesized either within stars or during supernovae.
The Big Bang is the scientific theory that is most consistent with observations of the past and present states of the universe, and it is widely accepted within the scientific community. It offers a comprehensive explanation for a broad range of observed phenomena, including the abundance of light elements, the cosmic microwave background, large scale structure, and the Hubble diagram. The core ideas of the Big Bang—the expansion, the early hot state, the formation of light elements, and the formation of galaxies—are derived from these and other observations. As the distance between galaxies increases today, in the past galaxies were closer together. The consequence of this is that the characteristics of the universe can be calculated in detail back in time to extremedensities and temperatures, while large particle accelerators replicate such conditions, resulting in confirmation and refinement of the details of the Big Bang model. On the other hand, these accelerators can only probe so far into high energy regimes, and astronomers are prevented from seeing the absolute earliest moments in the universe by various cosmological horizons. The earliest instant of the Big Bang expansion is still an area of open investigation. The Big Bang theory does not provide any explanation for the initial conditions of the universe; rather, it describes and explains the general evolution of the universe going forward from that point on.
Georges Lemaître first proposed what became the Big Bang theory in what he called his “hypothesis of the primeval atom”. Over time, scientists built on his initial ideas to form the modern synthesis. The framework for the Big Bang model relies on Albert Einstein‘sgeneral relativity and on simplifying assumptions such as homogeneity and isotropy of space. The governing equations were first formulated by Alexander Friedmann and similar solutions were worked on by Willem de Sitter. In 1929, Edwin Hubble discovered that the distances to far away galaxies were strongly correlated with their redshifts—an idea originally suggested by Lemaître in 1927. Hubble’s observation was taken to indicate that all very distant galaxies and clusters have an apparent velocity directly away from our vantage point: the farther away, the higher the apparent velocity, regardless of direction. Assuming that we are not at the center of a giant explosion, the only remaining interpretation is that all observable regions of the universe are receding from each other.
While the scientific community was once divided between supporters of two different expanding universe theories—the Big Bang and the Steady State theory, observational confirmation of the Big Bang scenario came with the discovery of the cosmic microwave background radiation in 1964, and later when its spectrum (i.e., the amount of radiation measured at each wavelength) was found to match that of thermal radiation from a black body. Since then, astrophysicists have incorporated observational and theoretical additions into the Big Bang model, and its parametrization as the Lambda-CDM model serves as the framework for current investigations of theoretical cosmology.
Extrapolation of the expansion of the Universe backwards in time using general relativity yields an infinite density and temperature at a finite time in the past. This singularity signals the breakdown of general relativity. How closely we can extrapolate towards the singularity is debated—certainly no closer than the end of the Planck epoch. This singularity is sometimes called “the Big Bang”, but the term can also refer to the early hot, dense phase itself,[notes 1] which can be considered the “birth” of our Universe. Based on measurements of the expansion using Type Ia supernovae, measurements of temperature fluctuations in the cosmic microwave background, and measurements of the correlation function of galaxies, the Universe has a calculated age of 13.772 ± 0.059 billion years. The agreement of these three independent measurements strongly supports the ΛCDM model that describes in detail the contents of the Universe. In 2013 new Planck data corrected this age to 13.798 ± 0.037 billion years.
The earliest phases of the Big Bang are subject to much speculation. In the most common models the Universe was filled homogeneouslyand isotropically with an incredibly high energy density and huge temperatures and pressures and was very rapidly expanding and cooling. Approximately 10−37 seconds into the expansion, a phase transition caused a cosmic inflation, during which the Universe grewexponentially. After inflation stopped, the Universe consisted of a quark–gluon plasma, as well as all other elementary particles.Temperatures were so high that the random motions of particles were at relativistic speeds, and particle–antiparticle pairs of all kinds were being continuously created and destroyed in collisions. At some point an unknown reaction called baryogenesis violated the conservation ofbaryon number, leading to a very small excess of quarks and leptons over antiquarks and antileptons—of the order of one part in 30 million. This resulted in the predominance of matter over antimatter in the present Universe.
The Universe continued to decrease in density and fall in temperature, hence the typical energy of each particle was decreasing. Symmetry breaking phase transitions put the fundamental forces of physics and the parameters of elementary particles into their present form. After about 10−11seconds, the picture becomes less speculative, since particle energies drop to values that can be attained in particle physics experiments. At about 10−6 seconds, quarks and gluons combined to form baryons such as protons and neutrons. The small excess of quarks over antiquarks led to a small excess of baryons over antibaryons. The temperature was now no longer high enough to create new proton–antiproton pairs (similarly for neutrons–antineutrons), so a mass annihilation immediately followed, leaving just one in 1010 of the original protons and neutrons, and none of their antiparticles. A similar process happened at about 1 second for electrons and positrons. After these annihilations, the remaining protons, neutrons and electrons were no longer moving relativistically and the energy density of the Universe was dominated by photons (with a minor contribution from neutrinos).
A few minutes into the expansion, when the temperature was about a billion (one thousand million; 109; SI prefix giga-) kelvin and the density was about that of air, neutrons combined with protons to form the Universe’s deuterium and helium nuclei in a process called Big Bang nucleosynthesis. Most protons remained uncombined as hydrogen nuclei. As the Universe cooled, the rest mass energy density of matter came to gravitationally dominate that of the photon radiation. After about 379,000 years the electrons and nuclei combined into atoms (mostly hydrogen); hence the radiation decoupled from matter and continued through space largely unimpeded. This relic radiation is known as the cosmic microwave background radiation.
Over a long period of time, the slightly denser regions of the nearly uniformly distributed matter gravitationally attracted nearby matter and thus grew even denser, forming gas clouds, stars, galaxies, and the other astronomical structures observable today. The details of this process depend on the amount and type of matter in the Universe. The four possible types of matter are known as cold dark matter, warm dark matter, hot dark matter, and baryonic matter. The best measurements available (from WMAP) show that the data is well-fit by a Lambda-CDM model in which dark matter is assumed to be cold (warm dark matter is ruled out by early reionization), and is estimated to make up about 23% of the matter/energy of the universe, while baryonic matter makes up about 4.6%. In an “extended model” which includes hot dark matter in the form of neutrinos, then if the “physical baryon density” Ωbh2 is estimated at about 0.023 (this is different from the ‘baryon density’ Ωb expressed as a fraction of the total matter/energy density, which as noted above is about 0.046), and the corresponding cold dark matter density Ωch2 is about 0.11, the corresponding neutrino density Ωvh2 is estimated to be less than 0.0062.
Independent lines of evidence from Type Ia supernovae and the CMB imply that the Universe today is dominated by a mysterious form of energy known as dark energy, which apparently permeates all of space. The observations suggest 73% of the total energy density of today’s Universe is in this form. When the Universe was very young, it was likely infused with dark energy, but with less space and everything closer together, gravity had the upper hand, and it was slowly braking the expansion. But eventually, after numerous billion years of expansion, the growing abundance of dark energy caused the expansion of the Universe to slowly begin to accelerate. Dark energy in its simplest formulation takes the form of the cosmological constant term in Einstein’s field equations of general relativity, but its composition and mechanism are unknown and, more generally, the details of its equation of state and relationship with the Standard Model of particle physics continue to be investigated both observationally and theoretically.
All of this cosmic evolution after the inflationary epoch can be rigorously described and modeled by the ΛCDM model of cosmology, which uses the independent frameworks of quantum mechanics and Einstein’s General Relativity. As noted above, there is no well-supported model describing the action prior to 10−15 seconds or so. Apparently a new unified theory of quantum gravitation is needed to break this barrier. Understanding this earliest of eras in the history of the Universe is currently one of the greatest unsolved problems in physics.
The Big Bang theory developed from observations of the structure of the Universe and from theoretical considerations. In 1912 Vesto Slipher measured the first Doppler shift of a “spiral nebula” (spiral nebula is the obsolete term for spiral galaxies), and soon discovered that almost all such nebulae were receding from Earth. He did not grasp the cosmological implications of this fact, and indeed at the time it was highly controversial whether or not these nebulae were “island universes” outside our Milky Way. Ten years later, Alexander Friedmann, a Russian cosmologist and mathematician, derived the Friedmann equations from Albert Einstein’s equations of general relativity, showing that the Universe might be expanding in contrast to the static Universe model advocated by Einstein at that time. In 1924 Edwin Hubble’s measurement of the great distance to the nearest spiral nebulae showed that these systems were indeed other galaxies. Independently deriving Friedmann’s equations in 1927, Georges Lemaître, a Belgian physicist and Roman Catholic priest, proposed that the inferred recession of the nebulae was due to the expansion of the Universe.
In 1931 Lemaître went further and suggested that the evident expansion of the universe, if projected back in time, meant that the further in the past the smaller the universe was, until at some finite time in the past all the mass of the Universe was concentrated into a single point, a “primeval atom” where and when the fabric of time and space came into existence.
Starting in 1924, Hubble painstakingly developed a series of distance indicators, the forerunner of the cosmic distance ladder, using the 100-inch (2,500 mm) Hooker telescope at Mount Wilson Observatory. This allowed him to estimate distances to galaxies whose redshifts had already been measured, mostly by Slipher. In 1929 Hubble discovered a correlation between distance and recession velocity—now known as Hubble’s law. Lemaître had already shown that this was expected, given the Cosmological Principle.
In the 1920s and 1930s almost every major cosmologist preferred an eternal steady state Universe, and several complained that the beginning of time implied by the Big Bang imported religious concepts into physics; this objection was later repeated by supporters of the steady state theory. This perception was enhanced by the fact that the originator of the Big Bang theory, Monsignor Georges Lemaître, was a Roman Catholic priest. Arthur Eddington agreed with Aristotle that the universe did not have a beginning in time, viz., that matter is eternal. A beginning in time was “repugnant” to him. Lemaître, however, thought that
If the world has begun with a single quantum, the notions of space and time would altogether fail to have any meaning at the beginning; they would only begin to have a sensible meaning when the original quantum had been divided into a sufficient number of quanta. If this suggestion is correct, the beginning of the world happened a little before the beginning of space and time.
During the 1930s other ideas were proposed as non-standard cosmologies to explain Hubble’s observations, including the Milne model, the oscillatory Universe (originally suggested by Friedmann, but advocated by Albert Einstein and Richard Tolman) and Fritz Zwicky’s tired light hypothesis.
After World War II, two distinct possibilities emerged. One was Fred Hoyle’s steady state model, whereby new matter would be created as the Universe seemed to expand. In this model the Universe is roughly the same at any point in time. The other was Lemaître’s Big Bang theory, advocated and developed by George Gamow, who introduced big bang nucleosynthesis (BBN) and whose associates, Ralph Alpher and Robert Herman, predicted the cosmic microwave background radiation (CMB). Ironically, it was Hoyle who coined the phrase that came to be applied to Lemaître’s theory, referring to it as “this big bang idea” during a BBC Radio broadcast in March 1949.[notes 4] For a while, support was split between these two theories. Eventually, the observational evidence, most notably from radio source counts, began to favor Big Bang over Steady State. The discovery and confirmation of the cosmic microwave background radiation in 1964 secured the Big Bang as the best theory of the origin and evolution of the cosmos. Much of the current work in cosmology includes understanding how galaxies form in the context of the Big Bang, understanding the physics of the Universe at earlier and earlier times, and reconciling observations with the basic theory.
Significant progress in Big Bang cosmology have been made since the late 1990s as a result of advances in telescope technology as well as the analysis of data from satellites such as COBE, the Hubble Space Telescope and WMAP. Cosmologists now have fairly precise and accurate measurements of many of the parameters of the Big Bang model, and have made the unexpected discovery that the expansion of the Universe appears to be accelerating.
he earliest and most direct observational evidence of the validity of the theory are the expansion of the universe according toHubble’s law (as indicated by the redshifts of galaxies), discovery and measurement of the cosmic microwave backgroundand the relative abundances of light elements produced by Big Bang nucleosynthesis. More recent evidence includes observations of galaxy formation and evolution, and the distribution of large-scale cosmic structures, These are sometimes called the “four pillars” of the Big Bang theory.
Precise modern models of the Big Bang appeal to various exotic physical phenomena that have not been observed in terrestrial laboratory experiments or incorporated into theStandard Model of particle physics. Of these features, dark matter is currently subjected to the most active laboratory investigations. Remaining issues include the cuspy halo problem and the dwarf galaxy problem of cold dark matter. Dark energy is also an area of intense interest for scientists, but it is not clear whether direct detection of dark energy will be possible. Inflation and baryogenesis remain more speculative features of current Big Bang models.[notes 5] Viable, quantitative explanations for such phenomena are still being sought. These are currently unsolved problems in physics.
Observations of distant galaxies and quasars show that these objects are redshifted—the light emitted from them has been shifted to longer wavelengths. This can be seen by taking a frequency spectrum of an object and matching the spectroscopic pattern of emission lines or absorption lines corresponding to atoms of the chemical elements interacting with the light. These redshifts are uniformly isotropic, distributed evenly among the observed objects in all directions. If the redshift is interpreted as a Doppler shift, the recessionalvelocity of the object can be calculated. For some galaxies, it is possible to estimate distances via the cosmic distance ladder. When the recessional velocities are plotted against these distances, a linear relationship known as Hubble’s law is observed:
- v = H0D,
- v is the recessional velocity of the galaxy or other distant object,
- D is the comoving distance to the object, and
- H0 is Hubble’s constant, measured to be 70.4 +1.3
−1.4 km/s/Mpc by the WMAP probe.
Hubble’s law has two possible explanations. Either we are at the center of an explosion of galaxies—which is untenable given the Copernican principle—or the Universe is uniformly expanding everywhere. This universal expansion was predicted from general relativity by Alexander Friedmann in 1922 and Georges Lemaître in 1927, well before Hubble made his 1929 analysis and observations, and it remains the cornerstone of the Big Bang theory as developed by Friedmann, Lemaître, Robertson, and Walker.
The theory requires the relation v = HD to hold at all times, where D is the comoving distance, v is the recessional velocity, and v, H, and D vary as the Universe expands (hence we write H0 to denote the present-day Hubble “constant”). For distances much smaller than the size of the observable Universe, the Hubble redshift can be thought of as the Doppler shift corresponding to the recession velocity v. However, the redshift is not a true Doppler shift, but rather the result of the expansion of the Universe between the time the light was emitted and the time that it was detected.
That space is undergoing metric expansion is shown by direct observational evidence of the Cosmological principle and the Copernican principle, which together with Hubble’s law have no other explanation. Astronomical redshifts are extremely isotropic and homogenous, supporting the Cosmological principle that the Universe looks the same in all directions, along with much other evidence. If the redshifts were the result of an explosion from a center distant from us, they would not be so similar in different directions.
Measurements of the effects of the cosmic microwave background radiation on the dynamics of distant astrophysical systems in 2000 proved the Copernican principle, that, on a cosmological scale, the Earth is not in a central position. Radiation from the Big Bang was demonstrably warmer at earlier times throughout the Universe. Uniform cooling of the cosmic microwave background over billions of years is explainable only if the Universe is experiencing a metric expansion, and excludes the possibility that we are near the unique center of an explosion.
Detailed observations of the morphology and distribution of galaxies and quasars are in agreement with the current state of the Big Bang theory. A combination of observations and theory suggest that the first quasars and galaxies formed about a billion years after the Big Bang, and since then larger structures have been forming, such as galaxy clusters and superclusters. Populations of stars have been aging and evolving, so that distant galaxies (which are observed as they were in the early Universe) appear very different from nearby galaxies (observed in a more recent state). Moreover, galaxies that formed relatively recently appear markedly different from galaxies formed at similar distances but shortly after the Big Bang. These observations are strong arguments against the steady-state model. Observations of star formation, galaxy and quasar distributions and larger structures agree well with Big Bang simulations of the formation of structure in the Universe and are helping to complete details of the theory.
Measurements of the redshift–magnitude relation for type Ia supernovae indicate that the expansion of the Universe has been accelerating since the Universe was about half its present age. To explain this acceleration, general relativity requires that much of the energy in the Universe consists of a component with large negative pressure, dubbed “dark energy”. Dark energy, though speculative, solves numerous problems. Measurements of the cosmic microwave background indicate that the Universe is very nearly spatially flat, and therefore according to general relativity the Universe must have almost exactly the critical density of mass/energy. But the mass density of the Universe can be measured from its gravitational clustering, and is found to have only about 30% of the critical density. Since theory suggests that dark energy does not cluster in the usual way it is the best explanation for the “missing” energy density. Dark energy also helps to explain two geometrical measures of the overall curvature of the Universe, one using the frequency ofgravitational lenses, and the other using the characteristic pattern of the large-scale structure as a cosmic ruler.
Negative pressure is believed to be a property of vacuum energy, but the exact nature and existence of dark energy remains one of the great mysteries of the Big Bang. Possible candidates include a cosmological constant and quintessence. Results from the WMAP team in 2008 are in accordance with a universe that consists of 73% dark energy, 23% dark matter, 4.6% regular matter and less than 1% neutrinos. According to theory, the energy density in matter decreases with the expansion of the Universe, but the dark energy density remains constant (or nearly so) as the Universe expands. Therefore matter made up a larger fraction of the total energy of the Universe in the past than it does today, but its fractional contribution will fall in the far future as dark energy becomes even more dominant.
During the 1970s and 1980s, various observations showed that there is not sufficient visible matter in the Universe to account for the apparent strength of gravitational forces within and between galaxies. This led to the idea that up to 90% of the matter in the Universe is dark matter that does not emit light or interact with normal baryonic matter. In addition, the assumption that the Universe is mostly normal matter led to predictions that were strongly inconsistent with observations. In particular, the Universe today is far more lumpy and contains far less deuterium than can be accounted for without dark matter. While dark matter has always been controversial, it is inferred by various observations: the anisotropies in the CMB, galaxy clustervelocity dispersions, large-scale structure distributions, gravitational lensing studies, and X-ray measurementsof galaxy clusters.
Indirect evidence for dark matter comes from its gravitational influence on other matter, as no dark matter particles have been observed in laboratories. Many particle physics candidates for dark matter have been proposed, and several projects to detect them directly are underway.
Globular cluster age
In the mid-1990s observations of globular clusters appeared to be inconsistent with the Big Bang theory. Computer simulations that matched the observations of the stellarpopulations of globular clusters suggested that they were about 15 billion years old, which conflicted with the 13.8 billion year age of the Universe. This issue was partially resolved in the late 1990s when new computer simulations, which included the effects of mass loss due to stellar winds, indicated a much younger age for globular clusters. There remain some questions as to how accurately the ages of the clusters are measured, but it is clear that observations of globular clusters no longer appear inconsistent with the Big Bang theory.
There are generally considered to be three outstanding problems with the Big Bang theory: the horizon problem, the flatness problem, and the magnetic monopole problem. The most common answer to these problems is inflationary theory; however, since this creates new problems, other options have been proposed, such as the Weyl curvature hypothesis.
The horizon problem results from the premise that information cannot travel faster than light. In a Universe of finite age this sets a limit—the particle horizon—on the separation of any two regions of space that are in causal contact. The observed isotropy of the CMB is problematic in this regard: if the Universe had been dominated by radiation or matter at all times up to the epoch of last scattering, the particle horizon at that time would correspond to about 2 degrees on the sky. There would then be no mechanism to cause wider regions to have the same temperature.
A resolution to this apparent inconsistency is offered by inflationary theory in which a homogeneous and isotropic scalar energy field dominates the Universe at some very early period (before baryogenesis). During inflation, the Universe undergoes exponential expansion, and the particle horizon expands much more rapidly than previously assumed, so that regions presently on opposite sides of the observable Universe are well inside each other’s particle horizon. The observed isotropy of the CMB then follows from the fact that this larger region was in causal contact before the beginning of inflation.
Heisenberg’s uncertainty principle predicts that during the inflationary phase there would be quantum thermal fluctuations, which would be magnified to cosmic scale. These fluctuations serve as the seeds of all current structure in the Universe. Inflation predicts that the primordial fluctuations are nearly scale invariant and Gaussian, which has been accurately confirmed by measurements of the CMB.
If inflation occurred, exponential expansion would push large regions of space well beyond our observable horizon.
The flatness problem (also known as the oldness problem) is an observational problem associated with a Friedmann–Lemaître–Robertson–Walker metric. The Universe may have positive, negative, or zero spatial curvature depending on its total energy density. Curvature is negative if its density is less than the critical density, positive if greater, and zero at the critical density, in which case space is said to be flat. The problem is that any small departure from the critical density grows with time, and yet the Universe today remains very close to flat.[notes 6] Given that a natural timescale for departure from flatness might be thePlanck time, 10−43 seconds, the fact that the Universe has reached neither a heat death nor a Big Crunch after billions of years requires an explanation. For instance, even at the relatively late age of a few minutes (the time of nucleosynthesis), the Universe density must have been within one part in 1014 of its critical value, or it would not exist as it does today.
A resolution to this problem is offered by inflationary theory. During the inflationary period, spacetime expanded to such an extent that its curvature would have been smoothed out. Thus, it is theorized that inflation drove the Universe to a very nearly spatially flat state, with almost exactly the critical density.
The magnetic monopole objection was raised in the late 1970s. Grand unification theories predicted topological defects in space that would manifest as magnetic monopoles. These objects would be produced efficiently in the hot early Universe, resulting in a density much higher than is consistent with observations, given that searches have never found any monopoles. This problem is also resolved by cosmic inflation, which removes all point defects from the observable Universe in the same way that it drives the geometry to flatness.
The future according to the Big Bang theory
Before observations of dark energy, cosmologists considered two scenarios for the future of the Universe. If the mass density of the Universe were greater than the critical density, then the Universe would reach a maximum size and then begin to collapse. It would become denser and hotter again, ending with a state similar to that in which it started—a Big Crunch. Alternatively, if the density in the Universe were equal to or below the critical density, the expansion would slow down but never stop. Star formation would cease with the consumption of interstellar gas in each galaxy; stars would burn out leaving white dwarfs, neutron stars, and black holes. Very gradually, collisions between these would result in mass accumulating into larger and larger black holes. The average temperature of the Universe would asymptotically approach absolute zero—a Big Freeze. Moreover, if the proton were unstable, then baryonic matter would disappear, leaving only radiation and black holes. Eventually, black holes would evaporate by emitting Hawking radiation. Theentropy of the Universe would increase to the point where no organized form of energy could be extracted from it, a scenario known as heat death.
Modern observations of accelerating expansion imply that more and more of the currently visible Universe will pass beyond our event horizon and out of contact with us. The eventual result is not known. The ΛCDM model of the Universe contains dark energy in the form of a cosmological constant. This theory suggests that only gravitationally bound systems, such as galaxies, will remain together, and they too will be subject to heat death as the Universe expands and cools. Other explanations of dark energy, called phantom energy theories, suggest that ultimately galaxy clusters, stars, planets, atoms, nuclei, and matter itself will be torn apart by the ever-increasing expansion in a so-called Big Rip.
Speculative physics beyond the Big Bang theory
This is an artist’s concept of the metric expansion of space, where space (including hypothetical non-observable portions of the Universe) is represented at each time by the circular sections. Note on the left the dramatic expansion (not to scale) occurring in the inflationary epoch, and at the center the expansion acceleration. The scheme is decorated with WMAP images on the left and with the representation of stars at the appropriate level of development.
While the Big Bang model is well established in cosmology, it is likely to be refined in the future. The equations of classical general relativity indicate a singularity at the origin of cosmic time, although this conclusion depends on several assumptions, and the equations break down at any time before the Universe reached the Planck temperature. A correct treatment of quantum gravity may avoid the would-be singularity.
It is unknown what could have caused the singularity to come into existence (if it had a cause), or how and why it first originated, though speculation abounds in the field of cosmogony. Some proposals, each of which entails untested hypotheses, are:
- Models including the Hartle–Hawking no-boundary condition in which the whole of space-time is finite; the Big Bang does represent the limit of time, but without the need for a singularity.
- Big Bang lattice model states that the Universe at the moment of the Big Bang consists of an infinite lattice offermions which is smeared over the fundamental domain so it has both rotational, translational, and gauge symmetry. The symmetry is the largest symmetry possible and hence the lowest entropy of any state.
- Brane cosmology models in which inflation is due to the movement of branes in string theory; the pre-Big Bang model; the ekpyrotic model, in which the Big Bang is the result of a collision between branes; and the cyclic model, a variant of the ekpyrotic model in which collisions occur periodically. In the latter model the Big Bang was preceded by a Big Crunch and the Universe endlessly cycles from one process to the other.
- Eternal inflation, in which universal inflation ends locally here and there in a random fashion, each end-point leading to a bubble universe expanding from its own big bang.
Proposals in the last two categories see the Big Bang as an event in either a much larger and older Universe, or in a multiverse.
Religious and philosophical interpretations
As a theory relevant to the origin of the universe, the Big Bang has significant bearing on religion and philosophy. As a result, it has become one of the liveliest areas in the discourse between science and religion. Some believe the Big Bang implies a creator, while others argue that Big Bang cosmology makes the notion of a creator superfluous.
Short bio of Bill Gates
As founder of Microsoft, Bill Gates is one of the most influential and richest people on the planet. Recent estimates of his wealth put it at $56 billion, this is the equivalent of the combined GDP of several African economies. In recent years he has retired from working full time at Microsoft, instead he has concentrated on working with his charitable foundation “The Bill and Melinda Gates Foundation”
Bill Gates foundation of Microsoft
Bill Gates founded Microsoft in 1976 when he formed a contract with MITTS (Micro Instrumentation and Telemetry Systems) to develop a basic operating system for their new microcomputers. In the early days Bill Gates would review every line of code. He was also involved in several aspects of Microsoft’s business such as packing and sending off orders.
The big break for Microsoft came in 1980 when IBM approached them for a new BASIC operating system for its new computers. In the early 1980s IBM was by far the leading PC manufacture. However increasingly there developed many IBM PC clones; (PCs developed by other companies compatible with IBM’s). Microsoft worked hard to sell its operating system to these other companies. Thus Microsoft was able to gain the dominant position of software manufacture just as the personal computer market started to boom. Since its early dominance no other company has come close to displacing Microsoft as the dominant provider of computer operating software.
Bill Gates – Windows
In 1990 Microsoft released its first version of Windows. This was a break through in operating software as it replaced text interfaces with graphical interfaces. It soon became a best seller and was able to capture the majority of the operating system market share. In 1995 Windows 95 was released, setting new standards and features for operating systems. This version of windows has been the backbone of all future releases from Windows 2000 to the latest XP and Vista.
Throughout his time in office Bill Gates has been keen to diversify the business of Microsoft. For example Microsoft’s Internet Explorer has become the dominant web browser, although this is mainly because it comes pre installed on most new computers. In one area at least Microsoft has not gained Monopoly power, and that is in the area of search engines. MSN live search has struggled to gain more than 12% of market share. In this respect Microsoft has been dwarfed by Google. Nevertheless the success of Microsoft in cornering various aspects of the software market has led to several anti trust cases. In 1998 US v Microsoft, Microsoft came close to being broken up into 3 smaller firms. However on appeal Microsoft were able to survive as a single firm.
Philanthropic Activities – Bill Gates
Bill Gates is married to Melinda French (married in 1992). They have 3 children Jennifer (1996), Rory (1999) and Phoebe (2002). With his wife Bill Gates formed the Bill & Melinda Gates Foundation. Bill Gates says much of the inspiration came from the example of David Rockefeller. Like Rockefeller, Gates has sought to focus on global issues ignored by the government; he also expressed an interest in improving the standards of public school education in the US. He has appeared with Oprah Winfrey to promote this objective. In respect to charitable, philanthropic activities Gates has also received encouragement from investor Warren Buffet. Recently Gates announced that from 2008 he would work full time on his philanthropic interests. Forbes magazine 2004 estimated that Gates has given over $24 billion dollars in the 4 years from 2000 to 2004.
Forested hills, romantic white-sand beaches and crystal-clear waters greet visitors to tropical Palau Langkawi, the largest of the 99 islands in Langkawi archipelago. Known mysteriously as “Legendary Island” because of myths associated with its ancient geological formations, it drifts serenely alongside Malaysia in the azure Andaman Sea. Sample local cuisine at the night markets, hike to dramatic waterfalls or dive into an underwater marine park to take a guided glimpse at life beneath the sea.
HERE ARE SOME PHOTOS
The islands are a part of the state of Kedah, which is adjacent to the Thai border. On 15 Jul 2008, Sultan Abdul Halim of Kedah consented to the change of name to Langkawi Permata Kedah in conjunction with his Golden Jubilee Celebration.
By far the largest of the islands is the eponymous Pulau Langkawi with a population of some 64,792, the only other inhabited island being nearby Pulau Tuba. Langkawi is also an administrative district with the town of Kuah as the capital and largest town.
The name “Langkawi” has two possible origins. First, it is believed to be related to the kingdom of Langkasuka, itself a version of theMalay negari alang-kah suka (“the land of all one’s wishes”), centered in modern-dayKedah. The historical record is sparse, but a Chinese Liang Dynasty record (c. 500 AD) refers to the kingdom of “Langgasu” as being founded in the 1st century AD. Second, it could be a combination of the Malay words ‘helang’, meaning “eagle” and ‘kawi’, meaning “reddish-brown” or “strong”, in old Malay.
Langkawi eventually came under the influence of the Sultanate of Kedah, but Kedah was conquered in 1821 by Siam and Langkawi along with it. The Anglo-Siamese Treaty of 1909 transferred power to the British, which held the state until independence, except for a brief period of Thai rule under the Japanese occupation of Malaya during World War II. Thai influences remain visible in the culture and food of Langkawi.
Langkawi remained a sleepy backwater until 1987, when the island was granted tax-free status with the intention of promoting tourism and improve the lives of the islanders.
This spectacular boom also coincided with the end of “Mahsuri’s Curse,” which was lifted with the birth of her 7th generation descendant. I hope I have given sufficient details and hope you can make plan to Langkawi.
Would you wish you had a brother or sister ?
Well I had a brother but I wish I had not. This is why. We will compete with each other and most of the time I would lose. Want to know why? My parents of course! Whenever we quarrel and I complain to my parents, they would usually say these words ” You are his brother! How can you do this and that and nag….” . They seldom scold my brother. He is naughty,cheeky and rude. He knows my weakness : easily get angry. So he took advantage of me to make me angry and when we start to quarrel, my parents usually blame it on me. There is a lot more examples.
Enough about the bad things, now for the positives ones. We would have a lot of fun together, playing and all sorts. Now he has kind of get addicted to electronic games while I prefer playing board games like Monopoly. However, he still play with me and I play with him too. There is one thing that we share in common. We exercise a lot . A lot. My parents usually say we over-exercise. We can have the stamina to exercise over 4 hours!
Now that I have shared my story, what’s your’s? please leave your answer in the comments. Thanks!
“It is not how much we do, but how much love we put in the doing. It is not how much we give, but how much love we put in the giving.”
– Mother Teresa
Mother Teresa (1910-1997) was a Roman Catholic nun, who devoted her life to serving the poor and destitute aroune the world. She spent many years in Calcutta, India where shed founded the Missionaries of Charity, a religious congregation devoted to helping those in great need. In 1979, Mother Teresa was awarded the Nobel Peace Prize and has become a symbol of charitable selfless work. She was beatified in 2003, the first step on the path to sainthood, within the Catholic church.
Mother Teresa was born, 1910, in Skopje, capital of the Republic of Macedonia. Little is known about her early life, but at a young age she felt a calling to be a nun and serve through helping the poor. At the age of 18 she was given permission to join a group of nuns in Ireland. After a few months of training, with the Sisters of Loreto, she was then given permission to travel to India. She took her formal religious vows in 1931, and chose to be named after St Therese of Lisieux – the patron saint of missionaries.
On her arrival in India, she began by working as a teacher, however the widespread poverty of Calcutta made a deep impression on her; and this led to her starting a new order called “The Missionaries of Charity”. The primary objective of this mission was to look after people, who nobody else was prepared to look after. Mother Teresa felt that serving others was a key principle of the teachings of Jesus Christ. She often mentioned the saying of Jesus,
“Whatever you do to the least of my brethren, you do it to me.”
As Mother Teresa said herself:
“Love cannot remain by itself — it has no meaning. Love has to be put into action, and that action is service .” – Mother Teresa
She experienced two particularly traumatic periods in Calcutta. The first was the Bengal famine of 1943 and the second was the Hindu/Muslim violence in 1946 – before the partition of India. In 1948, she left the convent to live full time amongst the poorest of Calcutta. She chose to wear a white Indian Sari, with blue trimmings – out of respect for the traditional Indian dress. For many years, Mother Teresa and a small band of fellow nuns survived on minimal income and food, often having to beg for funds. But, slowly her efforts with the poorest were noted and appreciated by the local community and Indian politicians.
In 1952, she opened her first home for the dying, which allowed people to die with dignity. Mother Teresa often spent time with those who were dying. Some have criticised the lack of proper medical attention, and refusal to give painkillers. But, others say that it afforded many neglected people the opportunity to die knowing someone cared.
Over time the work grew. Missions were started overseas, and by 2013, there are 700 missions operating in over 130 countries. The scope of their work also expanded to include orphanages, and hospices for those with terminal illness.
“Not all of us can do great things. But we can do small things with great love.”
— Mother Teresa
Mother Teresa never sought to convert those of an another faith. Those in her dying homes were given the religious rites appropriate to their faith. However, she had a very firm Catholic faith and took a strict line on abortion, the death penalty and divorce – even if her position was unpopular. Her whole life was influenced by her faith and religion, even though at times she confessed she didn’t feel the presence of God.
The Missionaries of Charity now has branches throughout the world including branches in the developed world where they work with the homeless and people affected with AIDS. In 1965, the Society became an International Religious Family by a decree of Pope Paul VI.
In the 1960s, the life of Mother Teresa was first brought to a wider public attention by Malcolm Muggeridge who wrote a book and produced a documentary called “Something Beautiful for God”.
In 1979, she was awarded the Nobel Peace Prize “for work undertaken in the struggle to overcome poverty and distress, which also constitutes a threat to peace.” She didn’t attend the ceremonial banquet, but asked that the $192,000 fund be given to the poor.
In later years, she was more active in western developed countries. She commented that though the west was materially prosperous, there was often a spiritual poverty.
“The hunger for love is much more difficult to remove than the hunger for bread.” — Mother Teresa
When she was asked how to promote world peace, she replied.
“Go home and love your family”
Over the last two decades of her life, Mother Teresa suffered various health problems but nothing could dissuade her from fulfilling her mission of serving the poor and needy. Until her very last illness she was active in travelling around the world to the different branches of “The Missionaries of Charity” During her last few years, she metPrincess Diana in the Bronx, New York. The two died within a week of each other.
Following Mother Teresa’s death the Vatican began the process of beatification, which is the second step on the way to canonisation and sainthood. Mother Teresa was formally beatified in October 2003 by Pope John Paul II and is now known as Blessed Teresa of Calcutta.
Mother Teresa was a living saint who offered a great example and inspiration to the world.
from now on,I will be writing both fictional and non-fiction stories. So at the start of the story, if you see this symbol ([ f ]) , it mean the story is fictional. If you see no symbols , it means that the story is non-fictional. Please note this. Thanks.