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84-522: Beth Rivkah Ladies College or Beth Rivkah Lubavitch is an Orthodox Jewish , comprehensive , primary and secondary day school for girls, located on Balaclava Road, East St Kilda in Melbourne , Australia. Established in 1956 and managed by the Chabad-Lubavitch movement's Yeshivah Centre , it goes from kindergarten to Year 12 . Most of its students come from non-Chabad families. In 2017,

168-441: A Belgian physicist and Roman Catholic priest , proposed that the recession of the nebulae was due to the expansion of the universe. He inferred the relation that Hubble would later observe, given the cosmological principle. 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

252-624: A Russian cosmologist and mathematician , derived the Friedmann equations from the Einstein field equations, showing that the universe might be expanding in contrast to the static universe model advocated by Albert Einstein at that time. In 1924, American astronomer Edwin Hubble 's measurement of the great distance to the nearest spiral nebulae showed that these systems were indeed other galaxies. Starting that same year, Hubble painstakingly developed

336-484: A future horizon , which limits the events in the future that we will be able to influence. The presence of either type of horizon depends on the details of the Friedmann–Lemaître–Robertson–Walker (FLRW) metric that describes the expansion of the universe. Our understanding of the universe back to very early times suggests that there is a past horizon, though in practice our view is also limited by

420-477: A 7-week day camp on the premises each summer for preschool through seventh grade. The camp is divided into three divisions: Kiddie Camp (Pre-1A), Younger Division (Grades 1 and 2) and Older Division (Grades 3 through 7). Beth Rivkah accepts all students regardless of religious affiliation or educational background. It also accepts students who cannot afford full tuition . The school has weathered financial shortfalls due to its tuition policy. In September 2014,

504-434: A comprehensive explanation for a broad range of observed phenomena, including the abundance of light elements , the cosmic microwave background (CMB) radiation , and large-scale structure . The uniformity of the universe, known as the flatness problem , is explained through cosmic inflation : a sudden and very rapid expansion of space during the earliest moments. Extrapolating this cosmic expansion backward in time using

588-538: A more generic early hot, dense phase of the universe. In either case, "the Big Bang" as an event is also colloquially referred to as the "birth" of our universe since it represents the point in history where the universe can be verified to have entered into a regime where the laws of physics as we understand them (specifically general relativity and the Standard Model of particle physics ) work. Based on measurements of

672-500: A process in the very early universe has reached thermal equilibrium is the ratio between the rate of the process (usually rate of collisions between particles) and the Hubble parameter . The larger the ratio, the more time particles had to thermalize before they were too far away from each other. According to the Big Bang models, the universe at the beginning was very hot and very compact, and since then it has been expanding and cooling. In

756-471: A rate that accelerates proportionally with distance. Independent of Friedmann's work, and independent of Hubble's observations, physicist Georges Lemaître proposed that the universe emerged from a "primeval atom " in 1931, introducing the modern notion of the Big Bang. Various cosmological models of the Big Bang explain the evolution of the observable universe from the earliest known periods through its subsequent large-scale form. These models offer

840-467: A series of distance indicators, the forerunner of the cosmic distance ladder , using the 100-inch (2.5 m) 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 recessional velocity —now known as Hubble's law. Independently deriving Friedmann's equations in 1927, Georges Lemaître ,

924-452: A surrounding space, the Big Bang only describes the intrinsic expansion of the contents of the universe. Another issue pointed out by Santhosh Mathew is that bang implies sound, which is not an important feature of the model. An attempt to find a more suitable alternative was not successful. The Big Bang models developed from observations of the structure of the universe and from theoretical considerations. In 1912, Vesto Slipher measured

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1008-646: A teacher training seminary. Other branches are located in Montreal, Quebec , Canada; Yerres , France; Melbourne , Australia; Casablanca , Morocco; and Kfar Chabad , Israel. Many Lubavitcher girls attend the Beth Rivkah school system from first through twelfth grades. Students at the one- to two-year, post-high-school teacher training seminary have the option of earning a teaching certificate, which can be used in both Chabad and non-Chabad Jewish schools. This article also discusses other Lubavitch girls' schools, as well as

1092-430: A temperature of approximately 10 degrees Celsius. Even the very concept of a particle breaks down in these conditions. A proper understanding of this period awaits the development of a theory of quantum gravity . The Planck epoch was succeeded by the grand unification epoch beginning at 10 seconds, where gravitation separated from the other forces as the universe's temperature fell. At approximately 10 seconds into

1176-1031: A variety of sources in order to comply with the Hasidic movement's religious beliefs. In high school, where students are required by the New York Board of Regents to study from specific textbooks, teachers append their own notations to pages describing theories such as the Big Bang and evolution to inform students of what they consider the Torah point of view on these topics. Novels read in English literature classes are also vetted for compliance with Chabad philosophy and religious beliefs. Beth Rivkah teachers employ pedagogical techniques such as "group work, cooperative learning, and multiple-intelligence methods", and attend both regional and national workshops sponsored by Chabad to improve their pedagogical methods. The Crown Heights school runs

1260-526: Is a physical theory that describes how the universe expanded from an initial state of high density and temperature . The notion of an expanding universe was first scientifically originated by physicist Alexander Friedmann in 1922 with the mathematical derivation of the Friedmann equations . The earliest empirical observation of the notion of an expanding universe is known as Hubble's Law , published in work by physicist Edwin Hubble in 1929, which discerned that galaxies are moving away from Earth at

1344-492: Is accelerating , an observation attributed to an unexplained phenomenon known as dark energy . The Big Bang models offer a comprehensive explanation for a broad range of observed phenomena, including the abundances of the light elements , the CMB , large-scale structure , and Hubble's law . The models depend on two major assumptions: the universality of physical laws and the cosmological principle . The universality of physical laws

1428-422: Is assumed to be cold. (Warm dark matter is ruled out by early reionization .) This CDM 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 the "physical baryon density" Ω b h 2 {\displaystyle \Omega _{\text{b}}h^{2}}

1512-582: Is considered the age of the universe . There remain aspects of the observed universe that are not yet adequately explained by the Big Bang models. After its initial expansion, the universe cooled sufficiently to allow the formation of subatomic particles , and later atoms . The unequal abundances of matter and antimatter that allowed this to occur is an unexplained effect known as baryon asymmetry . These primordial elements—mostly hydrogen , with some helium and lithium —later coalesced through gravity , forming early stars and galaxies. Astronomers observe

1596-403: Is estimated at 0.023. (This is different from the 'baryon density' Ω b {\displaystyle \Omega _{\text{b}}} expressed as a fraction of the total matter/energy density, which is about 0.046.) The corresponding cold dark matter density Ω c h 2 {\displaystyle \Omega _{\text{c}}h^{2}} is about 0.11, and

1680-533: Is in session six days a week, excluding Shabbat (Saturday), with a half-day scheduled on Fridays to accommodate Shabbat preparations. The school day runs from 9 am to 4 pm, with a half-hour break for lunch. Judaic studies – including Bible, Midrash , Jewish law , Jewish history, Hebrew , Yiddish , and the writings of the Chabad Rebbes – are taught in the mornings. Secular subjects such as English, mathematics, geography, science, and American history are taught in

1764-425: Is interpreted as a Doppler shift, the recessional velocity 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 = H 0 D {\displaystyle v=H_{0}D} where Hubble's law implies that

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1848-536: Is modeled by a cosmological constant term in Einstein field equations of general relativity, but its composition and mechanism are unknown. More generally, the details of its equation of state and relationship with the Standard Model of particle physics continue to be investigated both through observation and theory. All of this cosmic evolution after the inflationary epoch can be rigorously described and modeled by

1932-473: Is no preferred (or special) observer or vantage point. To this end, the cosmological principle has been confirmed to a level of 10 via observations of the temperature of the CMB. At the scale of the CMB horizon, the universe has been measured to be homogeneous with an upper bound on the order of 10% inhomogeneity, as of 1995. An important feature of the Big Bang spacetime is the presence of particle horizons . Since

2016-410: Is one of the underlying principles of the theory of relativity . The cosmological principle states that on large scales the universe is homogeneous and isotropic —appearing the same in all directions regardless of location. These ideas were initially taken as postulates, but later efforts were made to test each of them. For example, the first assumption has been tested by observations showing that

2100-432: Is the proper distance, v {\displaystyle v} is the recessional velocity, and v {\displaystyle v} , H {\displaystyle H} , and D {\displaystyle D} vary as the universe expands (hence we write H 0 {\displaystyle H_{0}} to denote the present-day Hubble "constant"). For distances much smaller than

2184-496: 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. "[The] big bang picture is too firmly grounded in data from every area to be proved invalid in its general features." The earliest and most direct observational evidence of

2268-487: The Milne model , the oscillatory universe (originally suggested by Friedmann, but advocated by Albert Einstein and Richard C. 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

2352-453: The Paris neighborhood of Yerres opened in 1947. It consists of an early childhood division, elementary school, high school, and seminary for girls. There is also a cheder for boys. As of 2015, the total enrollment is 600 students. Beth Rivkah Academy of Montreal opened in 1956. In 1967 it opened a facility for 500 students, with dormitory accommodations for 180. As of 2015, enrollment in

2436-488: 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. Viable, quantitative explanations for such phenomena are still being sought. These are unsolved problems in physics. Observations of distant galaxies and quasars show that these objects are redshifted:

2520-410: The "four pillars" of the Big Bang models. 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 the Standard Model of particle physics. Of these features, dark matter is currently the subject of most active laboratory investigations. Remaining issues include the cuspy halo problem and

2604-450: The 1978 Nobel Prize in Physics . The surface of last scattering corresponding to emission of the CMB occurs shortly after recombination , the epoch when neutral hydrogen becomes stable. Prior to this, the universe comprised a hot dense photon-baryon plasma sea where photons were quickly scattered from free charged particles. Peaking at around 372 ± 14 kyr , the mean free path for

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2688-549: The Beth Rivkah school had some 300 students. The Beit Rivkah College in Kfar Chabad , Israel, opened in 1957. Originally a teacher training institute , it evolved into a two-year seminary , and then a teachers college which bestows both B.A. and M.A. degrees. As of 2010, enrollment was 1,000 students in Kfar Chabad and in branches in Jerusalem and Safed . See Midrasha § Certifications . Big Bang The Big Bang

2772-533: The Big Bang. Then, from the 1970s to the 1990s, cosmologists worked on characterizing the features of the Big Bang universe and resolving outstanding problems. In 1981, Alan Guth made a breakthrough in theoretical work on resolving certain outstanding theoretical problems in the Big Bang models with the introduction of an epoch of rapid expansion in the early universe he called "inflation". Meanwhile, during these decades, two questions in observational cosmology that generated much discussion and disagreement were over

2856-462: The Big Bang. Since the early universe did not immediately collapse into a multitude of black holes, matter at that time must have been very evenly distributed with a negligible density gradient . The earliest phases of the Big Bang are subject to much speculation, given the lack of available data. In the most common models the universe was filled homogeneously and isotropically with a very high energy density and huge temperatures and pressures , and

2940-624: The Pre-1A, elementary and high school divisions did not open on time for the fall semester due to financial difficulties; the early childhood center, which is government-funded, was not affected. Beth Rivkah has a dress code. In addition to a school uniform, jewelry and grooming guidelines are enforced in accordance with the laws of tzniut (modesty). In 2012, the Crown Heights school ordered students to delete their Facebook accounts or face expulsion. Since many girls are named Chaya Mushka after

3024-595: The Rebbetzin of the seventh Lubavitcher Rebbe, teachers call on students by their surnames . The seventh Lubavitcher Rebbe, Rabbi Menachem Mendel Schneerson, founded other branches of Beth Rivkah in Yerres , France; Montreal, Quebec , Canada; Melbourne , Australia; Casablanca , Meknes , and Sefrou , Morocco; and Kfar Chabad , Israel in the 1940s and 1950s. By 1967, there were 98 Beth Rivkah schools worldwide, with an enrollment of 40,000 students. The Beth Rivkah school in

3108-464: The absence of a perfect cosmological principle , 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 irregular behavior, known as the gravitational singularity , indicates that general relativity is not an adequate description of the laws of physics in this regime. Models based on general relativity alone cannot fully extrapolate toward

3192-791: The afternoons. While in previous decades the language of instruction was Yiddish, the school now teaches religious subjects in Hebrew and secular subjects in English. Yiddish is taught as a second language. An optional Yiddish track is offered in first grade. As a private school certified by the State of New York, Beth Rivkah is required to teach science (biology and chemistry), history (U.S. and world history), English literature, and mathematics (algebra, geometry, and trigonometry), among other subjects. For fifth-grade science and sixth-grade world history, however, Chabad educators eschew state-mandated booklets and textbooks and instead use material that they collect from

3276-497: The age measured today). This issue was later resolved when new computer simulations, which included the effects of mass loss due to stellar winds , indicated a much younger age for globular clusters. Significant progress in Big Bang cosmology has 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 the Cosmic Background Explorer (COBE),

3360-411: The big-bang predictions by Alpher, Herman and Gamow around 1950. Through the 1970s, the radiation was found to be approximately consistent with a blackbody spectrum in all directions; this spectrum has been redshifted by the expansion of the universe, and today corresponds to approximately 2.725 K. This tipped the balance of evidence in favor of the Big Bang model, and Penzias and Wilson were awarded

3444-432: The corresponding neutrino density Ω v h 2 {\displaystyle \Omega _{\text{v}}h^{2}} 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 appears to homogeneously permeate all of space. Observations suggest that 73% of

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3528-452: The determination of the Hubble constant is known as Hubble tension . Techniques based on observation of the CMB suggest a lower value of this constant compared to the quantity derived from measurements based on the cosmic distance ladder. In 1964, Arno Penzias and Robert Wilson serendipitously discovered the cosmic background radiation, an omnidirectional signal in the microwave band. Their discovery provided substantial confirmation of

3612-445: The early childhood division, elementary school, and high school is 600 students aged 18 months to 18 years. Approximately 10 percent of students are immigrants, and there is a significant percentage of special-needs students in the elementary and high school divisions. In addition to providing religious and secular studies, the academy is an accredited French-language school. The Beth Rivkah Ladies College in Melbourne , Australia

3696-591: The expansion using Type Ia supernovae and measurements of temperature fluctuations in the cosmic microwave background, the time that has passed since that event—known as the " age of the universe "—is 13.8 billion years. Despite being extremely dense at this time—far denser than is usually required to form a black hole —the universe did not re-collapse into a singularity. Commonly used calculations and limits for explaining gravitational collapse are usually based upon objects of relatively constant size, such as stars, and do not apply to rapidly expanding space such as

3780-400: The expansion, a phase transition caused a cosmic inflation , during which the universe grew exponentially , unconstrained by the light speed invariance , and temperatures dropped by a factor of 100,000. This concept is motivated by the flatness problem , where the density of matter and energy is very close to the critical density needed to produce a flat universe . That is, the shape of

3864-685: The family are enrolled in the schools. Beth Rivkah schools were established in Casablanca , Meknes , and Sefrou , Morocco, in the mid-1950s. According to a 1956 survey, these schools had a combined enrollment of 374 students that year. With the migration of Moroccan Jews to Israel and France in the 1950s, the Lubavitch yeshiva for boys, Oholei Yosef Yitzchok, and the Beth Rivkah school for girls were centered in Casablanca and dormitory facilities were opened to accommodate students from other locales. By 1980,

3948-415: 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 ,

4032-404: The gravitational effects of an unknown dark matter surrounding galaxies. Most of the gravitational potential in the universe seems to be in this form, and the Big Bang models and various observations indicate that this excess gravitational potential is not created by baryonic matter , such as normal atoms. Measurements of the redshifts of supernovae indicate that the expansion of the universe

4116-440: The known laws of physics , the models describe an increasingly concentrated cosmos preceded by a singularity in which space and time lose meaning (typically named "the Big Bang singularity"). Physics lacks a widely accepted theory of quantum gravity that can model the earliest conditions of the Big Bang. In 1964 the CMB was discovered, which convinced many cosmologists that the competing steady-state model of cosmic evolution

4200-411: The lambda-CDM model of cosmology, which uses the independent frameworks of quantum mechanics and general relativity. There are no easily testable models that would describe the situation prior to approximately 10 seconds. Understanding this earliest of eras in the history of the universe is one of the greatest unsolved problems in physics . English astronomer Fred Hoyle is credited with coining

4284-487: The largest possible deviation of the fine-structure constant over much of the age of the universe is of order 10 . Also, general relativity has passed stringent tests on the scale of the Solar System and binary stars . The large-scale universe appears isotropic as viewed from Earth. If it is indeed isotropic, the cosmological principle can be derived from the simpler Copernican principle , which states that there

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4368-479: The late 1950s to the 1970s due to the high birthrate among Lubavitcher families, and the influx of Soviet and Iranian Jewish refugees to New York City. By the early 1980s, enrollment exceeded 600 students. In 1988 the seventh Lubavitcher Rebbe presided at a groundbreaking ceremony for Campus Chomesh, which he established as a memorial to his Rebbetzin, Chaya Mushka Schneerson , who had died that year. The four-story, 125,000 square feet (11,600 m ) campus occupies

4452-405: 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 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

4536-453: 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

4620-460: The observational evidence, most notably from radio source counts , began to favor Big Bang over steady state. The discovery and confirmation of the CMB in 1964 secured the Big Bang as the best theory of the origin and evolution of the universe. In 1968 and 1970, Roger Penrose , Stephen Hawking , and George F. R. Ellis published papers where they showed that mathematical singularities were an inevitable initial condition of relativistic models of

4704-482: The opacity of the universe at early times. So our view cannot extend further backward in time, though the horizon recedes in space. If the expansion of the universe continues to accelerate, there is a future horizon as well. Some processes in the early universe occurred too slowly, compared to the expansion rate of the universe, to reach approximate thermodynamic equilibrium . Others were fast enough to reach thermalization . The parameter usually used to find out whether

4788-404: The original matter particles 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

4872-515: 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 (CDM), warm dark matter , hot dark matter , and baryonic matter . The best measurements available, from the Wilkinson Microwave Anisotropy Probe (WMAP), show that the data is well-fit by a Lambda-CDM model in which dark matter

4956-469: The other forces, with only the electromagnetic force and weak nuclear force remaining unified. Inflation stopped locally at around 10 to 10 seconds, with the observable universe's volume having increased by a factor of at least 10 . Reheating followed as the inflaton field decayed, until the universe obtained the temperatures required for the production of a quark–gluon plasma as well as all other elementary particles . Temperatures were so high that

5040-427: 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. 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

5124-512: The photon radiation . The recombination epoch began after about 379,000 years, when the electrons and nuclei combined into atoms (mostly hydrogen ), which were able to emit radiation. This relic radiation, which continued through space largely unimpeded, is known as the cosmic microwave background. After the recombination epoch, the slightly denser regions of the uniformly distributed matter gravitationally attracted nearby matter and thus grew even denser, forming gas clouds, stars, galaxies, and

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5208-506: The picture becomes less speculative, since particle energies drop to values that can be attained in particle accelerators . At about 10 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 no longer high enough to create either new proton–antiproton or neutron–antineutron pairs. A mass annihilation immediately followed, leaving just one in 10 of

5292-623: The post secondary institutions available. The sixth Lubavitcher Rebbe named Beth Rivkah after his grandmother, Rebbetzin Rivkah Schneersohn, wife of the fourth Lubavitcher Rebbe, Rabbi Shmuel Schneersohn . Beth Rivkah of Crown Heights is spread over two campuses. The early childhood center (including a Head Start Program ) and elementary school are located at Campus Chomesh at 470 Lefferts Avenue. The high school, teacher training seminary, and administrative offices are located at 310 Crown Street. The Beth Rivkah elementary school for girls

5376-481: The precise values of the Hubble Constant and the matter-density of the universe (before the discovery of dark energy, thought to be the key predictor for the eventual fate of the universe ). In the mid-1990s, observations of certain globular clusters appeared to indicate that they were about 15 billion years old, which conflicted with most then-current estimates of the age of the universe (and indeed with

5460-461: 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, with the electromagnetic force and weak nuclear force separating at about 10 seconds. After about 10 seconds,

5544-427: 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 of baryon 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

5628-657: The school had the distinction of having the Chief Rabbi of Israel come and address students. Rabbi David Lau was visiting Melbourne on his Australia tour. Shimon Waronker became the principal in 2020. Beth Rivkah It was established in 1941 by Rabbi Yosef Yitzchak Schneersohn , the sixth Lubavitcher Rebbe , and developed by his son-in-law, Rabbi Menachem Mendel Schneerson , the seventh Lubavitcher Rebbe. The flagship school in Crown Heights, Brooklyn , includes an early childhood division, elementary school, high school, and

5712-410: The singularity. In some proposals, such as the emergent Universe models, the singularity is replaced by another cosmological epoch. A different approach identifies the initial singularity as a singularity predicted by some models of the Big Bang theory to have existed before the Big Bang event. This primordial singularity is itself sometimes called "the Big Bang", but the term can also refer to

5796-415: The site of the former Lefferts General Hospital and two adjacent structures, covering nearly one city block. The campus accommodates over 2,000 students with close to 100 classrooms, as well as science labs, computer centers, libraries, a sports gymnasium, and a rooftop playground. Philanthropist Ronald Perelman provided nearly half of the $ 15 million funding for the campus, which opened in 1995. School

5880-490: The size of the observable universe , the Hubble redshift can be thought of as the Doppler shift corresponding to the recession velocity v {\displaystyle v} . For distances comparable to the size of the observable universe, the attribution of the cosmological redshift becomes more ambiguous, although its interpretation as a kinematic Doppler shift remains the most natural one. An unexplained discrepancy with

5964-406: The steady-state theory. This perception was enhanced by the fact that the originator of the Big Bang concept, 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, disagreed: If the world has begun with a single quantum ,

6048-447: The temperature was about a billion kelvin and the density of matter in the universe was comparable to the current density of Earth's atmosphere, neutrons combined with protons to form the universe's deuterium and helium nuclei in a process called Big Bang nucleosynthesis (BBN). Most protons remained uncombined as hydrogen nuclei. As the universe cooled, the rest energy density of matter came to gravitationally dominate that of

6132-465: The term "Big Bang" during a talk for a March 1949 BBC Radio broadcast, saying: "These theories were based on the hypothesis that all the matter in the universe was created in one big bang at a particular time in the remote past." However, it did not catch on until the 1970s. It is popularly reported that Hoyle, who favored an alternative " steady-state " cosmological model, intended this to be pejorative, but Hoyle explicitly denied this and said it

6216-452: The total energy density of the present day universe is in this form. When the universe was very young it was likely infused with dark energy, but with everything closer together, gravity predominated, braking the expansion. Eventually, after billions of years of expansion, the declining density of matter relative to the density of dark energy allowed the expansion of the universe to begin to accelerate. Dark energy in its simplest formulation

6300-416: The universe has no overall geometric curvature due to gravitational influence. Microscopic quantum fluctuations that occurred because of Heisenberg's uncertainty principle were "frozen in" by inflation, becoming amplified into the seeds that would later form the large-scale structure of the universe. At a time around 10 seconds, the electroweak epoch begins when the strong nuclear force separates from

6384-422: The universe has a finite age, and light travels at a finite speed, there may be events in the past whose light has not yet had time to reach earth. This places a limit or a past horizon on the most distant objects that can be observed. Conversely, because space is expanding, and more distant objects are receding ever more quickly, light emitted by us today may never "catch up" to very distant objects. This defines

6468-490: The universe is uniformly expanding everywhere. This cosmic expansion was predicted from general relativity by Friedmann in 1922 and Lemaître in 1927, well before Hubble made his 1929 analysis and observations, and it remains the cornerstone of the Big Bang model as developed by Friedmann, Lemaître, Robertson, and Walker. The theory requires the relation v = H D {\displaystyle v=HD} to hold at all times, where D {\displaystyle D}

6552-449: The validity of the theory are the expansion of the universe according to Hubble's law (as indicated by the redshifts of galaxies), discovery and measurement of the cosmic microwave background and the relative abundances of light elements produced by Big Bang nucleosynthesis (BBN). More recent evidence includes observations of galaxy formation and evolution , and the distribution of large-scale cosmic structures . These are sometimes called

6636-422: Was falsified , since the Big Bang models predict a uniform background radiation caused by high temperatures and densities in the distant past. A wide range of empirical evidence strongly favors the Big Bang event, which is now essentially universally accepted. Detailed measurements of the expansion rate of the universe place the Big Bang singularity at an estimated 13.787 ± 0.020   billion years ago, which

6720-473: Was Lemaître's Big Bang theory, advocated and developed by George Gamow , who introduced BBN and whose associates, Ralph Alpher and Robert Herman , predicted the 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. For a while, support was split between these two theories. Eventually,

6804-465: Was established by Rabbi Yosef Yitzchok Schneersohn in Brooklyn , New York, in 1941, two years after he founded the first boys' yeshiva in that city. The initial enrollment of about 30 students met in a rented storefront. The high school was established in 1955, and the teacher training seminary opened in Crown Heights in 1960. The elementary and high school divisions experienced significant growth from

6888-755: Was established in 1956. Part of the Yeshivah Centre educational network, which includes the Yeshivah College for boys founded in 1954, the Beth Rivkah Ladies College consists of a preschool, elementary school, and high school for girls. A sister school, Ohel Chana , is a teacher training seminary. Both Beth Rivkah and Yeshivah College enroll students from non-Chabad families. In 2014 the educational network made headlines by capping tuition fees at 8% of family income for low wage-earners and 18% for high wage-earners, notwithstanding how many children in

6972-411: Was just a striking image meant to highlight the difference between the two models. Helge Kragh writes that the evidence for the claim that it was meant as a pejorative is "unconvincing", and mentions a number of indications that it was not a pejorative. The term itself has been argued to be a misnomer because it evokes an explosion. The argument is that whereas an explosion suggests expansion into

7056-474: Was very rapidly expanding and cooling. The period up to 10 seconds into the expansion, the Planck epoch , was a phase in which the four fundamental forces —the electromagnetic force , the strong nuclear force , the weak nuclear force , and the gravitational force , were unified as one. In this stage, the characteristic scale length of the universe was the Planck length , 1.6 × 10  m , and consequently had

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