title: Nightmare Alley (1947 film)

text: On December 12, 2017, Fox Searchlight Pictures announced that Guillermo del Toro would be directing a new adaptation of the novel, co-writing the screenplay with Kim Morgan. In April 2019, Leonardo DiCaprio was negotiating to star in del Toro's film. In August 2019, it was reported that Cate Blanchett was negotiating to co-star with Bradley Cooper in the film. On September 4, 2019, Rooney Mara was cast in the film. Filming commenced in January 2020 and production wrapped in December 2020. The film was released on December 17, 2021.


title: Hubble's law

text: Hubble's law, also known as the Hubble–Lemaître law, is the observation in physical cosmology that galaxies are moving away from Earth at speeds proportional to their distance. In other words, the farther they are, the faster they are moving away from Earth. The velocity of the galaxies has been determined by their redshift, a shift of the light they emit toward the red end of the visible spectrum.


title: Hubble's law

text: Hubble's law is considered the first observational basis for the expansion of the universe, and today it serves as one of the pieces of evidence most often cited in support of the Big Bang model.


title: Hubble's law

text: The motion of astronomical objects due solely to this expansion is known as the Hubble flow. It is described by the equation , with "H" the constant of proportionality—the Hubble constant—between the "proper distance" "D" to a galaxy, which can change over time, unlike the comoving distance, and its speed of separation "v", i.e. the derivative of proper distance with respect to the cosmological time coordinate. (See "" for some discussion of the subtleties of this definition of "velocity".)


title: Hubble's law

text: The Hubble constant is most frequently quoted in (km/s)/Mpc, thus giving the speed in km/s of a galaxy away, and its value is about . However, the SI unit of "H" is simply s, and the SI unit for the reciprocal of "H" is simply the second. The reciprocal of "H" is known as the Hubble time. The Hubble constant can also be interpreted as the relative rate of expansion. In this form "H" = 7%/Gyr, meaning that at the current rate of expansion it takes a billion years for an unbound structure to grow by 7%.


title: Hubble's law

text: Although widely attributed to Edwin Hubble, the notion of the universe expanding at a calculable rate was first derived from general relativity equations in 1922 by Alexander Friedmann. Friedmann published a set of equations, now known as the Friedmann equations, showing that the universe might be expanding, and presenting the expansion speed if that were the case. Then Georges Lemaître, in a 1927 article, independently derived that the universe might be expanding, observed the proportionality between recessional velocity of, and distance to, distant bodies, and suggested an estimated value for the proportionality constant; this constant, when Edwin Hubble confirmed the existence of cosmic expansion and determined a more accurate value for it two years later, came to be known by his name as the Hubble constant. Hubble inferred the recession velocity of the objects from their redshifts, many of which were earlier measured and related to velocity by Vesto Slipher in 1917. Though the Hubble constant "H" is roughly constant in the velocity-distance space at any given moment in time, the Hubble parameter "H", of which the Hubble constant is the current value, varies with time, so the term "constant" is sometimes thought of as somewhat of a misnomer.


title: Hubble's law

text: A decade before Hubble made his observations, a number of physicists and mathematicians had established a consistent theory of an expanding universe by using Einstein's field equations of general relativity. Applying the most general principles to the nature of the universe yielded a dynamic solution that conflicted with the then-prevalent notion of a static universe.


title: Hubble's law

text: In 1912, Vesto M. Slipher measured the first Doppler shift of a "spiral nebula" (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.


title: Hubble's law

text: In 1922, Alexander Friedmann derived his Friedmann equations from Einstein's field equations, showing that the universe might expand at a rate calculable by the equations. The parameter used by Friedmann is known today as the scale factor and can be considered as a scale invariant form of the proportionality constant of Hubble's law. Georges Lemaître independently found a similar solution in his 1927 paper discussed in the following section. The Friedmann equations are derived by inserting the metric for a homogeneous and isotropic universe into Einstein's field equations for a fluid with a given density and pressure. This idea of an expanding spacetime would eventually lead to the Big Bang and Steady State theories of cosmology.


title: Hubble's law

text: In 1927, two years before Hubble published his own article, the Belgian priest and astronomer Georges Lemaître was the first to publish research deriving what is now known as Hubble's law. According to the Canadian astronomer Sidney van den Bergh, "the 1927 discovery of the expansion of the universe by Lemaître was published in French in a low-impact journal. In the 1931 high-impact English translation of this article, a critical equation was changed by omitting reference to what is now known as the Hubble constant." It is now known that the alterations in the translated paper were carried out by Lemaître himself.


title: Hubble's law

text: Before the advent of modern cosmology, there was considerable talk about the size and shape of the universe. In 1920, the Shapley–Curtis debate took place between Harlow Shapley and Heber D. Curtis over this issue. Shapley argued for a small universe the size of the Milky Way galaxy, and Curtis argued that the universe was much larger. The issue was resolved in the coming decade with Hubble's improved observations.


title: Hubble's law

text: Edwin Hubble did most of his professional astronomical observing work at Mount Wilson Observatory, home to the world's most powerful telescope at the time. His observations of Cepheid variable stars in "spiral nebulae" enabled him to calculate the distances to these objects. Surprisingly, these objects were discovered to be at distances which placed them well outside the Milky Way. They continued to be called "nebulae", and it was only gradually that the term "galaxies" replaced it.


title: Hubble's law

text: The parameters that appear in Hubble's law, velocities and distances, are not directly measured. In reality we determine, say, a supernova brightness, which provides information about its distance, and the redshift "z" = ∆"λ"/"λ" of its spectrum of radiation. Hubble correlated brightness and parameter "z".


title: Hubble's law

text: Combining his measurements of galaxy distances with Vesto Slipher and Milton Humason's measurements of the redshifts associated with the galaxies, Hubble discovered a rough proportionality between redshift of an object and its distance. Though there was considerable scatter (now known to be caused by peculiar velocities—the 'Hubble flow' is used to refer to the region of space far enough out that the recession velocity is larger than local peculiar velocities), Hubble was able to plot a trend line from the 46 galaxies he studied and obtain a value for the Hubble constant of 500 (km/s)/Mpc (much higher than the currently accepted value due to errors in his distance calibrations; see cosmic distance ladder for details).


title: Hubble's law

text: At the time of discovery and development of Hubble's law, it was acceptable to explain redshift phenomenon as a Doppler shift in the context of special relativity, and use the Doppler formula to associate redshift "z" with velocity. Today, in the context of general relativity, velocity between distant objects depends on the choice of coordinates used, and therefore, the redshift can be equally described as a Doppler shift or a cosmological shift (or gravitational) due to the expanding space, or some combination of the two.


title: Hubble's law

text: Hubble's law can be easily depicted in a "Hubble diagram" in which the velocity (assumed approximately proportional to the redshift) of an object is plotted with respect to its distance from the observer. A straight line of positive slope on this diagram is the visual depiction of Hubble's law.


title: Hubble's law

text: After Hubble's discovery was published, Albert Einstein abandoned his work on the cosmological constant, which he had designed to modify his equations of general relativity to allow them to produce a static solution, which he thought was the correct state of the universe. The Einstein equations in their simplest form model generated either an expanding or contracting universe, so Einstein's cosmological constant was artificially created to counter the expansion or contraction to get a perfect static and flat universe. After Hubble's discovery that the universe was, in fact, expanding, Einstein called his faulty assumption that the universe is static his "biggest mistake". On its own, general relativity could predict the expansion of the universe, which (through observations such as the bending of light by large masses, or the precession of the orbit of Mercury) could be experimentally observed and compared to his theoretical calculations using particular solutions of the equations he had originally formulated.


title: Hubble's law

text: In 1931, Einstein made a trip to Mount Wilson Observatory to thank Hubble for providing the observational basis for modern cosmology.


title: Hubble's law

text: The cosmological constant has regained attention in recent decades as a hypothetical explanation for dark energy.


title: Hubble's law

text: The discovery of the linear relationship between redshift and distance, coupled with a supposed linear relation between recessional velocity and redshift, yields a straightforward mathematical expression for Hubble's law as follows:


title: Hubble's law

text: Hubble's law is considered a fundamental relation between recessional velocity and distance. However, the relation between recessional velocity and redshift depends on the cosmological model adopted and is not established except for small redshifts.


title: Hubble's law

text: For distances "D" larger than the radius of the Hubble sphere "r" , objects recede at a rate faster than the speed of light ("See" Uses of the proper distance for a discussion of the significance of this):


title: Hubble's law

text: Since the Hubble "constant" is a constant only in space, not in time, the radius of the Hubble sphere may increase or decrease over various time intervals. The subscript '0' indicates the value of the Hubble constant today. Current evidence suggests that the expansion of the universe is accelerating ("see" Accelerating universe), meaning that for any given galaxy, the recession velocity dD/dt is increasing over time as the galaxy moves to greater and greater distances; however, the Hubble parameter is actually thought to be decreasing with time, meaning that if we were to look at some "fixed" distance D and watch a series of different galaxies pass that distance, later galaxies would pass that distance at a smaller velocity than earlier ones.


title: Hubble's law

text: Redshift can be measured by determining the wavelength of a known transition, such as hydrogen α-lines for distant quasars, and finding the fractional shift compared to a stationary reference. Thus, redshift is a quantity unambiguous for experimental observation. The relation of redshift to recessional velocity is another matter. For an extensive discussion, see Harrison.


title: Hubble's law

text: The redshift "z" is often described as a "redshift velocity", which is the recessional velocity that would produce the same redshift "if" it were caused by a linear Doppler effect (which, however, is not the case, as the shift is caused in part by a cosmological expansion of space, and because the velocities involved are too large to use a non-relativistic formula for Doppler shift). This redshift velocity can easily exceed the speed of light. In other words, to determine the redshift velocity "v", the relation:


title: Hubble's law

text: is used. That is, there is "no fundamental difference" between redshift velocity and redshift: they are rigidly proportional, and not related by any theoretical reasoning. The motivation behind the "redshift velocity" terminology is that the redshift velocity agrees with the velocity from a low-velocity simplification of the so-called Fizeau–Doppler formula.


title: Hubble's law

text: Here, "λ", "λ" are the observed and emitted wavelengths respectively. The "redshift velocity" "v" is not so simply related to real velocity at larger velocities, however, and this terminology leads to confusion if interpreted as a real velocity. Next, the connection between redshift or redshift velocity and recessional velocity is discussed. This discussion is based on Sartori.


title: Hubble's law

text: Suppose "R(t)" is called the "scale factor" of the universe, and increases as the universe expands in a manner that depends upon the cosmological model selected. Its meaning is that all measured proper distances "D(t)" between co-moving points increase proportionally to "R". (The co-moving points are not moving relative to each other except as a result of the expansion of space.) In other words:


title: Hubble's law

text: where "t" is some reference time. If light is emitted from a galaxy at time "t" and received by us at "t", it is redshifted due to the expansion of space, and this redshift "z" is simply:


title: Hubble's law

text: Suppose a galaxy is at distance "D", and this distance changes with time at a rate "dD". We call this rate of recession the "recession velocity" "v":


title: Hubble's law

text: From this perspective, Hubble's law is a fundamental relation between (i) the recessional velocity contributed by the expansion of space and (ii) the distance to an object; the connection between redshift and distance is a crutch used to connect Hubble's law with observations. This law can be related to redshift "z" approximately by making a Taylor series expansion:


title: Hubble's law

text: If the distance is not too large, all other complications of the model become small corrections, and the time interval is simply the distance divided by the speed of light:


title: Hubble's law

text: According to this approach, the relation is an approximation valid at low redshifts, to be replaced by a relation at large redshifts that is model-dependent. See velocity-redshift figure.


title: Hubble's law

text: Strictly speaking, neither "v" nor "D" in the formula are directly observable, because they are properties "now" of a galaxy, whereas our observations refer to the galaxy in the past, at the time that the light we currently see left it.


title: Hubble's law

text: For relatively nearby galaxies (redshift "z" much less than unity), "v" and "D" will not have changed much, and "v" can be estimated using the formula formula_16 where "c" is the speed of light. This gives the empirical relation found by Hubble.


title: Hubble's law

text: For distant galaxies, "v" (or "D") cannot be calculated from "z" without specifying a detailed model for how "H" changes with time. The redshift is not even directly related to the recession velocity at the time the light set out, but it does have a simple interpretation: is the factor by which the universe has expanded while the photon was travelling towards the observer.


title: Hubble's law

text: In using Hubble's law to determine distances, only the velocity due to the expansion of the universe can be used. Since gravitationally interacting galaxies move relative to each other independent of the expansion of the universe, these relative velocities, called peculiar velocities, need to be accounted for in the application of Hubble's law.


title: Hubble's law

text: The Finger of God effect is one result of this phenomenon. In systems that are gravitationally bound, such as galaxies or our planetary system, the expansion of space is a much weaker effect than the attractive force of gravity.


title: Hubble's law

text: The parameter formula_3 is commonly called the ""Hubble constant"", but that is a misnomer since it is constant in space only at a fixed time; it varies with time in nearly all cosmological models, and all observations of far distant objects are also observations into the distant past, when the “constant” had a different value. The ""Hubble parameter"" is a more correct term, with formula_18 denoting the present-day value.


title: Hubble's law

text: Another common source of confusion is that the accelerating universe does "not" imply that the Hubble parameter is actually increasing with time; since formula_19, in most accelerating models formula_20 increases relatively faster than formula_21, so H decreases with time. (The recession velocity of one chosen galaxy does increase, but different galaxies passing a sphere of fixed radius cross the sphere more slowly at later times.)


title: Hubble's law

text: From this it is seen that the Hubble parameter is decreasing with time, unless formula_24; the latter can only occur if the universe contains phantom energy, regarded as theoretically somewhat improbable.


title: Hubble's law

text: However, in the standard Lambda cold dark matter model (Lambda-CDM or ΛCDM model), formula_25 will tend to −1 from above in the distant future as the cosmological constant becomes increasingly dominant over matter; this implies that formula_26 will approach from above to a constant value of ≈ 57 (km/s)/Mpc, and the scale factor of the universe will then grow exponentially in time.


title: Hubble's law

text: The mathematical derivation of an idealized Hubble's law for a uniformly expanding universe is a fairly elementary theorem of geometry in 3-dimensional Cartesian/Newtonian coordinate space, which, considered as a metric space, is entirely homogeneous and isotropic (properties do not vary with location or direction). Simply stated the theorem is this:


title: Hubble's law

text: In fact, this applies to non-Cartesian spaces as long as they are locally homogeneous and isotropic, specifically to the negatively and positively curved spaces frequently considered as cosmological models (see shape of the universe).


title: Hubble's law

text: An observation stemming from this theorem is that seeing objects recede from us on Earth is not an indication that Earth is near to a center from which the expansion is occurring, but rather that "every" observer in an expanding universe will see objects receding from them.


title: Hubble's law

text: The value of the Hubble parameter changes over time, either increasing or decreasing depending on the value of the so-called deceleration parameter formula_27, which is defined by


title: Hubble's law

text: In a universe with a deceleration parameter equal to zero, it follows that "H" = 1/"t", where "t" is the time since the Big Bang. A non-zero, time-dependent value of formula_27 simply requires integration of the Friedmann equations backwards from the present time to the time when the comoving horizon size was zero.


title: Hubble's law

text: It was long thought that "q" was positive, indicating that the expansion is slowing down due to gravitational attraction. This would imply an age of the universe less than 1/"H" (which is about 14 billion years). For instance, a value for "q" of 1/2 (once favoured by most theorists) would give the age of the universe as 2/(3"H"). The discovery in 1998 that "q" is apparently negative means that the universe could actually be older than 1/"H". However, estimates of the age of the universe are very close to 1/"H".


title: Hubble's law

text: The expansion of space summarized by the Big Bang interpretation of Hubble's law is relevant to the old conundrum known as Olbers' paradox: If the universe were infinite in size, static, and filled with a uniform distribution of stars, then every line of sight in the sky would end on a star, and the sky would be as bright as the surface of a star. However, the night sky is largely dark.


title: Hubble's law

text: Since the 17th century, astronomers and other thinkers have proposed many possible ways to resolve this paradox, but the currently accepted resolution depends in part on the Big Bang theory, and in part on the Hubble expansion: In a universe that exists for a finite amount of time, only the light of a finite number of stars has had enough time to reach us, and the paradox is resolved. Additionally, in an expanding universe, distant objects recede from us, which causes the light emanated from them to be redshifted and diminished in brightness by the time we see it.


title: Hubble's law

text: Instead of working with Hubble's constant, a common practice is to introduce the dimensionless Hubble constant, usually denoted by "h" and commonly referred to as "little h", then to write Hubble's constant "H" as "h" × 100 km⋅s⋅Mpc, all the relative uncertainty of the true value of "H" being then relegated to "h". The dimensionless Hubble constant is often used when giving distances that are calculated from redshift "z" using the formula . Since "H" is not precisely known, the distance is expressed as:


title: Hubble's law

text: Occasionally a reference value other than 100 may be chosen, in which case a subscript is presented after "h" to avoid confusion; e.g. h denotes formula_33, which implies formula_34.


title: Hubble's law

text: This should not be confused with the dimensionless value of Hubble's constant, usually expressed in terms of Planck units, obtained by multiplying "H" by 1.75 × 10 (from definitions of parsec and "t"), for example for "H" = 70, a Planck unit version of 1.2 × 10 is obtained.


title: Hubble's law

text: A value for formula_27 measured from standard candle observations of Type Ia supernovae, which was determined in 1998 to be negative, surprised many astronomers with the implication that the expansion of the universe is currently "accelerating" (although the Hubble factor is still decreasing with time, as mentioned above in the Interpretation section; see the articles on dark energy and the ΛCDM model).


title: Hubble's law

text: where formula_3 is the Hubble parameter, formula_20 is the scale factor, "G" is the gravitational constant, formula_39 is the normalised spatial curvature of the universe and equal to −1, 0, or 1, and formula_40 is the cosmological constant.


title: Hubble's law

text: If the universe is matter-dominated, then the mass density of the universe formula_41 can just be taken to include matter so


title: Hubble's law

text: where formula_43 is the density of matter today. From the Friedmann equation and thermodynamic principles we know for non-relativistic particles that their mass density decreases proportional to the inverse volume of the universe, so the equation above must be true. We can also define (see density parameter for formula_44)


title: Hubble's law

text: where the subscript nought refers to the values today, and formula_50. Substituting all of this into the Friedmann equation at the start of this section and replacing formula_20 with formula_52 gives


title: Hubble's law

text: If the universe is both matter-dominated and dark energy-dominated, then the above equation for the Hubble parameter will also be a function of the equation of state of dark energy. So now:


title: Hubble's law

text: where formula_55 is the mass density of the dark energy. By definition, an equation of state in cosmology is formula_56, and if this is substituted into the fluid equation, which describes how the mass density of the universe evolves with time, then


title: Hubble's law

text: Therefore, for dark energy with a constant equation of state "w", formula_61. If this is substituted into the Friedman equation in a similar way as before, but this time set formula_62, which assumes a spatially flat universe, then (see shape of the universe)


title: Hubble's law

text: If the dark energy derives from a cosmological constant such as that introduced by Einstein, it can be shown that formula_64. The equation then reduces to the last equation in the matter-dominated universe section, with formula_65 set to zero. In that case the initial dark energy density formula_66 is given by


title: Hubble's law

text: The Hubble constant formula_73 has units of inverse time; the Hubble time "t" is simply defined as the inverse of the Hubble constant, i.e.


title: Hubble's law

text: This is slightly different from the age of the universe which is approximately 13.8 billion years. The Hubble time is the age it would have had if the expansion had been linear, and it is different from the real age of the universe because the expansion is not linear; they are related by a dimensionless factor which depends on the mass-energy content of the universe, which is around 0.96 in the standard ΛCDM model.


title: Hubble's law

text: We currently appear to be approaching a period where the expansion of the universe is exponential due to the increasing dominance of vacuum energy. In this regime, the Hubble parameter is constant, and the universe grows by a factor "e" each Hubble time:


title: Hubble's law

text: Likewise, the generally accepted value of 2.27 Es means that (at the current rate) the universe would grow by a factor of formula_76 in one exasecond.


title: Hubble's law

text: Over long periods of time, the dynamics are complicated by general relativity, dark energy, inflation, etc., as explained above.


title: Hubble's law

text: The Hubble length or Hubble distance is a unit of distance in cosmology, defined as formula_77 — the speed of light multiplied by the Hubble time. It is equivalent to 4,420 million parsecs or 14.4 billion light years. (The numerical value of the Hubble length in light years is, by definition, equal to that of the Hubble time in years.) The Hubble distance would be the distance between the Earth and the galaxies which are "currently" receding from us at the speed of light, as can be seen by substituting formula_78 into the equation for Hubble's law, .


title: Hubble's law

text: The Hubble volume is sometimes defined as a volume of the universe with a comoving size of formula_79 The exact definition varies: it is sometimes defined as the volume of a sphere with radius formula_80 or alternatively, a cube of side formula_79 Some cosmologists even use the term Hubble volume to refer to the volume of the observable universe, although this has a radius approximately three times larger.


title: Hubble's law

text: The value of the Hubble constant is estimated by measuring the redshift of distant galaxies and then determining the distances to them by some other method than Hubble's law. This approach forms part of the cosmic distance ladder for measuring distances to extragalactic objects. Uncertainties in the physical assumptions used to determine these distances have caused varying estimates of the Hubble constant.


title: Hubble's law

text: Multiple methods have been used to determine the Hubble constant. "Late universe" measurements using calibrated distance ladder techniques have converged on a value of approximately . Since 2000, "early universe" techniques based on measurements of the cosmic microwave background have become available, and these agree on a value near . (This is accounting for the change in the expansion rate since the early universe, so is comparable to the first number.) As techniques have improved, the estimated measurement uncertainties have shrunk, but the range of measured values has not, to the point that the disagreement is now highly statistically significant. This discrepancy is called the Hubble tension.


title: Hubble's law

text: In December 2021, "National Geographic" reported that the cause of the Hubble tension discrepancy is not known. However, if the cosmological principle fails (see "Violations of the cosmological principle" in the "Lambda-CDM model" article), then the existing interpretations of the Hubble constant and the Hubble tension have to be revised, which might resolve the Hubble tension.


title: Hubble's law

text: One possibility is that the Hubble tension is caused by the KBC Void, as measuring galactic supernovae inside a void is predicted by some authors to yield a larger local value for the Hubble constant than cosmological measures of the Hubble constant. However, other work has found no evidence for this in observations, finding the scale of the claimed underdensity to be incompatible with observations which extend beyond its radius. Important deficiencies were subsequently pointed out in this analysis, leaving open the possibility that the Hubble tension is indeed caused by outflow from the KBC Void.


title: Hubble's law

text: Another possibility is that the Hubble tension calls for new physics beyond the ΛCDM model. Moritz Haslbauer and collaborators have proposed modified Newtonian dynamics as a possible solution to the Hubble tension, while Marc Kamionkowski and collaborators have proposed an early dark energy model as a possible solution to the Hubble tension.


title: Hubble's law

text: Others have suggested that at least a portion of the tension could be a result of underestimation of uncertainties in data.


title: Hubble's law

text: The observations of astronomer Walter Baade led him to define distinct "populations" for stars (Population I and Population II). The same observations led him to discover that there are two types of Cepheid variable stars. Using this discovery he recalculated the size of the known universe, doubling the previous calculation made by Hubble in 1929. He announced this finding to considerable astonishment at the 1952 meeting of the International Astronomical Union in Rome.


title: Hubble's law

text: For most of the second half of the 20th century, the value of formula_73 was estimated to be between 50 and .


title: Hubble's law

text: The value of the Hubble constant was the topic of a long and rather bitter controversy between Gérard de Vaucouleurs, who claimed the value was around 100, and Allan Sandage, who claimed the value was near 50. In one demonstration of vitriol shared between the parties, when Sandage and Gustav Andreas Tammann (Sandage’s research colleague) formally acknowledged the shortcomings of confirming the systematic error of their method in 1975, Vaucouleurs responded “It is unfortunate that this sober warning was so soon forgotten and ignored by most astronomers and textbook writers”. In 1996, a debate moderated by John Bahcall between Sidney van den Bergh and Gustav Tammann was held in similar fashion to the earlier Shapley–Curtis debate over these two competing values.


title: Hubble's law

text: This previously wide variance in estimates was partially resolved with the introduction of the ΛCDM model of the universe in the late 1990s. With the ΛCDM model observations of high-redshift clusters at X-ray and microwave wavelengths using the Sunyaev–Zel'dovich effect, measurements of anisotropies in the cosmic microwave background radiation, and optical surveys all gave a value of around 70 for the constant.


title: Hubble's law

text: More recent measurements from the Planck mission published in 2018 indicate a lower value of , although, even more recently, in March 2019, a higher value of has been determined using an improved procedure involving the Hubble Space Telescope. The two measurements disagree at the 4.4"σ" level, beyond a plausible level of chance. The resolution to this disagreement is an ongoing area of active research.


title: Hubble's law

text: In October 2018, scientists presented a new third way (two earlier methods, one based on redshifts and another on the cosmic distance ladder, gave results that do not agree), using information from gravitational wave events (especially those involving the merger of neutron stars, like GW170817), of determining the Hubble constant.


title: Hubble's law

text: In July 2019, astronomers reported that a new method to determine the Hubble constant, and resolve the discrepancy of earlier methods, has been proposed based on the mergers of pairs of neutron stars, following the detection of the neutron star merger of GW170817, an event known as a dark siren. Their measurement of the Hubble constant is (km/s)/Mpc.


title: Hubble's law

text: Also in July 2019, astronomers reported another new method, using data from the Hubble Space Telescope and based on distances to red giant stars calculated using the tip of the red-giant branch (TRGB) distance indicator. Their measurement of the Hubble constant is (km/s)/Mpc.


title: Hubble's law

text: In February 2020, the Megamaser Cosmology Project published independent results that confirmed the distance ladder results and differed from the early-universe results at a statistical significance level of 95%. In July 2020, measurements of the cosmic background radiation by the Atacama Cosmology Telescope predict that the Universe should be expanding more slowly than is currently observed.


title: Bootstrapping (statistics)

text: Bootstrapping is any test or metric that uses random sampling with replacement (e.g. mimicking the sampling process), and falls under the broader class of resampling methods. Bootstrapping assigns measures of accuracy (bias, variance, confidence intervals, prediction error, etc.) to sample estimates. This technique allows estimation of the sampling distribution of almost any statistic using random sampling methods.


title: Bootstrapping (statistics)

text: Bootstrapping estimates the properties of an estimand (such as its variance) by measuring those properties when sampling from an approximating distribution. One standard choice for an approximating distribution is the empirical distribution function of the observed data. In the case where a set of observations can be assumed to be from an independent and identically distributed population, this can be implemented by constructing a number of resamples with replacement, of the observed data set (and of equal size to the observed data set).


title: Bootstrapping (statistics)

text: It may also be used for constructing hypothesis tests. It is often used as an alternative to statistical inference based on the assumption of a parametric model when that assumption is in doubt, or where parametric inference is impossible or requires complicated formulas for the calculation of standard errors.


title: Bootstrapping (statistics)

text: The bootstrap was published by Bradley Efron in "Bootstrap methods: another look at the jackknife" (1979), inspired by earlier work on the jackknife. Improved estimates of the variance were developed later. A Bayesian extension was developed in 1981. The bias-corrected and accelerated (BCa) bootstrap was developed by Efron in 1987, and the ABC procedure in 1992.


title: Bootstrapping (statistics)

text: The basic idea of bootstrapping is that inference about a population from sample data (sample → population) can be modeled by "resampling" the sample data and performing inference about a sample from resampled data (resampled → sample). As the population is unknown, the true error in a sample statistic against its population value is unknown. In bootstrap-resamples, the 'population' is in fact the sample, and this is known; hence the quality of inference of the 'true' sample from resampled data (resampled → sample) is measurable.


title: Bootstrapping (statistics)

text: More formally, the bootstrap works by treating inference of the true probability distribution "J", given the original data, as being analogous to an inference of the empirical distribution "Ĵ", given the resampled data. The accuracy of inferences regarding "Ĵ" using the resampled data can be assessed because we know "Ĵ". If "Ĵ" is a reasonable approximation to "J", then the quality of inference on "J" can in turn be inferred.


title: Bootstrapping (statistics)

text: As an example, assume we are interested in the average (or mean) height of people worldwide. We cannot measure all the people in the global population, so instead, we sample only a tiny part of it, and measure that. Assume the sample is of size "N"; that is, we measure the heights of "N" individuals. From that single sample, only one estimate of the mean can be obtained. In order to reason about the population, we need some sense of the variability of the mean that we have computed. The simplest bootstrap method involves taking the original data set of heights, and, using a computer, sampling from it to form a new sample (called a 'resample' or bootstrap sample) that is also of size "N". The bootstrap sample is taken from the original by using sampling with replacement (e.g. we might 'resample' 5 times from [1,2,3,4,5] and get [2,5,4,4,1]), so, assuming "N" is sufficiently large, for all practical purposes there is virtually zero probability that it will be identical to the original "real" sample. This process is repeated a large number of times (typically 1,000 or 10,000 times), and for each of these bootstrap samples, we compute its mean (each of these is called a "bootstrap estimate"). We now can create a histogram of bootstrap means. This histogram provides an estimate of the shape of the distribution of the sample mean from which we can answer questions about how much the mean varies across samples. (The method here, described for the mean, can be applied to almost any other statistic or estimator.)


title: Bootstrapping (statistics)

text: A great advantage of bootstrap is its simplicity. It is a straightforward way to derive estimates of standard errors and confidence intervals for complex estimators of the distribution, such as percentile points, proportions, odds ratio, and correlation coefficients. However, despite its simplicity, bootstrapping can be applied to complex sampling designs (e.g. for population divided into s strata with n observations per strata, bootstrapping can be applied for each strata). Bootstrap is also an appropriate way to control and check the stability of the results. Although for most problems it is impossible to know the true confidence interval, bootstrap is asymptotically more accurate than the standard intervals obtained using sample variance and assumptions of normality. Bootstrapping is also a convenient method that avoids the cost of repeating the experiment to get other groups of sample data.


title: Bootstrapping (statistics)

text: Bootstrapping depends heavily on the estimator used and, though simple, ignorant use of bootstrapping will not always yield asymptotically valid results and can lead to inconsistency. Although bootstrapping is (under some conditions) asymptotically consistent, it does not provide general finite-sample guarantees. The result may depend on the representative sample. The apparent simplicity may conceal the fact that important assumptions are being made when undertaking the bootstrap analysis (e.g. independence of samples or large enough of a sample size) where these would be more formally stated in other approaches. Also, bootstrapping can be time-consuming and there are not many available software for bootstrapping as it is difficult to automate using traditional statistical computer packages.


title: Bootstrapping (statistics)

text: Scholars have recommended more bootstrap samples as available computing power has increased. If the results may have substantial real-world consequences, then one should use as many samples as is reasonable, given available computing power and time. Increasing the number of samples cannot increase the amount of information in the original data; it can only reduce the effects of random sampling errors which can arise from a bootstrap procedure itself. Moreover, there is evidence that numbers of samples greater than 100 lead to negligible improvements in the estimation of standard errors. In fact, according to the original developer of the bootstrapping method, even setting the number of samples at 50 is likely to lead to fairly good standard error estimates.


title: Bootstrapping (statistics)

text: However, Athreya has shown that if one performs a naive bootstrap on the sample mean when the underlying population lacks a finite variance (for example, a power law distribution), then the bootstrap distribution will not converge to the same limit as the sample mean. As a result, confidence intervals on the basis of a Monte Carlo simulation of the bootstrap could be misleading. Athreya states that "Unless one is reasonably sure that the underlying distribution is not heavy tailed, one should hesitate to use the naive bootstrap".


title: Bootstrapping (statistics)

text: In univariate problems, it is usually acceptable to resample the individual observations with replacement ("case resampling" below) unlike subsampling, in which resampling is without replacement and is valid under much weaker conditions compared to the bootstrap. In small samples, a parametric bootstrap approach might be preferred. For other problems, a "smooth bootstrap" will likely be preferred.


title: Bootstrapping (statistics)

text: The bootstrap is generally useful for estimating the distribution of a statistic (e.g. mean, variance) without using normality assumptions (as required, e.g., for a z-statistic or a t-statistic). In particular, the bootstrap is useful when there is no analytical form or an asymptotic theory (e.g., an applicable central limit theorem) to help estimate the distribution of the statistics of interest. This is because bootstrap methods can apply to most random quantities, e.g., the ratio of variance and mean. There are at least two ways of performing case resampling.


title: Bootstrapping (statistics)

text: Consider a coin-flipping experiment. We flip the coin and record whether it lands heads or tails. Let be 10 observations from the experiment. if the i th flip lands heads, and 0 otherwise. By invoking the assumption that the average of the coin flips is normally distributed, we can use the t-statistic to estimate the distribution of the sample mean,


title: Bootstrapping (statistics)

text: Such a normality assumption can be justified either as an approximation of the distribution of each "individual" coin flip or as an approximation of the distribution of the "average" of a large number of coin flips. The former is a poor approximation because the true distribution of the coin flips is Bernoulli instead of normal. The latter is a valid approximation in "infinitely large" samples due to the central limit theorem.


title: Bootstrapping (statistics)

text: However, if we are not ready to make such a justification, then we can use the bootstrap instead. Using case resampling, we can derive the distribution of formula_3. We first resample the data to obtain a "bootstrap resample". An example of the first resample might look like this . There are some duplicates since a bootstrap resample comes from sampling with replacement from the data. Also the number of data points in a bootstrap resample is equal to the number of data points in our original observations. Then we compute the mean of this resample and obtain the first "bootstrap mean": "μ"*. We repeat this process to obtain the second resample "X"* and compute the second bootstrap mean "μ"*. If we repeat this 100 times, then we have "μ"*, "μ"*, ..., "μ"*. This represents an "empirical bootstrap distribution" of sample mean. From this empirical distribution, one can derive a "bootstrap confidence interval" for the purpose of hypothesis testing.


title: Bootstrapping (statistics)

text: In regression problems, "case resampling" refers to the simple scheme of resampling individual cases – often rows of a data set. For regression problems, as long as the data set is fairly large, this simple scheme is often acceptable. However, the method is open to criticism.


title: Bootstrapping (statistics)

text: In regression problems, the explanatory variables are often fixed, or at least observed with more control than the response variable. Also, the range of the explanatory variables defines the information available from them. Therefore, to resample cases means that each bootstrap sample will lose some information. As such, alternative bootstrap procedures should be considered.


title: Bootstrapping (statistics)

text: Bootstrapping can be interpreted in a Bayesian framework using a scheme that creates new data sets through reweighting the initial data. Given a set of formula_4 data points, the weighting assigned to data point formula_5 in a new data set formula_6 is formula_7, where formula_8 is a low-to-high ordered list of formula_9 uniformly distributed random numbers on formula_10, preceded by 0 and succeeded by 1. The distributions of a parameter inferred from considering many such data sets formula_6 are then interpretable as posterior distributions on that parameter.


title: Bootstrapping (statistics)

text: Under this scheme, a small amount of (usually normally distributed) zero-centered random noise is added onto each resampled observation. This is equivalent to sampling from a kernel density estimate of the data. Assume "K" to be a symmetric kernel density function with unit variance. The standard kernel estimator formula_12 of formula_13 is


title: Bootstrapping (statistics)

text: where formula_15 is the smoothing parameter. And the corresponding distribution function estimator formula_16 is


title: Bootstrapping (statistics)

text: Based on the assumption that the original data set is a realization of a random sample from a distribution of a specific parametric type, in this case a parametric model is fitted by parameter θ, often by maximum likelihood, and samples of random numbers are drawn from this fitted model. Usually the sample drawn has the same sample size as the original data. Then the estimate of original function F can be written as formula_18. This sampling process is repeated many times as for other bootstrap methods. Considering the centered sample mean in this case, the random sample original distribution function formula_19 is replaced by a bootstrap random sample with function formula_20, and the probability distribution of formula_21 is approximated by that of formula_22, where formula_23, which is the expectation corresponding to formula_20. The use of a parametric model at the sampling stage of the bootstrap methodology leads to procedures which are different from those obtained by applying basic statistical theory to inference for the same model.


title: Bootstrapping (statistics)

text: Another approach to bootstrapping in regression problems is to resample residuals. The method proceeds as follows.


title: Bootstrapping (statistics)

text: This scheme has the advantage that it retains the information in the explanatory variables. However, a question arises as to which residuals to resample. Raw residuals are one option; another is studentized residuals (in linear regression). Although there are arguments in favor of using studentized residuals; in practice, it often makes little difference, and it is easy to compare the results of both schemes.


title: Bootstrapping (statistics)

text: When data are temporally correlated, straightforward bootstrapping destroys the inherent correlations. This method uses Gaussian process regression (GPR) to fit a probabilistic model from which replicates may then be drawn. GPR is a Bayesian non-linear regression method. A Gaussian process (GP) is a collection of random variables, any finite number of which have a joint Gaussian (normal) distribution. A GP is defined by a mean function and a covariance function, which specify the mean vectors and covariance matrices for each finite collection of the random variables.


title: Bootstrapping (statistics)

text: For any finite collection of variables, "x", ..., "x", the function outputs formula_35 are jointly distributed according to a multivariate Gaussian with mean formula_36 and covariance matrix formula_37


title: Bootstrapping (statistics)

text: According to the equations above, the outputs "y" are also jointly distributed according to a multivariate Gaussian. Thus,


title: Bootstrapping (statistics)

text: The wild bootstrap, proposed originally by Wu (1986), is suited when the model exhibits heteroskedasticity. The idea is, as the residual bootstrap, to leave the regressors at their sample value, but to resample the response variable based on the residuals values. That is, for each replicate, one computes a new formula_55 based on


title: Bootstrapping (statistics)

text: so the residuals are randomly multiplied by a random variable formula_57 with mean 0 and variance 1. For most distributions of formula_58 (but not Mammen's), this method assumes that the 'true' residual distribution is symmetric and can offer advantages over simple residual sampling for smaller sample sizes. Different forms are used for the random variable formula_57, such as


title: Bootstrapping (statistics)

text: The block bootstrap is used when the data, or the errors in a model, are correlated. In this case, a simple case or residual resampling will fail, as it is not able to replicate the correlation in the data. The block bootstrap tries to replicate the correlation by resampling inside blocks of data (see Blocking (statistics)). The block bootstrap has been used mainly with data correlated in time (i.e. time series) but can also be used with data correlated in space, or among groups (so-called cluster data).


title: Bootstrapping (statistics)

text: In the moving block bootstrap, introduced by Künsch (1989), data is split into "n" − "b" + 1 overlapping blocks of length "b": Observation 1 to b will be block 1, observation 2 to "b" + 1 will be block 2, etc. Then from these "n" − "b" + 1 blocks, "n"/"b" blocks will be drawn at random with replacement. Then aligning these n/b blocks in the order they were picked, will give the bootstrap observations.


title: Bootstrapping (statistics)

text: This bootstrap works with dependent data, however, the bootstrapped observations will not be stationary anymore by construction. But, it was shown that varying randomly the block length can avoid this problem. This method is known as the "stationary bootstrap." Other related modifications of the moving block bootstrap are the "Markovian bootstrap" and a stationary bootstrap method that matches subsequent blocks based on standard deviation matching.


title: Bootstrapping (statistics)

text: Vinod (2006), presents a method that bootstraps time series data using maximum entropy principles satisfying the Ergodic theorem with mean-preserving and mass-preserving constraints. There is an R package, meboot, that utilizes the method, which has applications in econometrics and computer science.


title: Bootstrapping (statistics)

text: Cluster data describes data where many observations per unit are observed. This could be observing many firms in many states or observing students in many classes. In such cases, the correlation structure is simplified, and one does usually make the assumption that data is correlated within a group/cluster, but independent between groups/clusters. The structure of the block bootstrap is easily obtained (where the block just corresponds to the group), and usually only the groups are resampled, while the observations within the groups are left unchanged. Cameron et al. (2008) discusses this for clustered errors in linear regression.


title: Bootstrapping (statistics)

text: The bootstrap is a powerful technique although may require substantial computing resources in both time and memory. Some techniques have been developed to reduce this burden. They can generally be combined with many of the different types of Bootstrap schemes and various choices of statistics.


title: Bootstrapping (statistics)

text: The ordinary bootstrap requires the random selection of n elements from a list, which is equivalent to drawing from a multinomial distribution. This may require a large number of passes over the data and is challenging to run these computations in parallel. For large values of n, the Poisson bootstrap is an efficient method of generating bootstrapped data sets. When generating a single bootstrap sample, instead of randomly drawing from the sample data with replacement, each data point is assigned a random weight distributed according to the Poisson distribution with formula_63. For large sample data, this will approximate random sampling with replacement. This is due to the following approximation:


title: Bootstrapping (statistics)

text: This method also lends itself well to streaming data and growing data sets, since the total number of samples does not need to be known in advance of beginning to take bootstrap samples.


title: Bootstrapping (statistics)

text: A way to improve on the poisson bootstrap, termed "sequential bootstrap", is by taking the first samples so that the proportion of unique values is ≈0.632 of the original sample size n. This provides a distribution with main empirical characteristics being within a distance of formula_65. Empirical investigation has shown this method can yield good results. This is related to the reduced bootstrap method.


title: Bootstrapping (statistics)

text: For massive data sets, it is often computationally prohibitive to hold all the sample data in memory and resample from the sample data. The Bag of Little Bootstraps (BLB) provides a method of pre-aggregating data before bootstrapping to reduce computational constraints. This works by partitioning the data set into formula_66 equal-sized buckets and aggregating the data within each bucket. This pre-aggregated data set becomes the new sample data over which to draw samples with replacement. This method is similar to the Block Bootstrap, but the motivations and definitions of the blocks are very different. Under certain assumptions, the sample distribution should approximate the full bootstrapped scenario. One constraint is the number of buckets formula_67where formula_68 and the authors recommend usage of formula_69 as a general solution.


title: Bootstrapping (statistics)

text: The bootstrap distribution of a point estimator of a population parameter has been used to produce a bootstrapped confidence interval for the parameter's true value if the parameter can be written as a function of the population's distribution.


title: Bootstrapping (statistics)

text: Population parameters are estimated with many point estimators. Popular families of point-estimators include mean-unbiased minimum-variance estimators, median-unbiased estimators, Bayesian estimators (for example, the posterior distribution's mode, median, mean), and maximum-likelihood estimators.


title: Bootstrapping (statistics)

text: A Bayesian point estimator and a maximum-likelihood estimator have good performance when the sample size is infinite, according to asymptotic theory. For practical problems with finite samples, other estimators may be preferable. Asymptotic theory suggests techniques that often improve the performance of bootstrapped estimators; the bootstrapping of a maximum-likelihood estimator may often be improved using transformations related to pivotal quantities.


title: Bootstrapping (statistics)

text: The bootstrap distribution of a parameter-estimator has been used to calculate confidence intervals for its population-parameter.


title: Bootstrapping (statistics)

text: There are several methods for constructing confidence intervals from the bootstrap distribution of a real parameter:


title: Bootstrapping (statistics)

text: Efron and Tibshirani suggest the following algorithm for comparing the means of two independent samples:


title: Bootstrapping (statistics)

text: Let formula_83 be a random sample from distribution F with sample mean formula_84 and sample variance formula_85. Let formula_86 be another, independent random sample from distribution G with mean formula_87 and variance formula_88


title: Bootstrapping (statistics)

text: The data set contains two outliers, which greatly influence the sample mean. (The sample mean need not be a consistent estimator for any population mean, because no mean needs to exist for a heavy-tailed distribution.) A well-defined and robust statistic for the central tendency is the sample median, which is consistent and median-unbiased for the population median.


title: Bootstrapping (statistics)

text: The bootstrap distribution for Newcomb's data appears below. We can reduce the discreteness of the bootstrap distribution by adding a small amount of random noise to each bootstrap sample. A conventional choice is to add noise with a standard deviation of formula_105 for a sample size "n"; this noise is often drawn from a Student-t distribution with "n-1" degrees of freedom. This results in an approximately-unbiased estimator for the variance of the sample mean. This means that samples taken from the bootstrap distribution will have a variance which is, on average, equal to the variance of the total population.


title: Bootstrapping (statistics)

text: Histograms of the bootstrap distribution and the smooth bootstrap distribution appear below. The bootstrap distribution of the sample-median has only a small number of values. The smoothed bootstrap distribution has a richer support. However, note that whether the smoothed or standard bootstrap procedure is favorable is case-by-case and is shown to depend on both the underlying distribution function and on the quantity being estimated.


title: Bootstrapping (statistics)

text: In this example, the bootstrapped 95% (percentile) confidence-interval for the population median is (26, 28.5), which is close to the interval for (25.98, 28.46) for the smoothed bootstrap.


title: Bootstrapping (statistics)

text: Bootstrap aggregating (bagging) is a meta-algorithm based on averaging model predictions obtained from models trained on multiple bootstrap samples.


title: Bootstrapping (statistics)

text: In situations where an obvious statistic can be devised to measure a required characteristic using only a small number, "r", of data items, a corresponding statistic based on the entire sample can be formulated. Given an "r"-sample statistic, one can create an "n"-sample statistic by something similar to bootstrapping (taking the average of the statistic over all subsamples of size "r"). This procedure is known to have certain good properties and the result is a U-statistic. The sample mean and sample variance are of this form, for "r" = 1 and "r" = 2.


title: V (2009 TV series)

text: V is an American science fiction drama television series that ran for two seasons on ABC, from November 3, 2009, to March 15, 2011. A remake of the 1983 miniseries created by Kenneth Johnson, the new series chronicles the arrival on Earth of a technologically-advanced alien species which ostensibly comes in peace, but actually has sinister motives. "V" stars Elizabeth Mitchell and Morena Baccarin, and is executive produced by Scott Rosenbaum, Yves Simoneau, Scott Peters, Steve Pearlman, and Jace Hall. The series was produced by The Scott Peters Company, HDFilms and Warner Bros. Television. On May 13, 2011, ABC cancelled the series after two seasons.


title: V (2009 TV series)

text: Giant spaceships appear over 29 major cities throughout the world, and Anna (Morena Baccarin), the beautiful and charismatic leader of the extraterrestrial "Visitors", declares that they come in peace. The Visitors claim to only need a small amount of Earth's resources, in exchange for which they will share their advanced technological and medical knowledge. As a small number of humans begin to doubt the sincerity of the seemingly benevolent Visitors, FBI counter-terrorism agent Erica Evans (Elizabeth Mitchell) discovers that the aliens are actually reptilian humanoids wearing pseudo-human skin, who have spent decades infiltrating human governments, businesses, and religious institutions, and are now in the final stages of their plan to take over the Earth. Erica joins the resistance movement, which includes Ryan (Morris Chestnut), a Visitor sleeper agent who over time developed human emotions and now wants to save humanity. Their rebellion becomes a part of a larger "Fifth Column" movement of both humans and Visitors opposed to Anna's vague but seemingly menacing plans for Earth and humanity, but their efforts are challenged as the Visitors have won favor among the people of Earth by curing a variety of diseases and have recruited Earth's youth – including Erica's son Tyler (Logan Huffman) – to serve them unknowingly as spies.


title: V (2009 TV series)

text: The series was announced in May 2009, to be executive produced by Scott Peters, Jace Hall, Steve Pearlman, and Jeffrey Bell. Filming of the post-pilot episodes began on August 10, 2009. Cast member Elizabeth Mitchell noted that the show would do service to the most iconic moments from the original franchise.


title: V (2009 TV series)

text: Peters later confirmed that in addition to potentially using cast members from the 1983 miniseries, the new series would nod to the original in other ways. He said that when asking people what they thought were the most memorable elements of "V", the top responses included "the huge ships, the red uniforms, eating the hamster, and [the] alien baby," adding that "we are well aware of those moments and are looking to put our own little spin on them to tip our hat to the old audience."


title: V (2009 TV series)

text: "Entertainment Weekly" put the original "V" on its 2008 list "The Sci-Fi 25: The Genre's Best Since 1982" and called Visitor leader Diana's devouring of a guinea pig "one of the best TV reveals ever." Asked about the 1983 reveal of the Visitors' reptilian appearance beneath their human disguise, Peters noted "That was the other one, of course... We tried to put our own [spin on it]. We're... a little bit different than their execution of it. It wasn't so much latex mask as it is real flesh and blood."


title: V (2009 TV series)

text: "Reuters" called the idea behind "V" "a powerhouse concept that combines conflict, suspense and imagination with some heavy-duty philosophical issues," noting that the update "preserves the original framework but shifts the atmosphere to accommodate contemporary concerns... the militaristic notes will be more subdued. Instead, there will be more of a post-9/11 emphasis on questions of trust and terror."


title: V (2009 TV series)

text: Production on the show was temporarily suspended in August 2009, pending the resolution of a dispute filed with the Writers Guild of America by original creator Kenneth Johnson. Warner Bros. sought to remove Johnson's "created by" status by claiming that the new show was so fundamentally changed from Johnson's original premise that it constituted a standalone work and not a remake. The Writers Guild, however, disagreed, and when production resumed in September 2009, Johnson retained the credit.


title: V (2009 TV series)

text: In September 2009, it was announced that four episodes of "V" would air in November 2009, and that the series would resume its 12-episode season in March 2010 after the 2010 Winter Olympics. ABC entertainment president Steve McPherson said, "We always intended to break the show up into 'pods' to make it more of an event." As production of the fourth episode of "V" wrapped, it was announced on November 3, 2009, that Scott Rosenbaum had been named executive producer and showrunner of the series, with Peters and Hall remaining as executive producers. Production of the remaining eight episodes resumed in January 2010 with new episodes returning March 30, 2010. On May 13, 2010, ABC renewed "V" for a second season. The second season premiered January 4, 2011, but the original order of 13 episodes was reduced to 10.


title: V (2009 TV series)

text: The series premiere of "V" received "generally favorable reviews", scoring 67 out of 100 on Metacritic based on reviews from 23 critics. E! Online stated "on a scale of 1 to 10, we give it an 11. "V" is the best pilot we've seen in, well, forever." "USA Today" Robert Bianco put "V" on his list of the top ten new shows, stating that the remake is well-made and "quickly establishes its own identity," and "The Hollywood Reporter" called the new series "clever enough for a cult following and accessible enough to reach a broad demo." King Features' entertainment reporter Cindy Elavsky calls "V" "the best new show on television, by far. The special effects are feature-film quality; the writing is intelligent and time-relevant; and the acting is first-rate. The first five minutes alone will hook you for the entire season." "The New York Times" wrote that "The ideas in "V," about alien encounters and mass delusion and media manipulation, are enticing. It's too bad that they're floating around in a show that at this early stage, is so slapdash and formulaic in its storytelling." "The A.V. Club" gave "V" premiere a 'C' rating, calling it "rote and by-the-numbers."


title: V (2009 TV series)

text: Metacritic gave the second-season premiere a score of 49/100 based on reviews from 13 critics, indicating mixed reviews.


title: V (2009 TV series)

text: The re-imagined series has been interpreted by some reviewers as an allegory of the presidency of Barack Obama. In his review of the show, Troy Patterson of "Slate" points out that bloggers and journalists had noticed parallels between the show's premise and the Obama administration, and writes that "if the show is to have the symbolic import that we expect from a science-fiction story, this is the only possible way to read "V" as a coherent text. The only problem with this analysis lies in its generous presupposition that the text is, in fact, coherent." Lisa de Moraes of "The Washington Post" noted in her review that the fact the series was debuting on the first anniversary of Obama's election "was not lost on some ... TV critics" and also remarked that the use of phrases present in the series (such as "hope", "change", and "Universal Health Care" being offered by the Visitors) made it seem as though "Lou Dobbs had taken over the network, as those things only became popular with the current administration." "Chicago Tribune" reviewer Glenn Garvin called the show "controversial", saying the series was "a barbed commentary on Obamamania that will infuriate the president's supporters and delight his detractors."


title: V (2009 TV series)

text: The show's cast and crew deny this interpretation. Actress Morena Baccarin acknowledges that she had modeled her character, Visitor leader Anna, after politicians but she and series executive producer Peters were surprised by the controversy. At a press conference at Summer TV Press Tour 2009, Peters said that the show was open to interpretation and that "people bring subjective thoughts to it... but there is no particular agenda." Bell agreed, stating that it was simply "a show about spaceships."


title: V (2009 TV series)

text: In retrospect, Baccarin said: "Originally what was intended with the show, the aliens—the visitors had been amongst us for hundreds of years and were the impetus and the catalyst for a lot of plagues and a lot of world wars, and had kind of instigated these things to kind of try to end humanity and to control humanity. I thought that was the direction that we were headed, and then we ended up having two or three different showrunners, and ABC didn’t really know which direction they wanted to take the show. It became kind of a mess, but what first attracted me to the show was definitely this possibility that we could make parallels to the modern world."


title: V (2009 TV series)

text: The pilot episode which aired on November 3, 2009, garnered 14.3 million viewers and scored a 5.2 rating among 18- to 49-year-olds, making it the highest debut of the 2009–10 season. The first four episodes of the first season averaged 9.75 million viewers and a 3.4 rating among 18- to 49-year-olds, ranking 34th in the television season. The remainder of season 1 began airing in March 2010, and by the end of the second half of the season the average viewer count had dropped to 5.72 million viewers and a 2.3 18–49 rating, ranking 89th.


title: V (2009 TV series)

text: The second season averaged 6.93 million viewers per episode and had an average 18–49 rating of 2.5, ranking 75th for the 2010–11 season.


title: V (2009 TV series)

text: In the UK, the show premiered on the premium channel Syfy. The original broadcast of the pilot was seen by 481,000 viewers and was the most watched show for the network for its entire first season. The second season premiered to 401,000 viewers, again becoming #1 for the network. In October 2010, when the show debuted on the free-to-air channel Channel One, it gained even higher ratings. The pilot episode garnered 541,000 viewers (and 338,000 for the repeat viewing two days later). The show remained the channel's number one show for several weeks, and was in the channel's top 3 for the entirety of its first season.


title: V (2009 TV series)

text: "V" was nominated for Outstanding Special Visual Effects for a Series at the 2010 Creative Arts Emmy Awards for the pilot episode. The show was also nominated for Favorite New TV Drama at the 36th People's Choice Awards and for Best Television Presentation. Morena Baccarin was nominated for Best Supporting Actress on Television at the 36th Saturn Awards. At the 37th Saturn Awards, the show received three nominations, for Best Network Series, Elizabeth Mitchell for Best Actress in Television, and Morena Baccarin for Best Supporting Actress in Television. At the 8th Visual Effects Society Awards, the show received nominations in the categories of Outstanding Visual Effects in a Broadcast Series and Outstanding Created Environment in a Broadcast Program or Commercial, winning in the Created Environment category for the Atrium and ship interiors.


title: V (2009 TV series)

text: Following ABC's cancellation of "V" in May 2011, the fan letter-writing campaign "Project Alice" began writing to Warner Bros. to renew the series on a different network. The campaign initially sought to get the show renewed on TNT, while later efforts had also concentrated on the CW Network as well. Both networks are owned by Warner Bros. Television's parent company, Time Warner. Ultimately the campaign was unsuccessful.


title: V (2009 TV series)

text: Special features on the first season DVD and Blu-ray include a commentary track on "Fruition" by executive producers Scott Rosenbaum and Steve Pearlman, deleted scenes, and four behind-the-scenes featurettes – "The Actor's Journey from Human to "V"", "An Alien in Human Skin: The Makeup FX of "V"", Breaking Story: The World of "V"", and "The Visual FX of "V"".


title: V (2009 TV series)

text: Special features on the second season DVD and Blu-ray include deleted and extended scenes, blooper reel, and two featurettes – "The Arc of Story: Mining the Human Evolution" and "A Visual Masterpiece for the Small Screen".


title: House Un-American Activities Committee

text: The House Committee on Un-American Activities (HCUA), popularly dubbed the House Un-American Activities Committee (HUAC), was an investigative committee of the United States House of Representatives, created in 1938 to investigate alleged disloyalty and subversive activities on the part of private citizens, public employees, and those organizations suspected of having either fascist or communist ties. It became a standing (permanent) committee in 1945, and from 1969 onwards it was known as the House Committee on Internal Security. When the House abolished the committee in 1975, its functions were transferred to the House Judiciary Committee.


title: House Un-American Activities Committee

text: The committee's anti-communist investigations are often associated with McCarthyism, although Joseph McCarthy himself (as a U.S. Senator) had no direct involvement with the House committee. McCarthy was the chairman of the Government Operations Committee and its Permanent Subcommittee on Investigations of the U.S. Senate, not the House.


title: House Un-American Activities Committee

text: The Overman Committee was a subcommittee of the Senate Judiciary Committee chaired by North Carolina Democratic Senator Lee Slater Overman that operated from September 1918 to June 1919. The subcommittee investigated German as well as "Bolshevik elements" in the United States.


title: House Un-American Activities Committee

text: This subcommittee was originally concerned with investigating pro-German sentiments in the American liquor industry. After World War I ended in November 1918, and the German threat lessened, the subcommittee began investigating Bolshevism, which had appeared as a threat during the First Red Scare after the Russian Revolution in 1917. The subcommittee's hearing into Bolshevik propaganda, conducted February 11 to March 10, 1919, had a decisive role in constructing an image of a radical threat to the United States during the first Red Scare.


title: House Un-American Activities Committee

text: U.S. Representative Hamilton Fish III (R-NY), who was a fervent anti-communist, introduced, on May 5, 1930, House Resolution 180, which proposed to establish a committee to investigate communist activities in the United States. The resulting committee, Special Committee to Investigate Communist Activities in the United States commonly known as the Fish Committee, undertook extensive investigations of people and organizations suspected of being involved with or supporting communist activities in the United States. Among the committee's targets were the American Civil Liberties Union and communist presidential candidate William Z. Foster. The committee recommended granting the United States Department of Justice more authority to investigate communists, and strengthening of immigration and deportation laws to keep communists out of the United States.


title: House Un-American Activities Committee

text: From 1934 to 1937, The committee, now named the Special Committee on Un-American Activities Authorized to Investigate Nazi Propaganda and Certain Other Propaganda Activities, chaired by John William McCormack (D-Mass.) and Samuel Dickstein (D-NY), held public and private hearings and collected testimony filling 4,300 pages. The Special Committee was widely known as the McCormack–Dickstein committee. Its mandate was to get "information on how foreign subversive propaganda entered the U.S. and the organizations that were spreading it." Its records are held by the National Archives and Records Administration as records related to HUAC.


title: House Un-American Activities Committee

text: In 1934, the Special Committee subpoenaed most of the leaders of the fascist movement in the United States. Beginning in November 1934, the committee investigated allegations of a fascist plot to seize the White House, known as the "Business Plot". Contemporary newspapers widely reported the plot as a hoax. However contemporary sources and some of those involved, such as Gen. Smedley Butler, confirmed the validity of such a plot.


title: House Un-American Activities Committee

text: It has been reported that while Dickstein served on this committee and the subsequent Special investigation Committee, he was paid $1,250 a month by the Soviet NKVD, which hoped to get secret congressional information on anti-communists and pro-fascists. A 1939 NKVD report stated Dickstein handed over "materials on the war budget for 1940, records of conferences of the budget subcommission, reports of the war minister, chief of staff and etc." However the NKVD was dissatisfied with the amount of information provided by Dickstein, after he was not appointed to HUAC to "carry out measures planned by us together with him." Dickstein unsuccessfully attempted to expedite the deportation of Soviet defector Walter Krivitsky, while the Dies Committee kept him in the country. Dickstein stopped receiving NKVD payments in February 1940.


title: House Un-American Activities Committee

text: On May 26, 1938, the House Committee on Un-American Activities was established as a special investigating committee, reorganized from its previous incarnations as the Fish Committee and the McCormack–Dickstein Committee, to investigate alleged disloyalty and subversive activities on the part of private citizens, public employees, and those organizations suspected of having communist or fascist ties; however, it concentrated its efforts on communists. It was chaired by Martin Dies Jr. (D-Tex.), and therefore known as the Dies Committee. Its records are held by the as records related to HUAC.


title: House Un-American Activities Committee

text: In 1938, Hallie Flanagan, the head of the Federal Theatre Project, was subpoenaed to appear before the committee to answer the charge the project was overrun with communists. Flanagan was called to testify for only a part of one day, while an administrative clerk from the project was called in for two entire days. It was during this investigation that one of the committee members, Joe Starnes (D-Ala.), famously asked Flanagan whether the English Elizabethan era playwright Christopher Marlowe was a member of the Communist Party, and mused that ancient Greek tragedian "Mr. Euripides" preached class warfare.


title: House Un-American Activities Committee

text: In 1939, the committee investigated people involved with pro-Nazi organizations such as Oscar C. Pfaus and George Van Horn Moseley. Moseley testified before the committee for five hours about a "Jewish Communist conspiracy" to take control of the US government. Moseley was supported by Donald Shea of the American Gentile League, whose statement was deleted from the public record as the committee found it so objectionable.


title: House Un-American Activities Committee

text: The committee also put together an argument for the internment of Japanese Americans known as the "Yellow Report". Organized in response to rumors of Japanese Americans being coddled by the War Relocation Authority (WRA) and news that some former inmates would be allowed to leave camp and Nisei soldiers to return to the West Coast, the committee investigated charges of fifth column activity in the camps. A number of anti-WRA arguments were presented in subsequent hearings, but Director Dillon Myer debunked the more inflammatory claims. The investigation was presented to the 77th Congress, and alleged that certain cultural traits – Japanese loyalty to the Emperor, the number of Japanese fishermen in the US, and the Buddhist faith – were evidence for Japanese espionage. With the exception of Rep. Herman Eberharter (D-Pa.), the members of the committee seemed to support internment, and its recommendations to expedite the impending segregation of "troublemakers", establish a system to investigate applicants for leave clearance, and step up Americanization and assimilation efforts largely coincided with WRA goals.


title: House Un-American Activities Committee

text: In 1946, the committee considered opening investigations into the Ku Klux Klan, but decided against doing so, prompting white supremacist committee member John E. Rankin (D-Miss.) to remark, "After all, the KKK is an old American institution." Instead of the Klan, HUAC concentrated on investigating the possibility that the American Communist Party had infiltrated the Works Progress Administration, including the Federal Theatre Project and the Federal Writers' Project. Twenty years later, in 1965–1966, however, the committee did conduct an investigation into Klan activities under chairman Edwin Willis (D-La.).


title: House Un-American Activities Committee

text: The House Committee on Un-American Activities became a standing (permanent) committee in 1945. Democratic Representative Edward J. Hart of New Jersey became the committee's first chairman. Under the mandate of Public Law 601, passed by the 79th Congress, the committee of nine representatives investigated suspected threats of subversion or propaganda that attacked "the form of government as guaranteed by our Constitution".


title: House Un-American Activities Committee

text: Under this mandate, the committee focused its investigations on real and suspected communists in positions of actual or supposed influence in the United States society. A significant step for HUAC was its investigation of the charges of espionage brought against Alger Hiss in 1948. This investigation ultimately resulted in Hiss's trial and conviction for perjury, and convinced many of the usefulness of congressional committees for uncovering communist subversion.


title: House Un-American Activities Committee

text: The chief investigator was Robert E. Stripling, senior investigator Louis J. Russell, and investigators Alvin Williams Stokes, Courtney E. Owens, and Donald T. Appell. The director of research was Benjamin Mandel.


title: House Un-American Activities Committee

text: In 1947, the committee held nine days of hearings into alleged communist propaganda and influence in the Hollywood motion picture industry. After conviction on contempt of Congress charges for refusal to answer some questions posed by committee members, "The Hollywood Ten" were blacklisted by the industry. Eventually, more than 300 artists – including directors, radio commentators, actors, and particularly screenwriters – were boycotted by the studios. Some, like Charlie Chaplin, Orson Welles, Alan Lomax, Paul Robeson, and Yip Harburg, left the U.S or went underground to find work. Others like Dalton Trumbo wrote under pseudonyms or the names of colleagues. Only about ten percent succeeded in rebuilding careers within the entertainment industry.


title: House Un-American Activities Committee

text: In 1947, studio executives told the committee that wartime films—such as "Mission to Moscow", "The North Star", and "Song of Russia"—could be considered pro-Soviet propaganda, but claimed that the films were valuable in the context of the Allied war effort, and that they were made (in the case of "Mission to Moscow") at the request of White House officials. In response to the House investigations, most studios produced a number of anti-communist and anti-Soviet propaganda films such as "The Red Menace" (August 1949), "The Red Danube" (October 1949), "The Woman on Pier 13" (October 1949), "Guilty of Treason" (May 1950, about the ordeal and trial of Cardinal József Mindszenty), "I Was a Communist for the FBI" (May 1951, Academy Award nominated for best documentary 1951, also serialized for radio), "Red Planet Mars" (May 1952), and John Wayne's "Big Jim McLain" (August 1952). Universal-International Pictures was the only major studio that did not purposefully produce such a film.


title: House Un-American Activities Committee

text: On July 31, 1948, the committee heard testimony from Elizabeth Bentley, an American who had been working as a Soviet agent in New York. Among those whom she named as communists was Harry Dexter White, a senior U.S. Treasury department official. The committee subpoenaed Whittaker Chambers on August 3, 1948. Chambers, too, was a former Soviet spy, by then a senior editor of "Time" magazine.


title: House Un-American Activities Committee

text: Chambers named more than a half-dozen government officials including White as well as Alger Hiss (and Hiss' brother Donald). Most of these former officials refused to answer committee questions, citing the Fifth Amendment. White denied the allegations, and died of a heart attack a few days later. Hiss also denied all charges; doubts about his testimony though, especially those expressed by freshman Congressman Richard Nixon, led to further investigation that strongly suggested Hiss had made a number of false statements.


title: House Un-American Activities Committee

text: Hiss challenged Chambers to repeat his charges outside a Congressional committee, which Chambers did. Hiss then sued for libel, leading Chambers to produce copies of State Department documents which he claimed Hiss had given him in 1938. Hiss denied this before a grand jury, was indicted for perjury, and subsequently convicted and imprisoned.


title: House Un-American Activities Committee

text: The present-day House of Representatives website on HUAC states, "But in the 1990s, Soviet archives conclusively revealed that Hiss had been a spy on the Kremlin’s payroll."


title: House Un-American Activities Committee

text: In the wake of the downfall of McCarthy (who never served in the House, nor on HUAC), the prestige of HUAC began a gradual decline in the late 1950s. By 1959, the committee was being denounced by former President Harry S. Truman as the "most un-American thing in the country today".


title: House Un-American Activities Committee

text: In May 1960, the committee held hearings in San Francisco City Hall which led to the infamous riot on May 13, when city police officers fire-hosed protesting students from the UC Berkeley, Stanford, and other local colleges, and dragged them down the marble steps beneath the rotunda, leaving some seriously injured. Soviet affairs expert William Mandel, who had been subpoenaed to testify, angrily denounced the committee and the police in a blistering statement which was aired repeatedly for years thereafter on Pacifica Radio station KPFA in Berkeley. An anti-communist propaganda film, "Operation Abolition", was produced by the committee from subpoenaed local news reports, and shown around the country during 1960 and 1961. In response, the Northern California ACLU produced a film called "Operation Correction", which discussed falsehoods in the first film. Scenes from the hearings and protest were later featured in the Academy Award-nominated 1990 documentary "Berkeley in the Sixties".


title: House Un-American Activities Committee

text: The committee lost considerable prestige as the 1960s progressed, increasingly becoming the target of political satirists and the defiance of a new generation of political activists. HUAC subpoenaed Jerry Rubin and Abbie Hoffman of the Yippies in 1967, and again in the aftermath of the 1968 Democratic National Convention. The Yippies used the media attention to make a mockery of the proceedings. Rubin came to one session dressed as a Revolutionary War soldier and passed out copies of the United States Declaration of Independence to those in attendance. Rubin then "blew giant gum bubbles, while his co-witnesses taunted the committee with Nazi salutes". Rubin attended another session dressed as Santa Claus. On another occasion, police stopped Hoffman at the building entrance and arrested him for wearing the United States flag. Hoffman quipped to the press, "I regret that I have but one shirt to give for my country", paraphrasing the last words of revolutionary patriot Nathan Hale; Rubin, who was wearing a matching Viet Cong flag, shouted that the police were communists for not arresting him as well.


title: House Un-American Activities Committee

text: Hearings in August 1966 called to investigate anti-Vietnam War activities were disrupted by hundreds of protesters, many from the Progressive Labor Party. The committee faced witnesses who were openly defiant.


title: House Un-American Activities Committee

text: In an attempt to reinvent itself, the committee was renamed as the Internal Security Committee in 1969.


title: House Un-American Activities Committee

text: The House Committee on Internal Security was formally terminated on January 14, 1975, the day of the opening of the 94th Congress. The committee's files and staff were transferred on that day to the House Judiciary Committee.


title: New Nintendo 3DS

text: The is a handheld game console produced by Nintendo. It is the fourth system in the Nintendo 3DS family of handheld consoles, following the original Nintendo 3DS, Nintendo 3DS XL, and Nintendo 2DS. The system was released in Japan on October 11, 2014, in Australia and New Zealand on November 21, 2014, on January 6, 2015 in Europe in a special Club Nintendo-exclusive "Ambassador Edition", and at retail in Europe on February 13, 2015. Like the original 3DS, the New Nintendo 3DS also has a larger variant, the New Nintendo 3DS XL, released in all three regions. In North America, the New Nintendo 3DS XL was released on February 13, 2015, while the standard-sized New Nintendo 3DS was released later on September 25, 2015.


title: New Nintendo 3DS

text: Improvements upon the previous models include upgraded processors and increased RAM, an analog pointing stick (C-Stick), two additional shoulder triggers (ZR and ZL), face detection for optimizing the autostereoscopic 3D display, an included 4 GB microSD card and built-in NFC, as well as minor design changes (such as colored face buttons, and the availability of face plates for the smaller-size model).


title: New Nintendo 3DS

text: The New Nintendo 3DS received positive reviews from critics; although criticized for certain aspects of their design (such as the microSD slot placement), the consoles were praised for their improved performance, additional control options, and better 3D image quality. In the July 2017 lead-up to the release of the New Nintendo 2DS XL, Nintendo confirmed that production on the standard-sized New Nintendo 3DS in Japan had ended. The XL model remained in production until July 2019, when production ceased and it was removed from their website.


title: New Nintendo 3DS

text: The New Nintendo 3DS family features various changes from prior models. The systems feature a slightly refined design, featuring colored face buttons resembling the Super Famicom's and PAL version Super Nintendo Entertainment System's color scheme. The New Nintendo 3DS's screen is 1.2 times the size of the original Nintendo 3DS, while the screen of the XL variant is the same size as its predecessor. Some models are produced with an IPS screen for the upper display, but some still retain the old TN screen for upper display. There is no known correlation between model number or production date and display type. Nintendo has also not publicly addressed the discrepancies in production. A new feature known as "Super Stable 3D" improves the quality of the systems' autostereoscopic 3D effects by using a sensor to detect the angle that the player is viewing the screen at, and adjusting the effects to compensate. The sensor is also used as an ambient light sensor for automatic brightness adjustment.


title: New Nintendo 3DS

text: Both systems' bodies are slightly larger than their previous iterations, with the XL variant weighing slightly less than the previous 3DS XL. The system's game card slot, stylus holder, and power button were re-located to the base. The hardware wireless switch was also replaced by a software toggle. The standard New Nintendo 3DS features interchangeable front and back plates; 38 different designs were available at launch in Japan. The XL variant does not allow use of these plates, instead having a couple of fixed metallic designs.


title: New Nintendo 3DS

text: The internal specifications of the device have also been updated, including additional processor cores, an increase to 256 MB of RAM, and near field communication support for use with Amiibo products. The Japanese model also includes the ability to pay for software on the Nintendo eShop using prepaid FeliCa-based transit cards such as Suica. Controls on the new systems were expanded with the inclusion of a pointing stick on the right hand side of the device, referred to as the "C-Stick", and additional ZL and ZR shoulder buttons, allowing for functionality equivalent to the Circle Pad Pro add-on peripheral released for the previous models. These additional buttons are backwards-compatible with games programmed for use with Circle Pad Pro.


title: New Nintendo 3DS

text: Unlike the previous models, which used standard SD cards, the New Nintendo 3DS line uses Micro-SD cards for data storage, which are stored alongside the battery behind the device's rear cover, which needs some screws to be removed in order to access the Micro-SD card slot. Data can also be transferred to and from the SD card wirelessly using any system with SMB client access, like PCs.


title: New Nintendo 3DS

text: The new systems continue to use the same AC adapter as the DSi, DSi XL, and other devices in the 3DS family; like the Nintendo 3DS XL in Japan and Europe, and for the first time in North America, an AC adapter is not included with the console and must be obtained separately.


title: New Nintendo 3DS

text: Aside from minor adjustments to reflect its hardware design differences, the system software of the New Nintendo 3DS is otherwise identical to that of the original 3DS, offering online features such as Nintendo Network for multiplayer and online gaming, Nintendo eShop for downloading and purchasing games, and StreetPass and SpotPass. The web browser was updated to include HTML5-based video playback support. On Japanese models, a content filter is active by default which can be disabled with the registration of a credit card, intended to prevent children from visiting mature websites.


title: New Nintendo 3DS

text: As with the DSi, DSi XL, and previous 3DS models, the New Nintendo 3DS family remains compatible with all games released for the DS, DSi, and 3DS (excluding games using the Game Boy Advance cartridge slot). Some 3DS games have improved performance and/or graphics on the new systems due to their upgraded hardware. The C-Stick and ZL/ZR controls are backwards compatible with games that support the Circle Pad Pro add-on. Some games, such as "Xenoblade Chronicles 3D", are specifically optimized for the upgraded hardware, and exclusive to New Nintendo 3DS with no support for prior models. In March 2016, Nintendo began to release SNES titles on Virtual Console for New 3DS; they support a "Perfect Pixel" mode, which allows the games to be played pillar boxed with square pixels rather than in their original 4:3 proportions.


title: New Nintendo 3DS

text: Like the previous models, all the 3DS games and downloaded software are region-locked (DS cartridges remain region-free). Due to its difference in size, peripherals designed to fit the shape of the original Nintendo 3DS cannot be used with the new system. Game data can be transferred from a previous 3DS system to a new system, either manually or wireless, though data from new systems cannot be transferred to older systems.


title: New Nintendo 3DS

text: On April 13, 2015, Unity Technologies announced that the Unity engine would support New Nintendo 3DS.


title: New Nintendo 3DS

text: The New Nintendo 3DS was first announced during a Japanese Nintendo Direct presentation streamed on August 29, 2014. The New Nintendo 3DS and 3DS LL were released in Japan on October 11, 2014; the regular-sized version was made available in black and white-colored versions, while the LL was made available in metallic black and metallic blue versions, with additional limited edition designs. Over 38 different face plate designs were available on launch in Japan, which were showcased in a pre-launch television commercial that featured J-pop performer Kyary Pamyu Pamyu. 230,000 units were sold in its first two days of availability.


title: New Nintendo 3DS

text: The New Nintendo 3DS and its XL variant were first released outside Japan—in Australia and New Zealand, on November 21, 2014, with the smaller model only available in white. In Europe, the New Nintendo 3DS was first made available online on January 6, 2015 in a special white "Ambassador Edition" bundle, exclusive to Club Nintendo members, with a charging dock and two face plates included.


title: New Nintendo 3DS

text: On January 14, 2015, Nintendo announced that the new systems would be released at retail in North America and Europe on February 13, 2015. In Europe, the New Nintendo 3DS was available in black or white, and its XL variant in Metallic Black or Metallic Blue. In North America, the XL model was released in Metallic Black and Metallic Red (renamed "New Black" and "New Red"). Special "" and "Monster Hunter 4 Ultimate"-themed variants were also released at launch in both regions. 335,000 units were sold during its first week of availability in Europe and North America.


title: New Nintendo 3DS

text: Only the XL model was originally released in North America; although Nintendo did not rule out the possibility of a release of the regular New Nintendo 3DS in the future, Nintendo of America representative Damon Baker explained that they did not want to confuse consumers, and that the face plates were not enough of a reason for the smaller-sized system to be released in North America. A social media campaign emerged that called upon Nintendo of America to release the model in North America. In March 2015, the FCC lifted its information embargo regarding regulation details performed in September 2014 on the standard New Nintendo 3DS model, suggesting Nintendo of America did indeed consider releasing the smaller standard model at one point.


title: New Nintendo 3DS

text: On August 31, 2015, at the GameStop Managers Conference in Las Vegas, Nintendo of America confirmed that the standard New 3DS system would launch in the region on September 25, 2015, with an ""-themed bundle including the console, game software, two faceplates, and an Amiibo card. The bundle was priced at $219.99. A second "The Legend of Zelda"-themed XL bundle, the "Hyrule Edition", was also announced as a GameStop exclusive for release on October 30, 2015. It was priced at $199.99.


title: New Nintendo 3DS

text: In January 2016, a special "Pokémon"-themed New Nintendo 3DS bundle was announced for release in North America on February 27, 2016, to coincide with the 20th anniversary Virtual Console release of the original "Pokémon" games. The model is bundled with both "Pokémon Red" and "Pokémon Blue", Charizard and Blastoise-themed faceplates, and a downloadable HOME Menu theme.


title: New Nintendo 3DS

text: In August 2016, a "Super Mario 3D Land" New 3DS bundle with two faceplates was released in North America as an exclusive to Target and Walmart. Nintendo released black- and white-colored New 3DS models with "Mario"-themed designs in North America in November 2016; for Black Friday, the two models were sold at US$99.99—a price only $20 higher than that of the 2DS.


title: New Nintendo 3DS

text: In July 2017, Nintendo confirmed, in the lead-up to the release of the New Nintendo 2DS XL, that production on the standard-sized New Nintendo 3DS in Japan had ended. The XL model had halted production in July 2019.