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Thursday, June 10, 2021

Observable universe

From Wikipedia, the free encyclopedia
 
Observable universe
Observable Universe with Measurements 01.png
Visualization of the whole observable universe. The scale is such that the fine grains represent collections of large numbers of superclusters. The Virgo Supercluster—home of Milky Way—is marked at the center, but is too small to be seen.
 
Diameter8.8×1026 m or 880 Ym (28.5 Gpc or 93 Gly)
Volume3.566×1080 m3
Mass (ordinary matter)1.5×1053 kg
Density (of total energy)9.9×10−27 kg/m3 (equivalent to 6 protons per cubic meter of space)
Age13.799±0.021 billion years
Average temperature2.72548 K
Contents

The observable universe is a ball-shaped region of the universe comprising all matter that can be observed from Earth or its space-based telescopes and exploratory probes at the present time, because the electromagnetic radiation from these objects has had time to reach the Solar System and Earth since the beginning of the cosmological expansion. There may be 2 trillion galaxies in the observable universe, although that number has recently been estimated at only several hundred billion based on new data from New Horizons. Assuming the universe is isotropic, the distance to the edge of the observable universe is roughly the same in every direction. That is, the observable universe has a spherical volume (a ball) centered on the observer. Every location in the universe has its own observable universe, which may or may not overlap with the one centered on Earth.

The word observable in this sense does not refer to the capability of modern technology to detect light or other information from an object, or whether there is anything to be detected. It refers to the physical limit created by the speed of light itself. No signal can travel faster than light, hence there is a maximum distance (called the particle horizon) beyond which nothing can be detected, as the signals could not have reached us yet. Sometimes astrophysicists distinguish between the visible universe, which includes only signals emitted since recombination (when hydrogen atoms were formed from protons and electrons and photons were emitted)—and the observable universe, which includes signals since the beginning of the cosmological expansion (the Big Bang in traditional physical cosmology, the end of the inflationary epoch in modern cosmology).

According to calculations, the current comoving distance—proper distance, which takes into account that the universe has expanded since the light was emitted—to particles from which the cosmic microwave background radiation (CMBR) was emitted, which represents the radius of the visible universe, is about 14.0 billion parsecs (about 45.7 billion light-years), while the comoving distance to the edge of the observable universe is about 14.3 billion parsecs (about 46.6 billion light-years), about 2% larger. The radius of the observable universe is therefore estimated to be about 46.5 billion light-years and its diameter about 28.5 gigaparsecs (93 billion light-years, or 8.8×1026 metres or 2.89×1027 feet), which equals 880 yottametres. The total mass of ordinary matter in the universe can be calculated using the critical density and the diameter of the observable universe to be about 1.5 × 1053 kg. In November 2018, astronomers reported that the extragalactic background light (EBL) amounted to 4 × 1084 photons.

As the universe's expansion is accelerating, all currently observable objects, outside our local supercluster, will eventually appear to freeze in time, while emitting progressively redder and fainter light. For instance, objects with the current redshift z from 5 to 10 will remain observable for no more than 4–6 billion years. In addition, light emitted by objects currently situated beyond a certain comoving distance (currently about 19 billion parsecs) will never reach Earth.

The universe versus the observable universe

The size of the whole universe is unknown, and it might be infinite in extent. Some parts of the universe are too far away for the light emitted since the Big Bang to have had enough time to reach Earth or space-based instruments, and therefore lie outside the observable universe. In the future, light from distant galaxies will have had more time to travel, so additional regions will become observable. However, owing to Hubble's law, regions sufficiently distant from the Earth are expanding away from it faster than the speed of light (special relativity prevents nearby objects in the same local region from moving faster than the speed of light with respect to each other, but there is no such constraint for distant objects when the space between them is expanding; see uses of the proper distance for a discussion) and furthermore the expansion rate appears to be accelerating owing to dark energy.

Assuming dark energy remains constant (an unchanging cosmological constant), so that the expansion rate of the universe continues to accelerate, there is a "future visibility limit" beyond which objects will never enter our observable universe at any time in the infinite future, because light emitted by objects outside that limit could never reach the Earth. (A subtlety is that, because the Hubble parameter is decreasing with time, there can be cases where a galaxy that is receding from the Earth just a bit faster than light does emit a signal that reaches the Earth eventually.) This future visibility limit is calculated at a comoving distance of 19 billion parsecs (62 billion light-years), assuming the universe will keep expanding forever, which implies the number of galaxies that we can ever theoretically observe in the infinite future (leaving aside the issue that some may be impossible to observe in practice due to redshift, as discussed in the following paragraph) is only larger than the number currently observable by a factor of 2.36.

Artist's logarithmic scale conception of the observable universe with the Solar System at the center, inner and outer planets, Kuiper belt, Oort cloud, Alpha Centauri, Perseus Arm, Milky Way galaxy, Andromeda Galaxy, nearby galaxies, Cosmic web, Cosmic microwave radiation and the Big Bang's invisible plasma on the edge. Celestial bodies appear enlarged to appreciate their shapes.

Though, in principle, more galaxies will become observable in the future, in practice, an increasing number of galaxies will become extremely redshifted due to ongoing expansion; so much so that they will seem to disappear from view and become invisible. An additional subtlety is that a galaxy at a given comoving distance is defined to lie within the "observable universe" if we can receive signals emitted by the galaxy at any age in its past history (say, a signal sent from the galaxy only 500 million years after the Big Bang), but because of the universe's expansion, there may be some later age at which a signal sent from the same galaxy can never reach the Earth at any point in the infinite future (so, for example, we might never see what the galaxy looked like 10 billion years after the Big Bang), even though it remains at the same comoving distance (comoving distance is defined to be constant with time—unlike proper distance, which is used to define recession velocity due to the expansion of space), which is less than the comoving radius of the observable universe. This fact can be used to define a type of cosmic event horizon whose distance from the Earth changes over time. For example, the current distance to this horizon is about 16 billion light-years, meaning that a signal from an event happening at present can eventually reach the Earth in the future if the event is less than 16 billion light-years away, but the signal will never reach the Earth if the event is more than 16 billion light-years away.

Both popular and professional research articles in cosmology often use the term "universe" to mean "observable universe". This can be justified on the grounds that we can never know anything by direct experimentation about any part of the universe that is causally disconnected from the Earth, although many credible theories require a total universe much larger than the observable universe.No evidence exists to suggest that the boundary of the observable universe constitutes a boundary on the universe as a whole, nor do any of the mainstream cosmological models propose that the universe has any physical boundary in the first place, though some models propose it could be finite but unbounded, like a higher-dimensional analogue of the 2D surface of a sphere that is finite in area but has no edge.

It is plausible that the galaxies within our observable universe represent only a minuscule fraction of the galaxies in the universe. According to the theory of cosmic inflation initially introduced by its founders, Alan Guth and D. Kazanas, if it is assumed that inflation began about 10−37 seconds after the Big Bang, then with the plausible assumption that the size of the universe before the inflation occurred was approximately equal to the speed of light times its age, that would suggest that at present the entire universe's size is at least 3 × 1023 (1.5 × 1034 light-years) times the radius of the observable universe.

If the universe is finite but unbounded, it is also possible that the universe is smaller than the observable universe. In this case, what we take to be very distant galaxies may actually be duplicate images of nearby galaxies, formed by light that has circumnavigated the universe. It is difficult to test this hypothesis experimentally because different images of a galaxy would show different eras in its history, and consequently might appear quite different. Bielewicz et al. claim to establish a lower bound of 27.9 gigaparsecs (91 billion light-years) on the diameter of the last scattering surface (since this is only a lower bound, since the whole universe is possibly much larger, even infinite). This value is based on matching-circle analysis of the WMAP 7 year data. This approach has been disputed.

Size

Hubble Ultra-Deep Field image of a region of the observable universe (equivalent sky area size shown in bottom left corner), near the constellation Fornax. Each spot is a galaxy, consisting of billions of stars. The light from the smallest, most redshifted galaxies originated nearly 14 billion years ago.

The comoving distance from Earth to the edge of the observable universe is about 14.26 gigaparsecs (46.5 billion light-years or 4.40×1026 m) in any direction. The observable universe is thus a sphere with a diameter of about 28.5 gigaparsecs (93 billion light-years or 8.8×1026 m). Assuming that space is roughly flat (in the sense of being a Euclidean space), this size corresponds to a comoving volume of about 1.22×104 Gpc3 (4.22×105 Gly3 or 3.57×1080 m3).

The figures quoted above are distances now (in cosmological time), not distances at the time the light was emitted. For example, the cosmic microwave background radiation that we see right now was emitted at the time of photon decoupling, estimated to have occurred about 380,000 years after the Big Bang, which occurred around 13.8 billion years ago. This radiation was emitted by matter that has, in the intervening time, mostly condensed into galaxies, and those galaxies are now calculated to be about 46 billion light-years from us. To estimate the distance to that matter at the time the light was emitted, we may first note that according to the Friedmann–Lemaître–Robertson–Walker metric, which is used to model the expanding universe, if at the present time we receive light with a redshift of z, then the scale factor at the time the light was originally emitted is given by

.

WMAP nine-year results combined with other measurements give the redshift of photon decoupling as z = 1091.64±0.47, which implies that the scale factor at the time of photon decoupling would be 11092.64. So if the matter that originally emitted the oldest cosmic microwave background (CMBR) photons has a present distance of 46 billion light-years, then at the time of decoupling when the photons were originally emitted, the distance would have been only about 42 million light-years.

The light-travel distance to the edge of the observable universe is the age of the Universe divided by the speed of light, 13.8 billion light years. This is the distance that a photon emitted shortly after the Big Bang, such as one from the cosmic microwave background, has travelled to reach observers on Earth. Because spacetime is curved, corresponding to the expansion of space, this distance does not correspond to the true distance at any moment in time.

Large-scale structure

Galaxy clusters, like RXC J0142.9+4438, are the nodes of the cosmic web that permeates the entire Universe.
 
An image and a video of a cosmological simulation of the local universe, showing large-scale structure of clusters of galaxies and dark matter

Sky surveys and mappings of the various wavelength bands of electromagnetic radiation (in particular 21-cm emission) have yielded much information on the content and character of the universe's structure. The organization of structure appears to follow a hierarchical model with organization up to the scale of superclusters and filaments. Larger than this (at scales between 30 and 200 megaparsecs), there seems to be no continued structure, a phenomenon that has been referred to as the End of Greatness.

Walls, filaments, nodes, and voids

Map of the cosmic web generated from a slime mould-inspired algorithm
 

The organization of structure arguably begins at the stellar level, though most cosmologists rarely address astrophysics on that scale. Stars are organized into galaxies, which in turn form galaxy groups, galaxy clusters, superclusters, sheets, walls and filaments, which are separated by immense voids, creating a vast foam-like structure sometimes called the "cosmic web". Prior to 1989, it was commonly assumed that virialized galaxy clusters were the largest structures in existence, and that they were distributed more or less uniformly throughout the universe in every direction. However, since the early 1980s, more and more structures have been discovered. In 1983, Adrian Webster identified the Webster LQG, a large quasar group consisting of 5 quasars. The discovery was the first identification of a large-scale structure, and has expanded the information about the known grouping of matter in the universe.

In 1987, Robert Brent Tully identified the Pisces–Cetus Supercluster Complex, the galaxy filament in which the Milky Way resides. It is about 1 billion light-years across. That same year, an unusually large region with a much lower than average distribution of galaxies was discovered, the Giant Void, which measures 1.3 billion light-years across. Based on redshift survey data, in 1989 Margaret Geller and John Huchra discovered the "Great Wall", a sheet of galaxies more than 500 million light-years long and 200 million light-years wide, but only 15 million light-years thick. The existence of this structure escaped notice for so long because it requires locating the position of galaxies in three dimensions, which involves combining location information about the galaxies with distance information from redshifts. Two years later, astronomers Roger G. Clowes and Luis E. Campusano discovered the Clowes–Campusano LQG, a large quasar group measuring two billion light-years at its widest point which was the largest known structure in the universe at the time of its announcement. In April 2003, another large-scale structure was discovered, the Sloan Great Wall. In August 2007, a possible supervoid was detected in the constellation Eridanus. It coincides with the 'CMB cold spot', a cold region in the microwave sky that is highly improbable under the currently favored cosmological model. This supervoid could cause the cold spot, but to do so it would have to be improbably big, possibly a billion light-years across, almost as big as the Giant Void mentioned above.

Unsolved problem in physics:

The largest structures in the universe are larger than expected. Are these actual structures or random density fluctuations?

Computer simulated image of an area of space more than 50 million light-years across, presenting a possible large-scale distribution of light sources in the universe—precise relative contributions of galaxies and quasars are unclear.

Another large-scale structure is the SSA22 Protocluster, a collection of galaxies and enormous gas bubbles that measures about 200 million light-years across.

In 2011, a large quasar group was discovered, U1.11, measuring about 2.5 billion light-years across. On January 11, 2013, another large quasar group, the Huge-LQG, was discovered, which was measured to be four billion light-years across, the largest known structure in the universe at that time. In November 2013, astronomers discovered the Hercules–Corona Borealis Great Wall, an even bigger structure twice as large as the former. It was defined by the mapping of gamma-ray bursts.

End of Greatness

The End of Greatness is an observational scale discovered at roughly 100 Mpc (roughly 300 million light-years) where the lumpiness seen in the large-scale structure of the universe is homogenized and isotropized in accordance with the Cosmological Principle. At this scale, no pseudo-random fractalness is apparent. The superclusters and filaments seen in smaller surveys are randomized to the extent that the smooth distribution of the universe is visually apparent. It was not until the redshift surveys of the 1990s were completed that this scale could accurately be observed.

Observations

"Panoramic view of the entire near-infrared sky reveals the distribution of galaxies beyond the Milky Way. The image is derived from the 2MASS Extended Source Catalog (XSC)—more than 1.5 million galaxies, and the Point Source Catalog (PSC)—nearly 0.5 billion Milky Way stars. The galaxies are color-coded by 'redshift' obtained from the UGC, CfA, Tully NBGC, LCRS, 2dF, 6dFGS, and SDSS surveys (and from various observations compiled by the NASA Extragalactic Database), or photo-metrically deduced from the K band (2.2 μm). Blue are the nearest sources (z < 0.01); green are at moderate distances (0.01 < z < 0.04) and red are the most distant sources that 2MASS resolves (0.04 < z < 0.1). The map is projected with an equal area Aitoff in the Galactic system (Milky Way at center)."

Another indicator of large-scale structure is the 'Lyman-alpha forest'. This is a collection of absorption lines that appear in the spectra of light from quasars, which are interpreted as indicating the existence of huge thin sheets of intergalactic (mostly hydrogen) gas. These sheets appear to be associated with the formation of new galaxies.

Caution is required in describing structures on a cosmic scale because things are often different from how they appear. Gravitational lensing (bending of light by gravitation) can make an image appear to originate in a different direction from its real source. This is caused when foreground objects (such as galaxies) curve surrounding spacetime (as predicted by general relativity), and deflect passing light rays. Rather usefully, strong gravitational lensing can sometimes magnify distant galaxies, making them easier to detect. Weak lensing (gravitational shear) by the intervening universe in general also subtly changes the observed large-scale structure.

The large-scale structure of the universe also looks different if one only uses redshift to measure distances to galaxies. For example, galaxies behind a galaxy cluster are attracted to it, and so fall towards it, and so are slightly blueshifted (compared to how they would be if there were no cluster) On the near side, things are slightly redshifted. Thus, the environment of the cluster looks somewhat squashed if using redshifts to measure distance. An opposite effect works on the galaxies already within a cluster: the galaxies have some random motion around the cluster center, and when these random motions are converted to redshifts, the cluster appears elongated. This creates a "finger of God"—the illusion of a long chain of galaxies pointed at the Earth.

Cosmography of Earth's cosmic neighborhood

At the centre of the Hydra-Centaurus Supercluster, a gravitational anomaly called the Great Attractor affects the motion of galaxies over a region hundreds of millions of light-years across. These galaxies are all redshifted, in accordance with Hubble's law. This indicates that they are receding from us and from each other, but the variations in their redshift are sufficient to reveal the existence of a concentration of mass equivalent to tens of thousands of galaxies.

The Great Attractor, discovered in 1986, lies at a distance of between 150 million and 250 million light-years (250 million is the most recent estimate), in the direction of the Hydra and Centaurus constellations. In its vicinity there is a preponderance of large old galaxies, many of which are colliding with their neighbours, or radiating large amounts of radio waves.

In 1987, astronomer R. Brent Tully of the University of Hawaii's Institute of Astronomy identified what he called the Pisces–Cetus Supercluster Complex, a structure one billion light-years long and 150 million light-years across in which, he claimed, the Local Supercluster was embedded.

Mass of ordinary matter

The mass of the observable universe is often quoted as 1050 tonnes or 1053 kg. In this context, mass refers to ordinary matter and includes the interstellar medium (ISM) and the intergalactic medium (IGM). However, it excludes dark matter and dark energy. This quoted value for the mass of ordinary matter in the universe can be estimated based on critical density. The calculations are for the observable universe only as the volume of the whole is unknown and may be infinite.

Estimates based on critical density

Critical density is the energy density for which the universe is flat. If there is no dark energy, it is also the density for which the expansion of the universe is poised between continued expansion and collapse. From the Friedmann equations, the value for critical density, is:

where G is the gravitational constant and H = H0 is the present value of the Hubble constant. The value for H0, due to the European Space Agency's Planck Telescope, is H0 = 67.15 kilometres per second per megaparsec. This gives a critical density of 0.85×10−26 kg/m3 (commonly quoted as about 5 hydrogen atoms per cubic metre). This density includes four significant types of energy/mass: ordinary matter (4.8%), neutrinos (0.1%), cold dark matter (26.8%), and dark energy (68.3%). Although neutrinos are Standard Model particles, they are listed separately because they are ultra-relativistic and hence behave like radiation rather than like matter. The density of ordinary matter, as measured by Planck, is 4.8% of the total critical density or 4.08×10−28 kg/m3. To convert this density to mass we must multiply by volume, a value based on the radius of the "observable universe". Since the universe has been expanding for 13.8 billion years, the comoving distance (radius) is now about 46.6 billion light-years. Thus, volume (4/3πr3) equals 3.58×1080 m3 and the mass of ordinary matter equals density (4.08×10−28 kg/m3) times volume (3.58×1080 m3) or 1.46×1053 kg.

Matter content—number of atoms

Assuming the mass of ordinary matter is about 1.45×1053 kg as discussed above, and assuming all atoms are hydrogen atoms (which are about 74% of all atoms in our galaxy by mass), the estimated total number of atoms in the observable universe is obtained by dividing the mass of ordinary matter by the mass of a hydrogen atom (1.45×1053 kg divided by 1.67×10−27 kg). The result is approximately 1080 hydrogen atoms, also known as the Eddington number.

Most distant objects

The most distant astronomical object yet announced as of 2016 is a galaxy classified GN-z11. In 2009, a gamma ray burst, GRB 090423, was found to have a redshift of 8.2, which indicates that the collapsing star that caused it exploded when the universe was only 630 million years old. The burst happened approximately 13 billion years ago, so a distance of about 13 billion light-years was widely quoted in the media (or sometimes a more precise figure of 13.035 billion light-years), though this would be the "light travel distance" rather than the "proper distance" used in both Hubble's law and in defining the size of the observable universe (cosmologist Ned Wright argues against the common use of light travel distance in astronomical press releases on this page, and at the bottom of the page offers online calculators that can be used to calculate the current proper distance to a distant object in a flat universe based on either the redshift z or the light travel time). The proper distance for a redshift of 8.2 would be about 9.2 Gpc, or about 30 billion light-years. Another record-holder for most distant object is a galaxy observed through and located beyond Abell 2218, also with a light travel distance of approximately 13 billion light-years from Earth, with observations from the Hubble telescope indicating a redshift between 6.6 and 7.1, and observations from Keck telescopes indicating a redshift towards the upper end of this range, around 7. The galaxy's light now observable on Earth would have begun to emanate from its source about 750 million years after the Big Bang.

Horizons

The limit of observability in our universe is set by a set of cosmological horizons which limit—based on various physical constraints—the extent to which we can obtain information about various events in the universe. The most famous horizon is the particle horizon which sets a limit on the precise distance that can be seen due to the finite age of the universe. Additional horizons are associated with the possible future extent of observations (larger than the particle horizon owing to the expansion of space), an "optical horizon" at the surface of last scattering, and associated horizons with the surface of last scattering for neutrinos and gravitational waves.

Universal resurrection

From Wikipedia, the free encyclopedia

The Last Trumpet sounded, detail of the Holy Thorn Reliquary, 1390s

General resurrection
or universal resurrection is the belief in a resurrection of the dead, or resurrection from the dead (Koine: ἀνάστασις [τῶν] νεκρῶν, anastasis [ton] nekron; literally: "standing up again of the dead") by which most or all people who have died would be resurrected (brought back to life). Various forms of this concept can be found in Bahai, Christian, Islamic, Jewish and Zoroastrian eschatology.

Rabbinic and Samaritan Judaism

Resurrection of the Dead, fresco from the Dura-Europos synagogue
 

There are three explicit examples in the Hebrew Bible of people being resurrected from the dead:

  • The prophet Elijah prays and God raises a young boy from death (1 Kings 17:17–24)
  • Elisha raises the son of the Shunammite woman (2 Kings 4:32–37); this was the very same child whose birth he previously foretold (2 Kings 4:8–16)
  • A dead man's body that was thrown into the dead Elisha's tomb is resurrected when the body touches Elisha's bones (2 Kings 13:21)

While there was no belief in personal afterlife with reward or punishment in Judaism before 200 BC, in later Judaism and Samaritanism it is believed that the God of Israel will one day give teḥiyyat ha-metim ("life to the dead") to the righteous during the Messianic Age, and they will live forever in the world to come (Olam Ha-Ba). Jews today base this belief on the Book of Isaiah (Yeshayahu), Book of Ezekiel (Yeḥez'qel), and Book of Daniel (Dani'el). Samaritans base it solely on a passage called the Haazinu in the Samaritan Pentateuch, since they accept only the Torah and reject the rest of the Hebrew Bible.

During the Second Temple period, Judaism developed a diversity of beliefs concerning the resurrection. The concept of resurrection of the physical body is found in 2 Maccabees, according to which it will happen through recreation of the flesh. Resurrection of the dead also appears in detail in the extra-canonical books of Enoch, in the Apocalypse of Baruch, and 2 Esdras. According to the British scholar in ancient Judaism Philip R. Davies, there is "little or no clear reference ... either to immortality or to resurrection from the dead" in the Dead Sea scrolls texts. Both Josephus and the New Testament record that the Sadducees did not believe in an afterlife, but the sources vary on the beliefs of the Pharisees. The New Testament claims that the Pharisees believed in the resurrection, but does not specify whether this included the flesh or not. According to Josephus, who himself was a Pharisee, the Pharisees held that only the soul was immortal and the souls of good people will be reincarnated and "pass into other bodies," while "the souls of the wicked will suffer eternal punishment." Paul the Apostle, who also was a Pharisee, said that at the resurrection what is "sown as a natural body is raised a spiritual body." Jubilees refers only to the resurrection of the soul, or to a more general idea of an immortal soul. The Second Temple Judaism tradition at Qumran held that there would be a resurrection of just and unjust, but of the very good and very bad, and of Jews only. The extent of the resurrection in 2 Baruch and 4 Ezra is debated by scholars.

The resurrection of the dead is a core belief in the Mishnah which was assembled in the early centuries of the Christian era. The belief in resurrection is expressed on all occasions in the Jewish liturgy; e.g., in the morning prayer Elohai Neshamah, in the Shemoneh 'Esreh and in the funeral services. Jewish halakhic authority Maimonides set down his Thirteen Articles of Faith which have ever since been printed in all Rabbinic Siddur (prayer books). Resurrection is the thirteenth principle: "I firmly believe that there will take place a revival of the dead at a time which will please the Creator, blessed be His name." Modern Orthodox Judaism holds belief in the resurrection of the dead to be one of the cardinal principles of Rabbinic Judaism.

Harry Sysling, in his 1996 study of Teḥiyyat Ha-Metim in the Palestinian Targumim, identifies a consistent usage of the term "second death" in texts from the Second Temple period and early rabbinical writings, but not in the Hebrew Bible. "Second death" is identified with judgment, followed by resurrection from Gehinnom ("Gehenna") at the Last Day.

Christianity

Detail from a North Mississippi Christian cemetery headstone with the inscription: "May the resurrection find thee On the bosom of thy God."

Epistles

In the First Epistle to the Corinthians chapter 15, ἀνάστασις νεκρῶν is used for the resurrection of the dead. In verses 54–55, Paul the Apostle is conveyed as quoting from the Book of Hosea 13:14 where he speaks of the abolition of death. In the Pauline epistles of the New Testament, Paul the Apostle wrote that those who will be resurrected to eternal life will be resurrected with spiritual bodies, which are imperishable; the "flesh and blood" of natural, perishable bodies cannot inherit the kingdom of God, and, likewise, those that are corruptible will not receive incorruption (1 Corinthians 15:35–54). Even though Paul does not explicitly establish that immortality excludes physical bodies, some scholars understand that according to Paul, flesh is simply to play no part, as people are made immortal.

Gospels and Acts

The Gospel of Matthew has Jesus famously teach/preach for the first time in 4:17, "Repent, for the kingdom of heaven is at hand." Matthew 6:19-21. It introduces the expression ἀναστάσεως τῶν νεκρῶν, which is used in a monologue by Jesus who speaks to the crowds about "the resurrection" called simply ῇ ἀναστάσει (Mat. 22:29–33). This type of resurrection refers to the raising up of the dead, all mankind, at the end of this present age, the general or universal resurrection.

In the canonical gospels, the resurrection of Jesus is described as a resurrection of the flesh: from the empty tomb in Mark; the women embracing the feet of the resurrected Jesus in Matthew; the insistence of the resurrected Jesus in Luke that he is of "flesh and bones" and not just a spirit or pneuma; to the resurrected Jesus encouraging the disciples to touch his wounds in John.

In Acts of the Apostles the expression ἀναστάσεως νεκρῶν was used by the Apostles and Paul the Apostle to defend the doctrine of the resurrection. Paul brought up the resurrection in his trial before Ananias ben Nedebaios. The expression was variously used in reference to a general resurrection (Acts 24:21) at the end of this present age (Acts 23:6, 24:15).

Acts 24:15 in the King James Version reads: "... there shall be a resurrection of the dead, both of the just and unjust."

Nicene Creed and early Christianity

Resurrection of the Flesh (c. 1500) by Luca Signorelli – based on 1 Corinthians 15: 52: "the trumpet shall sound, and the dead shall be raised incorruptible, and we shall be changed." Chapel of San Brizio, Duomo, Orvieto.

Most Christian denominations profess the Nicene Creed, which affirms the resurrection of the dead; most English versions of the Nicene Creed in current use include the phrase: "We look for the resurrection of the dead, and the life of the world to come."

The Christian writers Irenaeus and Justin Martyr, in the 2nd century, wrote against the idea that only the soul survived. (The word "soul" is unknown in the Aramaic; it entered Christian theology through the Greek.) Justin Martyr insists that a man is both soul and body and Christ has promised to raise both, just as his own body was raised.

The Christian doctrine of resurrection is based on Christ's resurrection. There was no ancient Greek belief in a general resurrection of the dead. Indeed, they held that once a body had been destroyed, there was no possibility of returning to life as not even the gods could recreate the flesh.

Several early Church Fathers, like Pseudo-Justin, Justin Martyr, Tatian, Irenaeus, and Athenagoras of Athens argue about the Christian resurrection beliefs in ways that answer to this traditional Greek scepticism to post-mortal physical continuity. The human body could not be annihilated, only dissolved – it could not even be integrated in the bodies of those who devoured it. Thus God only had to reassemble the minute parts of the dissolved bodies in the resurrection.

Traditional Christian Churches, i.e. ones that adhere to the creeds, continue to uphold the belief that there will be a general and universal resurrection of the dead at "the end of time", as described by Paul when he said: "He hath appointed a day, in which he will judge the world" (Acts 17:31 KJV) and "There shall be a resurrection of the dead, both of the just and unjust" (Acts 24:15 KJV).

Modern Era

Early Christian church fathers defended the resurrection of the dead against the pagan belief that the immortal soul went to the underworld immediately after death. Currently, however, it is a popular Christian belief that the souls of the righteous go to Heaven.

At the close of the medieval period, the modern era brought a shift in Christian thinking from an emphasis on the resurrection of the body back to the immortality of the soul. This shift was a result of a change in the zeitgeist, as a reaction to the Renaissance and later to the Enlightenment. André Dartigues has observed that especially "from the 17th to the 19th century, the language of popular piety no longer evoked the resurrection of the soul but everlasting life. Although theological textbooks still mentioned resurrection, they dealt with it as a speculative question more than as an existential problem."

This shift was supported not by any scripture, but largely by the popular religion of the Enlightenment, deism. Deism allowed for a supreme being, such as the philosophical first cause, but denied any significant personal or relational interaction with this figure. Deism, which was largely led by rationality and reason, could allow a belief in the immortality of the soul, but not necessarily in the resurrection of the dead. American deist Ethan Allen demonstrates this thinking in his work, Reason the Only Oracle of Man (1784) where he argues in the preface that nearly every philosophical problem is beyond humanity's understanding, including the miracles of Christianity, although he does allow for the immortality of an immaterial soul.

Influence on secular law and custom

In Christian theology, it was once widely believed that to rise on Judgment Day the body had to be whole and preferably buried with the feet to the east so that the person would rise facing God. An Act of Parliament from the reign of King Henry VIII stipulated that only the corpses of executed murderers could be used for dissection. Restricting the supply to the cadavers of murderers was seen as an extra punishment for the crime. If one believes dismemberment stopped the possibility of resurrection of an intact body on judgment day, then a posthumous execution is an effective way of punishing a criminal. Attitudes towards this issue changed very slowly in the United Kingdom and were not manifested in law until the passing of the Anatomy Act in 1832. For much of the British population it was not until the 20th century that the link between the body and resurrection was finally broken as cremation was only made legal in 1902.

Denominational views

In Catholicism, Augustine of Hippo believed in a universal resurrection of bodies for all immortal souls. According to the Catholic Encyclopedia: "No doctrine of the Christian Faith", says St. Augustine, "is so vehemently and so obstinately opposed as the doctrine of the resurrection of the flesh." This opposition had begun long before the days of St. Augustine." According to the Summa Theologica, spiritual beings that have been restored to glorified bodies will have the following basic qualities:

  • Impassibility (incorruptible / painless) – immunity from death and pain
  • Subtility (permeability) – freedom from restraint by matter
  • Agility – obedience to spirit with relation to movement and space (the ability to move through space and time with the speed of thought)
  • Clarity – resplendent beauty of the spirit manifested in the body (as when Jesus was transfigured on Mount Tabor)

According to the Catholic Encyclopedia (1911) article on "General resurrection" "The Fourth Lateran Council (1215) teaches that all men, whether elect or reprobate, "will rise again with their own bodies which they now bear about with them" (chapter "Firmiter"). In the language of the creeds and professions of faith this return to life is called resurrection of the body (resurrectio carnis, resurrectio mortuorum, anastasis ton nekron) for a double reason: first, since the soul cannot die, it cannot be said to return to life; second the heretical contention of Hymeneus and Philitus that the Scriptures denote by resurrection not the return to life of the body, but the rising of the soul from the death of sin to the life of grace, must be excluded."

The Catechism of the Catholic Church says:

997 What is "rising"? In death, the separation of the soul from the body, the human body decays and the soul goes to meet God, while awaiting its reunion with its glorified body. God, in his almighty power, will definitively grant incorruptible life to our bodies by reuniting them with our souls, through the power of Jesus' Resurrection.

998 Who will rise? All the dead will rise, "those who have done good, to the resurrection of life, and those who have done evil, to the resurrection of judgment."

999 How? Christ is raised with his own body: "See my hands and my feet, that it is I myself"; but he did not return to an earthly life. So, in him, "all of them will rise again with their own bodies which they now bear," but Christ "will change our lowly body to be like his glorious body," into a "spiritual body":

But someone will ask, "How are the dead raised? With what kind of body do they come?" You foolish man! What you sow does not come to life unless it dies. and what you sow is not the body which is to be, but a bare kernel ....What is sown is perishable, what is raised is imperishable.... the dead will be raised imperishable.... For this perishable nature must put on the imperishable, and this mortal nature must put on immortality.(1 Cor 15:35-37. 42. 53).

1001 When? Definitively "at the last day," "at the end of the world." Indeed, the resurrection of the dead is closely associated with Christ's Parousia:

For the Lord himself will descend from heaven, with a cry of command, with the archangel's call, and with the sound of the trumpet of God. and the dead in Christ will rise first. (1 Thess 4:16)

1038 The resurrection of all the dead, "of both the just and the unjust" (Acts 24:15), will precede the Last Judgment. This will be "the hour when all who are in the tombs will hear [the Son of man's] voice and come forth, those who have done good, to the resurrection of life, and those who have done evil, to the resurrection of judgment" (Jn 5:28-29).

In Anglicanism, scholars such as the Bishop of Durham N. T. Wright, have defended the primacy of the resurrection in Christian faith. Interviewed by Time in 2008, senior Anglican bishop and theologian N. T. Wright spoke of "the idea of bodily resurrection that people deny when they talk about their 'souls going to Heaven,'" adding: "I've often heard people say, 'I'm going to heaven soon, and I won't need this stupid body there, thank goodness.' That's a very damaging distortion, all the more so for being unintentional." Instead, Wright explains: "In the Bible we are told that you die, and enter an intermediate state." This is "conscious," but "compared to being bodily alive, it will be like being asleep." This will be followed by resurrection into new bodies, he says. "Our culture is very interested in life after death, but the New Testament is much more interested in what I've called the life after life after death."

Among the original Forty-Two Articles of the Church of England, one read: "The resurrection of the dead is not as yet brought to pass, as though it only belonged to the soul, which by the grace of Christ is raised from the death of sin, but it is to be looked for at the last day; for then (as Scripture doth most manifestly testify) to all that be dead their own bodies, flesh and bone shall be restored, that the whole man may (according to his works) have other reward or punishment, as he hath lived virtuously, or wickedly."

Of Baptists, James Leo Garrett Jr., E. Glenn Hinson, and James E. Tull write that "Baptists traditionally have held firmly to the belief that Christ rose triumphant over death, sin, and hell in a bodily resurrection from the dead."

In Lutheranism, Martin Luther personally believed and taught resurrection of the dead in combination with soul sleep. However, this is not a mainstream teaching of Lutheranism and most Lutherans traditionally believe in resurrection of the body in combination with the immortal soul. According to the Lutheran Church–Missouri Synod (LCMS), on the last day all the dead will be resurrected. Their souls will then be reunited with the same bodies they had before dying. The bodies will then be changed, those of the wicked to a state of everlasting shame and torment, those of the righteous to an everlasting state of celestial glory.

In Methodism, the Reverend M. Douglas Meeks, professor of theology and Wesleyan studies at Vanderbilt Divinity School, states that "it is very important for Christians to hold to the resurrection of the body." F. Belton Joyner in United Methodist Answers, states that the "New Testament does not speak of a natural immortality of the soul, as if we never actually die. It speaks of resurrection of the body, the claim that is made each time we state the historic Apostles' Creed and classic Nicene Creed," given in The United Methodist Hymnal. In ¶128 of the Book of Discipline of the Free Methodist Church it is written: "There will be a bodily resurrection from the dead of both the just and the unjust, they that have done good unto the resurrection of life, they that have done evil unto the resurrection of the damnation. The resurrected body will be a spiritual body, but the person will be whole identifiable. The Resurrection of Christ is the guarantee of resurrection unto life to those who are in Him." John Wesley, the founder of the Methodist Church, in his sermon On the Resurrection of the Dead, defended the doctrine, stating "There are many places of Scripture that plainly declare it. St. Paul, in the 53d verse of this chapter, tells us that 'this corruptible must put on incorruption, and this mortal must put on immortality.' [1 Corinthians 15:53]." In addition, notable Methodist hymns, such as those by Charles Wesley, link 'our resurrection and Christ's resurrection".

In Christian conditionalism, there are several churches, such as the Anabaptists and Socinians of the Reformation, then Seventh-day Adventist Church, Christadelphians, Jehovah's Witnesses, and theologians of different traditions who reject the idea of the immortality of a non-physical soul as a vestige of Neoplatonism, and other pagan traditions. In this school of thought, the dead remain dead (and do not immediately progress to a Heaven, Hell, or Purgatory) until a physical resurrection of some or all of the dead occurs at the end of time, or in Paradise restored on earth, in a general resurrection. Some groups, Christadelphians in particular, consider that it is not a universal resurrection, and that at this time of resurrection that the Last Judgment will take place.

The first-century treatise Didache comments 'Not the resurrection of everyone, but, as it says, "The Lord will come and all his holy ones with him" (16.7)

Many Evangelicals believe in a universal resurrection, but divided into two separate resurrections; at the Second Coming and then again at the Great White Throne. The Doctrinal Basis of the Evangelical Alliance affirms belief in "the resurrection of the body, the judgment of the world by our Lord Jesus Christ, with the eternal blessedness of the righteous, and the eternal punishment of the wicked."

Latter Day Saints believe that God has a plan of salvation. Before the resurrection, the spirits of the dead are believed to exist in a place known as the spirit world, which is similar to, yet fundamentally distinct from, the traditional concept of Heaven and Hell. It is believed that the spirit retains its wants, beliefs, and desires in the afterlife. Doctrine of The Church of Jesus Christ of Latter-day Saints teaches that Jesus Christ was the first person to be resurrected, and that all those who have lived on the earth will be resurrected because of Jesus Christ, regardless of their righteousness. The Church teaches that not all are resurrected at the same time; the righteous will be resurrected in a "first resurrection" and unrepentant sinners in a "last resurrection." The resurrection is believed to unite the spirit with the body again, and the Church teaches that the body (flesh and bone) will be made whole and become incorruptible, a state which includes immortality. There is also a belief in Latter-day Saint doctrine that a few exceptional individuals were removed from the earth "without tasting of death." This is referred to as translation, and these individuals are believed to have retained their bodies in a purified form, though they too will eventually be required to receive resurrection.

Some millennialists interpret the Book of Revelation as requiring two physical resurrections of the dead, one before the Millennium, the other after it.

Mortalists, those Christians who do not believe that humans have immortal souls, may believe in a universal resurrection, such as Martin Luther, and Thomas Hobbes in Leviathan. Some mortalist denominations may believe in a universal resurrection of all the dead, but in two resurrection events, one at either end of a millennium, such as Seventh-day Adventists. Other mortalist denominations deny a universal resurrection, such as Christadelphians and hold that the dead count three groups; the majority who will never be raised, those raised to condemnation, and a second final destruction in the "Second Death", and those raised to eternal life.

Islam

According to Islamic eschatology, the Day of Resurrection (yawm al-qiyāmah) is believed to be God's final assessment of humanity. The sequence of events (according to the most commonly held belief) is the annihilation of all creatures, resurrection of the body, and the judgment of all sentient creatures. The exact time when these events will occur is unknown, however there are said to be major and minor signs which are to occur near the time of Qiyamah (end time). Many Quranic verses, especially the earlier ones, are dominated by the idea of the nearing of the day of resurrection.

In the sign of nafkhatu'l-ula, a trumpet will be sounded for the first time, and result in the death of the remaining sinners. Then there will be a period of forty years. The eleventh sign is the sounding of a second trumpet to signal the resurrection as ba'as ba'da'l-mawt. Then all will be naked and running to the Place of Gathering, while the enemies of Allah will be travelling on their faces with their legs upright.

The Day of Resurrection is one of the six articles of Islamic faith. Everybody will account for their deeds in this world and people will go to heaven or hell.

Bahai Faith

Zoroastrianism

The Zoroastrian belief in an end times renovation of the earth is known as frashokereti, which includes some form of revival of the dead that can be attested from no earlier than the 4th century BCE. As distinct from Judaism this is the resurrection of all the dead to universal purification and renewal of the world. In the frashokereti doctrine, the final renovation of the universe is when evil will be destroyed, and everything else will be then in perfect unity with God (Ahura Mazda). The term probably means "making wonderful, excellent". The doctrinal premises are (1) good will eventually prevail over evil; (2) creation was initially perfectly good, but was subsequently corrupted by evil; (3) the world will ultimately be restored to the perfection it had at the time of creation; (4) the "salvation for the individual depended on the sum of (that person's) thoughts, words and deeds, and there could be no intervention, whether compassionate or capricious, by any divine being to alter this." Thus, each human bears the responsibility for the fate of his own soul, and simultaneously shares in the responsibility for the fate of the world.

Problem of Hell


Trinitarian universalism

From Wikipedia, the free encyclopedia
The highest heaven from Gustave Doré's illustrations to the Divine Comedy.

Trinitarian Universalism is a variant of belief in universal salvation, the belief that every person will be saved, that also held the Christian belief in Trinitarianism (as opposed to, or contrasted with, liberal Unitarianism which is more usually associated with Unitarian Universalism). It was particularly associated with an ex-Methodist New England minister, John Murray, and after his death in 1815 the only clergy known to be preaching Trinitarian Universalism were Paul Dean of Boston and Edward Mitchell in New York.

History

Traditionally, the doctrine of Universalism was traced by Universalist historians back to the teachings of Origen of Alexandria (c.185–284), an influential early Church Father and writer. Origen believed in apocatastasis, the ultimate restoration and reconciliation of creation with God, which was interpreted by Universalists historians to mean the salvation and reconciliation with God of all souls which had ever existed, including Satan and his demons. However more recent research has shown that this analysis of Origen's views is uncertain. Origen also believed in the pre-existence of souls and that glorified Man may have to go through cycles of sin and redemption before reaching perfection. The teachings of Origen were declared anathema at the Ecumenical Council of 553, centuries after his death, though Gregory of Nyssa, another figure to whom Universalist historians attributed Universalist belief, was commended as an Orthodox defender of the faith by the same Council. Universalist historians have also identified Johannes Scotus Eriugena (815–877), and Amalric of Bena (c. 1200) as Universalists. Much of this research was incorporated by French priest Pierre Batiffol into an article on Apocatastasis later translated for the 1911 Catholic Encyclopedia.

During the Protestant Reformation, all doctrines and practices of the Catholic (Universal) Church were re-examined and numerous sects formed, although none revived the belief (originally attributed to Origen) in universal reconciliation. In 1525, Hans Denck (1425–1527) was accused of being a Universalist, but this is now considered unlikely.

Jane Leade (1623–1704), a mystic who claimed to have seen heaven and hell, started a Universalist congregation, the Philadelphians, which dissipated after her death. She was a Behmenist rather than orthodox Trinitarian.

John Murray (1741–1815) was forced to leave the Methodist Church because of his Universalism. In 1770, he came to New England and is credited with being the Father of Universalism in North America. Although Murray was a Trinitarian (as was his mentor, James Relly), his successor, Hosea Ballou (1771–1852) was a strong Unitarian who opposed Trinitarianism, Calvinism, and legalism. During his tenure, Universalism became linked with liberal theology as well as Unitarianism.

Modern Trinitarian Universalists include Robin Parry an evangelical writer, who under the pseudonym of "Gregory MacDonald" released a book The Evangelical Universalist, (2006) and Thomas Talbott author of The Inescapable Love of God (1999).

Philosophy

Thomas Talbott offers three propositions which are biblically based, but which he asserts to be mutually exclusive:

  1. God is omnipotent and exercises sovereign control over all aspects of human life and history.
  2. God is omni-benevolent, is ontologically Love, and desires the salvation of all people.
  3. Some (many) persons will experience everlasting, conscious torment in a place of (either literal or metaphorical) fire.

Traditional theology clarifies omnipotence or omni-benevolence to resolve the contradiction. Calvinism resolves it by positing a doctrine of limited atonement, which claims that God's love is restricted. Only a select number of people are elected to be saved, which includes redemption and purification. This demonstrates a special love, and most people (the 'eternally reprobate' or non-elect) are given only common grace and tolerance. This bifurcation of grace intends to retain a doctrine of God's omnibenevolence and a doctrine of hell. In comparison, Arminianism resolves the contradiction by rejecting divine omnipotence with respect to human will. This is commonly referred to as synergism. It posits that human beings have an inviolable free will, which allows the choice of accepting or rejecting God's grace. Universalists disagree with the third claim, and argue that all people receive salvation.

Bible passages cited to support Universalism

Universalism and heresy

Heresy is "adherence to a religious opinion contrary to church dogma". Because dogma varies among denominations, what is considered heresy by one denomination or congregation may be accepted as doctrine or opinion by another. In a socially free world, free moral agents may identify with whichever perspectives and positions, persons and communities, and traditions (or subtraditions) they find most intellectually, emotionally, and spiritually palatable. However, the results of their exercise of this operational freedom may be understood or interpreted differently by different persons.

There are three (3) generally accepted understandings of hell:

  1. A literal place of fire where the damned suffer eternal conscious torment.
  2. A metaphorical hell where the suffering is real but is not literally fire and brimstone. The pain may be physical, emotional or spiritual.
  3. Conditional, where souls are punished until retributive justice is met or accomplished, after which these punished souls are annihilated.

There is also the doctrine of purgatory, distinct from hell, where imperfect souls are cleansed and made ready for heaven. It may be a place of rehabilitation, correction, or retribution.

Universalists believe that every person will be saved, where more orthodox Roman Catholics believe that only those who died in God's grace will find purgation for their venial sins in Purgatory.

The Argument

There are four (4) major theories about human salvation in Christendom:

  1. Exclusivism: Salvation is exclusively found in Christianity. Anyone who is not a Christian will go to hell.
  2. Inclusivism: Some adherents of other religions may find salvation, but it is still only Jesus Christ who can (and may or will) save them.
  3. Pluralism: One's own religion is not the sole and exclusive source of truth; salvation, in principle, may be found in any religion, although salvation is not necessarily found in one's search of any (other) religion(s).
  4. Universalism: All persons (and peoples?) will be saved.

Christian denominations and churches will generally profess one of the above to be true and the others as error; however, they are not all mutually exclusive. For example, some who hold to #4 "Universalism" also hold to #1 "Exclusivism." For these, anyone who is not a Christian will go to hell, but ultimately everyone will become a Christian and therefore be saved. Others may be #2 "Inclusivists" and #3 "Pluralists." For those who might hold to these, because God may use the tools of any particular religion or culture to reveal his grace in Christ(Inclusivism), other religions therefore, potentially exhibiting the effects of this work, may in fact hold valuable insights to truth for theology(Pluralism), consequently calling the members of a particular congregation/denomination/religion to be open to that possibility.

Objections

Arminian objections

Arminianism holds that God will not abrogate humanity's free will because love must be chosen, not forced, and that some people will choose alienation from God over consummation, and so God has "graciously" provided a place for them to exist. C.S. Lewis speculated, through literary allegory, that hell is locked from within but few will leave because over a lifetime and through the coming ages, they will become more and more at home in hell.

A Trinitarian Universalist believer might counter that for God to allow his misguided and confused children to suffer eternal separation from him is the very opposite of grace, runs counter to his loving and sovereign nature, and would compare unfavorably to the attitude and behavior of even average human parents toward their children. The Bible seems to teach that those who believe do so because God caused them to believe, not by any freedom of choice of their own (Ephesians 2:8–10), and they might cite the following in support their answer:

"He choose us in Him before the foundation of the world, that we would be holy and blameless before Him. In love He predestined us to adoption as sons through Jesus Christ to Himself, according to the kind intention of His will, to the praise of the glory of His grace, which He freely bestowed on us in the Beloved." Ephesians 1:4–6

"For He says to Moses, 'I will have mercy on whom I have mercy, and I will have compassion on whom I have compassion.' So then it {does} not {depend} on the man who wills or the man who runs, but on God who has mercy." Romans 9:15–16 (See also: John 15:16, Philippians 1:29, Ephesians 1:11)

Also, the Bible in several places refers to freedom being only for those freed through Christ, and that those who are not in Christ are in darkness under the dominion of Satan (Acts 26:18), and are slaves to sin (John 8:34). Therefore, it would make no sense to maintain that someone can have the "freedom" to "reject God"—it is only by sin that people reject God. Those in sin are slaves to sin and Satan, and therefore it is only God who can, by his grace, release them from that bondage and make them able to believe:

"The Lord's bond-servant must not be quarrelsome, but be kind to all, able to teach, patient when wronged, with gentleness correcting those who are in opposition, if perhaps God may grant them repentance leading to the knowledge of the truth, and they may come to their senses {and escape} from the snare of the devil, having been held captive by him to do his will."

Mortalist objections

Mortalists object that, in their view, the Bible does not teach torment of souls, either in Hades, nor at the Last Day in Gehenna.

Hope of universal salvation

Apart from the dogmatic belief that a sentence of endless torment in hell is incompatible with God's moral character there are notable theologians who believe that God wants everyone to be saved and that it is possible for God to save everyone but, at the same time, they will not limit God's sovereign right to choose not to save everyone.

While Thomas Talbott, "Gregory MacDonald" (the penname for Robin Parry) and Eric Reitan regard everlasting punishment as impossible, Reformed, neo-orthodox theologian Karl Barth and Catholic theologian Hans Urs von Balthasar believed that the eventual salvation of all was merely a possibility.

Operator (computer programming)

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