Search This Blog

Friday, November 14, 2025

Paranormal

From Wikipedia, the free encyclopedia
https://en.wikipedia.org/wiki/Paranormal

Paranormal events are purported phenomena described in popular culture, folklore, and other non-scientific bodies of knowledge, whose existence within these contexts is described as being beyond the scope of normal scientific understanding. Notable paranormal beliefs include those that pertain to extrasensory perceptions (for example, telepathy), and the pseudosciences of ghost hunting, cryptozoology, and ufology.

Proposals regarding the paranormal are different from scientific hypotheses or speculations extrapolated from scientific evidence because scientific ideas are grounded in empirical observations and experimental data gained through the scientific method. In contrast, those who argue for the existence of the paranormal explicitly do not base their arguments on empirical evidence but rather on anecdote, testimony and suspicion. The standard scientific models give the explanation that what appears to be paranormal phenomena is usually a misinterpretation, misunderstanding or anomalous variation of natural phenomena.

Etymology

The term paranormal has existed in the English language since at least 1920. The word consists of two parts: para and normal. The definition implies that the scientific explanation of the world around us is normal and anything that is above, beyond, or contrary to that is para.

Paranormal subjects

On the classification of paranormal subjects, psychologist Terence Hines said in his book Pseudoscience and the Paranormal (2003):

The paranormal can best be thought of as a subset of pseudoscience. What sets the paranormal apart from other pseudosciences is a reliance on explanations for alleged phenomena that are well outside the bounds of established science. Thus, paranormal phenomena include extrasensory perception (ESP), telekinesis, ghosts, poltergeists, life after death, reincarnation, faith healing, human auras, and so forth. The explanations for these allied phenomena are phrased in vague terms of "psychic forces", "human energy fields", and so on. This is in contrast to many pseudoscientific explanations for other nonparanormal phenomena, which, although very bad science, are still couched in acceptable scientific terms.

Ghost hunting

Ghost hunting is the investigation of locations that are reportedly haunted by ghosts. Typically, a ghost-hunting team will attempt to collect evidence supporting the existence of paranormal activity.

In traditional ghostlore, and fiction featuring ghosts, a ghost is a manifestation of the spirit or soul of a person. Alternative theories expand on that idea and include belief in the ghosts of deceased animals. Sometimes the term "ghost" is used synonymously with any spirit or demon; however, in popular usage the term typically refers to the spirit of a deceased person.

The belief in ghosts as souls of the departed is closely tied to the concept of animism, an ancient belief that attributed souls to everything in nature. As the 19th-century anthropologist George Frazer explained in his classic work, The Golden Bough (1890), souls were seen as the 'creature within' which animated the body. Although the human soul was sometimes symbolically or literally depicted in ancient cultures as a bird or other animal, it was widely held that the soul was an exact reproduction of the body in every feature, even down to the clothing worn by the person. This is depicted in artwork from various ancient cultures, including such works as the ancient Egyptian Book of the Dead (c. 1550 BCE), which shows deceased people in the afterlife appearing much as they did before death, including the style of dress.

Ufology

The possibility of extraterrestrial life is not, in itself, a paranormal subject. Many scientists are actively engaged in the search for unicellular life within the Solar System, carrying out studies on the surface of Mars and examining meteors that have fallen to Earth. Projects such as SETI are conducting an astronomical search for radio activity that would show evidence of intelligent life outside the Solar System. Scientific theories of how life developed on Earth allow for the possibility that life also developed on other planets. The paranormal aspect of extraterrestrial life centers largely around the belief in unidentified flying objects (UFOs) and the phenomena said to be associated with them.

Early in the history of UFO culture, believers divided themselves into two camps. The first held a rather conservative view of the phenomena, interpreting them as unexplained occurrences that merited serious study. They began calling themselves "ufologists" in the 1950s and felt that logical analysis of sighting reports would validate the notion of extraterrestrial visitation.

The second camp held a view that coupled ideas of extraterrestrial visitation with beliefs from existing quasi-religious movements. Typically, these individuals were enthusiasts of occultism and the paranormal. Many had backgrounds as active Theosophists or spiritualists, or were followers of other esoteric doctrines. In contemporary times, many of these beliefs have coalesced into New Age spiritual movements.

Both secular and spiritual believers describe UFOs as having abilities beyond what are considered possible according to known aerodynamic constraints and physical laws. The transitory events surrounding many UFO sightings preclude any opportunity for the repeat testing required by the scientific method. Acceptance of UFO theories by the larger scientific community is further hindered by the many possible hoaxes associated with UFO culture.

Cryptozoology

Cryptozoology is a pseudoscience and subculture that aims to prove the existence of entities from the folklore record, such as Bigfoot, chupacabras, or Mokele-mbembe. Cryptozoologists refer to these entities as cryptids, a term coined by the subculture.

Paranormal research

Approaching the paranormal from a research perspective is often difficult because of the lack of acceptable physical evidence from most of the purported phenomena. By definition, the paranormal (or supernatural) does not conform to conventional expectations of nature. Therefore, a phenomenon cannot be confirmed as paranormal using the scientific method because, if it could be, it would no longer fit the definition. (However, confirmation would result in the phenomenon being reclassified as part of science.) Despite this problem, studies on the paranormal are periodically conducted by researchers from various disciplines. Some researchers simply study the beliefs in the paranormal regardless of whether the phenomena are considered to objectively exist. This section deals with various approaches to the paranormal: anecdotal, experimental, and participant-observer approaches and the skeptical investigation approach.

Anecdotal approach

Charles Fort, 1920. Fort is perhaps the most widely known collector of paranormal stories.

An anecdotal approach to the paranormal involves the collection of stories told about the paranormal.

Charles Fort (1874–1932) is perhaps the best-known collector of paranormal anecdotes. Fort is said to have compiled as many as 40,000 notes on unexplained paranormal experiences, though there were no doubt many more. These notes came from what he called "the orthodox conventionality of Science", which were odd events originally reported in magazines and newspapers such as The Times and scientific journals such as Scientific American, Nature and Science. From this research Fort wrote seven books, though only four survive: The Book of the Damned (1919), New Lands (1923), Lo! (1931) and Wild Talents (1932); one book was written between New Lands and Lo!, but it was abandoned and absorbed into Lo!

Reported events that he collected include teleportation (a term Fort is generally credited with coining); poltergeist events; falls of frogs, fishes, and inorganic materials of an amazing range; crop circles; unaccountable noises and explosions; spontaneous fires; levitation; ball lightning (a term explicitly used by Fort); unidentified flying objects; mysterious appearances and disappearances; giant wheels of light in the oceans; and animals found outside their normal ranges (see phantom cat). He offered many reports of OOPArts, the abbreviation for "out of place" artifacts: strange items found in unlikely locations. He is perhaps the first person to explain strange human appearances and disappearances by the hypothesis of alien abduction and was an early proponent of the extraterrestrial hypothesis.

Fort is considered by many as the father of modern paranormalism, which is the study of the paranormal.

The magazine Fortean Times continues Charles Fort's approach, regularly reporting anecdotal accounts of the paranormal.

Such anecdotal collections, lacking the reproducibility of empirical evidence, are not amenable to scientific investigation. The anecdotal approach is not a scientific approach to the paranormal because it leaves verification dependent on the credibility of the party presenting the evidence. Nevertheless, it is a common approach to investigating paranormal phenomena.

Parapsychology

Participant of a Ganzfeld experiment which proponents say may show evidence of telepathy.

Experimental investigation of the paranormal has been conducted by parapsychologists. J. B. Rhine popularized the now famous methodology of using card-guessing and dice-rolling experiments in a laboratory in the hopes of finding evidence of extrasensory perception. However, it was revealed that Rhine's experiments contained methodological flaws and procedural errors.

In 1957, the Parapsychological Association was formed as the preeminent society for parapsychologists. In 1969, they became affiliated with the American Association for the Advancement of Science. Criticisms of the field were focused in the creation (in 1976) of the Committee for the Scientific Investigation of Claims of the Paranormal (now called the Committee for Skeptical Inquiry) and its periodical, the Skeptical Inquirer. Eventually, more mainstream scientists became critical of parapsychology as an endeavor, and statements by the National Academies of Science and the National Science Foundation cast a pall on the claims of evidence for parapsychology. Today, many cite parapsychology as an example of a pseudoscience. Parapsychology has been criticized for continuing investigation despite being unable to provide convincing evidence for the existence of any psychic phenomena after more than a century of research.

By the 2000s, the status of paranormal research in the United States had greatly declined from its height in the 1970s, with the majority of work being privately funded and only a small amount of research being carried out in university laboratories. In 2007, Britain had a number of privately funded laboratories in university psychology departments. Publication remained limited to a small number of niche journals, and to date there have been no experimental results that have gained wide acceptance in the scientific community as valid evidence of the paranormal.

Participant-observer approach

A ghost hunter taking an EMF reading, which proponents claim may be connected to paranormal activity

While parapsychologists look for quantitative evidence of the paranormal in laboratories, a great number of people immerse themselves in qualitative research through participant-observer approaches to the paranormal. Participant-observer methodologies have overlaps with other essentially qualitative approaches, including phenomenological research that seeks largely to describe subjects as they are experienced, rather than to explain them.

Participant observation suggests that by immersing oneself in the subject that is being studied, a researcher is presumed to gain understanding of the subject. Criticisms of participant observation as a data-gathering technique are similar to criticisms of other approaches to the paranormal, but also include an increased threat to the scientific objectivity of the researcher, unsystematic gathering of data, reliance on subjective measurement, and possible observer effects (i.e. observation may distort the observed behavior). Specific data-gathering methods, such as recording EMF (electromagnetic field) readings at haunted locations, have their own criticisms beyond those attributed to the participant-observer approach itself.

Participant observation, as an approach to the paranormal, has gained increased visibility and popularity through reality television programs like Ghost Hunters, and the formation of independent ghost hunting groups that advocate immersive research at alleged paranormal locations. One popular website for ghost hunting enthusiasts lists over 300 of these organizations throughout the United States and the United Kingdom.

Skeptical scientific investigation

James Randi was a well-known investigator of paranormal claims.

Scientific skeptics advocate critical investigation of claims of paranormal phenomena: applying the scientific method to reach a rational, scientific explanation of the phenomena to account for the paranormal claims, taking into account that alleged paranormal abilities and occurrences are sometimes hoaxes or misinterpretations of natural phenomena. A way of summarizing this method is by the application of Occam's razor, which suggests that the simpler solution is usually the correct one.

The Committee for Skeptical Inquiry (CSI), formerly the Committee for the Scientific Investigation of Claims of the Paranormal (CSICOP), is an organization that aims to publicize the scientific, skeptical approach. It carries out investigations aimed at understanding paranormal reports in terms of scientific understanding, and publishes its results in the Skeptical Inquirer magazine.

CSI's Richard Wiseman draws attention to possible alternative explanations for perceived paranormal activity in his article, The Haunted Brain. While he recognizes that approximately 15% of people believe they have experienced an encounter with a ghost, he reports that only 1% report seeing a full-fledged ghost while the rest report strange sensory stimuli, such as seeing fleeting shadows or wisps of smoke, or the sensation of hearing footsteps or feeling a presence. Wiseman makes the claim that, rather than experiencing paranormal activity, it is activity within our own brains that creates these strange sensations.

Michael Persinger proposed that ghostly experiences could be explained by stimulating the brain with weak magnetic fields. Swedish psychologist Pehr Granqvist and his team, attempting to replicate Persinger's research, determined that the paranormal sensations experienced by Persinger's subjects were merely the result of suggestion, and that brain stimulation with magnetic fields did not result in ghostly experiences.

Oxford University Justin Barrett has theorized that "agency"—being able to figure out why people do what they do—is so important in everyday life, that it is natural for our brains to work too hard at it, thereby detecting human or ghost-like behavior in everyday meaningless stimuli.

James Randi, an investigator with a background in illusion, felt that the simplest explanation for those claiming paranormal abilities is often trickery, illustrated by demonstrating that the spoon bending abilities of psychic Uri Geller can easily be duplicated by trained stage magicians. He was also the founder of the James Randi Educational Foundation and its million dollar challenge that offered a prize of $1,000,000 to anyone who could demonstrate evidence of any paranormal, supernatural or occult power or event, under test conditions agreed to by both parties. Despite many declarations of supernatural ability, the prize was never claimed.

Psychology

In "anomalistic psychology", paranormal phenomena have naturalistic explanations resulting from psychological and physical factors which have sometimes given the impression of paranormal activity to some people, in fact, where there have been none. The psychologist David Marks wrote that paranormal phenomena can be explained by magical thinking, mental imagery, subjective validation, coincidence, hidden causes, and fraud. According to studies some people tend to hold paranormal beliefs because they possess psychological traits that make them more likely to misattribute paranormal causation to normal experiences. Research has also discovered that cognitive bias is a factor underlying paranormal belief.

Chris French, founder of the Anomalistic Psychology Research Unit.

Many studies have found a link between personality and psychopathology variables correlating with paranormal belief. Some studies have also shown that fantasy proneness correlates positively with paranormal belief.

Bainbridge (1978) and Wuthnow (1976) found that the most susceptible people to paranormal belief are those who are poorly educated, unemployed or have roles that rank low among social values. The alienation of these people due to their status in society is said to encourage them to appeal to paranormal or magical beliefs.

Research has associated paranormal belief with low cognitive ability, low IQ and a lack of science education.Intelligent and highly educated participants involved in surveys have proven to have less paranormal belief. Tobacyk (1984) and Messer and Griggs (1989) discovered that college students with better grades have less belief in the paranormal.

In a case study (Gow, 2004) involving 167 participants the findings revealed that psychological absorption and dissociation were higher for believers in the paranormal. Another study involving 100 students had revealed a positive correlation between paranormal belief and proneness to dissociation. A study (Williams et al. 2007) discovered that "neuroticism is fundamental to individual differences in paranormal belief, while paranormal belief is independent of extraversion and psychoticism". A correlation has been found between paranormal belief and irrational thinking.

In an experiment Wierzbicki (1985) reported a significant correlation between paranormal belief and the number of errors made on a syllogistic reasoning task, suggesting that believers in the paranormal have lower cognitive ability. A relationship between narcissistic personality and paranormal belief was discovered in a study involving the Australian Sheep-Goat Scale.

De Boer and Bierman wrote:

In his article 'Creative or Defective' Radin (2005) asserts that many academics explain the belief in the paranormal by using one of the three following hypotheses: Ignorance, deprivation or deficiency. 'The ignorance hypothesis asserts that people believe in the paranormal because they're uneducated or stupid. The deprivation hypothesis proposes that these beliefs exist to provide a way to cope in the face of psychological uncertainties and physical stressors. The deficiency hypothesis asserts that such beliefs arise because people are mentally defective in some way, ranging from low intelligence or poor critical thinking ability to a full-blown psychosis' (Radin). The deficiency hypothesis gets some support from the fact that the belief in the paranormal is an aspect of a schizotypical personality (Pizzagalli, Lehman and Brugger, 2001).

A psychological study involving 174 members of the Society for Psychical Research completed a delusional ideation questionnaire and a deductive reasoning task. As predicted, the study showed that "individuals who reported a strong belief in the paranormal made more errors and displayed more delusional ideation than skeptical individuals". There was also a reasoning bias which was limited to people who reported a belief in, rather than experience of, paranormal phenomena. The results suggested that reasoning abnormalities may have a causal role in the formation of paranormal belief.

Research has shown that people reporting contact with aliens have higher levels of absorption, dissociativity, fantasy proneness and tendency to hallucinate.

Findings have shown in specific cases that paranormal belief acts as a psychodynamic coping function and serves as a mechanism for coping with stress. Survivors from childhood sexual abuse, violent and unsettled home environments have reported to have higher levels of paranormal belief. A study of a random sample of 502 adults revealed paranormal experiences were common in the population which were linked to a history of childhood trauma and dissociative symptoms. Research has also suggested that people who perceive themselves as having little control over their lives may develop paranormal beliefs to help provide an enhanced sense of control. The similarities between paranormal events and descriptions of trauma have also been noted.

Gender differences in surveys on paranormal belief have reported women scoring higher than men overall and men having greater belief in UFOs and extraterrestrials. Surveys have also investigated the relationship between ethnicity and paranormal belief. In a sample of American university students (Tobacyk et al. 1988) it was found that people of African descent have a higher level of belief in superstitions and witchcraft while belief in extraterrestrial life forms was stronger among people of European descent. Otis and Kuo (1984) surveyed Singapore university students and found Chinese, Indian and Malay students to differ in their paranormal beliefs, with the Chinese students showing greater skepticism.

According to American surveys analysed by Bader et al. (2011) African Americans have the highest belief in the paranormal and while the findings are not uniform the "general trend is for whites to show lesser belief in most paranormal subjects".

Polls show that about fifty percent of the United States population believe in the paranormal. Robert L. Park says a lot of people believe in it because they "want it to be so".

A 2013 study that utilized a biological motion perception task discovered a "relation between illusory pattern perception and supernatural and paranormal beliefs and suggest that paranormal beliefs are strongly related to agency detection biases".

A 2014 study discovered that schizophrenic patients have more belief in psi than healthy adults.

Neuroscience

Some scientists have investigated possible neurocognitive processes underlying the formation of paranormal beliefs. In a study (Pizzagalli et al. 2000) data demonstrated that "subjects differing in their declared belief in and experience with paranormal phenomena as well as in their schizotypal ideation, as determined by a standardized instrument, displayed differential brain electric activity during resting periods." Another study (Schulter and Papousek, 2008) wrote that paranormal belief can be explained by patterns of functional hemispheric asymmetry that may be related to perturbations during fetal development.

It was also realized that people with higher dopamine levels have the ability to find patterns and meanings where there are none. This is why scientists have connected high dopamine levels with paranormal belief.

Criticism

Some scientists have criticized the media for promoting paranormal claims. In a report by Singer and Benassi in 1981, they wrote that the media may account for much of the near universality of paranormal belief, as the public are constantly exposed to films, newspapers, documentaries and books endorsing paranormal claims while critical coverage is largely absent. According to Paul Kurtz, "In regard to the many talk shows that constantly deal with paranormal topics, the skeptical viewpoint is rarely heard; and when it is permitted to be expressed, it is usually sandbagged by the host or other guests." Kurtz described the popularity of public belief in the paranormal as a "quasi-religious phenomenon", a manifestation of a transcendental temptation, a tendency for people to seek a transcendental reality that cannot be known by using the methods of science. Kurtz compared this to a primitive form of magical thinking.

Terence Hines has written that on a personal level, paranormal claims could be considered a form of consumer fraud as people are "being induced through false claims to spend their money—often large sums—on paranormal claims that do not deliver what they promise" and uncritical acceptance of paranormal belief systems can be damaging to society.

Belief polls

While the existence of paranormal phenomena is controversial and debated passionately by both proponents of the paranormal and by skeptics, surveys are useful in determining the beliefs of people in regards to paranormal phenomena. These opinions, while not constituting scientific evidence for or against, may give an indication of the mindset of a certain portion of the population (at least among those who answered the polls). The number of people worldwide who believe in parapsychological powers has been estimated to be 3 to 4 billion.

A survey conducted in 2006 by researchers from Australia's Monash University sought to determine the types of phenomena that people claim to have experienced and the effects these experiences have had on their lives. The study was conducted as an online survey with over 2,000 respondents from around the world participating. The results revealed that around 70% of the respondents believe to have had an unexplained paranormal event that changed their life, mostly in a positive way. About 70% also claimed to have seen, heard, or been touched by an animal or person that they knew was not there; 80% have reported having a premonition, and almost 50% stated they recalled a previous life.

Polls were conducted by Bryan Farha at Oklahoma City University and Gary Steward of the University of Central Oklahoma in 2006. They found fairly consistent results compared to the results of a Gallup poll in 2001.

Percentage of U.S. citizens polled
Phenomena Farha-Steward (2006) Gallup (2001) Gallup (2005)
Belief Unsure Disbelief Belief Unsure Disbelief Belief Unsure Disbelief
Psychic, Spiritual healing 57 26 18 54 19 26 55 17 26
ESP 29 39 33 50 20 27 41 25 32
Haunted houses 41 25 35 42 16 41 37 16 46
Demonic possession 41 28 32 41 16 41 42 13 44
Ghosts 40 27 34 38 17 44 32 19 48
Telepathy 25 34 42 36 26 35 31 27 42
Extraterrestrials visited Earth in the past 18 34 49 33 27 38 24 24 51
Clairvoyance and Prophecy 24 33 43 32 23 45 26 24 50
Mediumship 16 29 55 28 26 46 21 23 55
Astrology 17 26 57 28 18 52 25 19 55
Witches 27 19 55 26 15 59 21 12 66
Reincarnation 16 28 57 25 20 54 20 20 59

A survey by Jeffrey S. Levin, associate professor at Eastern Virginia Medical School, found that more than two thirds of the United States population reported having at least one mystical experience.

A 1996 Gallup poll estimated that 71% of the people in the U.S. believed that the government was covering up information about UFOs. A 2002 Roper poll conducted for the Sci Fi channel reported that 56% thought UFOs were real craft and 48% that aliens had visited the Earth.

A 2001 National Science Foundation survey found that 9% of people polled thought astrology was very scientific, and 31% thought it was somewhat scientific. About 32% of Americans surveyed stated that some numbers were lucky, while 46% of Europeans agreed with that claim. About 60% of all people polled believed in some form of Extra-sensory perception and 30% thought that "some of the unidentified flying objects that have been reported are really space vehicles from other civilizations."

In 2017 the Chapman University Survey of American Fears asked about seven paranormal beliefs and found that "the most common belief is that ancient advanced civilizations such as Atlantis once existed (55%). Next was that places can be haunted by spirits (52%), aliens have visited Earth in our ancient past (35%), aliens have come to Earth in modern times (26%), some people can move objects with their minds (25%), fortune tellers and psychics can survey the future (19%), and Bigfoot is a real creature. Only one-fourth of respondents didn't hold at least one of these beliefs."

Paranormal challenges

In 1922, Scientific American offered two US$2,500 offers: (1) for the first authentic spirit photograph made under test conditions, and (2) for the first psychic to produce a "visible psychic manifestation". Harry Houdini was a member of the investigating committee. The first medium to be tested was George Valiantine, who claimed that in his presence spirits would speak through a trumpet that floated around a darkened room. For the test, Valiantine was placed in a room, the lights were extinguished, but unbeknownst to him his chair had been rigged to light a signal in an adjoining room if he ever left his seat. Because the light signals were tripped during his performance, Valiantine did not collect the award. The last to be examined by Scientific American was Mina Crandon in 1924.

Since then, many individuals and groups have offered similar monetary awards for proof of the paranormal in an observed setting. These prizes have a combined value of over $2.4 million.

The James Randi Educational Foundation offered a prize of a million dollars to a person who could prove that they had supernatural or paranormal abilities under appropriate test conditions. Several other skeptic groups also offer a monied prize for proof of the paranormal, including the largest group of paranormal investigators, the Independent Investigations Group, which has chapters in Hollywood; Atlanta; Denver; Washington, D.C.; Alberta, B.C.; and San Francisco. The IIG offers a $100,000 prize and a $5,000 finders fee if a claimant can prove a paranormal claim under 2 scientifically controlled tests. Founded in 2000 no claimant has passed the first (and lower odds) of the test.

Electric sail

From Wikipedia, the free encyclopedia
The Heliopause Electrostatic Rapid Transit System (HERTS) is a spacecraft concept using an electric sail

An electric sail (also known as an electric solar wind sail or an E-sail) is a proposed form of spacecraft propulsion using the dynamic pressure of the solar wind as a source of thrust. It creates a "virtual" sail by using small wires to form an electric field that deflects solar wind protons and extracts their momentum. The idea was first conceptualised by Pekka Janhunen in 2006 at the Finnish Meteorological Institute.

Principles of operation and design

Principles of operation of an electrical sail

The electric sail consists of a number of thin, long and conducting tethers which are kept in a high positive potential by an onboard electron gun. The positively charged tethers deflect solar wind protons, thus extracting momentum from them. Simultaneously they attract electrons from the solar wind plasma, producing an electron current. The electron gun compensates for the arriving electric current.

One way to deploy the tethers is to rotate the spacecraft, using centrifugal force to keep them stretched. By fine-tuning the potentials of individual tethers and thus the solar wind force individually, the spacecraft's attitude can be controlled.

E-sail missions can be launched at almost any time with only minor variations in travel time. By contrast, conventional slingshot missions must wait for the planets to reach a particular alignment.

Artist's rendering of ESTCube-1, launched in May 2013, which was intended to be the first satellite to test an electric sail.

The electric solar wind sail has little in common with the traditional solar sail. The E-sail gets its momentum from the solar wind ions, whilst a photonic sail is propelled by photons. Thus, the available pressure is only about 1% of photon pressure; however, this may be compensated by the simplicity of scale-up. In the E-sail, the part of the sail is played by straightened conducting tethers (made of wires) which are placed radially around the host ship. The wires are electrically charged and thus an electric field is created around the wires. The electric field of the wires extends a few dozen metres into the surrounding solar wind plasma. The penetration distance depends on the solar wind plasma density and it scales as the plasma Debye length. Because the solar wind electrons affect the electric field (similarly to the photons on a traditional solar sail), the effective electric radius of the tethers is based on the electric field that is generated around the tether rather than the actual tether itself. This fact also makes it possible to manoeuvre by regulating the tethers' electric charge.

A full-sized sail would have 50–100 straightened tethers with a length of about 20 km (12 mi) each.

Compared to a reflective solar light sail, another propellantless deep space propulsion system, the electric solar wind sail could continue to accelerate at greater distances from the Sun, still developing thrust as it cruises toward the outer planets. By the time it reaches the ice giants, it may have accumulated as much as 20 km/s (45,000 mph; 72,000 km/h) velocity, which is on par with the New Horizons probe, but without gravity assists.

In order to minimise damage to the thin tethers from micrometeoroids, the tethers would be formed from multiple strands, 25–50 micrometers in diameter, welded together at regular intervals. Thus, even if one wire were severed, a conducting path along the full length of the braided wire would remain in place. The feasibility of using ultrasonic welding was demonstrated at the University of Helsinki in January 2013.

Development history

Graphical overview electric sail development

Academy of Finland has been funding electric sail development since 2007.

To test the technology, a new European Union-backed electric sail study project was announced by the FMI in December 2010. The EU funding contribution was 1.7 million euros. Its goal was to build laboratory prototypes of the key components, it involved five European countries and ended in November 2013. In the EU evaluation, the project got the highest marks in its category. An attempt was made to test the working principles of the electric sail in low Earth orbit in the Estonian nanosatellite ESTCube-1 (2013-2015), but there was a technical failure and the attempt was unsuccessful. The piezoelectric motor used to unfurl the sail failed to turn the reel. In subsequent ground-based testing, a likely reason for the failure was found in a slipring contact which was likely physically damaged by launch vibration.

An international research team that includes Janhunen received funding through a 2015 NIAC Phase II solicitation for further development at NASA's Marshall Space Flight Center. Their research project is called 'Heliopause Electrostatic Rapid Transit System' (HERTS). The Heliopause Electrostatic Rapid Transit System (HERTS) concept is currently being tested. For HERTS, it might take only 10 to 15 years to make the trip of over 100 astronomical units (15 billion kilometers). In the HERTS concept, multiple, 20 kilometer or so long, 1 millimeter thin, positively charged wires would be extended from a rotating spacecraft.

A new satellite launched in June 2017, the Finnish Aalto-1 nanosatellite, currently in orbit, will test the electric sail for deorbiting in 2019.

In 2017, Academy of Finland granted Centre of Excellence funding for 2018–2025 to a team that includes Janhunen and members from universities, to establish a Finnish Centre of Excellence in Research of Sustainable Space.

Intrinsic limitations

Almost all Earth-orbiting satellites are inside Earth's magnetosphere. However, the electric sail cannot be used inside planetary magnetospheres because the solar wind does not penetrate them, allowing only slower plasma flows and magnetic fields. Instead, inside a planetary magnetosphere, the electric sail may function as a brake, allowing deorbiting of satellites.

Like for other solar sail technologies, while modest variation of the thrust direction can be achieved by inclining the sail, the thrust vector always points more or less radially outward from the Sun. It has been estimated that maximum operational inclination would be 60°, resulting in a thrusting angle of 30° from the outward radial direction. However, like with the sails of a ship, tacking could be used for changing the trajectory. Interstellar ships approaching a sun might use solar wind flow for braking.

Applications

  • Fast missions (> 50 km/s [110,000 mph; 180,000 km/h] or 10 AU [0.00016 light-years; 4.8×10−5 parsecs]) out of the Solar System and heliosphere with small or modest payload
  • As a brake for a small interstellar probe which has been accelerated to high speed by some other means such as laser lightsail
  • Inward-spiralling missions to study the Sun at a closer distance
  • Two-way missions to inner Solar System objects such as asteroids
  • Off-Lagrange point solar wind monitoring spacecraft for predicting space weather with a longer warning time than 1 hour

Fast missions to planet Uranus

Janhunen et al. have proposed a mission to Uranus powered by an electric sail. The mission could reach its destination in about the same time that the earlier Galileo space probe required to arrive at Jupiter, just over one fourth as far away. Galileo took 6 years to reach Jupiter at a cost of $1.6 billion, while Cassini-Huygens took 7 years to get to Saturn and cost almost as much. The sail is expected to consume 540 watts, producing about 0.5 newtons accelerating the craft by about 1 mm/s2. The craft would reach a velocity of about 20 km/s (45,000 mph; 72,000 km/h) by the time it reaches Uranus, 6 years after launch. The downside is that the electric sail cannot be used as a brake, so the craft arrives at a speed of 20 km/s (45,000 mph; 72,000 km/h), limiting the missions to flybys or atmospheric entry missions. Braking would require a conventional chemical rocket.

The proposed craft has three parts: the E-sail module with solar panels and reels to hold the wires; the main body, including chemical thrusters for adjusting trajectory en route and at destination and communications equipment; and a research module to enter Uranus's atmosphere and make measurements for relay to Earth via the main body.

Necromancy

From Wikipedia, the free encyclopedia
https://en.wikipedia.org/wiki/Necromancy
Illustration portraying a scene from the Bible wherein the Witch of Endor uses a necromantic ritual to conjure the spirit of Samuel at the behest of Saul; from the frontispiece of Sadducismus Triumphatus (1681) by Joseph Glanvill.
Necromancy (/ˈnɛkrəmænsi/) is the practice of magic involving communication with the dead by summoning their spirits as apparitions or visions for the purpose of divination; imparting the means to foretell future events and discover hidden knowledge. Sometimes categorized under death magic, the term is occasionally also used in a more general sense to refer to black magic or witchcraft as a whole.

Etymology

The word necromancy is adapted from Late Latin necromantia: a loan word from the post-Classical Greek νεκρομαντεία (nekromanteía, or 'divination through a dead body'), a compound of Ancient Greek νεκρός (nekrós, or 'dead body') and μαντεία (manteía, or 'divination').

The Koine Greek compound form was first documented in the writings of Origen of Alexandria in the 3rd century AD. The Classical Greek term was ἡ νέκυια (nekyia), from the episode of the Odyssey in which Odysseus visits the realm of the dead souls, and νεκρομαντεία in Hellenistic Greek; necromantīa in Latin, and necromancy in 17th-century English.

Antiquity

Early necromancy was related to – and most likely evolved from – forms of shamanism or prehistoric ritual magic that calls upon spirits such as the ghosts of deceased forebears. Classical necromancers addressed the dead in "a mixture of high-pitch squeaking and low droning", comparable to the trance-state mutterings of shamans. Necromancy was prevalent throughout antiquity with records of its practice in ancient Egypt, Babylonia, Greece, ancient Etruria, Rome, and China. In his Geographica, Strabo refers to νεκρομαντία (nekromantia), or "diviners by the dead", as the foremost practitioners of divination among the people of Persia, and it is believed to have also been widespread among the peoples of Chaldea (particularly the Hermeticists, or "star-worshipers") and Babylonia. The Babylonian necromancers were called manzazuu or sha'etemmu, and the spirits they raised were called etemmu. Traditional Chinese folk religion involves necromancy in seeking blessing from dead ancestors through ritual displays of filial piety.

The oldest literary account of necromancy is found in Homer's Odyssey. Under the direction of Circe, a powerful sorceress, Odysseus travels to the underworld (katabasis) in order to gain insight about his impending voyage home by raising the spirits of the dead through the use of spells which Circe has taught him. He wishes to invoke and question the shade of Tiresias in particular; however, he is unable to summon the seer's spirit without the assistance of others. The Odyssey's passages contain many descriptive references to necromantic rituals: rites must be performed around a pit with fire during nocturnal hours, and Odysseus has to follow a specific recipe, which includes the blood of sacrificial animals, to concoct a libation for the ghosts to drink while he recites prayers to both the ghosts and gods of the underworld.

Practices such as these, varying from the mundane to the grotesque, were commonly associated with necromancy. Rituals could be quite elaborate, involving magic circles, wands, talismans, and incantations. The necromancer might also surround himself with morbid aspects of death, which often included wearing the deceased's clothing and consuming foods that symbolized lifelessness and decay such as unleavened black bread and unfermented grape juice. Some necromancers even went so far as to take part in the mutilation and consumption of corpses. These ceremonies could carry on for hours, days, or even weeks, leading up to the eventual summoning of spirits. Frequently they were performed in places of interment or other melancholy venues that suited specific guidelines of the necromancer. Additionally, necromancers preferred to summon the recently departed based on the premise that their revelations were spoken more clearly. This timeframe was usually limited to the twelve months following the death of the physical body; once this period elapsed, necromancers would evoke the deceased's ghostly spirit instead.

While some cultures considered the knowledge of the dead to be unlimited, ancient Greeks and Romans believed that individual shades knew only certain things. The apparent value of their counsel may have been based on things they knew in life or knowledge they acquired after death. Ovid writes in his Metamorphoses of a marketplace in the underworld where the dead convene to exchange news and gossip.

Prohibited among Israelites

There are also several references to necromancers – called "bone-conjurers" among Jews of the later Hellenistic period – in the Bible. The Book of Deuteronomy (18:9–12) explicitly warns the Israelites against engaging in the Canaanite practice of divination from the dead:

9When thou art come into the land which the LORD thy God giveth thee, thou shalt not learn to do according to the abominations of those nations. 10There shall not be found among you any one who maketh his son or his daughter to pass through the fire, or who useth divination, or an observer of times, or an enchanter, or a witch, 11or a charmer, or a consulter with familiar spirits, or a wizard, or a necromancer. 12For all who do these things are an abomination unto the LORD, and because of these abominations the LORD thy God doth drive them out from before thee (KJV).

Though Mosaic Law prescribed the death penalty to practitioners of necromancy (Leviticus 20:27), this warning was not always heeded. One of the foremost examples is when King Saul had the Witch of Endor invoke the spirit of Samuel, a judge and prophet, from Sheol to divine the outcome of a coming battle (1 Samuel 28:3–25). However, the so-called witch was shocked at the presence of a familiar spirit in the image of Samuel for in I Sam 28:7 states "Behold, there is a woman that hath a familiar spirit at Endor" and in I Sam 28:12 says, "when the woman saw Samuel, she cried out in a loud voice", and the familiar spirit questioned his reawakening, asking as if he were Samuel the Prophet, "Why hast thou disquieted me?" Saul died the next day in combat, with Chronicles 10:13 implying this was due to the prohibition against necromancy.

Early and High Middle Age

Many medieval writers believed that actual resurrection required the assistance of God. They saw the practice of necromancy as conjuring demons who took the appearance of spirits. The practice became known explicitly as maleficium, and the Catholic Church condemned it. Though the practitioners of necromancy were linked by many common threads, there is no evidence that these necromancers ever organized as a group. One noted commonality among practitioners of necromancy was usually the utilization of certain toxic and hallucinogenic plants from the nightshade family such as black henbane, jimson weed, belladonna or mandrake, usually in magic salves or potions.

Medieval necromancy is believed to be a synthesis of astral magic derived from Arabic influences and exorcism derived from Christian and Jewish teachings. Arabic influences are evident in rituals that involve moon phases, sun placement, day and time. Fumigation and the act of burying images are also found in both astral magic and necromancy. Christian and Jewish influences appear in the symbols and in the conjuration formulas used in summoning rituals.

Practitioners were often members of the Christian clergy, though some nonclerical practitioners are recorded. In some instances, mere apprentices or those ordained to lower orders dabbled in the practice. They were connected by a belief in the manipulation of spiritual beings – especially demons – and magical practices. These practitioners were almost always literate and well educated. Most possessed basic knowledge of exorcism and had access to texts of astrology and of demonology. Clerical training was informal and university-based education rare. Most were trained under apprenticeships and were expected to have a basic knowledge of Latin, ritual and doctrine. This education was not always linked to spiritual guidance and seminaries were almost non-existent. This situation allowed some aspiring clerics to combine Christian rites with occult practices despite its condemnation in Christian doctrine.

Medieval practitioners believed they could accomplish three things with necromancy: will manipulation, illusions, and knowledge:

  • Will manipulation affects the mind and will of another person, animal, or spirit. Demons are summoned to cause various afflictions on others, "to drive them mad, to inflame them to love or hatred, to gain their favor, or to constrain them to do or not do some deed."
  • Illusions involve reanimation of the dead or conjuring food, entertainment, or a mode of transportation.
  • Knowledge is allegedly discovered when demons provide information about various things. This might involve identifying criminals, finding items, or revealing future events.

The act of performing medieval necromancy usually involved magic circles, conjurations, and sacrifices such as those shown in the Munich Manual of Demonic Magic:

  • Circles were usually traced on the ground, though cloth and parchment were sometimes used. Various objects, shapes, symbols, and letters may be drawn or placed within that represent a mixture of Christian and occult ideas. Circles were usually believed to empower and protect what was contained within, including protecting the necromancer from the conjured demons. A text known as the Heptameron explain the function of the circle thusly: "But because the greatest power is attributed to the Circles; (For they are certain fortresses to defend the operators safe from the evil Spirits;)..."
  • Conjuration is the method of communicating with the demons to have them enter the physical world. It usually employs the power of special words and stances to call out the demons and often incorporated the use of Christian prayers or biblical verses. These conjurations may be repeated in succession or repeated to different directions until the summoning is complete.
  • Sacrifice was the payment for summoning; though it may involve the flesh of a human being or animal, it could sometimes be as simple as offering a certain object. Instructions for obtaining these items were usually specific. The time, location, and method of gathering items for sacrifice could also play an important role in the ritual.

The rare confessions of those accused of necromancy suggest that there was a range of spell casting and related magical experimentation. It is difficult to determine if these details were due to their practices, as opposed to the whims of their interrogators. John of Salisbury is one of the first examples related by Richard Kieckhefer, but as a Parisian ecclesiastical court record of 1323 shows, a "group who were plotting to invoke the demon Berich from inside a circle made from strips of cat skin" were obviously participating in what the Church would define as "necromancy".

Herbert Stanley Redgrove claims necromancy as one of three chief branches of medieval ceremonial magic, alongside black magic and white magic. This does not correspond to contemporary classifications, which often conflate "nigromancy" ("black-knowledge") with "necromancy" ("death-knowledge").

Late Middle Ages to Renaissance

Engraving of occultists John Dee and Edward Kelley "in the act of invoking the spirit of a deceased person"; from Astrology (1806) by Ebenezer Sibly.

In the wake of inconsistencies of judgment, necromancers and other practitioners of the magic arts were able to utilize spells featuring holy names with impunity, as any biblical references in such rituals could be construed as prayers rather than spells. As a consequence, the necromancy that appears in the Munich Manual of Demonic Magic is an evolution of these theoretical understandings. It has been suggested that the authors of the Manual knowingly designed the book to be in discord with ecclesiastical law. The main recipe employed throughout the Manual used the same religious language and names of power alongside demonic names. An understanding of the names of God derived from apocryphal texts and the Hebrew Torah required that the author of such rites have at least a casual familiarity with these sources.

Within the tales related in occult manuals are found connections with stories from other cultures' literary traditions. For instance, the ceremony for conjuring a horse closely relates to the Arabic One Thousand and One Nights and French romances; Chaucer's The Squire's Tale also bears marked similarities. This becomes a parallel evolution of spells to foreign gods or demons that were once acceptable, and frames them into a new Christian context, albeit demonic and forbidden. As the material for these manuals was apparently derived from scholarly magical and religious texts from a variety of sources in many languages, the scholars who studied these texts likely manufactured their own aggregate sourcebook and manual with which to work spells or magic.

In the notebooks of Leonardo da Vinci, it is stated that "Of all human opinions that is to be reputed the most foolish which deals with the belief in Necromancy, the sister of Alchemy, which gives birth to simple and natural things."

Modern era

In the present day, necromancy is more generally used as a term to describe manipulation of death and the dead, or the pretense thereof, often facilitated through the use of ritual magic or some other kind of occult ceremony. Contemporary séances, channeling and Spiritualism verge on necromancy when supposedly invoked spirits are asked to reveal future events or secret information. Necromancy may also be presented as sciomancy, a branch of theurgic magic.

As to the practice of necromancy having endured in one form or another throughout the millennia, An Encyclopædia of Occultism states:

The art is of almost universal usage. Considerable difference of opinion exists among modern adepts as to the exact methods to be properly pursued in the necromantic art, and it must be borne in mind that necromancy, which in the Middle Ages was called sorcery, shades into modern spiritualistic practice. There is no doubt, however, that necromancy is the touch-stone of occultism, for if, after careful preparation the adept can carry through to a successful issue, the raising of the soul from the other world, he has proved the value of his art.

Contemporary pop-culture

The archvillain in J.R.R. Tolkien's Lord of the Rings fantasy, Sauron, first reappears in the environs of Middle Earth as 'the Necromancer of Dol Guldur' in Tolkien's standalone prologue to the trilogy The Hobbit. In fictional settings such as Dungeons & Dragons, or fantasy video games, necromancy is associated with the reanimation of corpses often meant to be used as weapons. This tradition appears to combine associations of conjuring the dead from European and Mediterranean traditions with elements involving Zombies that seem to derive from Caribbean folklore and practice.

Necromancy is a form of magic in the Skulduggery Pleasant series, by Irish author Derek Landy. This form of magic is mostly concerned with the manipulation of shadow, darkness and life energy. In the series the most famous Necromancer is Lord Vile. The protagonist Valkyrie Cain deals with the allure of this form of magic and its consequences for much of her adult life.

Nanobiotechnology

From Wikipedia, the free encyclopedia ...