Pair production

From Wikipedia, the free encyclopedia

https://en.wikipedia.org/wiki/Pair_production 

 

Light–matter interaction

Pair production is the creation of a subatomic particle and its antiparticle from a neutral boson. Examples include creating an electron and a positron, a muon and an antimuon, or a proton and an antiproton. Pair production often refers specifically to a photon creating an electron–positron pair near a nucleus. As energy must be conserved, for pair production to occur, the incoming energy of the photon must be above a threshold of at least the total rest mass energy of the two particles created. Conservation of energy and momentum are the principal constraints on the process. All other conserved quantum numbers (angular momentum, electric charge, lepton number) of the produced particles must sum to zero – thus the created particles shall have opposite values of each other. For instance, if one particle has electric charge of +1 the other must have electric charge of −1, or if one particle has strangeness of +1 then another one must have strangeness of −1.

The probability of pair production in photon–matter interactions increases with photon energy and also increases approximately as the square of the atomic number (number of protons) of the nearby atom.

Photon to electron and positron

Diagram showing the process of electron–positron pair production. In reality the produced pair are nearly collinear. The black dot labelled 'Z' represents an adjacent atom, with atomic number Z.

For photons with high photon energy (MeV scale and higher), pair production is the dominant mode of photon interaction with matter. These interactions were first observed in Patrick Blackett's counter-controlled cloud chamber, leading to the 1948 Nobel Prize in Physics. If the photon is near an atomic nucleus, the energy of a photon can be converted into an electron–positron pair:

(Z+)γ → e⁻
 + e⁺

Plot of photon energies calculated for a given element (atomic number Z) at which the cross section value for the process on the right becomes larger than the cross section for the process on the left. For calcium (Z=20), Compton scattering starts to dominate at hυ=0.08 MeV and ceases at 12 MeV.

Subatomic particle pair production

The photon's energy is converted to particle mass in accordance with Einstein's equation, E = mc²; where E is energy, m is mass and c is the speed of light. The photon must have higher energy than the sum of the rest mass energies of an electron and positron (2 × 511 keV = 1.022 MeV, resulting in a photon wavelength of 1.2132 pm) for the production to occur. (Thus, pair production does not occur in medical X-ray imaging because these X-rays only contain ~ 150 keV.) The photon must be near a nucleus in order to satisfy conservation of momentum, as an electron–positron pair produced in free space cannot satisfy conservation of both energy and momentum. Because of this, when pair production occurs, the atomic nucleus receives some recoil. The reverse of this process is electron–positron annihilation.

Basic kinematics

These properties can be derived through the kinematics of the interaction. Using four vector notation, the conservation of energy–momentum before and after the interaction gives:

${\displaystyle p_{\gamma }=p_{{\text{e}}^{-}}+p_{{\text{e}}^{+}}+p_{\text{ʀ}}}$

where ${\displaystyle p_{\text{ʀ}}}$ is the recoil of the nucleus. Note the modulus of the four vector

${\displaystyle A\equiv (A^0,\mathbf{A})}$

is

${\displaystyle A^2=A^{\mu }{A}_{\mu }=-(A^0{)}^2+\mathbf{A}\cdot \mathbf{A}}$

which implies that ${\displaystyle (p_{\gamma }{)}^2=0}$ for all cases and ${\displaystyle (p_{{\text{e}}^{-}}{)}^2=-m_{\text{e}}^2{c}^2}$. We can square the conservation equation

${\displaystyle (p_{\gamma }{)}^2=(p_{{\text{e}}^{-}}+p_{{\text{e}}^{+}}+p_{\text{ʀ}}{)}^2}$

However, in most cases the recoil of the nucleus is small compared to the energy of the photon and can be neglected. Taking this approximation of ${\displaystyle p_R\approx 0}$ and expanding the remaining relation

${\displaystyle (p_{\gamma }{)}^2\approx (p_{{\text{e}}^{-}}{)}^2+2p_{{\text{e}}^{-}}{p}_{{\text{e}}^{+}}+(p_{{\text{e}}^{+}}{)}^2}$

${\displaystyle -2m_{\text{e}}^2{c}^2+2\left(-\frac{E^2}{c^2}+{\mathbf{p}}_{{\text{e}}^{-}}\cdot {\mathbf{p}}_{{\text{e}}^{+}}\right)\approx 0}$

${\displaystyle 2({\gamma }^2-1)m_{\text{e}}^2{c}^2(\cos {\theta }_{\text{e}}-1)\approx 0}$

Therefore, this approximation can only be satisfied if the electron and positron are emitted in very nearly the same direction, that is, ${\displaystyle {\theta }_{\text{e}}\approx 0}$.

This derivation is a semi-classical approximation. An exact derivation of the kinematics can be done taking into account the full quantum mechanical scattering of photon and nucleus.

Energy transfer

The energy transfer to electron and positron in pair production interactions is given by

${\displaystyle (E_k^{pp}{)}_{\text{tr}}=h\nu -2m_{\text{e}}{c}^2}$

where ${\displaystyle h}$ is the Planck constant, ${\displaystyle \nu }$ is the frequency of the photon and the ${\displaystyle 2m_{\text{e}}{c}^2}$ is the combined rest mass of the electron–positron. In general the electron and positron can be emitted with different kinetic energies, but the average transferred to each (ignoring the recoil of the nucleus) is

${\displaystyle ({\overline{E}}_k^{pp}{)}_{\text{tr}}=\frac{1}{2}(h\nu -2m_{\text{e}}{c}^2)}$

Cross section

See also: Gamma ray cross section

Feynman diagram of electron–positron pair production. One must calculate multiple diagrams to get the net cross section

The exact analytic form for the cross section of pair production must be calculated through quantum electrodynamics in the form of Feynman diagrams and results in a complicated function. To simplify, the cross section can be written as:

${\displaystyle \sigma =\alpha r_{\text{e}}^2{Z}^{2}P(E,Z)}$

where ${\displaystyle \alpha }$ is the fine-structure constant, ${\displaystyle r_{\text{e}}}$ is the classical electron radius, ${\displaystyle Z}$ is the atomic number of the material, and ${\displaystyle P(E,Z)}$ is some complex-valued function that depends on the energy and atomic number. Cross sections are tabulated for different materials and energies.

In 2008 the Titan laser, aimed at a 1 millimeter-thick gold target, was used to generate positron–electron pairs in large numbers.

Astronomy

Pair production is invoked in the heuristic explanation of hypothetical Hawking radiation. According to quantum mechanics, particle pairs are constantly appearing and disappearing as a quantum foam. In a region of strong gravitational tidal forces, the two particles in a pair may sometimes be wrenched apart before they have a chance to mutually annihilate. When this happens in the region around a black hole, one particle may escape while its antiparticle partner is captured by the black hole.

Pair production is also the mechanism behind the hypothesized pair-instability supernova type of stellar explosion, where pair production suddenly lowers the pressure inside a supergiant star, leading to a partial implosion, and then explosive thermonuclear burning. Supernova SN 2006gy is hypothesized to have been a pair production type supernova.

100 Year Starship

From Wikipedia, the free encyclopedia

https://en.wikipedia.org/wiki/100_Year_Starship 

The 100 Year Starship project (100YSS) was a one-year joint U.S. Defense Advanced Research Projects Agency (DARPA) and National Aeronautics and Space Administration (NASA) effort "to take the first step in the next era of space exploration—a journey between the stars". The study explored development of a viable and sustainable model for persistent, long-term, private-sector investment into the myriad of disciplines needed to make interstellar space travel practicable and feasible. The goal was to examine what it would take — organizationally, technically, sociologically and ethically — to develop the ability to send humans to another star within 100 years. The study culminated in a $500,000 grant awarded to a consortium under the lead of the Dorothy Jemison Foundation for Excellence, which led to the creation of an independent organization inheriting the name 100 Year Starship from DARPA. Annual 100YSS symposia were organized from 2011 to 2015, and again in 2023.

Origin

The 100 Year Starship study was conceived in the summer of 2010 by the director of the DARPA Tactical Technology Office, David Neyland, as an effort seeded by DARPA to develop a viable and sustainable model for persistent, long-term, private-sector investment into the myriad of disciplines needed to make long-distance space travel practicable and feasible. The study was intended to foster a rebirth of a sense of wonder among students, academia, industry, researchers and the general population to consider "why not" and to encourage them to tackle whole new classes of research and development related to all the issues surrounding long duration, long distance spaceflight. DARPA suggested that such research might benefit the Department of Defense and NASA, as well as the private and commercial sector. This was similar to how science fiction spurred generations of scientists and engineers to follow the career paths they did, as an avenue to capture the imagination of people who normally wouldn't think of doing research and development and tag them with something they would be excited about. The inspiration for 100YSS was the Robert Heinlein 1956 science fiction novel, Time for the Stars, in which the Long Range Foundation created technologies that took generations to deliver, but eventually benefited the entire species. Neyland assigned the Tactical Technology Office's Paul Eremenko to be the program manager and study coordinator for 100YSS. Eremenko convinced NASA Ames Research Center director Pete Worden to collaborate with DARPA on the project. DARPA funded the effort with $1M and NASA Ames provided $100k of support funding. DARPA intended to begin the yearlong 100YSS study on 1/11/11, with a gathering of visionaries for strategic planning, followed by a commercial request for proposals in the summer of 2011, then an international symposium in the fall of 2011 and finally an award of a research foundation grant in late 2011. However, Worden preempted DARPA and prematurely announced the nascent study prior to internal government coordination, at San Francisco's Long Conversation conference in October 2010. This caused considerable issue within government circles and forced DARPA to immediately follow-up with an early press release from Eremenko.

100YSS Strategic Planning Session

On January 10 & 11, 2011, DARPA gathered 30 scientists, entrepreneurs and science fiction writers in a two-day by-invitation-only brainstorming session in northern California, at Cavallo Point, near San Francisco, to chart the course for the 100 Year Starship study. The agenda consisted of cycling through the "why, what, and how" to create an organization that could sustain research that could lead to the creation of a starship in roughly 100 years.

Non-affiliated attendees included:

• Elizabeth Bear (science fiction writer)
• Jim Benford (Microwave Sciences)
• Peter Diamandis (Xprize Foundation, facilitator for the 100YSS Strategic Planning Session)
• Lou Friedman (Planetary Society [retired])
• Joe Haldeman (science fiction writer)
• Barbara Marx Hubbard (Foundation for Conscious Evolution)
• Mae Jemison (Former Astronaut, active in various educational endeavors)
• Harry Kloor (Chief science advisor for the X Prize organization)
• Marc Millis (Tau Zero Foundation)
• Alexander Rose (Long Now Foundation)
• Jack Sarfatti (StarDrive.org)
• Dan Sherkow (Global Universal Entertainment)
• Jill Tarter (Search for Extraterrestrial Intelligence – SETI Inst.)
• Jacques Vallée (Euro-America Ventures & Co-developer of ARPANET [led to Internet])
• Craig Venter (J. Craig Venter Institute, first to sequence the human genome)
• Claudia Welss (Assistant to Barbara Marx Hubbard)

DARPA attendees:

• David Neyland (Progenitor of 100YSS, director of the DARPA Tactical Technology Office)
• Paul Eremenko (coordinator and program manager for 100YSS)
• Roger Hall (DARPA space systems program manager)

NASA attendees:

• Pete Worden (NASA-Ames Director)
• Jay Falker (NASA-HQ & NIAC lead)
• Rachel Hoover (NASA-Ames, Public Affairs)
• Peter Klupar (NASA-Ames)
• Larry Lemke (NASA-Ames)
• Creon Levit (NASA-Ames – assigned to lead this 100-yr study)
• Lisa Lockyer (NASA-Ames)
• Alex MacDonald (NASA-Ames)
• Dawn McIntosh (NASA-Ames – on temporary assignment to DARPA for 100YSS)
• Alen Weston (NASA-Ames)
• Matt Daniels (NASA-Ames & Stanford PhD student)

A majority of participants agreed on three immediate-term issues associated with the creation of a new organization or foundation of this nature: intellectual property (IP), credibility, and leadership and governance.

100YSS Request for Information and Solicitation

On May 3, 2011, DARPA released a Request for Information (RFI) seeking ideas for an organization, business model and approach appropriate for a self-sustaining investment vehicle in support of the 100 Year Starship Study.

Attributes of interest in the RFI included:

• Long-term survivability over a century-long time horizon;
• Self-governance, independent of government participation or oversight;
• Self-sustainment, independent of government funding; and
• Relevance to the goal of moving humanity toward the goal of interstellar travel, including related technological, biological, social, economic, and other issues.

Respondents to the RFI needed to describe an organization and approach for the establishment and operation of the 100 Year Starship research entity (or foundation):

• Organizational structure;
• Governance mechanism;
• Investment strategy and criteria; and
• Business model for long-term self-sustainment.

DARPA received over 150 responses to the RFI.

The RFI was followed on August 26, 2011 by formal solicitation for award of a grant. To meet the needs of the August 26th solicitation DARPA planned to award in the late fall 2011 a single entity, organization or foundation a grant for initial startup, operating expenses and initial intellectual property.

100 Year Starship Symposia

On June 15, 2011, DARPA announced the 100 Year Starship Study Public Symposium, organized by DARPA's Tactical Technology Office director, David Neyland, with NASA Ames serving as execution agent. DARPA planned to encourage dialog about "all the aspects of interstellar flight ... hoping that ethicists, lawyers, science fiction writers, technologists and others, will participate." DARPA contended that the "useful, unanticipated consequences of such research – benefits from improved propulsion to energy storage and life support – can ultimately benefit the Department of Defense and to NASA, as well as the private and commercial sector."

DARPA and NASA solicited papers for the symposium on topics including:

• Time-Distance Solutions [propulsion, time/space manipulation and/or dilation, near speed of light navigation, faster than light navigation, observations and sensing at near speed of light or faster than light]
• Education, Social, Economic and Legal Considerations [education as a mission, who goes, who stays, to profit or not, economies in space, communications back to earth, political ramifications, round-trip legacy investments and assets left behind]
• Philosophical, and Religious Considerations [why go to the stars, moral and ethical issues, implications of finding habitable worlds, implications of finding life elsewhere, implications of being left behind]
• Biology and Space Medicine [physiology in space, psychology in space, human life suspension (e.g., cryogenic), medical facilities and capabilities in space, on-scene (end of journey) spawning from genetic material]
• Habitats and Environmental Science [to have gravity or not, space and radiation effects, environmental toxins, energy collection and use, agriculture, self-supporting environments, optimal habitat sizing]
• Destinations [criteria for destination selection, what do you take, how many destinations and missions, probes versus journeys of faith]
• Communication of the Vision [storytelling as a means of inspiration, linkage between incentives, payback and investment, use of movies, television and books to popularize long term research and long term journeys]

Three days prior to the start of the Symposium, then director of DARPA, Dr. Regina E. Dugan, and her deputy, Dr Kaighan (Ken) Gabriel, discussed the plan and intent of the symposium with Neyland and requested he cancel the entire event. Neyland explained how visible and public it was, with world travelers already en route to attend. He suggested that cancelling would have a more negative impact than letting it happen. Dugan and Gabriel agreed to let the symposium proceed, but required removal of all DARPA and NASA logos and emblems, as well as curtailing participation by DARPA personnel. They also insisted that no public video, audio recordings or photography would be allowed, and no proceedings or papers would be officially published.

The symposium was held in Orlando, Florida, from September 30 to October 2, 2011. It included presentations on the technology, biology, physics, philosophy, sociology, and economics of interstellar flight. More than 500 papers were submitted and more than 700 people attended. Select papers from the conference were published in the Journal of the British Interplanetary Society.

Neyland, who orchestrated the one-year starship study, provided the welcome and introduction at the Symposium, but no other DARPA personnel spoke. No high-level NASA officials spoke at the symposium either, other than Pete Worden, director of the NASA Ames Research Center in California, whom Neyland described as a "co-conspirator" and who was often regarded as a maverick in the space agency.

In 2012, after the Jemison Foundation was named as the winner of the DARPA 100YSS grant, it organized the second symposium in Houston. Papers on many subjects related to interstellar flight and organizational foundations were presented. In 2013 and 2014 symposia were held in Houston, and a fifth in November 2015. The sixth symposium was held in Nairobi, Kenya from January 31-February 4, 2023.

100YSS Intellectual Property

By design, DARPA invested in the instruments of intellectual property to support the eventual selection of an organization to carry the 100YSS vision forward. DARPA established and copyrighted the 100YSS.org website and trademarked the original names, acronyms, logos and artwork. At the award of the 100YSS grant, 100YSS intellectual property rights and trademarks were passed in perpetuity to the new 100YSS organization.

Foundation

The 100 Year Starship study was the name of the one-year DARPA project to explore development of a viable and sustainable model for persistent, long-term, private-sector investment into the myriad of disciplines needed to make interstellar space travel practicable and feasible. The outcome of the study was the selection of an organization to carry the vision forward. The winning bid was the Dorothy Jemison Foundation for Excellence, partnering with Icarus Interstellar and the Foundation for Enterprise Development, led by the American physician and former NASA astronaut Mae Jemison. In 2012, the consortium was awarded a $500,000 grant for further work. The new organization was granted the 100YSS intellectual property from DARPA and maintained the organizational name 100 Year Starship. It was planned that the Dorothy Jemison Foundation for Excellence would team up with Icarus Interstellar, where the latter would work on the technical challenges of 100YSS.

After the Jemison Foundation was named as the winner of the grant, it organized the second symposium in Houston. Papers on many subjects related to interstellar flight and organizational foundations were presented. In 2013 and 2014 symposia were also held in Houston, and a fifth was held in Austria in November 2015.

Canopus Awards

2015 Canopus Awards

In 2015, the 100 Year Starship project hosted its first Canopus Awards for excellence in interstellar writing. The winners were announced October 30, 2015, at the symposium:

• Previously Published Long-Form Fiction (40,000 words or more): InterstellarNet: Enigma by Edward M. Lerner (FoxAcre). ISBN 978-1936771646
• Previously Published Short-Form Fiction (1,000–40,000 words): "The Waves" by Ken Liu (Asimov's 12/12)
• Original Fiction (1,000–5,000 words): "Everett's Awakening" by Yelcho (i.e., R. Buckalew)
• Original Nonfiction (1,000–5,000 words): "Finding Earth 2.0 from the Focus of the Solar Gravitational Lens" by Louis Friedman and Slava Turyshev

2017 Canopus Awards

A second Canopus Award competition was run in 2017. The winners were:

• Previously Published Long-Form Fiction (40,000 words or more): The Three-Body Problem, by Liu Cixin, translated by Ken Liu (published by Tor)
• Previously Published Short-Form Fiction (1,000–40,000 words): "Slow Bullets" by Alastair Reynolds (published by Tachyon Publications)
• Previously Published Nonfiction (1,000–40,000 words): Welcome to Mars: Making a Home on the Red Planet, by Buzz Aldrin and Marianne Dyson (published by National Geographic)
• Original Fiction (1,000–5,000 words): "The Quest for New Cydonia" by Russell Hemmell
• Original Nonfiction (1,000–5,000 words): "Microbots—The Seeds of Interstellar Civilization" by Robert Buckalew
• Original College Writing (1,000–5,000 words): "A Kingdom of Ends" by Ryan Burgess

2023 Canopus Awards

A third Canopus Award competition has been announced for 2023. A new category, "Original Local Short-form Fiction," open to continental African writers, was introduced for the 2023 award. The finalists, by category, are:

• Published Long-Form Fiction:
  • Escaping Exodus by Nicky Drayden (published by HarperVoyager)
  • Light Chaser by Peter F. Hamilton and Gareth L. Powell (published by Tor)
  • Sweep of Stars by Maurice Broaddus (published by Tor)
  • Braking Day by Adam Oyebanji (published by DAW)
  • Project Hail Mary by Andy Weir (published by Ballantine Books)
  • Sentient by Jeff Lemire and Gabriel Hernandez Walta (published by TKO)
• Published Short-Form Fiction:
  • "Drift-Flux" by Wole Talabi (published in AfroSFv3)
  • "Verisya" by Mari Ness (published in Daily Science Fiction)
  • "Repairs at the Beijing West Space Elevator" by Alex Shvartsman (published in Analog Science Fiction & Fact)
  • "A Sun Will Always Sing" by Karin Lowachee (published in TheVerge.com)
  • "Generations" by Osahon Ize-Iyamu (published in Bikes Not Rockets)
  • "The Hind" by Kevin J. Anderson and Rick Wilber (published in Asimov's Science Fiction)
  • "Tau Ceti Said What?" by Jack McDevitt (published in Asimov's Science Fiction)
• Published Long-Form Nonfiction:
  • A Traveler's Guide to the Stars by Les Johnson (published by Princeton University Press)
  • Extraterrestrial by Avi Loeb (published by Mariner Books)
  • Imagined Life by James Trefil and Michael Summers (published by Smithsonian Books)
  • The Case for Space: How the Revolution in Spaceflight Opens Up a Future of Limitless Possibility by Robert Zubrin (published by Prometheus)
  • Starship Citizens: Indigenous Principles for 100 Year Interstellar Voyages by Dawn Marsden (published by Wood Lake Publishing)
• Published Short-Form Nonfiction:
  • "Language Development During Interstellar Travel" by A. McKenzie and J. Punske (published in Acta Futura)
  • "Artificial Intelligence for Interstellar Travel" by Andreas M. Hein and Stephen Baxter (published in the Journal of the British Interplanetary Society)
  • "Navigation and Star Identification for an Interstellar Mission" by Paul McKee, Jacob Kowalski, and John A. Christian (published in Acta Astronautica)
  • "Joining the 'Galactic Club': What Price Admission? A Hypothetical Case Study of the Impact of Human Rights on a Future Accession of Humanity to Interstellar Civilization Networks" by Michael Bohlander (published in Futures)
  • "Migrating Extraterrestrial Civilizations and Interstellar Colonization: Implications for SETI and SETA" by Irina K. Romanovskaya (published in the International Journal of Astrobiology)
• Published Digital Presentation:
  • Space Haven by Bugbyte LTD. (published by Bugbyte LTD.)
  • The Outer Worlds by Obsidian Entertainment (published by Private Division)
  • Ixion by Bulwark Studios (published by Kasedo Games)
  • Colony Ship by Iron Tower Studio (published by Iron Tower Studio)
  • The Sights of Space: A Voyage to Alien Worlds by MelodySheep (published by MelodySheep)
  • The Fermi Paradox by Anomaly Games (published by Anomaly Games)
• Original Short-Form Fiction:
  • "Tess 16201c" by Faith Guptill
  • "Ortygia" by Scott Jessop
  • "The Interlopers" by Robert Buckalew
  • "We Should Have Guessed" by Terry Franklin
  • "The Living Archaeologist" by Jamiella Brooks
• Original Local Short-Form Fiction:
  • "Gumbojena" by Chioniso Tsikisayi (Zimbabwe)
  • "Space Frenemies" by Oluwatoyin Magbagbeola (Nigeria)
  • "One More Chance" by Chioma Mildred Okonkwo (Nigeria)
• "Incubation" by Amadin Ogbewe (Nigeria)

Criticism

The 100 Year Starship was named in 2012 by U.S. Senator Tom Coburn as one of the 100 most wasteful government spending projects. Coburn specifically cited a 100 Year Starship workshop that included one session, titled "Did Jesus Die for Klingons Too?" that debated the implications for Christian philosophy should life be found on other planets.

Multipotentiality

From Wikipedia, the free encyclopedia

https://en.wikipedia.org/wiki/Multipotentiality 

Multipotentiality is an educational and psychological term referring to the ability and preference of a person, particularly one of strong intellectual or artistic curiosity, to excel in two or more different fields.

It can also refer to an individual whose interests span multiple fields or areas, rather than being strong in just one. Such traits are called multipotentialities, while "multipotentialites" has been suggested as a name for those with this trait.

By contrast, those whose interests lie mostly within a single field are called "specialists".

History

Etymology

An early instance of the term in the record comes from relevant research in giftedness.

In 1972, R.H. Frederickson et al. defined a multipotentialed person as someone who, "when provided with appropriate environments, can select and develop a number of competencies to a high level".

On October 22, 2008, Douglas Hannay began a blog that lasted some eight years. His first blog referred to multipotentializing as excelling in multiple fields of energy. The blog was then copied in its entirety to Facebook on September 22, 2016, after viewing Emilie Wapnick's TED talk on being a multipotentialite during October 2015.

In 2010, multipotentiality appeared again in Tamara Fisher's article in Education Week. She defines it thus:

Multipotentiality is the state of having many exceptional talents, any one or more of which could make for a great career for that person.

— Tamara Fisher, Education Week

During 2015, Emilie Wapnick coined the term "multipotentialite", perhaps to establish a shared identity for the community. They define it this way:

A multipotentialite is someone with many interests and creative pursuits.

Although multipotentialite is a modern term, the idea of someone with many passions is not new. Any student of history often hears mention of polymaths or Renaissance people. Multipotentialites have, indeed, existed as long as human societies.

While the strengths of multipotentialites are not always appreciated in post-industrial capitalist societies, there have been times throughout history when being well-versed in multiple disciplines was considered the ideal. And, of course, multipotentiality is highly valued in certain spaces, contexts and cultures today.

When multipotentialites are supported and encouraged to embrace their diverse skills and experiences, they're able to tap into their super powers: idea synthesis, rapid learning, adaptability, big picture thinking, relating to and translating between different types of people, "languages", and modes of thought.

The ability to draw from and integrate a range of diverse ideas makes multipotentialites particularly well-suited to solving complex, multifactorial problems. And, their unconventional backgrounds help them develop unique voices and contribute fresh perspectives wherever they go.

— Emilie Wapnick, Terminology, Puttylike

Relevant terminology

While the term "multipotentialite" is often used interchangeably with polymath or Renaissance Person, the terms are not identical. One need not be an expert in any particular field to be a multipotentialite.

Indeed, Isis Jade  makes a clear distinction between multipotentiality and polymaths. Multipotentiality refers simply to one's potential in multiple fields owing to his/her diverse interests and attempts. Polymaths, on the other hand, are distinguished by their mastery and expertise in several fields. In this sense, multipotentialites can be viewed as potential polymaths.

Other terms used to refer to multipotentialites are "scanners", "slashers", "generalist", "multipassionate", "RP2", and "multipods", among others.

Context

With the advent of the industrial age, cultural norms have shifted in favor of specialization. Indeed, in the modern day, the more narrow the specialization, the higher the pay and respect accorded, for example: PhD graduates, and specialized lawyers, doctors, and engineers. The aphorism Jack of all trades, master of none emphasizes this. Older emphasis towards generalism and multiple potentials such as Renaissance humanism and the Renaissance man were replaced.

However, the convergence economy, Internet age, connectivity, the rise of the Creative Class, and other modern developments are bringing about a return of a more positive opinion for generalists and multipotentialites.

In Specialization, Polymaths And The Pareto Principle In A Convergence Economy, Jake Chapman writes:

Economists tell us that the history of human labor is one of continually increasing specialization. In the days of the hunter-gatherer, every member of the tribe would have been expected to command some degree of proficiency with each task.

As we progressed along the economic continuum from hunter-gatherer through agrarian and industrial and now into post-industrial economies, the labor force has become more fragmented, with workers having more and more specialized skill sets. ... Historically, specialization has been a path to prosperity. Although specialization has certain economic advantages, in the era of technological convergence, well-educated generalists will be those who are the most valuable. It is time for a renaissance of the "Renaissance Man". ... The Renaissance thinkers recognized both the potential of individuals as well as the enormous value to being well-rounded. Unfortunately, somewhere along the way the idea of someone who dabbled in many fields lost its cultural appeal and we began to praise those who sought deep subject matter expertise.

We now live in a world where distinctions between formerly separate industries are breaking down and the real opportunities for growth are where those industries intersect. Harnessing these 21st-century opportunities will require people who are "jacks of all trades, masters of none", or, perhaps more accurately, master polymaths.

— Jake Chapman

Business

Organizations such as startups that require adaptability and holding multiple roles can employ several multipotentialites and have one specialist as a resource.

In Specialization, Polymaths And The Pareto Principle In A Convergence Economy, Chapman said:

In the modern world, where a very common job might require someone to be a social-media expert, public speaker, writer and data analyst, the polymath wins and the deep subject-matter expert is relegated to a back corner to be used as a resource for others. As an investor, if I were going to pick the perfect team, it would be a group of rock-star polymaths with a single subject matter expert as a resource.

— Jake Chapman, In Specialization, Polymaths And The Pareto Principle In A Convergence Economy

Stretch Magazine discusses the role of multipotentialites in organizations and how they will believe they will be more in demand in the future.

Criticism of specialization

Historical context, current conventional wisdom, comparative advantage, USP, among others contribute to the wide acceptance of specialization.

Proponents of specialization above cite excellence and its perceived higher rewards compared to mediocrity in everything. Proponents of multiple capabilities below emphasize the importance of adaptability.

In "Master of Many Trades", Robert Twigger goes so far as to coin the word "monopath": "It means a person with a narrow mind, a one-track brain, a bore, a super-specialist, an expert with no other interests — in other words, the role-model of choice in the Western world."

This sentiment is not new. In Time Enough for Love (1973), Robert A. Heinlein wrote:

A human being should be able to change a diaper, plan an invasion, butcher a hog, conn a ship, design a building, write a sonnet, balance accounts, build a wall, set a bone, comfort the dying, take orders, give orders, cooperate, act alone, solve equations, analyze a new problem, pitch manure, program a computer, cook a tasty meal, fight efficiently, die gallantly. Specialization is for insects.

— Robert A. Heinlein, Time Enough for Love

In an article on the decline of polymathy, Felipe Fernández-Armesto wrote, "Universities bear some responsibility for its extinction. Classical Greece, Renaissance Italy and Victorian England all revered and rewarded generalists, for whom today universities have little or no space or patience. Enclosed departments in discrete spaces, with their own journals and jargons, are a legacy of lamentable, out-of-date ways of organising knowledge and work."

Impact

In a world that overvalues specialization, the term and its increasing popularity (especially among the blogging community) have contributed to the revival of awareness on the importance of generalists. It was even used in a competition's training session.

In the current economy, Creativity and the rise of the Creative Class are linked to divergent thinking and innovative solutions to current problems. Because new ideas can be found in the intersection of multiple fields, they would benefit from the advantages of multipotentialites.

Human migration

From Wikipedia, the free encyclopedia

https://en.wikipedia.org/wiki/Human_migration

Human migration is the movement of people from one place to another, with intentions of settling, permanently or temporarily, at a new location (geographic region). The movement often occurs over long distances and from one country to another (external migration), but internal migration (within a single country) is the dominant form of human migration globally.

Migration is often associated with better human capital at both individual and household level, and with better access to migration networks, facilitating a possible second move. It has a high potential to improve human development, and some studies confirm that migration is the most direct route out of poverty. Age is also important for both work and non-work migration. People may migrate as individuals, in family units or in large groups. There are four major forms of migration: invasion, conquest, colonization and emigration/immigration.

People moving from their home due to forced displacement (such as a natural disaster or civil disturbance) may be described as displaced persons or, if remaining in the home country, internally-displaced persons. People who flee to a different country due to political, religious, or other types of persecution in their home country can formally request shelter in the host country. These people are commonly referred to as asylum seekers. If the application is approved, their legal classification changes to that of refugees.

Definition

Depending on the goal and reason for relocation, migrants can be divided into three categories: migrants, refugees, and asylum seekers. Each category is defined broadly as the combination of circumstances that motivate a person to change their location. As such, migrants are traditionally described as persons who change the country of residence for general reasons. These purposes may include better job opportunities or healthcare needs. This term is the most widely understood, as anyone changing their geographical location permanently is a migrant.

In contrast, refugees are defined by the UNHCR as "persons forced to flee their country because of violence or persecution". The reasons for the refugees' migration usually involve war actions within the country or other forms of oppression, coming either from the government or non-governmental sources. Refugees are usually associated with people who must unwillingly relocate as fast as possible; hence, such migrants are likely to relocate undocumented.

Asylum seekers are associated with persons who also leave their country unwillingly, yet, who also do not do so under oppressing circumstances such as war or death threats. The motivation to leave the country for asylum seekers might involve an unstable economic or political situation or high rates of crime. Thus, asylum seekers relocate predominantly to escape the degradation of the quality of their lives.

Nomadic movements usually are not regarded as migrations, as the movement is generally seasonal, there is no intention to settle in the new place, and only a few people have retained this form of lifestyle in modern times. Temporary movement for travel, tourism, pilgrimages, or the commute is also not regarded as migration, in the absence of an intention to live and settle in the visited places.

Migration patterns and related numbers

There exist many statistical estimates of worldwide migration patterns. The World Bank has published three editions of its Migration and Remittances Factbook, beginning in 2008, with a second edition appearing in 2011 and a third in 2016. The International Organisation for Migration (IOM) has published ten editions of the World Migration Report since 1999. The United Nations Statistics Division also keeps a database on worldwide migration. Recent advances in research on migration via the Internet promise better understanding of migration patterns and migration motives.

Structurally, there is substantial South–South and North–North migration; in 2013, 38% of all migrants had migrated from developing countries to other developing countries, while 23% had migrated from high-income OECD countries to other high-income countries. The United Nations Population Fund says that "while the North has experienced a higher absolute increase in the migrant stock since 2000 (32 million) compared to the South (25 million), the South recorded a higher growth rate. Between 2000 and 2013, the average annual rate of change of the migrant population in developing regions (2.3%) slightly exceeded that of the developed regions (2.1%)."

Substantial internal migration can also take place within a country, either seasonal human migration (mainly related to agriculture and tourism to urban places), or shifts of the population into cities (urbanisation) or out of cities (suburbanisation). However, studies of worldwide migration patterns tend to limit their scope to international migration.

International migrants, 1970–2015

Year	Number of migrants	Migrants as a % of the world's population
1970	84,460,125	2.3%
1975	90,368,010	2.2%
1980	101,983,149	2.3%
1985	113,206,691	2.3%
1990	152,563,212	2.9%
1995	160,801,752	2.8%
2000	172,703,309	2.8%
2005	191,269,100	2.9%
2010	221,714,243	3.2%
2015	243,700,236	3.3%
2020	280 598 105	3.6%

Almost half of these migrants are women, one of the most significant migrant-pattern changes in the last half-century. Women migrate alone or with their family members and community. Even though female migration is largely viewed as an association rather than independent migration, emerging studies argue complex and manifold reasons for this.

As of 2019, the top ten immigration destinations were:

• United States
• Germany
• Saudi Arabia
• Russian Federation
• United Kingdom
• United Arab Emirates
• France
• Canada
• Australia
• Italy

In the same year, the top countries of origin were:

• India
• Mexico
• China
• Russian Federation
• Syrian Arab Republic
• Bangladesh
• Pakistan
• Philippines
• Afghanistan
• Indonesia

Besides these rankings, according to absolute numbers of migrants, the Migration and Remittances Factbook also gives statistics for top immigration destination countries and top emigration origin countries according to percentage of the population; the countries that appear at the top of those rankings are entirely different from the ones in the above rankings and tend to be much smaller countries.

Typical grocery store on 8th Avenue in one of the Brooklyn Chinatowns on Long Island, New York.

New York City's multiple Chinatowns in Queens, Manhattan, and Brooklyn are thriving as traditionally urban enclaves, as large-scale Chinese immigration continues into New York, with the largest metropolitan Chinese population outside Asia, The New York metropolitan area contains the largest ethnic Chinese population outside of Asia, comprising an estimated 893,697 uniracial individuals as of 2017.

As of 2013, the top 15 migration corridors (accounting for at least two million migrants each) were:

1. Mexico–United States
2. Russian Federation–Ukraine
3. Bangladesh–India
4. Ukraine–Russian Federation
5. Kazakhstan–Russian Federation
6. China–United States
7. Russian Federation–Kazakhstan
8. Afghanistan–Pakistan
9. Afghanistan–Iran
10. China–Hong Kong
11. India–United Arab Emirates
12. West Bank and Gaza–Jordan
13. India–United States
14. India–Saudi Arabia
15. Philippines–United States

Economic impacts

World economy

Dorothea Lange, Drought refugees from Oklahoma camping by the roadside, Blythe, California, 1936

The impacts of human migration on the world economy have been largely positive. In 2015, migrants, who constituted 3.3% of the world population, contributed 9.4% of global GDP.

At a microeconomic level, the value of a human mobility is largely recognized by firms. A 2021 survey by the Boston Consulting Group found that 72% of 850+ executives across several countries and industries believed that migration benefited their countries, and 45% considered globally diverse employees a strategic advantage.

According to the Centre for Global Development, opening all borders could add $78 trillion to the world GDP.

Remittances

Remittances (funds transferred by migrant workers to their home country) form a substantial part of the economy of some countries. The top ten remittance recipients in 2018.

Rank	Country	Remittance (in billions of US dollars)	Percent of GDP
1	India	80	2.80
2	China	67	0.50
3	Philippines	34	9.14
4	Mexico	34	1.54
5	France	25	0.96
6	Nigeria	22	5.84
7	Egypt	20	8.43
8	Pakistan	20	6.57
9	Bangladesh	18	5.73
10	Vietnam	14	6.35

In addition to economic impacts, migrants also make substantial contributions in sociocultural and civic-political life. Sociocultural contributions occur in the following areas of societies: food/cuisine, sport, music, art/culture, ideas and beliefs; civic-political contributions relate to participation in civic duties in the context of accepted authority of the State. It is in recognition of the importance of these remittances that the United Nations Sustainable Development Goal 10 targets to substantially reduce the transaction costs of migrants remittances to less than 3% by 2030.

Voluntary and forced migration

Migration is usually divided into voluntary migration and forced migration. The distinction between involuntary (fleeing political conflict or natural disaster) and voluntary migration (economic or labour migration) is difficult to make and partially subjective, as the motivators for migration are often correlated. The World Bank estimated that, as of 2010, 16.3 million or 7.6% of migrants qualified as refugees. This number grew to 19.5 million by 2014 (comprising approximately 7.9% of the total number of migrants, based on the figure recorded in 2013). At levels of roughly 3 percent the share of migrants among the world population has remained remarkably constant over the last 5 decades.

Voluntary migration

See also: Free State Project

Voluntary migration is based on the initiative and the free will of the person and is influenced by a combination of factors: economic, political and social: either in the migrants' country of origin (determinant factors or "push factors") or in the country of destination (attraction factors or "pull factors"). "Push-pull factors" are the reasons that push or attract people to a particular place. "Push" factors are the negative aspects(for example wars) of the country of origin, often decisive in people's choice to emigrate. The "pull" factors are the positive aspects of a different country that encourages people to emigrate to seek a better life. For example, the government of Armenia periodically gives incentives to people who will migrate to live in villages close to the border with Azerbaijan. This is an implementation of a push strategy, and the reason people do not want to live near the border is security concerns given tensions and hostility because of Azerbaijan.

Although the push-pull factors are opposed, both are sides of the same coin, being equally important. Although specific to forced migration, any other harmful factor can be considered a "push factor" or determinant/trigger factor, such examples being: poor quality of life, lack of jobs, excessive pollution, hunger, drought or natural disasters. Such conditions represent decisive reasons for voluntary migration, the population preferring to migrate in order to prevent financially unfavorable situations or even emotional and physical suffering.

Forced migration

There are contested definitions of forced migration. However, the editors of a leading scientific journal on the subject, the Forced Migration Review, offer the following definition: Forced migration refers to the movements of refugees and internally displaced people (displaced by conflict) as well as people displaced by natural or environmental disasters, chemical or nuclear disasters, famine, or development projects. These different causes of migration leave people with one choice, to move to a new environment. Immigrants leave their beloved homes to seek a life in camps, spontaneous settlement, and countries of asylum.

By the end of 2018, there were an estimated 67.2 million forced migrants globally – 25.9 million refugees displaced from their countries, and 41.3 million internally displaced persons that had been displaced within their countries for different reasons. In 2022, 6 million Ukrainian people fled their country; meanwhile, 3 million Syrian people fled in 3 years.

Transit migration

Transit migration is a highly debated term with no official definition. The common understanding is that it describes immigrants who are in the process of moving to an end goal country. The term was first coined by the UN in 1990 to describe immigrants who were traveling through countries surrounding Europe to end up in a European Union state. Another example of transit migrants is Central Americans who travel through Mexico in order to live in the United States.

The term "transit migration" has generated a lot of debate among migration scholars and immigration institutions. Some criticize it as a Eurocentric term that was coined to place responsibility of migrants on states outside the European Union; and also to pressure those states to prevent migration onward to the European Union. Scholars note that EU countries also have identical migrant flows and therefore it is not clear (illogical or biased) why it is only migrants in non-EU countries that are labeled as transit migrants. It is also argued that the term "transit" glosses over the complexity and difficulty of migrant journeys: migrants face many types of violence while in transit; migrants often have no set end destination and must adjust their plan as they move (migrant journeys can take years and go through several stages).

Contemporary labor migration theories

Overview

Numerous causes impel migrants to move to another country. For instance, globalization has increased the demand for workers in order to sustain national economies. Thus one category of economic migrants – generally from impoverished developing countries – migrates to obtain sufficient income for survival. Such migrants often send some of their income homes to family members in the form of economic remittances, which have become an economic staple in a number of developing countries. People may also move or are forced to move as a result of conflict, of human-rights violations, of violence, or to escape persecution. In 2014, the UN Refugee agency estimated that around 59.5 million people fell into this category. Other reasons people may move include to gain access to opportunities and services or to escape extreme weather. This type of movement, usually from rural to urban areas, may be classed as internal migration. Sociology-cultural and ego-historical factors also play a major role. In North Africa, for example, emigrating to Europe counts as a sign of social prestige. Moreover, many countries were former colonies. This means that many have relatives who live legally in the (former) colonial metro pole and who often provide important help for immigrants arriving in that metropole.

Relatives may help with job research and with accommodation. The geographical proximity of Africa to Europe and the long historical ties between Northern and Southern Mediterranean countries also prompt many to migrate. Whether a person decides to move to another country depends on the relative skill premier of the source and host countries. One is speaking of positive selection when the host country shows a higher skill premium than the source country. On the other hand, negative selection occurs when the source country displays a lower skill premium. The relative skill premia define migrants selectivity. Age heaping techniques display one method to measure the relative skill premium of a country. A number of theories attempt to explain the international flow of capital and people from one country to another.

Research contributions

Recent academic output on migration comprises mainly journal articles. The long-term trend shows a gradual increase in academic publishing on migration, which is likely to be related to the general expansion of academic literature production, and the increased prominence of migration research. Migration and its research have further changed with the revolution in information and communication technologies.

Neoclassical economic theory

Main article: Neoclassical economics

This migration theory states that the main reason for labour migration is wage difference between two geographic locations. These wage differences are usually linked to geographic labour demand and supply. It can be said that areas with a shortage of labour but an excess of capital have a high relative wage while areas with a high labour supply and a dearth of capital have a low relative wage. Labour tends to flow from low-wage areas to high-wage areas. Often, with this flow of labour comes changes in the sending and the receiving country. Neoclassical economic theory best describes transnational migration because it is not confined by international immigration laws and similar governmental regulations.

Dual labor market theory

Dual labour market theory states that pull factors in more developed countries mainly cause migration. This theory assumes that the labour markets in these developed countries consist of two segments: the primary market, which requires high-skilled labour, and the secondary market, which is very labour-intensive, requiring low-skilled workers. This theory assumes that migration from less developed countries into more developed countries results from a pull created by a need for labour in the developed countries in their secondary market. Migrant workers are needed to fill the lowest rung of the labour market because the native labourers do not want to do these jobs as they present a lack of mobility. This creates a need for migrant workers. Furthermore, the initial dearth in available labour pushes wages up, making migration even more enticing.

New economics of labor migration

This theory states that migration flows and patterns cannot be explained solely at the level of individual workers and their economic incentives but that wider social entities must also be considered. One such social entity is the household. Migration can be viewed as a result of risk aversion from a household that has insufficient income. In this case, the household needs extra capital that can be achieved through remittances sent back by family members who participate in migrant labour abroad. These remittances can also have a broader effect on the economy of the sending country as a whole as they bring in capital. Recent research has examined a decline in US interstate migration from 1991 to 2011, theorising that the reduced interstate migration is due to a decline in the geographic specificity of occupations and an increase in workers' ability to learn about other locations before moving there, through both information technology and inexpensive travel. Other researchers find that the location-specific nature of housing is more important than moving costs in determining labour reallocation.

Relative deprivation theory

Main article: Relative deprivation

Relative deprivation theory states that awareness of the income difference between neighbours or other households in the migrant-sending community is essential in migration. The incentive to migrate is a lot higher in areas with a high level of economic inequality. In the short run, remittances may increase inequality, but in the long run, they may decrease it. There are two stages of migration for workers: first, they invest in human capital formation, and then they try to capitalise on their investments. In this way, successful migrants may use their new capital to provide better schooling for their children and better homes for their families. Successful high-skilled emigrants may serve as an example for neighbours and potential migrants who hope to achieve that level of success.

World systems theory

World-systems theory looks at migration from a global perspective. It explains that interaction between different societies can be an important factor in social change. Trade with one country, which causes an economic decline in another, may create incentive to migrate to a country with a more vibrant economy. It can be argued that even after decolonisation, the economic dependence of former colonies remains on mother countries. However, this view of international trade is controversial, and some argue that free trade can reduce migration between developing and developed countries. It can be argued that the developed countries import labour-intensive goods, which causes an increase in the employment of unskilled workers in the less developed countries, decreasing the outflow of migrant workers. Exporting capital-intensive goods from rich countries to developing countries also equalises income and employment conditions, thus slowing migration. In either direction, this theory can be used to explain migration between countries that are geographically far apart.

Osmosis theory

Based on the history of human migration osmosis theory studies the evolution of its natural determinants. In this theory migration is divided into two main types: simple and complicated. The simple migration is divided, in its turn, into diffusion, stabilisation and concentration periods. During these periods, water availability, adequate climate, security and population density represent the natural determinants of human migration. The complicated migration is characterised by the speedy evolution and the emergence of new sub-determinants, notably earning, unemployment, networks, and migration policies. Osmosis theory explains analogically human migration by the biophysical phenomenon of osmosis. In this respect, the countries are represented by animal cells, the borders by the semipermeable membranes and the humans by ions of water. According to the theory, according to the osmosis phenomenon, humans migrate from countries with less migration pressure to countries with high migration pressure. To measure the latter, the natural determinants of human migration replace the variables of the second principle of thermodynamics used to measure the osmotic pressure.

Social-scientific theories

Sociology

Main article: Sociology of immigration

A number of social scientists have examined immigration from a sociological perspective, paying particular attention to how immigration affects and is affected by, matters of race and ethnicity, as well as social structure. They have produced three main sociological perspectives:

• symbolic interactionism, which aims to understand migration via face-to-face interactions on a micro-level
• social conflict theory, which examines migration through the prism of competition for power and resources
• structural functionalism (based on the ideas of Émile Durkheim), which examines the role of migration in fulfilling certain functions within each society, such as the decrease of despair and aimlessness and the consolidation of social networks

In the 21st century, as attention has shifted away from countries of destination, sociologists have attempted to understand how transnationalism allows us to understand the interplay between migrants, their countries of destination, and their countries of origins. In this framework, work on social remittances by Peggy Levitt and others has led to a stronger conceptualisation of how migrants affect socio-political processes in their countries of origin. Much work also takes place in the field of integration of migrants into destination-societies.

Political science

Political scientists have put forth a number of theoretical frameworks relating to migration, offering different perspectives on processes of security, citizenship, and international relations. The political importance of diasporas has also become in the 21st century a growing field of interest, as scholars examine questions of diaspora activism, state-diaspora relations, out-of-country voting processes, and states' soft power strategies. In this field, the majority of work has focused on immigration politics, viewing migration from the perspective of the country of destination. With regard to emigration processes, political scientists have expanded on Albert Hirschman's framework on '"voice" vs. "exit" to discuss how emigration affects the politics within countries of origin.

Historical theories

Ravenstein

Certain laws of social science have been proposed to describe human migration. The following was a standard list after Ernst Georg Ravenstein's proposal in the 1880s:

1. every migration flow generates a return or counter migration.
2. the majority of migrants move a short distance.
3. migrants who move longer distances tend to choose big-city destinations.
4. urban residents are often less migratory than inhabitants of rural areas.
5. families are less likely to make international moves than young adults.
6. most migrants are adults.
7. large towns grow by migration rather than natural increase.
8. migration stage by stage (step migration).
9. urban, rural difference.
10. migration and technology.
11. economic condition.

Push and pull

Demographer Everett S. Lee's model divides factors causing migrations into two groups of factors: push and pull. Push factors are things that are unfavourable about the home area that one lives in, and pull factors are things that attract one to another host area.

Push factors:

• Not enough jobs
• Few opportunities
• Conscription (draft young men into army)
• Famine or drought
• Political fear of persecution
• Poor medical care
• Loss of wealth
• Natural disasters
• Death threats
• Desire for more political or religious freedom
• Pollution
• Poor housing
• Discrimination
• Poor chances of marrying
• War or threat of invasion
• Disease

Pull factors:

• Job opportunities
• Better living conditions
• The feeling of having more political or religious freedom
• Enjoyment
• Education
• Better medical care
• Attractive climates
• Security
• Family links
• Industry
• Better chances of marrying

Climate cycles

The modern field of climate history suggests that the successive waves of Eurasian nomadic movement throughout history have had their origins in climatic cycles, which have expanded or contracted pastureland in Central Asia, especially Mongolia and to its west the Altai Mountains. People were displaced from their home ground by other tribes trying to find land that essential flocks could graze, each group pushing the next further to the south and west, into the highlands of Anatolia, the Pannonian Plain, into Mesopotamia, or southwards, into the rich pastures of China. Bogumil Terminski uses the term "migratory domino effect" to describe this process in the context of Sea People invasion.

Food, sex, and security

The theory is that migration occurs because individuals search for food, sex and security outside their usual habitation; Idyorough (2008) believes that towns and cities are a creation of the human struggle to obtain food, sex and security. To produce food, security and reproduction, human beings must, out of necessity, move out of their usual habitation and enter into indispensable social relationships that are cooperative or antagonistic. Human beings also develop the tools and equipment to interact with nature to produce the desired food and security. The improved relationship (cooperative relationships) among human beings and improved technology further conditioned by the push and pull factors all interact together to cause or bring about migration and higher concentration of individuals into towns and cities. The higher the technology of production of food and security and the higher the cooperative relationship among human beings in the production of food and security and the reproduction of the human species, the higher would be the push and pull factors in the migration and concentration of human beings in towns and cities. Countryside, towns and cities do not just exist, but they do so to meet the basic human needs of food, security and the reproduction of the human species. Therefore, migration occurs because individuals search for food, sex and security outside their usual habitation. Social services in the towns and cities are provided to meet these basic needs for human survival and pleasure.

Other models

• Zipf's inverse distance law (1956)
• Gravity model of migration and the friction of distance
• Radiation law for human mobility
• Buffer theory
• Stouffer's theory of intervening opportunities (1940)
• Zelinsky's Mobility Transition Model (1971)
• Bauder's regulation of labour markets (2006): "suggests that the international migration of workers is necessary for the survival of industrialised economies...[It] turns the conventional view of international migration on its head: it investigates how migration regulates labour markets, rather than labour markets shaping migration flows."

Migration governance

By their very nature, international migration and displacement are transnational issues concerning the origin and destination States and States through which migrants may travel (often referred to as "transit" States) or in which they are hosted following displacement across national borders. And yet, somewhat paradoxically, the majority of migration governance has historically remained with individual states. Their policies and regulations on migration are typically made at the national level. For the most part, migration governance has been closely associated with State sovereignty. States retain the power of deciding on the entry and stay of non-nationals because migration directly affects some of the defining elements of a State. Comparative surveys reveal varying degrees of openness to migrants across countries, considering policies such as visa availability, employment prerequisites, and paths to residency.

Bilateral and multilateral arrangements are features of migration governance at an international level. There are several global arrangements in the form of international treaties in which States have reached an agreement on the application of human rights and the related responsibilities of States in specific areas. The 1966 International Covenant on Civil and Political Rights and the 1951 Convention Relating to the Status of Refugees (Refugee Convention) are two significant examples notable for being widely ratified. Other migration conventions have not been so broadly accepted, such as the International Convention on the Protection of the Rights of All Migrant Workers and Members of Their Families, which still has no traditional countries of destination among its States parties. Beyond this, there have been numerous multilateral and global initiatives, dialogues and processes on migration over several decades. The Global Compact for Safe, Orderly and Regular Migration (Global Compact for Migration) is another milestone, as the first internationally negotiated statement of objectives for migration governance striking a balance between migrants' rights and the principle of States' sovereignty over their territory. Although it is not legally binding, the Global Compact for Migration was adopted by consensus in December 2018 at a United Nations conference in which more than 150 United Nations Member States participated and, later that same month, in the United Nations General Assembly (UNGA), by a vote among the Member States of 152 to 5 (with 12 abstentions).

Migration programs

Colonialism and colonization opens up distant territories and their people to migration, having dominated what is identified as modern migration. Colonialism globalized systems of migration and established ties effective until today.

While classic modern colonialism relied on the subjugation and rule of local indigenous peoples by small groups of conquering metropolitan people, soon forced migration, through slavery or indentured servitude supplanted the subjugated local indigenous peoples. Settler colonialism later continued or established the rule of the colonizers through migration, particularly settlement. Settler colonies relied on the attraction of metropolitan migrants with the promise of settlement and increasingly outnumbering, displacing or killing indigenous peoples.

Only in the late stage of colonialism migration flows oriented towards the metropole instead of out or outside of it. After decolonization migration ties between former colonies to former metropoles have been continuing. Today's independent countries have developed selective or targeted foreign worker policies or programs, with the aim of boosting economies with skilled or relatively cheap new local labour, while discrimination and exploitation are often fed by ethnic nationalist opposition to such policies.