Wikipedia - Mean Field Theory
Field of reference: Physics
Description: Multi-particle physical systems are so complex that only a very efficient approximate treatment is possible. The mean free theory describes such physical systems as individual particles evolving under the influence of an effective force, which is the combined force exerted by the rest of the system.
"Mean field theory (MFT, also known as self-consistent field theory) is a method to analyse physical systems with multiple bodies. A many-body system with interactions is generally very difficult to solve exactly, except for extremely simple cases (random field theory, 1D Ising model). The n-body system is replaced by a 1-body problem with a chosen good external field. The external field replaces the interaction of all the other particles to an arbitrary particle."
| שייך לנושאים: 1-13 - חינוך אינטגרלי, -מקורות מדעיים, הטבע, 2. הטבע כמערכת |
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Wikipedia - Principle of Min. Energy
Field of reference: Physics
Description: Closed physical systems will tend to "arrange" their sub-systems (elements) in such a way that will minimize the system's potential energy while at the same time maximize it's entropy (the level of complexity). In general, lower energy states corresponds with lower entropy, therefore keeping a balance between maximum entropy and minimum energy has some unique and interesting manifestations in physical systems.
"A closed system, on the other hand, is a system which is connected to another system, and may exchange energy, but not mass, with the other system. If, rather than an isolated system, we have a closed system, in which the entropy rather than the energy remains constant, then it follows from the first and second laws of thermodynamics that the energy of that system will drop to a minimum value at equilibrium, transferring its energy to the other system. To restate: * The maximum entropy principle: For a closed system with fixed internal energy (i.e. an isolated system), the entropy is maximized at equilibrium. * The minimum energy principle: For a closed system with fixed entropy, the total energy is minimized at equilibrium. This should not be confused with the minimum total potential energy principle which states that, at equilibrium, the total potential energy of a system with dissipation will be at a minimum, which is a special case of the maximum entropy principle."
| שייך לנושאים: 1-13 - חינוך אינטגרלי, -מקורות מדעיים, הטבע, 2. הטבע כמערכת |
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Wikipedia - Geomagnetic storm
Field of reference: Physics
Description: Geomagnetic activity on the sun may have far reaching implications on life here on Earth.
"A geomagnetic storm is caused by a solar wind shock wave and/or cloud of magnetic field which interacts with the Earth's magnetic field. The increase in the solar wind pressure initially compresses the magnetosphere and the solar wind magnetic field will interact with the Earth's magnetic field and transfer an increased amount of energy into the magnetosphere. .... In 1989, a geomagnetic storm energized ground induced currents which disrupted electric power distribution throughout most of Quebec province and caused aurorae as far south as Texas."
| שייך לנושאים: 1-13 - חינוך אינטגרלי, -מקורות מדעיים, הטבע, 2. הטבע כמערכת |
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Wikipedia - Tide
Field of reference: Physics
Description: Tides result from the interplay of the (opposite) gravitational forces exerted on the earth by the sun and the moon.
"Tides are the rise and fall of sea levels caused by the combined effects of the gravitational forces exerted by the moon and the sun and the rotation of the earth."
| שייך לנושאים: 1-13 - חינוך אינטגרלי, -מקורות מדעיים, הטבע, 2. הטבע כמערכת |
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Anita Kelleher
Field of reference: Interdisciplinary
Description: As the natural system approaches collapse it is sensitive and responds to small catalysts of change.
"As a way of understanding elements of the Megacrisis, it can produce useful insights but as a means of defining the Megacrisis a complex systems map might provide a deeper understanding of the interconnectedness of these elements and a means to better appreciate the complexity. As Laszlo emphasizes: 'the doomsday arguments [Decline to Disaster scenario] miss a basic point: they do not recognize that humanity is also a dynamic system capable of rapid transformation. As the natural system approaches collapse it is sensitive and responds to small catalysts of change' (2008, p.15).
These small catalysts of change were described in the Tao Te Ching, as 'the ripple effect' (Heider, 1985, p.107). One small pebble dropped into a pond creates multiple ripples. One person can influence a family; one family a community; one community a nation; one nation a world. Lorenz used the term 'butterfly effect' whereby a butterfly flaps its wings in one part of the world and creates a tsunami elsewhere (Hilborn, 2004). The dropped pebble or the flapping wing represents a small change in the initial condition of the system, creating a chain of events leading to large-scale alterations. A non-linear systems map would endeavour to identify where to drop the pebbles."
| שייך לנושאים: 1-13 - חינוך אינטגרלי, -מקורות מדעיים, הטבע, 2. הטבע כמערכת |
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