A general heading which covers a wide variety of complex views on
→ quantum theory. As the first and the founding interpretation of the
→ quantum mechanics, it was developed in the late 1920's
mainly by the Danish physicist Niels Bohr, but also Werner Heisenberg, Max Born and
other physicists who made important contributions to the overall understanding of this field.
Bohr expressed himself on the subject at various meetings and later published
several articles and comments, but he never wrote a systematic and complete version
of his views. There is not a unique Copenhagen Interpretation but various more or less
complete versions, the common denominator of which is mainly the work of Bohr.
Among those opposed to the Copenhagen Interpretation have been Albert Einstein,
Erwin Schrödinger, Louis de Broglie, Max Planck, David Bohm, Alfred Landé,
Karl Popper, and Bertrand Russell. The Copenhagen Interpretation recognizes that
the deterministic picture of the universe that works so well at the macroscopic level
does not work for the world at the
quantum level. The universe at the quantum level is predictable only in a statistical sense.
This implies that we can never really know the nature of quantum phenomena.
The four cornerstones of the Copenhagen Interpretation are:
→ wave-particle duality,
the probability → wave function, the
→ uncertainty principle, and the significance of the
→ observer. The observer is of the utmost importance
because he causes the reality to unfold in the way it does. The key feature of
the Copenhagen Interpretation is a concept known as the
→ collapse of the wave function, for which there
is no known physical
explanation; see also → Schrodinger's cat.

Copenhagen, from Dan. København
"merchant's port," from køber "merchant" ("buyer") +
havn "port,"
from the fact that the originator and chief interpreter of this
school was Niels Bohr whose headquarters was in Copenhagen;
→ interpretation.

O.E. open "not closed down, raised up," also "uncovered, bare; plain, evident,"
related to up; from P.Gmc. *upana (cf. O.N. opinn,
Swed. öppen, Dan. aaben, O.Fris. epen, O.H.G. offan
"open"), from PIE *upo "up from under, over;" cf. L. sub; Gk. hypo;
O.Pers. upā (prep.) "under, with;" Av. upā, upa
(prep.; prevb) "toward, with, on, in;"
Mod.Pers. bâ "with," from abâ;
Skt. úpa (adv., prevb., prep.) "toward, with, under, on."

Bâz "open," from Mid.Pers. abâz-, apâc-, O.Pers. apa- [pref.]
"away, from;" Av. apa- [pref.] "away, from,"
apaš [adv.] "toward the back;" cf. Skt. ápāñc
"situated behind."

open cluster

خوشهیِ باز

xuše-ye bâz (#)

Fr.: amas ouvert

A loose grouping of dozens or hundreds of young stars
distributed in a region a few light-years across. Open
clusters are relatively young, typically containing many hot, highly
luminous stars. They are located within the disk of the Galaxy,
whence their older name Galactic clusters.

In the context of solar physics, a → magnetic field line
when it crosses the solar surface only once, i.e., when it goes from surface to infinity.
This is the case at a sufficiently large scale in → coronal holes.
This is mostly not the case in → active regions.

A space of infinite volume without any boundary.
Triangles which lie on the surface of an open space will have a sum of
angles which is less than 180°. An open space has a negative → curvature.
See also → open Universe,
→ closed space.