Sun

The Sun (in Greek: Helios, in Latin: Sol) is the star at the center of the Solar System and is by far the most important source of energy for life on Earth. It is a nearly perfect spherical ball of hot plasma, with internal convective motion that generates a magnetic field via a dynamo process. Its diameter is about 109 times that of Earth, and it has a mass about 330,000 times that of Earth, accounting for about 99.86% of the total mass of the Solar System.About three quarters of the Sun's mass consists of hydrogen; the rest is mostly helium, with much smaller quantities of heavier elements, including oxygen, carbon, neon and iron.

The Sun is a G-type main-sequence star (G2V) based on spectral class and it is informally referred to as a yellow dwarf. It formed approximately 4.567 billion years ago from the gravitational collapse of matter within a region of a large molecular cloud. Most of this matter gathered in the center, whereas the rest flattened into an orbiting disk that became the Solar System. The central mass became increasingly hot and dense, eventually initiating nuclear fusion in its core. It is thought that almost all stars form by this process.

Sun (disambiguation)

The Sun is the star at the center of the Solar System.

Sun or the Sun may also refer to:

Other common meanings

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The Sun (Sydney)

The Sun was an afternoon tabloid newspaper, first published under this name in 1910. It was acquired from Associated Newspapers by Fairfax Holdings in Sydney, Australia in 1953, as the afternoon companion to The Sydney Morning Herald. The former Sunday edition, the Sunday Sun was discontinued and merged with the Sunday Herald into the tabloid Sun-Herald at the same time.

Publication of The Sun ceased on 14 March 1988. Some of its content, and sponsorship of the Sydney City to Surf footrace, was continued in The Sun-Herald.

References

Field of sets

In mathematics a field of sets is a pair where is a set and is an algebra over i.e., a non-empty subset of the power set of closed under the intersection and union of pairs of sets and under complements of individual sets. In other words forms a subalgebra of the power set Boolean algebra of . (Many authors refer to itself as a field of sets. The word "field" in "field of sets" is not used with the meaning of field from field theory.) Elements of are called points and those of are called complexes and are said to be the admissible sets of .

Fields of sets play an essential role in the representation theory of Boolean algebras. Every Boolean algebra can be represented as a field of sets.

Fields of sets in the representation theory of Boolean algebras

Stone representation

Every finite Boolean algebra can be represented as a whole power set - the power set of its set of atoms; each element of the Boolean algebra corresponds to the set of atoms below it (the join of which is the element). This power set representation can be constructed more generally for any complete atomic Boolean algebra.