The Sun

Earth's Sun

The Sun is the star at the center of the Solar System. The Earth and other matter (including other planets, asteroids, meteoroids, comets and dust) orbit the Sun, which by itself accounts for more than 99% of the solar system's mass. Energy from the Sun—in the form of insolation from sunlight—supports almost all life on Earth via photosynthesis, and drives the Earth's climate and weather.

About 74% of the Sun's mass is hydrogen, 25% is helium, and the rest is made up of trace quantities of heavier elements. The Sun has a spectral class of G2V. "G2" means that it has a surface temperature of approximately 5,500 K, giving it a white color, which, because of atmospheric scattering, appears yellow. Its spectrum contains lines of ionized and neutral metals as well as very weak hydrogen lines. The "V" suffix indicates that the Sun, like most stars, is a main sequence star. This means that it generates its energy by nuclear fusion of hydrogen nuclei into helium and is in a state of hydrostatic balance, neither contracting nor expanding over time. There are more than 100 million G2 class stars in our galaxy. Because of logarithmic size distribution, the Sun is actually brighter than 85% of the stars in the Galaxy, most of which are red dwarfs.

The Sun orbits the center of the Milky Way galaxy at a distance of approximately 25,000 to 28,000 light-years from the galactic center, completing one revolution in about 225–250 million years. The orbital speed is 217 km/s, equivalent to one light-year every 1,400 years, and one AU every 8 days.

The Sun is a third generation star, whose formation may have been triggered by shockwaves from a nearby supernova. This is suggested by a high abundance of heavy elements such as gold and uranium in the solar system; these elements could most plausibly have been produced by endergonic nuclear reactions during a supernova, or by transmutation via neutron absorption inside a massive second-generation star.

Sunlight is the main source of energy near the surface of Earth. The solar constant is the amount of power that the Sun deposits per unit area that is directly exposed to sunlight. The solar constant is equal to approximately 1,370 watts per square meter of area at a distance of one AU from the Sun (that is, on or near Earth). Sunlight on the surface of Earth is attenuated by the Earth's atmosphere so that less power arrives at the surface—closer to 1,000 watts per directly exposed square meter in clear conditions when the Sun is near the zenith. This energy can be harnessed via a variety of natural and synthetic processes—photosynthesis by plants captures the energy of sunlight and converts it to chemical form (oxygen and reduced carbon compounds), while direct heating or electrical conversion by solar cells are used by solar power equipment to generate electricity or to do other useful work. The energy stored in petroleum and other fossil fuels was originally converted from sunlight by photosynthesis in the distant past.

The Solar System

The solar system is the stellar system comprising the Sun and the retinue of celestial objects gravitationally bound to it: currently eight official planets (according to the International Astronomical Union) and their 162 known moons,[1] as well as dwarf planets, asteroids, meteoroids, planetoids, comets, and interplanetary dust. From 1930 to 2006 there were nine official planets, but Pluto's status was changed to that of a "dwarf planet" on August 24, 2006 by the IAU.

The principal component of the solar system is the Sun; a main sequence G2 star that contains 99.86% of the system's known mass and dominates it gravitationally. Because of its large mass, the Sun has an interior density high enough to sustain nuclear fusion, releasing enormous amounts of energy, most of which is radiated into space in the form of electromagnetic radiation, including visible light. The Sun's two largest orbiting bodies, Jupiter and Saturn, account for more than 90% of the system's remaining mass. (The currently hypothetical Oort cloud, should its existence be confirmed, would also hold a substantial percentage).

In broad terms, the charted regions of the solar system consist of the Sun, four rocky bodies close to it called the terrestrial planets, an inner belt of rocky asteroids, four gas giant planets, and an outer belt of small, icy bodies known as the Kuiper belt. One planet, Pluto, is also a member of the Kuiper belt. In order of their distances from the Sun, the major planets are Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus and Neptune. All planets but two are in turn orbited by natural satellites (usually termed "moons" after Earth's Moon) and the largest are encircled by planetary rings of dust and other particles. The planets (with the exception of Earth) are named after gods and goddesses from Greco-Roman mythology.The definition of the term "planet" was decided by the International Astronomical Union, in a vote on August 24, 2006. This new definiton most directly affects Pluto, which is now not considered one of major planetary bodies, leaving our Solar System with eight major planets.

Energy

Energy

Energy is a fundamental concept of physics, with applications throughout the natural sciences. Everything in the known universe is composed fundamentally of energy.

Conversavation of Energy

Energy is subject to a strict global conservation law; that is, it can neither be created nor destroyed. Most kinds of energy (with gravitational energy being a notable exception) are also subject to strict local conservation laws, as well. In this case, energy can only be exchanged between adjacent regions of space, and all observers agree as to the volumetric density of energy in any given space. There is also a global law of conservation of energy, stating that the total energy of the universe cannot change; this is a corollary of the local law, but not vice versa. Conservation of energy is associated with the symmetry of the laws of physics, namely invariance with respect to time (via Noether's theorem).

Total Energy of a System

The total energy of a system can be subdivided and classified in various ways. For example, it is sometimes convenient to distinguish kinetic energy from potential energy. It may also be convenient to distinguish gravitational energy, electrical energy, thermal energy, and other forms. These classifications overlap; for instance thermal energy usually consists partly of kinetic and partly of potential energy.

Transfer of Energy

The transfer of energy can take various forms; familiar examples include work, heat flow, and advection. The word "energy" is also used outside of physics in many ways, which can lead to ambiguity and inconsistency. The vernacular terminology is not consistent with technical terminology. For example, the important public-service announcement, "Please conserve energy" uses vernacular notions of "conservation" and "energy" which make sense in their own context but are incompatible with the technical notions of "conservation" and "energy" that are used in the law of conservation of energy.

Special Relativity

In classical physics energy is considered a scalar quantity, having no direction in space. In special relativity energy is not a Lorentz scalar, but rather one component of the energy-momentum 4-vector, such that energy is associated with the timelike direction. In other words, energy is invariant with respect to spacelike rotations, but not invariant with respect to boosts.

Astronomy and cosmology

The phenomona of stars, nova, supernova, quasars and gamma ray bursts are the universe's highest-output energy transformations of matter. All stellar phenomena (including solar activity) are driven by various kinds of energy transformations. Energy in such transformations is either from:

1. Gravitational collapse of matter, usually molecular hydrogen, into various classes of astronomical objects (stars, black holes, etc.)


2. or from nuclear fusion of lighter elements, in this case, primarily hydrogen.

Dark Energy

Dark energy is believed to make up 70% of the universe. Light elements, primarily hydrogen and helium, were created in the Big Bang. These light elements were spread too fast and too thinly in the Big Bang process through nucleosynthesis to form the most stable medium-sized atomic nuclei, like iron and nickel. This fact allows for later energy release, as such intermediate-sized elements are formed in our era. The formation of such atoms powers the steady energy-releasing reactions in stars, and also contributes to sudden energy releases, such as in novae.

Black Holes

Gravitational collapse of matter into black holes is also thought to power the very most energetic processes, generally seen at the centers of galaxies. Some believe black holes lead to an alternate web of universes as mass entering the black holes accelerates beyond the boundaries of Relativistic Physics. This is a moment where the universe contracts to an infinitesimal point, relatively speaking and then expands equally and oppositely in a completely different dimension of space and time.

Cosmologists are still unable to explain all cosmological phenomena purely on the basis of known conventional forms of energy, for example those related to the accelerating expansion of the universe. Dark Energy is necessary to describe certain cosmological observations, particularly regarding black holes, where light travels faster than the speed of light.

Etymology

Energy comes from the Greek ενέργεια, where εν- means "in" and έργον "work". The compound εν-εργεια in Epic Greek meant "divine action" or "magical operation"; it was later used by Aristotle with the meaning of "activity, operation" or "vigour", and by Diodorus Siculus for "force of an engine."

Carbon 6 Atom and It's Fundamental Particles

Carbon

Overview

Carbon occurs in all organic life and is the basis of organic chemistry. This nonmetal also has the interesting chemical property of being able to bond with itself and a wide variety of other elements, forming nearly ten million known compounds. When united with oxygen it forms carbon dioxide, which is vital to plant growth. When united with hydrogen, it forms various compounds called hydrocarbons which are essential to industry in the form of fossil fuels. When combined with both oxygen and hydrogen it can form many groups of compounds including fatty acids, which are essential to life, and esters, which give flavor to many fruits. The isotope carbon-14 is commonly used in radioactive dating.

Notable characteristics

Carbon is a remarkable element for many reasons. Its different forms include the hardest naturally occurring substance (diamond) and one of the softest substances (graphite) known. Moreover, it has a great affinity for bonding with other small atoms, including other carbon atoms, and its small size makes it capable of forming multiple bonds. These attributes are mostly responsible for carbon's unique ability to form such numerous compounds, in fact, the majority of all chemical compounds.

We Are Carbon Based Life

Carbon compounds form the basis of all life on Earth and the carbon-nitrogen cycle provides some of the energy produced by the Sun and other stars. Moreover, carbon has the highest melting/sublimation point of all elements. At atmospheric pressure it has no actual melting point. Its triple point is at 10 MPa (100 bar), so it sublimates above 4000 K. Thus it remains solid at higher temperatures than the highest melting point metals like tungsten or rhenium, regardless of its allotropic form.

Carbon Not Present during Early Period of Big Bang

Carbon was not created during the initial expansion of the Big Bang. This is due to the fact that it needs a triple collision of alpha particles (helium nuclei), in order to be produced. The universe initially expanded and cooled too fast for that to be possible. It is produced, however, in the interior of stars in the horizontal branch, where stars transform a helium core into carbon by means of the triple-alpha process. It was also created in a multi-atomic state.

Applications

Carbon is a very important component of all known living systems, along with Hydrogen, Oxygen and Nitrogen. Without it, life as we know it could not exist. The major economic use of carbon is in the form of hydrocarbons, most notably the fossil fuel methane gas and crude oil (petroleum). Crude oil is used by the petrochemical industry to produce, amongst others, gasoline and kerosene, through a distillation process, in refineries. Crude oil forms the raw material for many synthetic substances, many of which are collectively called plastics.

Other uses

• The isotope carbon-14 was discovered on February 27, 1940 and is used in radiocarbon dating.
• Graphite is combined with clays to form the 'lead' used in pencils.
• Diamond is used for decorative purposes, and also as drill bits and other applications making use of its hardness.
• Carbon is added to iron to make steel.
• Carbon is used as a neutron moderator in nuclear reactors.
• Carbon fibre, which is mainly used for composite materials, as well as high-temperature gas filtration.
• Carbon black is used as a filler in rubber and plastic compounds.
• Graphite carbon in a powdered, caked form is used as charcoal for grilling, artwork and other uses.
• Activated charcoal is used in medicine (as powder or compounded in tablets or capsules) to adsorb toxins, poisons, or gases from the digestive system.
• The chemical and structural properties of fullerenes, in the form of carbon nanotubes, has promising potential uses in the nascent field of nanotechnology.

History and Etymology

Carbon was discovered in prehistory and was known to the ancients, who manufactured it by burning organic material in insufficient oxygen (making charcoal). Diamonds have long been considered rare and beautiful. One of the last-known allotropes of carbon, fullerenes, were discovered as byproducts of molecular beam experiments in the 1980s.

The name comes from French charbone, which in turn came from Latin carbo, meaning charcoal. In German and Dutch, the names for carbon are Kohlenstoff and koolstof respectively, both literally meaning "coal-stuff".