What makes the sun so hot and what makes it give off such a bright light?

Question

Dont tell me it is because of the gases that make up the sun because there are gases every where around us.What makes the hydrogen and helium and other gases in the sun to became so hot that they give warmth and produce light.

Answer 1

the Sun is fueled by nuclear fusion reactions.

To understand how our Sun works, it helps to imagine that the inside of the Sun is made up of different layers, one inside the other. The core, or the center of the Sun, is the region where the energy of the Sun is produced. Even on Earth we know that the Sun produces energy because we see sunlight and we feel hot on a summer day.

The Sun's energy, which is produced in the core, travels outwards. The energy travels first through the radiative zone, where particles of light (photons) carry the energy. It actually takes millions of years for a photon to move to the next layer, the convection zone.

At the convection zone, energy is transferred more rapidly. This time it is the motion of the gases in the Sun that transfers the energy outwards. The gas at this layer mixes and bubbles, like the motion in a pot of boiling water.This bubbling effect is seen on the surface of the Sun, and is called granulation.

The visible solar atmosphere consists of three regions: the photosphere, the chromosphere, and the solar corona. Most of the visible (white) light comes from the photosphere, this is the part of the Sun we actually see. The chromosphere and corona also emit white light, and can be seen when the light from the photosphere is blocked out, as occurs in a solar eclipse. The sun emits electromagnetic radiation at many other wavelengths as well. Different types of radiation (such as radio, ultraviolet, X-rays, and gamma rays) originate from different parts of the sun. Scientists use special instruments to detect this radiation and study different parts of the solar atmosphere.

The solar atmosphere is so hot that the gas is primarily in a plasma state: electrons are no longer bound to atomic nuclei, and the gas is made up of charged particles (mostly protons and electrons). In this charged state, the solar atmosphere is greatly influenced by the strong solar magnetic fields that thread through it. These magnetic fields, and the outer solar atmosphere (the corona) extend out into interplanetary space as part of the solar wind.

The Sun is not a quiet place, but one that exhibits sudden releases of energy. One of the most frequently observed events are solar flares: sudden, localized, transient increases in brightness that occur in active regions near sunspots. They are usually most easily seen in H-alpha and X-rays, but may have effects in the entire elecromagnetic spectrum. The X-ray brightness from a large flare often exceeds the X-ray output from the rest of the Sun. Another type of event, the coronal mass ejection, typically disrupt helmet streamers in the solar corona. As much as 1e13 (10,000,000,000,000) kilograms of material can be ejected into the solar wind. Coronal mass ejections propagate out in the solar wind, where they may encounter the Earth and influence geomagnetic activity. Coronal mass ejections are often (but not always) accompanied by prominence eruptions, where the cool, dense prominence material also erupts outward.

All of these forms of solar activity are believed to be driven by energy release from the solar magnetic field. How this energy release occurs, and the relationship between different types of solar activity, is one of the many puzzles facing solar physicists today. The amount of solar activity on the Sun is not constant, and is closely related to the typical number of sunspots that are visible. The number of sunspots and the levels of solar activity vary with an 11 year period known as the solar cycle.

In about 5 billion years, the hydrogen in the center of the Sun will start to run out. The helium will get squeezed. This will speed up the hydrogen burning. Our star will slowly puff into a red giant. It will eat all of the inner planets, even the Earth.
As the helium gets squeezed, it will soon get hot enough to burn into carbon. At the same time, the carbon can also join helium to form oxygen. The Sun is not very big compared to some stars. It will never get hot enough in the center to burn carbon and oxygen. These elements will collect in the center of the star. Later it will shed most of its outer layers, creating a planetary nebula, and reveal a hot white dwarf star.

Nearly 99 percent of all stars in the galaxy will end their lives as white dwarfs. By studying the stars that have already changed, we can learn about the fate of our own Sun.

Answer 2

It is the gas. I am sorry you don't like that answer, but just because it is boring to you does not make it untrue. I can tell you that at such high pressure and heat that is there this makes the hydrogen brake down to helium and this loss of mass is what actually creates the heat and the light. It is a giant plasma nuclear fusion chamber.
B

Answer 3

Short answer is gravity and magnetic pressure make the sun into a hydrogen fusion reactor. Hydrogen molecules fuse together to become helium. This is a radioactive reaction. so light and heat and ionized particles are released. The sun is in effect a huge hydrogen bomb that has been exploding for a long time.

Answer 4

Nuclear Fusion.

2 hydrogen atoms get fused together to make a helium atom. When that happens a small amount of mass is lost in the form of energy.

Answer 5

Nuclear reactions happening inside the gases present in sun emit heat and light. Both the heat emitted and the light radiated are so strong that you see this effect.

Answer 6

It depends what you mean by the "tip of the sun". The outer visible surface (the photosphere) of the sun is about 5700 degrees; the layer just outside that (the corona) can reach up to a million degrees. As others have mentioned, lightning is about 30,000 degrees.

Answer 7

it is all because of the nuclear reactions between hydogen and helium

Answer 8

The easiest answer is because of the nuclear reactions that are taking place in the sun and on the suns surface... the sun really isnt made of gas, it is one huge nuclear powerplant.... like all stars, it creates its engery through a complex and sustained nuclear reaction.


but here is the long version:



While the Sun is an averaged-sized star, it contains approximately 99% of the total mass of the solar system. The Sun is a near-perfect sphere, with an oblateness estimated at about 9 millionths,[7] which means that its polar diameter differs from its equatorial diameter by only 10 km. While the Sun does not rotate as a solid body (the rotational period is 25 days at the equator and about 35 days at the poles), it takes approximately 28 days to complete one full rotation; the centrifugal effect of this slow rotation is 18 million times weaker than the surface gravity at the Sun's equator. Tidal effects from the planets do not significantly affect the shape of the Sun.

The Sun does not have a definite boundary as rocky planets do, nor even a radius where the density suddenly begins to fall off; in its outer parts the density of its gases drops approximately exponentially with increasing distance from the center of the Sun. Nevertheless, the Sun has a well-defined interior structure, described below. The Sun's radius is measured from its center to the edge of the photosphere. This is simply the layer above which the gases are too cool or too thin to radiate a significant amount of light; the photosphere is the surface most readily visible to the naked eye. Most of the Sun's mass lies within about 0.7 radii of the center.

The solar interior is not directly observable, and the Sun itself is opaque to electromagnetic radiation. However, just as seismology uses waves generated by earthquakes to reveal the interior structure of the Earth, the discipline of helioseismology makes use of pressure waves (infrasound) traversing the Sun's interior to measure and visualize the Sun's inner structure. Computer modeling of the Sun is also used as a theoretical tool to investigate its deeper layers.


[edit] Core
The core of the Sun is considered to extend from the center to about 0.2 solar radii. It has a density of up to 150,000 kg/m3 (150 times the density of water on Earth) and a temperature of close to 13,600,000 kelvins (by contrast, the surface of the Sun is close to 5,785 kelvins (1/2350th of the core)). Through most of the Sun's life, energy is produced by nuclear fusion through a series of steps called the p-p (proton-proton) chain; this process converts hydrogen into helium. The core is the only location in the Sun that produces an appreciable amount of heat via fusion: the rest of the star is heated by energy that is transferred outward from the core. All of the energy produced by fusion in the core must travel through many successive layers to the solar photosphere before it escapes into space as sunlight or kinetic energy of particles.

About 8.9×1037 protons (hydrogen nuclei) are converted into helium nuclei every second, releasing energy at the matter-energy conversion rate of 4.26 million tonnes per second, 383 yottawatts (383×1024 W) or 9.15×1010 megatons of TNT per second. The rate of nuclear fusion depends strongly on density, so the fusion rate in the core is in a self-correcting equilibrium: a slightly higher rate of fusion would cause the core to heat up more and expand slightly against the weight of the outer layers, reducing the fusion rate and correcting the perturbation; and a slightly lower rate would cause the core to cool and shrink slightly, increasing the fusion rate and again reverting it to its present level.

The high-energy photons (gamma and X-rays) released in fusion reactions take a long time to reach the Sun's surface, slowed down by the indirect path taken, as well as by constant absorption and reemission at lower energies in the solar mantle. Estimates of the "photon travel time" range from as much as 50 million years[8] to as little as 17,000 years.[9] After a final trip through the convective outer layer to the transparent "surface" of the photosphere, the photons escape as visible light. Each gamma ray in the Sun's core is converted into several million visible light photons before escaping into space. Neutrinos are also released by the fusion reactions in the core, but unlike photons they very rarely interact with matter, so almost all are able to escape the Sun immediately. For many years measurements of the number of neutrinos produced in the Sun were much lower than theories predicted, a problem which was recently resolved through a better understanding of the effects of neutrino oscillation.


[edit] Radiation zone
From about 0.2 to about 0.7 solar radii, solar material is hot and dense enough that thermal radiation is sufficient to transfer the intense heat of the core outward. In this zone there is no thermal convection; while the material grows cooler as altitude increases, this temperature gradient is slower than the adiabatic lapse rate and hence cannot drive convection. Heat is transferred by radiation—ions of hydrogen and helium emit photons, which travel a brief distance before being reabsorbed by other ions. Light in this layer takes millions of years to escape and from there takes about 8 minutes to reach Earth.


[edit] Convection zone

Structure of the SunFrom about 0.7 solar radii to the Sun's visible surface, the material in the Sun is not dense enough or hot enough to transfer the heat energy of the interior outward via radiation. As a result, thermal convection occurs as thermal columns carry hot material to the surface (photosphere) of the Sun. Once the material cools off at the surface, it plunges back downward to the base of the convection zone, to receive more heat from the top of the radiative zone. Convective overshoot is thought to occur at the base of the convection zone, carrying turbulent downflows into the outer layers of the radiative zone.

The thermal columns in the convection zone form an imprint on the surface of the Sun, in the form of the solar granulation and supergranulation. The turbulent convection of this outer part of the solar interior gives rise to a "small-scale" dynamo that produces magnetic north and south poles all over the surface of the Sun.


[edit] Photosphere
The visible surface of the Sun, the photosphere, is the layer below which the Sun becomes opaque to visible light. Above the photosphere visible sunlight is free to propagate into space, and its energy escapes the Sun entirely. The change in opacity is due to the decreasing amount of H- ions, which absorb visible light easily. Conversely, the visible light we see is produced as electrons react with hydrogen atoms to produce H- ions. [10] [11] The photosphere is actually tens to hundreds of kilometres thick, being slightly less opaque than air on Earth. Because the upper part of the photosphere is cooler than the lower part, an image of the Sun appears brighter in the center than on the edge or limb of the solar disk, in a phenomenon is known as limb darkening. Sunlight has approximately a black-body spectrum that indicates its temperature is about 6,000 K, interspersed with atomic absorption lines from the tenuous layers above the photosphere. The photosphere has a particle density of about 1023 m−3 (this is about 1% of the particle density of Earth's atmosphere at sea level).

During early studies of the optical spectrum of the photosphere, some absorption lines were found that did not correspond to any chemical elements then known on Earth. In 1868, Norman Lockyer hypothesized that these absorption lines were because of a new element which he dubbed "helium", after the Greek Sun god Helios. It was not until 25 years later that helium was isolated on Earth.[12]


[edit] Atmosphere

During a total solar eclipse, the Sun's atmosphere is more apparent to the eye.The parts of the Sun above the photosphere are referred to collectively as the solar atmosphere. They can be viewed with telescopes operating across the electromagnetic spectrum, from radio through visible light to gamma rays, and comprise five principal zones: the temperature minimum, the chromosphere, the transition region, the corona, and the heliosphere. The heliosphere, which may be considered the tenuous outer atmosphere of the Sun, extends outward past the orbit of Pluto to the heliopause, where it forms a sharp shock front boundary with the interstellar medium. The chromosphere, transition region, and corona are much hotter than the surface of the Sun; the reason why is not yet known.

The coolest layer of the Sun is a temperature minimum region about 500 km above the photosphere, with a temperature of about 4,000 K. This part of the Sun is cool enough to support simple molecules such as carbon monoxide and water, which can be detected by their absorption spectra.

Above the temperature minimum layer is a thin layer about 2,000 km thick, dominated by a spectrum of emission and absorption lines. It is called the chromosphere from the Greek root chroma, meaning color, because the chromosphere is visible as a colored flash at the beginning and end of total eclipses of the Sun. The temperature in the chromosphere increases gradually with altitude, ranging up to around 100,000 K near the top.

Above the chromosphere is a transition region in which the temperature rises rapidly from around 100,000 K to coronal temperatures closer to one million K. The increase is because of a phase transition as helium within the region becomes fully ionized by the high temperatures. The transition region does not occur at a well-defined altitude. Rather, it forms a kind of nimbus around chromospheric features such as spicules and filaments, and is in constant, chaotic motion. The transition region is not easily visible from Earth's surface, but is readily observable from space by instruments sensitive to the far ultraviolet portion of the spectrum.

The corona is the extended outer atmosphere of the Sun, which is much larger in volume than the Sun itself. The corona merges smoothly with the solar wind that fills the solar system and heliosphere. The low corona, which is very near the surface of the Sun, has a particle density of 1014 m−3–1016 m−3. (Earth's atmosphere near sea level has a particle density of about 2×1025 m−3.) The temperature of the corona is several million kelvin. While no complete theory yet exists to account for the temperature of the corona, at least some of its heat is known to be from magnetic reconnection.

The heliosphere extends from approximately 20 solar radii (0.1 AU) to the outer fringes of the solar system. Its inner boundary is defined as the layer in which the flow of the solar wind becomes superalfvénic—that is, where the flow becomes faster than the speed of Alfvén waves. Turbulence and dynamic forces outside this boundary cannot affect the shape of the solar corona within, because the information can only travel at the speed of Alfvén waves. The solar wind travels outward continuously through the heliosphere, forming the solar magnetic field into a spiral shape, until it impacts the heliopause more than 50 AU from the Sun. In December 2004, the Voyager 1 probe passed through a shock front that is thought to be part of the heliopause. Both of the Voyager probes have recorded higher levels of energetic particles as they approach the boundary.[13]