THE+SUN

__**THE SUN**__ - Grace Ying

__**Orbital Period**__ **Every single star has their own orbit period around a source. The closer to the centre of the source, the shorter period they have. Our Sun is the centre of the solar system, so the period of Sun in our solar system is __ZERO__.**

**Basically, the Sun is orbiting around a galaxy, the Milky Way, in about 220 km/s and it is located in the outer part of the galaxy which about 30,000 light years from the galaxy's centre. It takes __225 Million years__ to orbit around the centre of the Milky Way once, and this period of the time is called a Cosmic Year.**

 **Our Sun is about 4.6 billion years old, thus, it has orbited the galaxy more than 20 times.** __**Date of discovery**__


 * The Earth is orbiting around the sun and the Sun is older than the Earth.** **To compare with the Earth, the Sun is very huge and hot, its sunlight can travel through space to the Earth, human can observe the Sun without any technology help. That is mean, human recognize the Sun when the dawn comes, we have always known the sun, and so, t****here is no discovery day or discoverer.**

__**History (scientific)**__

**__Mythology__** **The Ancient Greeks named the Sun - Helios** **The Ancient Romans named the Sun - Sol** **The Ancient Egypt named the Sun as Ra/ Re** **Japan and the Sun**
 * The Sun is a big hot giant ball which contain large among of hydogen and located in the centre of the Solar System, planets in the Solar system orbit around it. Scientists believe life exist because of the Sun, the Sun rise and set everyday, and the Sun gives us light in the day time. Before inventions of light and fire, Moon is the only lighting object in the night and it halped guide people at night time.**
 * The Sun is very important. In ancient** ** period, people think the Sun is a unique object and thus there were many countries worship the Sun.**
 * The first accurate distance of the Sun was measured by a Greek philosopher, Anaxagora. He was threatened to dead because he says the Sun is a burning ball of fire, not a god.**
 * Ancient people think the SUn is orbited around the Earth, but a astronomer, Nicolaus Copernicus, who first proposed a Sun-centered Solar System. His ideas guide Galileo and other astronomers to have futher exploration and they proved the Sun is the centre of the Solar System**
 * In 1930s, astrophysicits Subrahmanyan Chandrasekhar and Hans Bethe developed a theoretical concept about the nuclear fusion which explained the structure of the Sun and other planets.**
 * **Helios is also representing the Sun god of the ancient Greeks**
 * **The guardian of oaths and the god of gift of sight**
 * **He drives his chariot from east to east across the sky every day and sails across the ocean each night by a huge cup[[image:mrconnorsses4ua/10-sun_god_rasvg1.png width="213" height="402" align="right"]]**
 * **He is the inventor of the four-house chariot**
 * **His chariot can fly**
 * **He worships on Rhodes**
 * **He was the chief god in the early 5th BC**
 * **But then he replaced by Apollo - the Sol**
 * **Apollo replaced Helios and becomes the person who represents the Sol**
 * **He is the god of science, mathematics, archery, and oracles and prophecy**
 * **The moon is his twin sister - Artemis**
 * **It is the Egyptian Sun God of the Heliopolis**
 * **Ra - the Horus of the Horizon**
 * **Egyptians believed Ra (the Sun) created the world**
 * **Sunrise was the symbol of creation**
 * **A body of man with a head of falcon, holding Sceptre and an Anhk is usually represented the Sun God Ra**


 * __The Original Japan Flag__ __The Japan Flag__ **


 * The national flag of Japan is called Nisshoki or Hinomaru, and it is mean the the sun-mark flag or the circle of the sun.**
 * Janpese think Japan is "the land of the rising sun"**
 * The red spot in the middel of the white flag is the symbol of the Sun**

__**Composition & Size**__ __**Atmospheric conditions **__
 * The symbol of the Sun shows a revolution of Japan, Japnese think the Sun is the God, the Sun can bring them succeful life**
 * **Size and other Informations** ||   ||||  **Composition**  ||
 * **Mass (kg)** || **1.99E+30** ||  || **Hydrogen** || **92.1000%** ||
 * **Mass (Earth = 1)** || **332,830** ||  || **Helium** || **7.8000%** ||
 * **Volume (kg)** || **1.1422 x 10^8** ||  || **Oxygen** || **0.0610%** ||
 * **Equatorial radius (km)** || **695,000** ||  || **Carbon** || **0.0300%** ||
 * **Equatorial radius (Earth = 1)** || **108.97** ||  || **Nitrogen** || **0.0084%** ||
 * **Equatorial Circumference (km^3)** || **4,379,000** ||  || **Neon** || **0.0076%** ||
 * **Surface Area (km^2)** || **6.087799x 10^12** ||  || **Iron** || **0.0037%** ||
 * **Mean density (gm/cm^3)** || **1.41** ||  || **Silicon** || **0.0031%** ||
 * **Rotational period (days)** || **25-36*** ||  || **Magnesium** || **0.0024%** ||
 * **Escape velocity (km/sec)** || **618.02** ||  || **Sulfur** || **0.0015%** ||
 * **Luminosity (ergs/sec)** || **3.83E+33** ||  || **All others** || **0.0015%** ||
 * **Magnitude (Vo)** || **-26.8** ||  ||   ||   ||
 * **Mean surface temperature** || **6,000°C** ||  ||   ||   ||
 * **Age (billion years)** || **4.5** ||  ||   ||   ||
 * By using telescopes and** **electromagnetic spectrum (from radio to visible light to gamma rays)** **to observe and determine the surface of the Sun. Scientist found there are layers of atmosphere on the sun, and these t****hree layers of the Sun's atmosphere are __the photosphere__, __the Chromosphere__, and __corona__.**

__**The Photosphere:**__ __**The Chromosphere:**__ __**Corona:**__
 * **The outer layer of the Sun, the surface**
 * **Actually, the Sun is a ball of gas, so there is no true 'surface'**
 * **We can see it when we look up to the sun**
 * Its temperature is about 5537.77 **°C**
 * **Sends light and heat into the space to other planets**
 * **186,300 m/s and it takes about 8 minutes to reach from the Sun to the earth**
 * **This layer is very important, because it helps to maintain and create lives in the Earth**
 * **In the middle of the Sun's atmosphere**
 * **A transition region**
 * **much hotter than photosphere**
 * **Can be observed when a full eclipse occurs**
 * **When the moon passes between Earth and the Sun, three planets form a line**
 * **The shadow of the moon blocked the Sun and it leads to eclipse occur**
 * **There are giant tongues of flame - Spicules**
 * **Jets of hot gas shoot to the upper less dense area**
 * **A transition region**
 * **much hotter than photosphere & chromosphere**
 * **Temperature is millions of degrees**
 * **Gases in this layer is very thin**

** __Resources significant & noteworthy features __ **
 * **The sun’s strong gravitational pull holds Earth and the other planet in place by its****274.0 m/s^2 of its****Equatorial Surface Gravity and the****Escape Velocity is 2,223,720 km/h**
 * **By sending Ulysses towards Jupiter with a booster rockets and uses the __Sun's gravity__ to hurl it into an orbit out of the Ecliptic Plane,****Ulysses becomes the first spacecraft to study our Sun’s poles**
 * **Sunlight provides by the Sun is very important, it creates life on the earth.**

__**What don’t we know?**__ **__Future plans or expeditions__** **There is an unsolved mystery of the sun involves the corona. As we know, above the Chromosphere, there is corona, and it is extending outward from the Sun which lead to the formation of 'solar wind'. The temperature of the corona is much hotter than chromosphere. Since Corona is on the outer suface of the Sun, scientist found that it is imposible for a cooler surface of the Sun transfer thermal energy to a hotter surface, which mean the outer surface of the Sun, corona, should be cooler than Chromospher. Scientists have been solving this mystery problem for more than 60 years, but there is no answer can be found.**   __**Videos About the Sun**__ media type="youtube" key="D2PtPoloR1g" height="360" width="640" ** __ The Solar System - The Sun __ ** media type="youtube" key="A2Y6ay-41No" height="360" width="640" media type="youtube" key="5JsqEsFpOgk" height="360" width="640" = __ Dark Future of the Sun - The Universe __ =
 * The Sun was created in 4.6 billion years ago and it h****as used up about half of the hydrogen in its core. the Sun is getting brighter and brighter, more helium is formed in the core and the temperature of the Sun is increasing. According to the graph 'Life Cycle of the Sun', when hydrogen fuel run out in the Sun, the Sun will grow bigger and bigger, and becomes a Red Giant. The pressure inside the core increase and lead to an expansion of the Sun and it will engluf the earth. When the Sun becomes a very large giant ball, it will suddenly collapses and explods, then it becomes a planetary nebula and then a white Dwarf.**
 * __ Haunting Images from the Sun __ **

__**Bibliography**__ [] [] [] [] []