Our+Sun

Our Sun. Freya Jones-Eriksson Shannon Vafapisheh 

Diameter: 1 390 000 km Mass: 1.989e30 kg Temperature: 5800 K (surface) 15 600 000 K (core)


 * At present the sun is 70% hydrogen and 28% helium. The other 2% is made up of various different metals.
 * The outer layers of the sun are a prime example of differential rotation. The surface near the equator rotates once every 25.4 days. At the poles the outer layer rotates as much as once ever 36 days.
 * This occurs because the sun not made up of a solid body, like Earth. It is made up of mostly unstable gases.
 * The //differential rotation// is even exhibited in the core, though it rotates as a solid body

The Surface and Core
 * The surface of the sun is called the photosphere
 * Sunspots are cooled regions on the Sun's surface. They are usually only 3800 K and can be as large as 50 000 km in diameter, or a couple hundred.
 * Sunspots are caused by currently unknown interactions with the sun's magnetic field.
 * The core of the sun is an extremely hot, and pressured place. The Sun's core, which is placed at approximately the inner 25% of it's radius, is 15.6 million K and the pressure is 250 billion atmospheres*.
 * At the centre of the core the density is 15o times more than that of water.
 * The sun, can create 386 billion billion mega Watts, approximately. This energy is produced through nuclear fusion* reactions.
 * Each second 700 000 000 tons of hydrogen are converted into 695 000 000 tons of helium. And 5 000 000 tons (3.86e33) of gamma ray energy. As this energy travels towards the surface, it is continuously absorbed and re-emitted into the atmosphered at lower and lower temperatures. Because of this, by the time the rays reach the surface of the Sun it is mostly visible light.

Radiative Zone
 * The Radiative Zone extends from 25% of the solar radius to 70% of it. Here the temperature decreases from around 15 600 000 K to approximately 2 000 000 K.
 * Here energy from the core, created by nuclear fusion, is emitted into the radiative zone as electromagnetic radiation. When the radiation travels among the atoms, it is absorbed and loses energy as it is re-emitted.
 * Though radiation travels at the speed of light. It bounces of atom after atom so it can take a long time to actually reach the convection zone.
 * In this zone you can find ionized atoms: hydrogen, helium nuclei and free electrons.
 * This state of matter is called plasma.

Convection Zone  The Corona and Solar Eclipse
 * The convention zone is considered to be the outside shell of the sun.
 * The Convective zone, which many consider to be the outer shell of the sun, is like a hazy fog. This is because here, the atoms have electrons, which can't happen closer to the core because they are stripped away by the heat. Atoms with electrons are able to absorb and emit radiation, making the zone slightly more opaque.
 * The energy in the zone is transferred much faster than it is in the radiative zone, because it is transferred through convection. The process of convection is where hot gas from the radiative zone comes up into the convection zone, expanding and rising since the convection zone is cooler than the radiative, and therefore less dense.
 * At the cool gas rises more to the surface, it cools off even more and starts sinking. As it nears the radiative zone, the gas heats and goes back towards the surface. This cycle continues, creating convection currents.
 * These currents created are visible on the sun's surface, resembling something boiling. The pattern is called: granulation.
 * The temperature of the Convection zone is approximately 15.6x10e6
 * The Corona spreads millions of kilometers into the space around the sun.
 * It has an approximate temperature of over 1 000 000 K
 * The Corona can only be seen during a solar eclipse. It is the light visible from behind the moon.
 * Though the sun is notably larger than the moon, as viewd from Earth they are the same size. The Moon orbits the earth, in the same orbit that the Earth rotates around the Sun, because of this there are times where the Moon completely covers the Sun. This is called a Solar Eclipse.
 * You can only see a complete Solar Eclipse from a certain region, known as the path of "Totality". The path is very narrow, just a few kilometers wide though thousands of kilometers long.
 * Since the path is so small, many people travel around the world just to witness one total eclipse.
 * If the alignment is off, resulting in only a partial amount of the solar disk being covered, it is called a partial eclipse.
 * Partial eclipses are visible in many places around the globe. If you stay home, you're likely to see several partial eclipses per decade.

The Sun's Effect on Earth
 * The Sun is on of our only sources of Vitamin D.
 * Vitamin D regulates the calcium and phosphorus levels in the blood, by helping the absorption of food in the intestines and by promoting re-absorption of calcium in the kidneys, which helps aid the mineralization of bone and prevents hypocalcemic tetany.
 * Without vitamin D, we would not have strong bones and teeth, which are crucial to our survival
 * If the Sun were any closer to the Earth, it would be to hot to live. If the Sun were any farther away, the Earth would be to cold to sustain life.
 * The seasons are directly impacted by the sun.
 * During our winter, the Earth is on a tilt, so our side faces farther away from the sun. Therefore the sun's rays are weaker, and don't have as much heat as they usually do.
 * This also causes the shorter days and nights.
 * When summer and spring roll around, the Earth changes it's tilt so that our side is now closer to the sun, therefore getting much more heat an light.
 * This is what makes the days so long and nights so short.
 * THe Sun makes the rainbow

Helios
 * Helios is the Greek god of the sun.
 * He is also known as Sol, the Roman god of sun
 * Sometimes Helios is referred to with the (epithet) Helios Panopets. THe most famous story is when Aphrodite, the lover of Hephaestus, secretly has sex with Ares. But Helios, the all seeing, spies on them and tell Hesphaestus, who in turn captures the two in invisible nets to punish them.
 * Helios is also mentioned in the Odyssey. Odysseus and his surviving crew land on Thrinacia, an island sacred and guarded by the sun god. Here Circe names him Hyperion rather than Helios. On this island the red cattle of the sun were kept. Odysseus warns his men not to eat the cattle, though the y do heedlessly. While they are killing the cattle, the guardians of the island, Helios' daughters, see what they are doing and tell their father. Helios appeals to Zeus, who destroys the ship and kills all the remaining men except Odysseus.
 * "You will now come to the Thrinacian island, and here you will see many herds of cattle and flocks of sheep belonging to the sun-god. There will be seven herds of cattle and seven flocks of sheep, with fifty heads in each flock. They do not breed, nor do they become fewer in number, and they are tended by the goddesses Phaethusa and Lampetia, who are children of the sun-god Hyperion by Neaera. Their mother when she had borne them and had done suckling them sent them to the Thrinacian island, which was a long way off, to live there and look after their father's flocks and herds " - Odysseus, from the Odyssey

Sol
 * Sol, was the Roman god of the Sun. Early on in the creation of the mythology Sol became associated with Janus, the sun god. Sol only re-appears in the late Roman Empire and an independent god.
 * Janus and Jana were worshipped during the Roman Kingdom period as the Sun and Moon.
 * Sol Indiges: "The native sun" or "the invoked sun" represents the agrarian form when Sol was worshipped.
 * Sol Indiges was later replaed by Sol Invictus.
 * Sol Invictus: "Unconquered Sun" was the Roman state-supported sun god.
 * It was created by the emperor Aurelian in 274. It continued, overshadowing other Eastern cults in importance, until the destruction of paganism by Theodusius I.
 * Though known as a god, "Unconquered Sun" is not found on any Roman document.
 * On December 25 the Roman's celebrated Dies Natalis Solis Invicti, the birthday os the unconquered sun." Because it was the first day after the Winter Solstice that you could detect lengthening in the days.

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