Our Solar System: The Sun

                    :: THE SUN ::                    

SUN FACT BOOK: FACTS ABOUT THE SUN

SUN PROFILE
Age	4.6 Billion Years
Type	Yellow Dwarf (G2V)
Diameter	13,92,684 km (8,65,374 mi)
Circumference at Equator	43,70,005.6 km (109 × Earth) (27,15,395.5 mi)
Mass	1,989,100,000,000,000,000,000 billion kg (333,060 x Earth)
Surface Temperature	5500°C (9941° Fahrenheit)

✪ The Sun is our nearest star.

✪ This huge ball of superhot gas is 1.4 million kilometres across, 109 times wider than Earth, and is 3,30,000 times heavier. About 13,00,000 Earths would fit inside the Sun.

✪ Sun contains 99.86% of the mass in the Solar System.

✪ Around 74% of the Sun’s mass is made up of hydrogen. Helium makes up around 24% while heavier elements such as oxygen, carbon, iron and neon make up the remaining percentage.

✪ The Sun generates huge amounts of energy by combining hydrogen nuclei into helium. This process is called nuclear fusion.

✪ Sun lies about 150 million km away from us. 

✪ It takes about 8 minutes for sunlight to reach us – even when it is travelling at about 3,00,000 km/s. This means that we see the Sun set eight minutes after the event has actually taken place!

✪ The Sun is 24,000-26,000 light years from the galactic centre and it takes the Sun 225-250 million years to complete an orbit of the centre of the Milky Way. It means The Sun travels at 220 kilometres per second.

✪ The distance from the Sun to Earth (149,600,000 km (92,960,000 miles) changes throughout the year as the Earth travels on an elliptical orbit around the Sun, the distance between the two bodies varies from 147 to 152 million kilometers.

✪ The distance between the Earth and the Sun is called an Astronomical Unit (AU).

✪ The surface of the Sun, called the photosphere, is at a temperature of about 5526.85°C (5800 K). Sunspots are "cool" regions, only 3526.85°C (3800 K) (they look dark only by comparison with the surrounding regions). Sunspots can be very large, as much as 50,000 km in diameter. Sunspots are caused by complicated and not very well understood interactions with the Sun's magnetic field.

✪ Chromosphere lies above the photosphere.

✪ The highly rarefied region above the chromosphere, called the corona, extends millions of kilometers into space but is visible only during a total solar eclipse. Temperatures in the corona are over 1,000,000 K.

✪ In addition to heat and light, the Sun also emits a low density stream of charged particles (mostly electrons and protons) known as the solar wind which propagates throughout the solar system at about 450 km/sec. The solar wind and the much higher energy particles ejected by solar flares can have dramatic effects on the Earth ranging from power line surges to radio interference to the beautiful aurora borealis (The Northern Lights) and aurora australis (The Southern Lights).

✪ The solar wind causes Radio Interference and the characteristics of tails of comets. It can also alter the trajectory of spacecraft.

"Distance of the Planets (Mercury, Venus, Earth, Mars, Jupiter) from the Sun in Astronomical Units (AU)"