Sunday, 26 May 2013

Sunday; amazing;


The Sun is the star at the center of the Solar System.
It has a diameter of about 1,392,684 km, about 109 times of Earth.
Three quarters of the Sun's mass consists of hydrogen, while the rest is mostly helium. The remainder consists of heavier elements,  oxygen, carbon, neon, iron, and others.
The sun generates its energy by nuclear fusion.
In its core, the Sun fuses 620 million metric tons of hydrogen each second.


The Sun is now thought to be brighter than about 85% of the stars in the Milky Way galaxy, most of which are red dwarfs.
The Sun's hot corona continuously expands in space.
It creates solar wind, a stream of charged particles, extending to the heliopause at roughly 100 astronomical units.
The bubble in the interstellar medium formed by the solar wind, the heliosphere, is the largest continuous structure in the Solar System.
Of the 50 nearest stellar systems within 17 light-years from Earth, the closest  a red dwarf named Proxima Centauri at approximately 4.2 light-years away.


The Sun orbits the centre of the Milky Way at a distance of approximately 24,000–26,000 light-years from the galactic centre. The sun completes one clockwise orbit, as viewed from the galactic north pole, in about 225–250 million years. 
The mean distance of the Sun from the Earth is approximately 149.6 million kilometres.  The distance varies as the Earth moves from perihelion in January to aphelion in July.
 At this average distance, light travels from the Sun to Earth in about 8 minutes and 19 seconds.
 The energy of this sunlight supports almost all life on Earth by photosynthesis, drives Earth's climate and weather. 
The enormous effect of the Sun on the Earth has been recognized since prehistoric times.
The Sun has been regarded by some cultures as a deity.

Currumbin-Valley April 17:29 PM

There are still anomalies in the Sun's behaviour that are not yet explained and may remain so. 

Note that the light-year is a measure of distance. It is not a measure of time, for which it is sometimes mistaken.

1 light-year = 9460730472580800 metres (exactly)
  ˜ 5.878625 trillion miles  ˜ 63241.077 astronomical units  ˜ 0.306601 parsecs

The figures above are based on a Julian year  of exactly 365.25 days.

©Photos/Text Ts

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