THE SUN

Although it is possible to look directly at the stars at night as they are so far away, it is very dangerous to look straight at the Sun. the intense brightness of the Sun can seriously harm the eyes, and as for that, astronomers never observe the Sun through telescopes like those used to study the planets and faraway stars. These telescopes would so concentrate the Sun's light which would be very harmful. Due to that, the scientists use special telescopes called solar telescopes that spreads out the bright Sun's light. There are also other types of telescopes and equipment that detects forms of radiation other than the sunlight that are discharged by the Sun.

Different from other telescopes used to study other objects in space, the solar telescopes are for one thing, long and must be housed in special buildings. the great length allows them to spread out light from the Sun as much as possible so that it can be studied safely. One of the instrument that form part of the telescope is a spectograph, a very sensitive instrument used to analyze the different the colors in light, in this case, the sunlight. As the light passes throught the spectograph, it emerges as a narrow beam of light. The light, then reflected from a diffraction grating, which spreads the light into a band of colors called spectrum. Appearing on this spectrum are dark lines, called absorption lines, which are places where the light is less intense.

In addition to light, the Sun also emits other types of radiation, which includes Ultraviolet (UV) rays, infrared radiation (heat), radio waves and X rays. Scientists use large ground-based radio telescopes to study radio waves. However, not all radiation reaches the Earth. Some infrared radiation , most UV rays and all X rays are stopped by the Earth's atmosphere. Studying the types of radiation, Scientist use various means of different types of satellite observatories that are orbiting the Earth.

Characteristics

Comparison of the Sun and Our Planet Earth

The sun is in fact a star of about average size; it comes into view larger than the other stars for the reason that of its relative closeness to the earth. The earth's distance from the sun diverges from 91,377,000 mi (147,053,000 km) at perihelion to 94,537,000 mi (152,138,000 km) at aphelion (see apsis ). The mean distance is c.92,960,000 mi (149,591,000 km); this is taken as the astronomical unit (AU) of distance used for measuring distances inside the solar system. The sun is just about 865,400 mi (1,392,000 km) in diameter, and its capacity is about 1,300,000 times that of the earth. The total mass of the whole solar system is about one of 700 the mass of the sun (which makes the mass of the sun 332,000 times the mass the earth). The gravity on the sun's surface is approximately 28 times that of the earth; meaning that a body on the surface of the sun would weigh about 28 times its weight on earth – this would also mean that we could weigh more than we already are on EARTH!!! Compared to earth, the density of the material composing the sun is about one fourth that of what we have here; compared with water, the sun's average density is 1.41. At the center of the sun, it has a density of over 100 times that we could get of water, a temperature of somewhere around 10 to 20 million degrees Celsius, and a pressure of greater than 1 billion atmospheres.

Interior

In the layers of the sun, the chromosphere is above the photosphere. Solar energy passes through this section on its way out from the core of the Sun. Flares and faculae rises in the chromosphere. The bright glowing hydrogen clouds are Faculae, which form above sections where sunspots form. On the other hand, flares are bright strands of scorching gas emerging from sunspot regions. Sunspots are dim depressions on the photosphere with a distinctive temperature of 4,000°C (7,000°F).

Sun is observed by astonomers with the help of solar telescope.

The outer part of the Sun's atmosphere is the corona. It is in this layer that prominences show. Prominences are massive clouds of glowing gas that blow up from the upper chromosphere. The outer region of the corona stretches remote into space and consists of units (particles) wandering slowly away from the Sun. The corona can only be seen during full solar eclipses

The bright exterior of the sun is called the photosphere. It has the temperature of about 6,000°C. The photosphere looks darker near the edge (limb) of the sun's disk since of greater absorption of light by the sun's atmosphere in that area. This occurrence is called limb darkening. At some point in an eclipse of the sun, the chromospheres and the corona (the external layers of the sun's atmosphere) are observed. Also of interest is the high-speed, feeble extension of the corona known as the solar wind.

The Surface

The sun spins on its axis from east to west, because of its gaseous nature

Observations and studies of sunspots and studies of the solar spectrum specify that the sun spins on its axis from east to west; because of its gaseous nature its rate of rotation differs to some point with latitude, the speed being supreme (a phase of almost 25 days) in the equatorial region and least at the poles (a phase of about 35 days). The axis of the sun is prone at an angle of about 7° to the level surface of the ecliptic.