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The Sun

The sun is a large spherical object. which is so hot that it is vapor and gas. There is heat and light occurring within the center. and transmitted to the surface and spread out into the surrounding space If we travel by spaceship away from the sun will see the sun get smaller and smaller until eventually only a bright spot will appear like a star appearing in the sky, the sun is a common star.

The Sun is 149.6 million kilometers from Earth on average but is much larger than the Earth, that is, its volume is 1,28 million times that of the Earth and its radius is 110 times that of the Earth. 700 times as much as the sun has substance. Also known as the mass of up to 333,000 times the mass of the Earth. but average The sun has a density of only 1.4 grams per cubic centimeter. when the earth has a density of 5.5 grams per cubic centimeter.

The Sun has a surface attraction that is 28 times the force of gravity on the Earth’s surface. which means An object that weighs 1 gram on Earth, if weighed on the Sun, would weigh 28 grams to launch a rocket from the Earth’s surface into space, regardless of the friction of the atmosphere. Must fire at a speed of 11.2 kilometers per second. in the same way If a rocket is launched from the surface of the Sun to fall into space Must shoot at a speed of 618 kilometers per second.

The sun shines bright all around. Equivalent to an electric bulb Three Billion Trillion Trillion Candles If you think of the energy that the sun exudes In terms of heat, light and other radiation, the sun is the engine. powerful Four hundred trillion kilowatts that the sun is the source. enormous energy.

However, the energy that the Sun radiates around in the form of light and heat, for example, is largely wasted. Only a small fraction of them land on the surface of the earth. But even this tiny fraction causes life to occur. And grow later for a long time until now.

The sun appeared from the eastern horizon. moving high into the middle of the sky and fell back to the western horizon regularly that day It’s because the world revolves around itself every day. It is not the actual motion of the sun. will see stars and planets appear in the sky even during the day that we can’t see the stars in that day because of the air and the dust in the air was completely drowned out by the sunlight. If you see stars in the daytime We will notice that the sun Slowly moving among the stars every day and will move in the sky for one year around this motion is not the true motion of the sun. If it’s because the Earth revolves around the sun Anniversary in one year.

What does “surface” of the sun mean?

As already mentioned The sun is a lump of gas, so the mention of “surface” seems meaningless in any sense. If we look at the edge of the sun should be able to see the edge of it is not clear, but in fact, if we look at the sun by telescope which has a device to filter light and heat In order to prevent damage to the eyes, it can be seen that the edge of the sun is considered sharp enough. Why is this gas so there are clear sharp edges.

However, when astronomers has introduced the physics of the dense deposition of gases And about the radiation of hot gas used to calculate the test and then found that the edge of the gas block. The intensity of the radiated radiation increases rapidly. in a short distance along the radial line towards the center The middle of the Sun, this distance is very short. compared to the radius of the sun itself. until common equipment The one we used to explore was able to see a bright edge which was quite sharp.

We may consider the edge of the sun. that can be explored in this ordinary light a little more thoroughly, if we look along the line that passes slightly above the rim of the sun; we may see things that are far from the sun can go out because the sun’s gas is not completely obscure, only when we slowly shift that line of sight very close to the edge of the sun The sun’s gas will cover the reticle even more, eventually as it moves towards the sun to some extent.

The light from objects behind the sun will never pass through because the sun’s gas is completely opaque. In this case, all the light that enters our eyes or devices comes from the gases in the Sun’s atmosphere. at this level. We see the sharp edges of the sun.
Astronomers have defined this level as the “surface” level of the Sun. for convenience In referring to the state of gases at different levels above or deep within the Sun.

The diagram on this page shows the sharp edge of the Sun. and deep in the atmosphere of the sun which may be seen down to various positions on the horoscope according to the relationship of Depth and opacity for gas radiation in the sun’s atmosphere.

In this diagram, the gas layers in the Sun’s atmosphere was enlarged to make the proportions thicker than reality compared to the inner part of the sun to show the criteria mentioned more clearly

A is a hypothetical object behind the sun. further in the direction opposite to the observer, if a beam of light from A traveling to the observer close to the Sun’s atmosphere and is not completely absorbed by the gases in the Sun’s atmosphere left to the observer’s eyes or equipment. It is considered that the path of the beam of light has not yet reached the edge of the moon.

But if this line of light is shifted very close to the sun to the level where the light is absorbed by the gas that envelops the sun The level is considered to be the edge of the Sun, for example, if the light from point B reaches the observer exactly. It is considered that the path that walks the light Near the edge of the sun.

when we consider the light coming from within the edge of the sun The closer it gets to the center of the moon, the more light comes in. from a deeper level, respectively. This is because the light comes from a level with the same total opacity, and the light near the edge comes from a higher level in the atmosphere. Consequently, the temperature and density are lower. The light coming from the central belt from the depths of the sun is higher, so the sun appears. very bright in the middle and the darkness near the edge of the moon.

If we look at the center of the sun We can look down 250 kilometers from this surface level, after that. The body of the sun becomes denser. gas light in a deeper level cannot pass out directly into space must be transmitted by reflecting or distributing in different directions by the atoms of the gas that are at a higher level before.

Conditions inside the sun

As already mentioned The sun is a very hot mass of matter. and can combine to form a spherical shape by the attraction between atoms and molecules gravity or gravity This gravitational force is directed towards the center. body of the sun which is at a certain level within the body will be deposited by the substance that is higher so it’s normal to have pressure and more dense substance at a higher level. According to this rule, it can be said that the pressure and The density of matter increase in depths within the Sun. Incidentally, under high pressure. The gas or vapor is forced to decrease in volume gradually.

If the atoms or molecules of the gas or vapor are not Fast enough to keep fighting The speed mentioned is obtained by high temperature. This is because the temperature of an object is the energy of motion. and the vibration of the atomic molecules in that matter For this reason, we can assume that Substance at a certain level within the Sun is in equilibrium when there is a temperature, pressure, and density appropriate to each other which will be higher and higher for the level deep within the sun.

Telescope 150 mm diameter of the High Altitude Observatory in Colorado The United States used to study the Sun.

At present, there are no survey equipment. that may be used to measure the physical condition of the interior Sun at a deeper level the knowledge we have in this regard Therefore, it is the result of calculations that rely on the criteria physics and externally measured quantities such as the size, mass and temperature of the Sun in level that can be seen by telescopes.

At the center of the Sun in a spherical region with a radius of about 200 thousand kilometers, which is sufficiently high temperature A thermonuclear reaction takes place. and gives energy in the form of gamma rays, which have a short wave size This radiation is radiated by relay. through the body of the sun out to a depth of about 140,000 kilometers from the surface of the moon The transfer of energy will vary. The method is from radiation (radiation) to conduction (convection) by which the hot gas floats. rise to a high level Up to the surface of the sun, it radiates light and heat into space, then when its temperature decreases, it sinks. This process is similar to the boiling of liquids such as water or oil that are boiled in a vessel over a stove to heat.

(a) is a sphere at the center of the Sun. It is the region where thermonuclear reactions occur. The energy produced in the form of gamma rays is radiated. and transmitted through the region

(b) out by means of suction and return radiation per interval from a depth of 500,000 kilometers to a depth of 140,000 kilometers from the sun’s surface in energy transfer by such radiation The energy of each unit of radiation gradually decreases and converts from gamma-rays to X-rays. Ultraviolet rays, light and heat waves

(c) the nature of the energy transfer changes to boiling. or convection by the movement of hot gas masses, that is, hot gas groups in the depths of the sun Will bring up to the surface level, emitting energy by radiation out into space. itself lowers the temperature, therefore shrinks, and has a higher density sinking back to a deeper level The upper part of the level (c) is the photosphere (P) has a depth of about 250 km. Only gases in this layer are present. to radiate directly into space

(d) above the photosphere, the chromosphere, is the level averaged only 5,000 km thick; above the chromosphere, is the coro level. Na

(e) is a spout of gas, or prominence, most of the condensed matter in the corona flows back to the chromosphere. along magnetic field lines at different points

(f) extending more than tens of millions of kilometers from the Sun

The atmosphere of the sun

The gas that envelops the Earth is the Earth’s atmosphere. gas that envelops the sun It’s on a level that we might be able to explore. The device is called is the atmosphere of the sun For the sake of understanding initially, we may The atmosphere of the Sun can be divided into three levels:

1. Photosphere

It is a gas envelops the Sun from surface level, deep within the Sun to a depth of about 250 kilometers, which is the deepest level we can see. we but is thicker and more translucent Moderately bright. Therefore, in some cases, the photosphere is said to be is the surface of the sun It is considered a feasible concept. Some important phenomena, such as horoscopes and clusters, dots, etc., are present in this photosphere.

full sun Taken with the Department of Physics’ Solar Reconnaissance Telescope. Chulalongkorn University By filtering only light with a wave size of 6,563 Angstrom, which is the light that comes from hydrogen gas. at the chromosphere, level enveloping the sun high from the photosphere up where hydrogen gas appears to illuminate is an area with a group of points and has a strong magnetic field Seen as long, winding black lines are called filaments at the edge of these filaments. appears as a floating gas stream at a high level from the chromosphere.

2. Chromosphere

The chromosphere is the atmosphere of the sun in the north The photosphere comes up. not a flat atmosphere but consists of hot gas streams in vapor form throwing up to a high level and a large number of hot gas streams moving in an arc from one position to another. The hot gas at this level consists mainly of hydrogen. There are also calcium, helium, etc., gas in the chromosphere. Radiates only the wave size coming from the gas. Some species, which are already very hot. Because of its emission line spectrum, special equipment is required to explore the chromosphere. movement of these gas streams Which has a diameter of about 1,000 kilometers and a speed of 20-30 kilometers per second and rises to a height of up to 20,000 kilometers in the control of the magnetic field on the sun. image of the chromosphere Therefore, it may tell about the magnetic field on the Sun as well.

The chromosphere at the Sun’s edge, photographed by R.B. Dunn, an observatory astronomer. at the top of Mount Sacramento In the United States, this set of photos was taken using a special filtering device. Assembled with curved metal screen plate to block glare from the photosphere This makes it possible to photograph the chromosphere. without having to wait for an eclipse to occur Gases in the chromosphere radiate only at certain wave sizes. structural features of the chromosphere Therefore, it is clearly visible only in light. with these wave sizes The four images were of the sun’s rim at a single location and time.

The top two images (a and b) had an exposure time ten times shorter than the two lower images (c and d). Figures A and Figure C were taken using light. The wave size is 4 Angstrom from the hydrogen gas. The images b and d were taken using light from hydrogen gas. Which has a wave size of 6,562.8 Angstrom can be seen that the chromosphere of the sun as seen at the edge of the sun The structure is characterized by a large number of jet flames. It is called spicules, which has a diameter of about 800 kilometers, may increase to a height of up to 10,000 kilometers, with an average life of about 10 minutes.

3. Corona

It is a covering for the sun. at a high level from the hot gas stream of chromosphere up This corona radiates from the sun. It can be examined more than seven million kilometers from the sun. An examination of the light from the corona, which is one-millionth of the light. from the sun Show that this corona has three important components:

3.1 High-temperature electrons
3.2 Dust particles orbiting the Sun at a close distance and reflect sunlight
3.3 The ions of the vapor are very hot until a large number of electrons are released from the orbit around the atom These ions radiate only at the wave size, i.e. the line spectrum.