What is the sun?
Problem description:
A giant reactor? Can be integrated for n hundred million years?
Analysis:
The composition of the sun
The sun is the nearest star to mankind. When astronomers want to test the structure and stability of stars collected from many disciplines,
In the theory of stellar evolution, the sun naturally becomes the touchstone of the theory. The current star theory has a great influence on the energy and structure of the sun.
Structure, composition change, total luminosity (luminous ability) and surface temperature, etc. , has been a considerable degree of understanding and explanation, but for
Turbulence, storm and various explosion phenomena in the solar atmosphere, such as material jet, explosion γ-ray, X-ray and violet light.
Outside lines and wireless radiation are not involved.
These solar activities are quite spectacular, and most of them have direct or indirect effects in a short time.
The earth's atmosphere, meteorology, geomagnetism and so on have deeply influenced human life and even led to the rise and fall of civilization.
With these solar activities, the change of solar energy output is only a few tenths of the normal output, but they are human beings.
A deep understanding of the nature of the sun provides quite a few clues, and astronomers also have quite a lot of evidence that others
Our stars also have similar or even stronger atmospheric activities.
Therefore, the study of the sun is not only because it is closely related to human beings, but also because it can verify the theory of stars and strengthen the observation of them.
What his distant star lacks. (Note 1)
I the structure of the sun (note 1)
1. External structure:
(A) Title-light ball
temperature
A. grain structure -6000k
B. Sunspot -4000k
2. Internal structure:
(a) The core: the place where the nuclear fusion reaction takes place-the energy of the sun.
A. The core of the sun accounts for about 50% of the total mass, and 10% of the radius of the sun is 99% of the energy source of the sun.
The pressure of the sun's core is 2.5 *101times of the atmospheric pressure of the earth, and the temperature is estimated to be about15,000,000 degrees, which is hydrogen.
Traveling proton mass
Neutron thermonuclear fusion reaction zone. The density of core material is 150 g/cm3, which is much higher than that of iron (7g/c).
Cubic meters. The weight of a cubic-sized core substance on the surface can reach 150g.
B The total solar output power (or luminosity, luminous capacity or luminous capacity: Lsun) is 3.826 * 1026.
Watts, most of which are provided by the core nuclear reaction. The core of the sun contains about 6.3 million tons of hydrogen per second.
Nuclear fusion reaction
It should be converted into helium, and the mass loss caused by this process is 0.72% of the converted mass (or 400 per second
Five hundred thousand tons). If it is assumed that only 10% of the total mass of the sun can participate in nuclear reactions, then the life of the sun is about10 billion years.
Sun shape
It was built five billion years ago, so it can last five billion years.
The composition of the sun
(b) Radiation layer: Energy is transmitted in the form of radiation.
A. The area from the core outward to 75% radius is called radiation layer, and γ -rays and X-rays from the core.
Children, constantly colliding with the material particles in the radiation layer, absorbed by the material particles and re-radiated, and finally mainly by
See the form of light transmission
It reaches the surface of the sun and then radiates in all directions.
B. In the radiation region, photons collide with matter particles every 1 cm, which is determined by the inner core.
The energy transmitted in the form of "light" takes about one million years of struggle and repeated makeovers to realize.
Radiation reaching the surface of the sun
The density from the shooting area to the core increases rapidly, and the sphere with a radius of half of the sun contains 90% of the sun.
Things.
(c) Troposphere: near the surface, with a thickness of about 654.38+500,000 kilometers, which transfers energy in the form of convection.
A. The temperature around the radiation area drops rapidly, and the transparency of the material is greatly reduced. In addition, the solar watch.
The radiation loss of the surface makes the temperature difference between the upper and lower parts very large, forming a strong troposphere dominated by turbulence.
B. The troposphere is almost completely opaque, and energy from the radiation layer convects in this layer.
The hot air mass is brought to the surface, and the colder air mass on the surface sinks, quite like a pot of water in a boiling state. Tropospheric region
The temperature is about
One million degrees.
In the troposphere, some energy from the sun is converted into kinetic energy of airflow, that is, sunlight.
All kinds of activities and jets in the sphere, chromosphere and corona are closely related to the troposphere.
Two. Composition of the Sun: (Note 2)
1. In terms of quality:
A. hydrogen-about 75%
B.helium-about 25%
2. In terms of atomic weight:
A. hydrogen-about 92. 1%
B. helium-about 7.8%
C. Remaining ingredients-about 0. 1%
Three. The atmosphere of the sun: (note 1)
1. Photosphere:
(1)
A. It is about 500 kilometers thick and the temperature is about 5800 K. The surface of the sun we see is the photosphere. careful
Observation shows that the particle size is about 1500 km, which is caused by convection.
Caused by it.
In addition, sunspots can be clearly seen.
B. the photosphere is quite opaque. When observing the sun, the line of sight in the middle of the solar disk and the surface of the photosphere.
Vertical, you can see the bottom of the high-temperature photosphere through a short distance, but at the edge of the disk, the line of sight is almost
The surface of the photosphere
Parallel, even if separated by a long distance, you can only see the upper layer of the photosphere with lower temperature, which is too
The composition of the sun
The phenomenon that the center of the positive plate is bright and the edge is dark is called edge darkness.
(b) photosphere spectrum
The solar spectrum seen by the earth mainly comes from the photosphere. The bottom of the photosphere is a dense plasma state.
Quality, emitting a thermal radiation spectrum equivalent to its surface temperature, its intensity is the largest in the visible range, and the spectrum type is the same as that of
5800K
The blackbody radiation is very similar. However, it is almost absent in the far ultraviolet region, X-ray region, gamma-ray region and far infrared region.
The radiation intensity of linear electric band is much higher than that of 5800K blackbody radiator, and it is unpredictable. These excess radiation sources
From the light
Non-thermal radiation of the thin solar atmosphere outside the sphere.
By analyzing the absorption lines on the continuous spectrum of the sun with a precision spectrometer, the solar atmosphere can be identified.
In addition to hydrogen, there are 57 elements such as iron, magnesium, aluminum, calcium, titanium, chromium, nickel and sodium. light
ball
The temperature of this layer is not enough to excite helium atoms, so the content of helium (second only to hydrogen) is in the photosphere spectrum.
There is no spectral line in.
2. chromosphere:
A chromosphere has no obvious upper boundary, and the gas density at the edge of the sun is very low, which makes this part glow.
Intensity, only one over ten thousand of the light ball. In a total solar eclipse, you can only see it when the surface of the moon just blocks all the photosphere.
Turn rosy.
Chromosphere, that's how chromosphere got his name.
B the temperature in chromosphere rises with the increase of height, from 4200K at the top of photosphere to tens of thousands of K ..
High temperature. According to the temperature rise, the color ball can be divided into three parts: the layer with a thickness of about 400 kilometers and the temperature.
Degree of 4200 kiloliters
To 5500K K, and then in the middle layer of 1200 km, the temperature slowly rises to 8000K K, and finally around 400.
The temperature in the upper layer of plum rose sharply to tens of thousands of degrees, and transited to millions of degrees in the corona at a height of less than 5000 kilometers.
Degree or above
High temperature.
C. The temperature of some chromospheres is higher than 20,000 degrees of the excited helium atom spectrum, so in the chromosphere spectrum, it can be
See the spectrum of helium atoms that can't be found in the spectrum of photosphere.
3. Corona:
The thickness of a is about 1.3 times the radius of the sun, and the temperature is about 1 10,000 k. ..
B during the total solar eclipse, a pale white halo can be seen around the sun after the colored ball covers the moon surface.
This is the corona. Coronal matter is very thin, and its density is about one billionth of that of the earth's surface atmosphere.
Shinengda
The high vacuum is lower, so it can only be observed during the total solar eclipse.
C the temperature of the corona is very high, which can reach more than 2 million degrees. Such high temperature may be caused by storage.
It is heated by the energy in the solar magnetic field, but the exact process needs further study.
D the radiation of the corona contains many sources, including the direct scattering of photosphere radiation by free electrons in the corona, and
There is a coronal emission line. Coronal emission lines are generated by highly ionized ions of matter at high temperature, for example,
The composition of the sun
Including
Iron ion spectral line with 13 electrons lost. These emission lines are ultraviolet rays and x-rays in coronal radiation.
One of the main sources of. In addition, the synchrotron radiation and other non-thermal radiation generated by the movement of electrons in the magnetic field also
Coronal radiation
The main source of.
4. Solar wind:
A. High-speed ionic gases (hydrogen ions or protons, electrons, ...) blown away from the sun are collectively called the solar wind.
B The temperature of the corona is over one million degrees, so the thermal motion of the corona particles is very fast.
The high-speed ions leaving the corona and away from the sun are the solar wind. The quality loss caused by solar wind is about 107 every year.
A lot, but
Compared with the total mass of the sun, it is still insignificant.
C The propagation speed of the solar wind is about 450km/s, and the solar probe Ulysses is the closest.
The data sent back shows that the speed of the solar wind flowing out of the solar polar region can be as high as 750 km/s, and
Polar sun
The composition of the wind is also slightly different.
D. If the high-energy particles in the solar wind directly hit the earth's surface, it will have an impact on the life and ecological environment of the earth.
A devastating impact. But the earth is shielded by magnetic field and atmosphere, and most high-energy particles are blocked inside the earth.
Outside, less
Particles that enter the earth from the polar regions collide with air molecules, so that the air molecules can freely co-flow.
There are magnificent aurora (Northern Lights = Northern Lights, Southern Lights = Australian Aurora) passing through here.
Medium-range high-energy particles
Most of the energy is lost and the harm is reduced. The earth's magnetic field is blown by the solar wind,
It forms an atmosphere, in which the front solar wind surface is compressed and the back solar wind surface is stretched.
E. There are 294 reliable records about aurora in ancient China, which were first recorded in The Ancient and Modern Books in 950 BC.
Integration. Editing of calendar images. Ordinary classic: "In the last years of King Zhao of Zhou, the night was bright and colorful ...". These records are mainly based on
various
Colors use "Qi" to describe the aurora, such as "Red Qi" and "Purple Qi". The ancients before the Western Han Dynasty regarded aurora as
Auspicious omen is often called "divine light" or "spirit". After the Western Han Dynasty, the aurora was gradually regarded as an ominous sign and the future.
War and disaster
Or an early warning of natural and man-made disasters.
Four. Surface activity of the sun: (note 1)
(a) Sunspots (Note 2)
A.it got its name because it looks darker than its surroundings.
B The diameter of a big sunspot can reach 50,000 kilometers, even bigger than the earth, twice as high as the earth.
C. Often appear in groups
D. The cycle is about 1 1 year-old people 13.3 years, and the short one is only 7.3 years.
E. reason-the rotation speed of the equatorial part of the sun (rotation period is about 25 days) is higher than that of the north and south poles (rotation).
The period is about 35 days), because of the different rotational speeds, the magnetic lines of force are intertwined. Turbulence inside the sun will
The composition of the sun
This magnetic field line correction
Nodes partially emerge from the surface of the sun, forming so-called sunspots. (babcock Theory) (Note 1)
Highlight:
A. a total lunar eclipse can be observed.
B the changes caused by the huge twisted magnetic field dragging the free gas can last for several hours to several days.
Weeks or months.
(c) solar flash:
A. the great energy change on the surface of the sun reaches its maximum in a few minutes, but less than an hour.
Eliminate teaching.
B it can radiate x-rays, ultraviolet rays, visible light, high-speed protons and electrons.
C huge lightning can release1025j = 2 *1015 tons of TNT explosive.
D. The high-speed particles radiated are the main reason for the aurora of the earth.
E. When the sun flashes, it will interfere with the earth communication (causing radiation damage to the passengers of the passenger plane).
(d) Coronal activity:
A. the same as the sunspot cycle.
B coronal hole: there is no loop in the magnetic field of the north and south poles, and all particles flow out from here.
Ginseng? conclusion
This planet, the sun that supplies the life energy of all things, is just a star from an astronomical point of view.
Compared with other stars in the universe, such as Ganges sand, the remarkable G2-type main sequence star has the quality and luminosity of the sun.
Ability, surface temperature and life span are all in the middle zone, and the age is just in middle age, which is considered as one.
Typical star.
The sun has a history of about 5 billion years and has consumed about half of its core hydrogen since its birth, which means that it
It will be stable for another 5 billion years, and finally the core hydrogen will be completely fused, further triggering the helium fusion reaction.
Finally, after rapidly expanding into a red giant, devouring the earth and even Mars, it evolved into planetary nebulae and white dwarfs.
It gradually cools and darkens in space, becoming black dwarf.
This planet we can see every day, we can't live without it, maybe one day, when the sun disappears.
At the end of the world.