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Mail Magazine 24...
Dynamic Solar System - the actual effects of climate change
The sun - the amazing star  
January 21, 2012 

This article references figures and graphics that will not be available if you click the link below. Also, it is the second of two articles. The first can be accessed at the link as well. 

In all cultures the sun determined the course of events. Very early, the sun’s importance to life on Earth has been detected. Even today “her” metal that has “her” color, is a synonym for prosperity and development - gold. More recently, like the alchemists of the Middle Ages tried to make gold from iron, it was started the attempt to make gold, i.e. the sun from greenhouse gases such as CO2. Like the alchemists of the Middle Ages, this attempt is doomed to fail. Part 2 shows the variable sun on long time scales. He moves out of view of the climate arlamists, which have a short-looking perspective and are eager for alleged disaster reports to link them to an alleged anthropogenic global warming. 

Approximately 99.98% of the total amount of energy the Earth results from the sun. The vanishingly small rest comes from geothermal heat sources. CO2 is irrelevant in the energy balance! The radiant energy emitted by the sun comes all out of her core area (approximately 25% of the solar radius), in which the merger takes place. It arises from the excess energy that arises from the fusion of hydrogen to helium, because the fusion of the hydrogen mass produced nearly 1% less helium. The emitted energy is composed mainly of photons, but also of neutrinos; the neutrinos leave the core zone immediately, the photons need through the interaction with the plasma on average about 10 million years. 

As the so-called main sequence star the sun increases her radiation every 100 million years to about 1%. By thermonuclear fusion four hydrogen atoms form one helium atom, which has about the mass of four hydrogen atoms (minus the small group which is converted in the merger by the Einstein formula for energy). By this, the number of atoms in the core is taking off slowly. A lower number density of atoms can not produce enough back pressure in the solar center as the hydrogen atoms before, whereby the solar center is contracting further thereby increasing the pressure and density until the pressure against the gravity of the overlying layers is back in balance. The higher density and temperature in the solar center result in faster fusion. The outer layers of the sun thereby increases and the Sun’s luminosity increases. The energy radiating surface increases. The following illustrations and explanations provide insight into the classification and life cycle of the sun. 

Both the temperature and luminosity of the sun are constantly changing as a result of nuclear fusion. 

Development phases of the sun 

The sun grew about 4.6 billion years ago in a spiral arm on the edge of our galaxy from a gas and dust cloud. The gas and dust cloud consisted of about 82% hydrogen, 17% helium and 1% other elements. Parts of matter itself came so close that they began to clump together by their mutual gravitational attraction. 

Figure 16 shows the stages of development (life cycle) of the sun. Once it was formed about 4.6 billion years ago with the ignition of nuclear fusion in its interior, the radiation pressure of the contraction of the sun, caused by gravity, countervailed, so that an equilibrium developed, and the sun reached the stage of a main sequence star, in which phase it remains for about 11 billion years. 

The supernovae of a red supergiant (massive star with 10 - 50 solar masses) at the edge of the galaxy, flung about 4.6 billion years ago large amounts of heavy elements such as silicon and iron in this cloud, thereby collapsing the gas and dust cloud. Under the force of gravity, she began to compress slowly and to rotate by the shock waves (impulse) of the supernovae. At its center, the cloud was compressed more and more dense, thus further increasing pressure and temperature. This meant that large amounts of energy were delivered in the form of radiation. A protostar was formed.

The illustrations show examples of two galactic clouds, in which current stars arise. Figure 17a; left, shows the 1,500 light years (ly) distant Horsehead nebula with a diameter of 3 LJ. Figure 17b, right, the 7000 LJ distant Eagle Nebula with a diameter of 20 LJ (NASA). 

By further compression of the particles in the center, the electro-magn. repulsion of the particles was subdued and the protons were blending with each other. The fusion was brought into action. From the protostar a star was born - the Sun. With the formation of the solar system over 99% of the matter were tied up in the sun. The rest formed by increasingly rapid rotation a flattened disk from which rings were formed first, then protoplanets and eventually the planets and their moons. 

At the age of 5.5 billion years, ie in 900 million years from today, the average temperature on Earth’s surface exceeds the for higher organisms critical value of 30C (Bounama, 2004). 1 to 2 billion years later, 100C are reached. 

In about three billion years, Milky Way and Andromeda (our neighboring galaxy, slightly larger at 2.2 million light years away) come up with a speed of more than 430,000 kilometers an hour together and finally merge with each other. As a result, a new elliptical galaxy will be formed. According to calculations the sun together with their satellites might find their existence on the edge of the new Super Galaxie. However, it could also be shredded by the cosmic crash, or the planetary system can be torn apart by galactic inferno. 

Figure 20a shows the 2.2 million light years distant Andromeda galaxy. It is like the Milky Way galaxy an extended bar, Source: NASA. Figure 20b, right, shows in artistic representation, the celestial spectacle in about 3 billion years as becomes evident from the Earth, Source: James Gitlin / STScI (Space Telescope Science Institute). 

Galactic crash of entire galaxies are not uncommon, but happen in space ever and anon. In the early universe such crashs were “on the agenda”. 

If the sun and the solar system survive this cosmic crash, the luminosity of the sun will have doubled in about 6.4 billion years and its size will 1.6-fold increase of its current value. The earth is in her heart no longer liquid and therefore there is no earthly magnetic field anymore, which could easily mute the strong sunlight and acts as a filter for X-ray and UV radiation, the solar wind. The Earth loses fast its meanwhile hot atmosphere. 

The hydrogen in the Sun’s core will be depleted in about 5 billion years. The burned-out helium-sun-center (called helium nucleus) contracts more and heats up so long, until the fusion of the still abundant hydrogen around the helium core into helium begins. This is known as a hydrogen-shellburning. In doing so, the sun produces more energy, the more the center of helium contracts and the further the hydrogen-fusion-shell eat through to the outside. In 6.4 billion years, the luminosity is already twice as high as today, and the solar radius is larger by about 60% than it is today. Over the next 1.3 billion years solar radius and luminosity grow massively. In about 7.4 billion years, the following picture will be seen from Earth (right side of the picture): 

Figure 22b shows the sun as a red giant in artistic presentation above the surface of the Earth and left in the comparison, the contemporary view. 

After another 200 million years, the luminosity reaches the thousands of current value and the outer layers swell up to a hundredfold, so that in spite of the larger luminosity the temperature of the sun’s surface decreases and the sunlight becomes reddish. The sun has become a red giant. All water on earth will long be evaporated. The following figure shows a size comparison of the size of the sun. 

Figure 23 shows the sun today (the little yellow dot, left) compared to the Sun as a red giant star to the right with a diameter of 1 AU (Astronomical Unit = distance Earth - Sun). The sun reaches almost to the present Earth’s orbit. 

During the development of the sun to a red giant, the ever-growing helium core contracts more and more under the influence of gravity and gets denser and hotter. Finally, the electrons form the nucleus of helium at high density, a so-called “degenerate Fermi gas,” similar to a fluid can not be compressed further for the time being. 

The temperature will reach the very high value of 100 million Kelvin in the helium center and even exceed (today’s solar center has about 15 million Kelvin) this. At this temperature (and pressure) the helium fusion ignites, merging helium into carbon. 

The helium in the solar center is in the so-called helium flash explosively converted into carbon. Within a few minutes energy is generated by the magnitude of an entire galaxy. The energy is not moving to the outside, but is required to repeal the degenerate center (Fermi gas). Thereby the helium center expands. The rest of the helium in the solar center slowly merges into further carbon and partially carbon also fuses with additional helium to oxygen. 

During the helium-and hydrogen-shellburning, the sun is shrinking due to slower back-pressure to gravity again to about 10-fold their present value. The red giant sun becomes a small white giant sun, a so-called “horizontal branch star”. For a certain period of time as a horizontal branch star it even pulsates. It is then a “RR Lyrae star” (they change their luminosity strictly periodic, and are named after the reference star “RR Lyrae” in the constellation Lyra). After another 100 million years, the helium in the center is consumed and converted into carbon and oxygen. The carbon-oxygen center contracts down to Earth size, with more than half of the total solar mass concentrated in this very compact hot center. 

In the much less dense gas above it forms a helium fusion shell, and above this shell the the hydrogen fusion shell is still burning . The outer layers of the sun in total inflate again strong and cool down. For a short time (about 20 million years), a red giant forms again, which is even larger than before - about 200 times larger than today’s sun and with 5,000-times the luminosity. So the sun reaches over the todays earth’s orbit. The loss of mass of the sun by the strong solar wind and thus the reduced force of gravity, based on the model calculations, the distance between the earth from the sun can increase to about 1.7 times the distance of today. 

By the migration of the helium fusion shell to the outside the red giant sun will eventually become unstable. Over a period of 500,000 years the sun blows in several violent convulsions (so-called “helium flash”) large parts of the outer, only weakly gravitationally bound solar layers (they are located relatively far away from mass core) into space and exposes its inner, Earth-sized core. 

Through this process, she loses virtually all still unspent fuel, totaling about 1 / 3 of its mass. The expanding cloud of gas and dust is called a “planetary nebula”, but has nothing to do with planets. The term has its origin in the fact, that these nebulae in previous telescopic had a similar appearance to gas planets. In comparison to the lifespan of the solar, the planetary nebulae exist only a short time, usually not more than some 10,000 years. In our galaxy about 1,500 planetary nebulae are known. Figure 24 shows some planetary nebulae. 

Figure 24, left, shows the Cat’s Eye Nebula (NGC 6543) in the constellation Draco, at a distance of about 3,300 light-years. The middle figure shows the well-known planetary nebula, the Ring Nebula in the constellation Lyra (NGC 6720, distance 4100 light years) and the right figure the Eskimo Nebula (NGC 2392) in the constellation Gemini, at a distance of 2,900 light-years. 

The remaining very hot naked sun center of carbon and oxygen is called a “white dwarf”. Although he is only as big as the earth, he has about half the original mass of the Sun. The particle density in a white dwarf is so high that one cubic centimeter of its mass weighs about 1 ton of weight in the terrestrial system. 

Figure 25: The white dwarf (artistic representation), which is remaining from the sun and has only the size of Earth, envelopes the Earth’s surface in a pale light. A merger on the remaining sun will not longer takes place. It shines because it has a surface temperature of more than 100,000 C, which decreases over the next billion years slowly. Their remaining mass of approximately 50% of the old solar mass is sufficient to bind the earth to it. It is impossible, that life may arise on the earth again. 

After this excursion into the future (the scenarios were developed according to the knowledge of astrophysics and summarize the current knowledge roughly), back to the present, and how the dynamic solar today and in the recent past influences weather and climate on Earth on smaller time scales and how it will continue moderating. For this we take a look at the sun in its interior. 

Figure 26 shows acoustic measured fluctuations and eddies in the solar interior (left and middle), and measured temperature-/density-changes in the Sun (right) Source: SOHO. The sun is not a static entity. Her energy fluctuations and their impact on the earth on small time scales are quite considerable. 

So far, only the fusion power of the sun was considered. In addition, the sun radiates electromagnetic energy generated off into space. While the fusion power is relatively constant over short time scales, the magnetic activity of the sun varies considerably, thus controlling our weather systems. 

The graphics are fascinating. See them, plus read this and other articles at Mail Magazine 24 




 
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