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Sunspots, by simple definition, are areas on the Sun's photosphere that are cooler and darker then the surrounding material. The Sunspots are cooler and darker regions on the Sun because they have a high magnetic activity that inhibits the convectional currents in the Sun, cooling down the photosphere, otherwise know as the radiating surface of the Sun (1).
There is a correlation between the number of Sunspots and the raise in temperatures on our Earth. This can be proved as the numbers of Sunspots have been increasing from the years 1996 through 2006, and during this increase, the temperatures on the Earth have been increasing. Evidently, the raise in temperature has a negative effect on the sea levels.
The main reasons for the solar variations to take place is because solar cycles take place. There have been many recorded solar cycles, however, only the 11-year and the 22-year solar cycles are thoroughly explainable.
The 11-year solar cycle involves the differential rotation of the Sun's convection zone. This convection zone stabilizes the magnetic flux and increases the magnetic field strength. This makes the convection zone rise into the photosphere and as they cool down Sunspots are formed. More the Sunspots, more the active radiation emitted by the Sun's apparent surface. The 11-year cycle is the rapid decrease, or the gradual increase in Sunspots. In the 22-year Sun cycle, the magnetic field of the Sun reverses during each 11-year cycle, such that after every two cycles, the magnetic poles return to their original state and position.
This experiment is based on the data that has been collected by various scientists for the past 400 years. This data shows the correlation between the increase in the number of Sunspots and the changes in the temperature and the increase in sea levels.
Abstract Word Count: 298
I would like to take this opportunity to extend my appreciation to Mr. Ramakrishna M Pradeep for his judgments in the practicality of my experiments. I would, most importantly, like to thank Mr. Sivakumar, my Extended Essay supervisor, for his constant help and guidance and his constant support even when things went haywire and especially when I mixed up my theories. I would also like to thank Mrs. Gauri Dabholkar for her helpful advice.
Also, I would like to take this opportunity to thank Rohan Sharma, my classmate in Physics Class, for helping me out in choosing this topic and having faith in me at all times.
Chapter 1: Introduction
What are Sunspots?
The Sun has been a specimen of study for the past 400 years. The Sun, being the center of the solar system, is our main source of light energy and life on Earth is dependant on this form of energy. Sunspots, as mentioned in the Abstract, are dark areas on the Sun's photosphere, which are relatively cooler than compared to the other, lighter regions on the Sun's apparent surface. Sunspots often appear in pairs or groups with specific magnetic polarities that indicate specific magnetic origins (1). These Sunspots constantly contract and relax as the move about the surface of the Sun.
The Sun is fundamentally composed of Helium at the photosphere, hydrogen, oxygen, carbon, sulphur, neon, silicon, magnesium and iron being its core. When the heat formed in the core, due to nuclear fission and fusion reactions, is not enough for it to radiate all the way through the layers of different gasses and reach the photosphere a dark spot is formed on the surface of the Sun. One of the theories for the dark coloration of the Sunspots is that they have a lighter Penumbra and a darker Umbra. A typical large Sunspot could have a temperature of 4,000K, which is much lower than the Sun's photosphere's temperature that surrounds the Sunspots, which is approximately 5,800K. Sunspots are capable of creating solar flares and solar storms.
A solar flare is an explosion in the Sun's atmosphere that can release as much as 6 - 1025 joules of energy (2). The heat generated form a solar flare is usually given out to space, however, the ray of heat curves due to gravity and either goes back into any part of the photosphere or into another Sunspot. A solar storm is a massive solar flare, whose heat can reach the Earth. As it reaches the Earth, it disrupts the magnetic flux on the Earth cutting off all sorts of electronic devices and communication lines.
This essay mainly focuses on the patterns of Sunspots over the past years and its correlation with our Earth's climate. When we look at the pattern of Sunspots on the Sun, starting from the year 1996 to the year 2006, it can be noticed that the number of Sunspots have been increasing. By this pattern it could be deduced that as the number of Sunspots increase on the Sun's surface, the photosphere becomes cooler. This in turn results in the core (and its near-by surroundings) becoming hotter which leads to the expansion of the core of the Sun. Automatically, due to the expansion of the core, the Sun turns into a Red Giant and leaves the main sequence. However, fortunately it will take another five billion years for the Sun to leave the main sequence and join the other Red Giants.
1.2 Instability in our Sun due to Sunspots.
Our Sun consists of interminable Sunspots. Sunspots create vast amount of instability in the Sun. However, areas that are brighter called Faculae usually surround these Sunspots. These areas re-establish the flow of energy on the Sun's photosphere. However, the Faculae, along with the Sunspot blocked regions of the Sun elevate the its surface temperature.
1.3 How does this instability in the Sun effect the life on Earth?
The instability in our Sun affects our Earth and the life on it greatly. As the number of Sunspots increase in number, so will the number of Faculae. This in turn increases the surface temperature of the Sun. The increase in the surface temperature of the Sun may prove fatal to life on Earth, as this will increase the wavelength of the rays that enter our atmosphere in turn increasing the temperature on our Earth. There have also been climatic issues regarding the instability in the Sun. There have been noticeable changes in the sea levels with relation to Sunspots. It has been seen that increased number of Sunspots, which leads to increased number of solar flares (increased solar activity), have resulted in the melting of the glaziers and thus, promoting an increase in the sea levels world wide. Data that has been recorded from the year 1920 to the year 2000 suggest that as the solar activity (Sunspots) increases, so does the sea level (due to the melting of glaziers) and vice versa. A positive correlation has been noticed between the number of Sunspots on the Sun and the sea levels.
1.4 How is this research going to take place?
As my data is dependant on the past 400 years, my data is mostly secondary source based. Most of the data that has bee collected, tabulated and has been put on a graph, which will be seen in the second chapter of this Extended Essay. Most of the data that has been tabulated has been obtained from educational websites and other books relating to this topic.
1.5 Why is research relating to Sunspots important?
The research of Sunspots can result in a lot of helpful information, may it be relating to the area of science or not. For example, when William Herschel studied the Sunspots in 1801, where ne noted a correlation between the Sunspot records and the Wheat prices (4). Some economic models have also been included, with regard to the Sunspots, as a way of taking into consideration the extrinsic fluctuations that occur in the field of asset pricing and financial crisis, et cetera (5).
1.6 Solar Variations.
Solar variations refer to the total changes in the amount of total solar radiation and its spectral distribution (6). This solar variation mostly affects the total and spectral irradiance of the Earth and its climate in turn. Solar irradiance, in simple terms, is the flux of radiant energy per unit area. Solar variation can also be defined as the changes in the number or amount of Sunspots on the surface of the Sun.
Solar Variations (including the 11-year cycle and the 22-year cycle) have greatly affected the climate on our Earth. Solar Variations and the temperature fluctuations on our planet are inter-related. It had been noticed, during the Maunder Minimum period, that most of the variations in the Earth's climate had taken place due to Solar Variation and Volcanic activity. It is believed that the variations in the Solar Irradiance have hardly been noticeable in the past; however, currently our Earth receives a total Solar Radiation of 1366 W/m2. Nonetheless, we cannot hold the fluctuations in solar irradiance responsible for the changes in our temperatures as there have been theories put forward suggesting that the changes in the solar irradiance of the Sun have nothing to do with the changes in the number of Sunspots (7). Also, there have been explanations where the Sunspots are being responsible for the changes in the climate, however, they are not being considered as the sole cause for the climatic changes fluctuations.
Chapter 2: Further Analysis:
2.1 Data Collection, Presentation and Analysis:
2.1.1 Changes in the Number of Sunspots from the 1900s to 2010:
Number of Sunspots
Fig 2.1.1: Shows the changes in the number of Sunspots in the past 100 years
The standard error for all the graphs involving the number of sunspots if ± 10 sunspots.
As it can be seen in the graph above, the number of sunspots have not been consistent in number, however, one aspect that is consistent is that fact that the numbe of Sunspots keep increasing, i.e even when the numbers decrease, they donot go as low the initial number (10 sunspots). From this, it can be deduced that the number of Sunspos are ever increasing.
2.1.2 Correlation between Sunspots and Carbon Dioxide Levels:
Number Of Sunspots
CO2 Concentration/ ppm
Fig 2.1.2: showing the correlation between the no: of Sunspots and the CO2 Concemtration.
The above graph shows the correlation between the sunspot numbers and the level of Carbon Dioxide concentration over the past hundred years (ranging from 1900 to 2000). The Blue trendline indicates the Number of Sunspots and the Green trendline indicates the CO2 concentration over the years.
It can be noticed that, as the number of Sunspots increase, so does the Carbon Dioxide concentration. However, this increase in the Carbon Dioxide concentration is not as drastic as the increase in the number of sunspots. This can be noticed in the year 1960, where, the number of sunspots increased from 60 to 85 and the concentration of Carbon Dioxide increased from 310ppm to only 317ppm.
2.1.3 Correlation between Sunspots and the Temperature on Earth:
Number Of Sunspots
Temperature Anomaly/ ËšC
Fig 2.1.3 showing the Correlation between the Sunspots and the Temperature
In the above graph, the correaltion between the number and sunspots and the increase in temperature is shown. The Blue line shows the fluctuation in the Temperature Anomalies, while the Red line shows the increase in the Number of Sunpots.
This data, just like the previous graph, is the data reating to the past 110 years (ranging from 1900 to 2000).
As it can be noticed, as the number of Sunpots keep increasing, the temperature anomalies keep decreasing. This can be noticed as the number of sunspots increase from 30 in 1900 to 85 in 1960, and the temperature anomalies decrease from - 0.4 in 1900 to - 0.11 in 1960.
2.1.4 Correlation between Sunspots and the changes in the Sea Levels:
Number Of Sunspots
Rise in Sea Levels/ mm per year
Fig 2.1.4: showing the rise in Sea level with respect to the number of Sunspots
The above graph shows the correlation between the number of Sunspots and the rise in the Sea level for the past 100 years (ranging from 1900 to 2000). The x-axis shows the increase in the number of sunspots while the y-axis shows the rise in the sea level.
As it can be noticed, there is a direct correlation between the number of sunspots and the rise in the sea levels. This can be reinforced by the graph itself. As the number of sunspots increase from 60 to 80 from 1940 to 1980, the sea level rose from about 1.5 mm/yr to 5.4 mm/yr.
As a result of the data provided above, it can be said that the number of Sunspots on the Sun's photosphere affects climatic changes on the earth, to some extent.
One of the most popular way of representing Sunspot values has been the through the Butterfly Diagram:
This graph shows the values for the number of Sunspots since the year 1870 and goes on till the current year, 2010. In this graph, it can be seen that as we go towards the right of the x-axis, i.e. as we ascend the years, it will be noticed that the number of Sunspots keep increasing. There is almost a linear increase in the number of Sunspots.
Chapter 3: Errors, Conclusion, Evaluation and Suggestions:
3.1 Sources of Errors:
Secondary Source Errors:
All the data that has been collected has been regarding the past 100 years ranging from the 1900s to 2000. However, there has been a very smaller amount of accurate data recorded for the years 2000 to 2010 (or even till 2009). That data, if collected, could have affected the conclusion of this essay.
There could have been some error while calculating the latitudes and longitudes of the Sunspots.
The angular velocity (the speed of rotation) of the Sun could have been misunderstood during the calculations.
The instruments used to record the readings from 1900 and onwards could have had some minor glitches in their calibrations.
The machines that were used could have been a little out dated and not as advanced as required due to which not many details were recorded and captured. Hence, the data could not have been as accurate as needed.
There is a possibility that while recording the data, the scientists who were looking at different areas in the Sun's surface may have counted one sunspot twice, or may have missed a sunspot.
Also, there could be a scenario where there could be lesser number of sunspots with a larger surface area that average. There could also be another scenario where there could be large number of sunspots with a surface are lower than average. This could tamper with the reading greatly as in these scenarios, the number of Sunspots do not matter any more.
As there were many scientists, and not only one, who recorded the number of Sunspots yearly, there could be a possibility where the same year has different readings of sunspots. For example, Scientist A may measure 80 sunspots, while Scientist B measures 67 sunspots. This could tamper with the readings, as we can never know which scientist is more accurate.
- The surface area of sunspots, all over the sun's photosphere is approximately the same.
3.2 Methods of Improvements:
These are the following methods of improvement that could have helped this essay in numerous ways:
There could have been an experiment devised where there could a telescope could have been used to record the number of Sunspots for a year or at least a month long.
More data regarding the recent years (2000 to 2010) could have been used to reinforce the following conclusion.
Check for more reliable secondary sources for the essay by check the number of footnotes used by the source.
3.3 Conclusion: Verification of the Temperature on Earth's Dependence on the Number of Sunspots on the Sun's Photosphere.
Based on the analysis on the data listed above, it can be concluded that the temperature on Earth is dependent on the number of Sunspots on the Sun's apparent surface.
This theory of mine is supported by the following facts:
In the figure 2.1.1, it can be noticed that the number of Sunspots keep increasing constantly. Similarly, figure 2.1.2 shows the increase in the amount of CO2 levels, which agrees with the figure 2.1.1. This is because, as the number of Sunspots increase, so does the amount of CO2. This hold true in this scenario as, when the amount of heat increases, a larger wavelength of the sun's rays is captured by the Earth's atmosphere, and more amount of Greenhouse gases are captured too, increasing the amount of CO2 on our Earth.
Also, when the number of Sunspots are compared to the variation in temperatures (in the figure 2.1.3), it is noticed that at the peak of the number of Sunspots (85 in the year 1960), the temperature decreased by - 0.11ËšC. This shows that as the number of Sunspots increase on the Sun's surface, the temperature decreases. Temperature and the number of Sunspots are inversely proportionate.
When the rise in sea level is looked at and compared to the increase in temperature in the figure 2.1.3, it will be noticed that in the year 2000, there was the highest increase in temperature (+ 0.31ËšC). This, when compared to the figure 2.1.4, shows that the highest rise in sea level took place when there was an increase in temperature (year 2000). Also, when we relate the Butterfly Diagram to the figure 2.1.1, there is a direct relation considering the fact that both the graphs have a linear increase in the Number of Sunspots.
Keeping these graphs and figures into consideration, it is safe to say that the number of Sunspots and the Temperatures on Earth are inversely proportionate. When the numbers of Sunspots increase, the temperature decreases. This is seen in the figure 2.1.3 where, as the numbers of sunspots increase, temperature anomalies tend towards zero, and when there was a drop in the number in the year 2000, the temperature anomaly increased.