Sunspots.pptx This ppt is all about sunspots

Sunspots are temporary spots on the Sun's surface that are darker than the surrounding area. They are regions of reduced surface temperature caused by concentrations of magnetic flux that inhibit convection. Sunspots appear within active regions, usually in pairs of opposite magnetic polarity.[2] Their number varies according to the approximately 11-year solar cycle.

Individual sunspots or groups of sunspots may last anywhere from a few days to a few months, but eventually decay. Sunspots expand and contract as they move across the surface of the Sun, with diameters ranging from 16 km (10 mi)[3] to 160,000 km (100,000 mi).[4] Larger sunspots can be visible from Earth without the aid of a telescope.[5] They may travel at relative speeds, or proper motions, of a few hundred meters per second when they first emerge.

Indicating intense magnetic activity, sunspots accompany other active region phenomena such as coronal loops, prominences, and reconnection events. Most solar flares and coronal mass ejections originate in these magnetically active regions around visible sunspot groupings. Similar phenomena indirectly observed on stars other than the Sun are commonly called starspots, and both light and dark spots have been measured.The earliest record of sunspots is found in the Chinese I Ching, completed before 800 BC. The text describes that a dou and mei were observed in the sun, where both words refer to a small obscuration.[7] The earliest record of a deliberate sunspot observation also comes from China, and dates to 364 BC, based on comments by astronomer Gan De (甘德) in a star catalogue.[8] By 28 BC, Chinese astronomers were regularly recording sunspot observations in official imperial records.[9]

The first clear mention of a sunspot in Western literature is circa 300 BC, by ancient Greek scholar Theophrastus, student of Plato and Aristotle and successor to the latter.[10]

The earliest known drawings of sunspots were made by English monk John of Worcester in December 1128.[11][12]

Sunspots were first observed telescopically in December 1610 by English astronomer Thomas Harriot.[13] His observations were recorded in his notebooks and were followed in March 1611 by observations and reports by Frisian astronomers Johannes and David Fabricius.[14][15] After Johannes Fabricius' death at the age of 29, his reports remained obscure and were overshadowed by the independent discoveries of and publications about sunspots by Christoph Scheiner and Galileo Galilei.[16] Galileo likely began telescopic sunspot observations around the same time as Harriot; however, Galileo's records did not start until 1612.In the early 19th Century, William Herschel was one of the first to equate sunspots with heating and cooling on Earth and believed that certain features of sunspots would indicate increased heating on Earth.[18] During his recognition of solar behavior and hypothesized solar structure, he inadvertently picked up the relative absence of sunspots from July

1. SUNSPOTS Presented By- Shweta Tiwari M.Sc. 4 th Semester A Dissertation on

2. LEARNING OBJECTIVES T he magnetic Sun Structure of Sun Sunspots Facts about Sunspots Why we count sunspots Statistical Analysis Observation of Sunspots Conclusion

3. The Magnetic Sun The sun is the small yellow G type star constitutes 98.8% of the mass of our solar system. Most of the gas in sun (91 percent) is hydrogen . Sun's magnetic field is generated by electrical currents generated by the flow of hot, ionized gases in the Sun's convection zone. Sunspots and Active Regions are manifestation of the magnetic field. Like Earth and other planets sun also rotates in its axis but its rotation is unique . I t is the closest astrophysical laboratory that one can use to study plasma and different models of magnetohydrodynamic (MHD) and MHD turbulence. This Photo by Unknown Author is licensed under CC BY-SA

4. Structure of Sun The different layers of the  Sun  are determined by the physical function they perform. Currently, astrophysics has a model of the solar structure made up of six layers divided into two groups: the inner and  outer layers of the Sun . Inner layer 1. Solar core 2. The radiative zone 3. The convective zone Outer layer 1. Photosphere 2. Chromosphere 3. Corona

5. Sunspots Sunspots   are  phenomena   on the Sun’s Photosphere appear as temporary spots that are darker than the surrounding areas. They are relatively cooler (2000K lesser) region of the sun’s atmosphere. A sunspot consists of two parts, a dark part (umbra) and a brighter part (penumbra), which surrounds the umbra. Due to their correlation with other kinds of  solar activity , sunspots can be used to help predict  space weather , the state of the   ionosphere , and conditions relevant to  short-wave   radio propagation or  satellite communications . 

6. Facts about Sunspots The number of sunspots on the face of the Sun varies with an 11 year period called the sunspot cycle. Solar Maximum- T he period in the sunspot cycle when solar activity is highest and sunspots are most abundant Solar Minimum- Solar minimum is the regular period of least solar activity in the Sun's 11-year solar cycle. Sunspots are actually fairly bright, but they appear dark because the rest of the Sun is so much brighter. Sunspots don’t stay in one place, the can travel across the face of the sun.

7. Why we need to count sunspots? S unspots number is counted to determine the magnitude and duration of a solar cycle. Sunspots are counted to determine the activity of Sun. By predicting sunspot activity, we can know what Sun would do ahead of time W e might also gain a better understanding of how the Sun works.

8. Statistical Analysis Objective – To analyse and predict the activity the sun by counting sunspot number. Sunspots prediction for 24 th solar cycle It was considered as a weak cycle by panel of experts. The panel declared that the cycle 24 th would be rather weak similar to solar cycle 16 th . Solar Cycle 24 would peak in May 2013. Observation- H ere data is taken from NASA’s data collection website named Omniweb. Graph source- NOAA

9. Observation of Sunspots Year Total Sunspots 2010 9077 2011 29485 2012 30936 2013 34224 2014 41326 2015 25392 2016 15873 2017 7887 2018 2590 The adjoining table shows the total number of sunspots observed each year from 2010 to 2018 Period of observation- Year 2010 to 2018 Start Date- 1 January 2010 End Date- 31 December 2018 Solar cycle – 24 th Maximum count – Year 2014 Minimum count – Year 2018

10. Conclusion Sunspots Year 41326 2014 34224 2013 30936 2012 29485 2011 25392 2015 15873 2016 9077 2010 7887 2017 2590 2018 Number of sunspots Observed in Descending order Maximum number of sunspots were observed in the year 2014 in this year solar activity was in peak. Minimum number of sunspots were observed in the year 2018 in this year very low solar activity was detected. Solar activity first increase from 2010 to 2013 . In 2014 the highest number of sunspots were observed it is the solar maximum period. From 2011 to 2018 number of sunspots continuously decreased causing solar minimum in the year 2018

11. Gra ph Plotting

12. Quick Overview The sun is a G type star. The Sun also rotates in its axis its rotation is called differential rotation. The Sun consists of total 2 layers inner and outer layer. Inner layer consists of three parts – the core , Radiative zone and convective zone. Outer atmosphere of sun consists of three parts – the photosphere, chromosphere and corona. Sunspots are relatively darker region in sun’s photosphere having temperature less than other parts of sun. Sunspots are often followed by solar flares which cause radio and magnetic disturbance in geomagnetic field. Statistical discussion of sunspot number as the main topic of dissertation and draw conclusions.