Our Sun

About the Sun The sun is by far the largest object in the solar system, containing more than 99.8% of the total mass of the solar system (Jupiter contains most of the rest).

Composition The sun is made of about 90% hydrogen and 8% helium, with traces of many other elements

Layers of the Sun

The central region in which fusion burns hydrogen to power the Sun is called the core.core Over time, the nuclear fusion reactions that fuel the sun's core are converting hydrogen into helium, changing the ratio of these two elements.nuclear fusion

Nuclear Fusion These reactions create a tremendous amount of energy, which appears as light, heat: the motion of atoms and particles within the sun

Energy of the Sun It takes several hundred thousand years for radiation to make its way from the core to the top of the radiative zone!

Solar zones The second layer is the radiative zone: Layer just outside the sun's core, where energy is transported mostly in the form of radiation. This region, while too cool for fusion to occur, is still very dense and hot- about 4 million degrees Kelvin.

Layer 2: The Convection Zone The solar layer just below the photosphere, in which plasmas circulate between the Sun's radiation zone and the solar atmosphere, carrying energy outward.

The Photosphere The lowest layer of the solar atmosphere, where the sun's visible spectrum of light (electromagnetic radiation) is released. It is visible "surface" we see in white-light images of the sun.

Chromosphere The chromosphere is a narrow layer above the photosphere that raises in temperature with height. Normally, it can't be seen by the naked eye because the light from the photosphere of the Sun overpowers it. chromospherephotosphere However, during a solar eclipse when this light is blocked out, it appears as a narrow, red ring around the Sun, with an irregular outer edge. The red from the chromosphere is also visible in prominences when they project from the Sun.solar eclipseprominences

Corona The outermost layer of the solar atmosphere, characterized by low densities and high temperatures, often several million degrees Kelvin.Kelvin.

Temperatures of the Sun

Sun’s Interior and Exterior

Exterior Activity Prominences Loops Flares Sunspots CME’s

Prominences

A prominence is a large, bright feature extending outward from the Sun's surface, often in a loop shape Sunloop Prominences are anchored to the Sun's surface in the photosphere, and extend outwards into the Sun's corona.photospherecorona A typical prominence extends over many thousands of kilometers; the largest on record was observed by the Solar and Heliospheric Observatory (SOHO) in 2010 and is estimated at over 700,000 kilometres (430,000 mi) long [1] – roughly the radius of the Sun.Solar and Heliospheric Observatory[1]

Loops Example of solar coronal loops observed by the Transition Region And Coronal Explorer (TRACE), 171 Å filter. These loops have a temperature of approximately 106 K. These loops contrast greatly with the cool chromosphere belowTRACEchromosphere These highly structured and elegant loops are a direct consequence of the twisted solar magnetic flux within the solar body.magnetic The population of coronal loops can be directly linked with the solar cycle; it is for this reason coronal loops are often found with sunspots at their footpoints.solar cyclesunspots

Loops

Flares A solar flare is a large explosion in the Sun's atmosphere that can release as much as about a sixth of the total energy output of the Sun each second.Suntotal energy output of the Sun each second Solar flares play havoc with our radios when they interact with the ionosphere of the Earth’s atmosphere.

Coronal Mass Ejection CME (coronal mass ejections) are a massive burst of solar wind, other light isotope plasma, and magnetic fields rising above the solar corona or being released into space.solar windsolarcorona CME’s can be caused by flares, prominences, loops and other types of solar activity.

Sunspots These are two pictures of different sunspots. The picture on the left shows the whole Sun with some large sunspot groups on it. The sunspot groups in that picture are as big as the giant planet Jupiter. The picture on the right is a closeup of some other sunspots. The larger sunspot on the right (top) is bigger than Earth! Images courtesy SOHO (NASA & ESA) and the Royal Swedish Academy of Sciences.

Sun’s Solar Cycle Approximately every 11 years (closer to 10.5) Scientists have been studying the sunspot activity for many years and have compiled much data on the subject Enough Data has been collected to determine the sun has a cycle where the magnetic field is reversed.

Solar Cycle The 11 year sunspot cycle is related to a 22 year cycle for the reversal of the Sun's magnetic field. In 1848 Johann Rudolf Wolf devised a method of counting sunspots on the solar disk called the Wolf number. Today the Wolf number (averaged from many observing sites) is used to keep track of the solar cycle.

Solar Cycle This graph shows the number of sunspots on the surface of the Sun each year from 1700 to Notice that the number of sunspots changes. Is there a pattern? Image courtesy of NOAA. NOAA/NGDC

Solar Cycle This graph shows the position of sunspots in the years from 1870 to Notice that the centerline, from left to right, is the equator of the Sun and that sunspots happen north and south, above and below this line. Courtesy of NASA. NASA's Marshall Space Flight Center

Sources mlhttp://cse.ssl.berkeley.edu/segwayed/lessons/sunspots/research2.ht ml content/171925main_heliolayers_label_516.jpg&imgrefurl= w.nasa.gov/mission_pages/hinode/solar_020.html&usg=__9_XYr4z 6Tb0rPZU62XJRIOFQmG8=&h=516&w=516&sz=64&hl=en&start=0 &zoom=1&tbnid=gZg2VNVGi3jo8M:&tbnh=114&tbnw=114&prev=/i mages%3Fq%3DLayers%2Bof%2Bthe%2Bsun%26um%3D1%26hl %3Den%26sa%3DX%26rls%3Dcom.microsoft:en- US%26rlz%3D1I7GPEA_en%26biw%3D1247%26bih%3D527%26t bs%3Disch:1&um=1&itbs=1&iact=rc&dur=172&ei=HsUjTcnICMSYn Af8zIDtDQ&oei=HsUjTcnICMSYnAf8zIDtDQ&esq=1&page=1&ndsp =21&ved=1t:429,r:0,s:0&tx=71&ty=55%26t bs%3Disch:1&um=1&itbs=1&iact=rc&dur=172&ei=HsUjTcnICMSYn Af8zIDtDQ&oei=HsUjTcnICMSYnAf8zIDtDQ&esq=1&page=1&ndsp =21&ved=1t:429,r:0,s:0&tx=71&ty=55

Sources efurl= VPDM=&h=858&w=758&sz=59&hl=en&start=0&zoom=1&tbnid=viGnDqCT36tnFM:&tbnh=113&tb nw=98&prev=/images%3Fq%3Djupiter%26um%3D1%26hl%3Den%26sa%3DN%26rls%3Dcom. microsoft:en- US%26rlz%3D1I7GPEA_en%26biw%3D1247%26bih%3D527%26tbs%3Disch:1&um=1&itbs=1&i act=hc&vpx=373&vpy=78&dur=140&hovh=239&hovw=211&tx=106&ty=128&ei=_swjTejJC9GNn QfGteXuDQ&oei=_swjTejJC9GNnQfGteXuDQ&esq=1&page=1&ndsp=24&ved=1t:429,r:2,s:0 (picture of Jupiter)vpy=78&dur=140&hovh=239&hovw=211&tx=106&ty=128&ei=_swjTejJC9GNn QfGteXuDQ&oei=_swjTejJC9GNnQfGteXuDQ&esq=1&page=1&ndsp=24&ved=1t:429,r:2,s:0 /oml631csgjs7/e4w1oo/fusion.jpg&imgrefurl= and-nuclear-power-plants&usg=__q- UMz0GKkezDHcSaUhX9paKCWUU=&h=312&w=400&sz=27&hl=en&start=0&zoom= 1&tbnid=k_e6oTKTYsh4DM:&tbnh=108&tbnw=139&prev=/images%3Fq%3Dnuclear %2Bfusion%26um%3D1%26hl%3Den%26sa%3DN%26rls%3Dcom.microsoft:en- US%26rlz%3D1I7GPEA_en%26biw%3D1247%26bih%3D527%26tbs%3Disch:1&um =1&itbs=1&iact=hc&vpx=226&vpy=218&dur=3891&hovh=198&hovw=254&tx=122&ty =71&ei=BdAjTe_mI8fOnAf96bzcDQ&oei=BdAjTe_mI8fOnAf96bzcDQ&esq=1&page= 1&ndsp=22&ved=1t:429,r:15,s:0 (fusion picture)%3Disch:1&um =1&itbs=1&iact=hc&vpx=226&vpy=218&dur=3891&hovh=198&hovw=254&tx=122&ty =71&ei=BdAjTe_mI8fOnAf96bzcDQ&oei=BdAjTe_mI8fOnAf96bzcDQ&esq=1&page= 1&ndsp=22&ved=1t:429,r:15,s:0

Sources (Chromosphere) heliospheric.engin.umich.edu/hjenning/Chromosphere.htmlhttp://solar- heliospheric.engin.umich.edu/hjenning/Chromosphere.html (Solar Eclipse Picture) Mosaic.jpg&imgrefurl= EQ=&h=6500&w=6500&sz=602&hl=en&start=0&zoom=1&tbnid=bci4Wa9vOj1BwM:&tbnh=107&tbnw=107&prev=/ images%3Fq%3Dchromosphere%26um%3D1%26hl%3Den%26sa%3DN%26rls%3Dcom.microsoft:en- US%26rlz%3D1I7GPEA_en%26biw%3D1247%26bih%3D527%26tbs%3Disch:1&um=1&itbs=1&iact=rc&ei=- NMjTcykMs6jnQeHuKTyDQ&oei=- NMjTcykMs6jnQeHuKTyDQ&esq=1&page=1&ndsp=24&ved=1t:429,r:2,s:0&tx=72&ty=48- NMjTcykMs6jnQeHuKTyDQ&esq=1&page=1&ndsp=24&ved=1t:429,r:2,s:0&tx=72&ty=48 stage1/images/sun.gif&imgrefurl= stage1/sun3.htm&usg=__d6q-5_- 5gUn3NlhgIIsMEgPK9xg=&h=304&w=315&sz=10&hl=en&start=0&zoom=1&tbnid=RcYLnyZ2MVFYfM:&tbnh=106 &tbnw=110&prev=/images%3Fq%3Dsun%26um%3D1%26hl%3Den%26rls%3Dcom.microsoft:en- US%26rlz%3D1I7GPEA_en%26biw%3D1247%26bih%3D527%26tbs%3Disch:1&um=1&itbs=1&iact=hc&vpx=385 &vpy=88&dur=609&hovh=221&hovw=229&tx=124&ty=118&ei=9tUjTczXEYSUnQeShs3SDQ&oei=9tUjTczXEYSU nQeShs3SDQ&esq=1&page=1&ndsp=24&ved=1t:429,r:2,s:0 (Sun Graphic)26bih%3D527%26tbs%3Disch:1&um=1&itbs=1&iact=hc&vpx=385 &vpy=88&dur=609&hovh=221&hovw=229&tx=124&ty=118&ei=9tUjTczXEYSUnQeShs3SDQ&oei=9tUjTczXEYSU nQeShs3SDQ&esq=1&page=1&ndsp=24&ved=1t:429,r:2,s:0

Sources All the solar activity information and pictures from: e.jpg (solar activity) e.jpg