Our Sun

1. Our Sun

2. Our Sun – The Abnormal Star • Fact – our sun is a star • Average in size (thus yellow in appearance) • Middle Age for a star • But it is not part of a multiple star cluster!

4. Anatomy of the Sun Chromosphere

5. Corona - 1,700,000° C Chromosphere - 27,800° C Photosphere - 6,000° C Convective Zone Anatomy of the Sun To convert °C to °F °F = (°C X 9/5) + 32 Radiative Zone The CORE – 15,000,000° K

6. TABLE 16.1 The Standard Solar Model

7. Core In solar astronomy, the innermost part of the Sun is where energy is generated by nuclear reactions.

8. Radiative Zone An interior layer of the Sun, lying between the core and the convection zone, where energy travels outward by radiation.

9. Convective Zone The layer of the Sun between the radiative zone and the photosphere where energy travels outward by convection.

10. Photosphere The visible surface of the Sun. It is a layer of gas that is heated enough to shine. It is the layer from which the light we actually see (with the human eye) is emitted. It is also the layer astronomer’s refer to as the Sun’s “surface.”

11. Circulation in the Sun

12. Chromosphere The layer above the photosphere and beneath the transition region and the corona. The chromosphere is hotter than the photosphere but not as hot as the corona.

13. Corona The outer layer of the sun. It looks like a halo and is visible during eclipses or from special telescopes. Extends about a million miles out into space.

14. Radiation AKA – Electromagnetic Radiation Energy created in the core radiates out through radiation zone Next, it moves from the core through the convection zone Finally, it exits the sun’s atmosphere

15. Nuclear Fusion The process by which multiple like-charged atomic nuclei join together to form a heavier nucleus.

16. Nuclear Fusion The process by which multiple like-charged atomic nuclei join together to form a heavier nucleus.

17. The proton–proton chain reaction dominates in stars the size of the Sun or smaller. In this reaction, hydrogen fuses to create helium and energy. At the current rate of fusion, the Sun should continue to burn for another 5 billion years.

18. Features of the Sun

19. Sunspots A temporary disturbed area in the solar photosphere - Cooler than the surrounding areas - Appear as dark spots - Made from strong magnetic fields. - Usually occur in pairs or groups of opposite polarity that move together across the surface of the sun. - Occur in an 11-year cycle Size comparison of Earth to a sunspot

20. 11-Year Solar Cycle

21. Prominences Loops of cool plasma that link different parts of sunspots.

22. A solar prominence is vast and awesome in size in contrast to our little Earth. But the Earth is so far from the sun that these prominences pose no danger. Image via NASA

23. Prominences Huge, high-arching plasma columns

24. Solar Flares May occur when prominences loop together, or sunspots move together. This produces a very violent eruption on the surface of the sun called a solar flare.

25. CME’s Coronal Mass Ejections Large amounts of electrically charged gas suddenly ejected from the Sun’s corona.

26. CME’s During periods of sunspot maximum, CME’s can occur two or three times each day.

27. CME’s http://www.mnn.com/earth-matters/space/stories/stunning-coronal-mass-ejection-erupts-from-sun-photo CME’s appear as a halo around the sun. They cause magnetic storms, which damage satellites, interfere with radio signals, and can damage electrical grids.

28. CME’s

29. CME’s – The Impact to Earth

30. Solar Wind The outflow of charged particles from the Sun’s corona.

31. Solar Winds and Earth When CME’s, in the form of a solar wind, interact with our magnetosphere, they can produce the light show called an Aurora. The charged particles carried by the solar wind generate electric currents at the poles. These currents ionize gases in the atmosphere, which produce the lights.

32. Solar Storm Geomagnetic storm produced by solar flares, CME’s or coronal holes. Can affect satellites, communication and navigation systems, and electrical systems.

33. The Light year! The distance light travels in one year in a vacuum Light travels at 300,000 km/sec or 186,000 mi/sec 1 light year = 9,460,730,472,580.8 km (That is approximately 9.5 trillion kilometers or 5.9 trillionmiles!!!) The distance from the Earth to the Sun is approximately 150,000,000 kilometers, or 93,000,000 miles. So then, how many light years is it from the Earth to the Sun?

34. How Long?

35. Solar Facts • * Average distance from Earth: 93 million miles (150 million kilometers) • * Radius: 418,000 miles (696,000 kilometers) • * Mass: 1.99 x 1030 kilograms (330,000 Earth masses) • * Makeup (by mass): 74% hydrogen, 25% helium, 1% other elements • Average temperature: 5,800°Kelvin (surface), • 15,500,000 ° Kelvin (core) • * Average density: 1.41 grams per cm3 • * Volume: 1.4 x 1027 cubic meters • * Rotational period: 25 days (center) to 35 days (poles) • * Distance from center of Milky Way: 25,000 light years • * Orbital speed/period: 138 miles per second/200 million years

37. Nuclear Fusion Hydrogen to Deuterium Deuterium to Helium-3 Helium-3 to Helium

38. Galaxies Massive, gravitationally bound systems that consists of stars and stellar remnants, an interstellar medium of gas and dust, and an important but poorly-understood component tentatively dubbed dark matter. Galaxies are grouped into larger units known as clusters. Our own Milky Way Galaxy belongs to the Local Group, and contains about 45 galaxies of various size and shape.

39. Galaxy Types Types of galaxies according to the Hubble classification scheme. E = Elliptical S = Spiral SB = Barred Spiral, a type of irregular galaxy

40. Elliptical Galaxies Galaxy Messier 59 Galaxy M49a Shaped like large, 3-dimensional ellipses. Shapes range from nearly spherical to highly flattened; Size ranges from hundreds of millions to over one trillion stars.

41. Spiral Galaxies Sombrero Galaxy Consist of a flat, rotating disk of stars, gas and dust, and a central concentration of stars known as the bulge. These are surrounded by a much fainter halo of stars, many of which reside in globular clusters. Andromeda Galaxy Pinwheel Galaxy

42. Irregular Galaxies NGC 1300, a Barred Spiral Galaxy This category contains all the galaxies that do not fit into the spiral or elliptical class. It includes such types as barred spiral, lenticular, dwarf, and ring galaxies. Hoag’s Object, a Ring Galaxy Magellanic Cloud, an irregular dwarf galaxy

43. When Galaxies Collide Collisions occur when two galaxies pass directly through each other and have sufficient relative momentum not to merge. Stars within the galaxies may not actually hit one another, but the gas and dust in each galaxy will mix and can trigger a burst of star formation.

44. The Milky Way Galaxy The Milky Way, sometimes called simply the Galaxy, is the galaxy in which our Solar System is located. It is a barred spiral galaxy that is part of the Local Group of galaxies. It is one of billions of galaxies in the observable universe. The Milky Way as seen from Death Valley, 2007. This is a panoramic picture.