The Sun: Size, Structure, and Solar System Models

1. Ch- 26 & 27

2. The Sun • Diameter • 1,400,000 km • more than 3 X’s the distance from Earth to the moon • Size • more than 1,000,000 Earth’s would fit in it • an average sized star • Composition • gas & plasma • Energy • Fusion • combining nuclei of elements • E=MC2 • Matter can be converted into energy • hydrogen into helium

3. Layers of The Sun

4. Layers of the Sun • Core • hydrogen and helium • Fuel • Plasma • 100 X’s as dense as water • 15,600,000 degrees C • Radiative zone • Plasma • 2,000,000 – 8,000,000 C • Convection zone • plasma rises and falls in convection currents • carries energy to the surface where it is given off • Photosphere • visible layer • 6,000 C

5. Layers of the Sun’s Atmosphere • Chromosphere • inner layer • 20,000 C • hydrogen emits light • solar prominences • thick clouds that extends thousands of kilometers • Corona • thin outer atmosphere • dim • 1,000,000 – 3,000,000 C

6. Other Solar Features • solar wind • given off by the corona • electrically charged particles • move about 450 km/s • deflected by Earth’s magnetic field • a.       auroras (northern lights) • Sunspots • dark areas that move left to right • shows sun is rotating at different speeds • hot and bright but surrounding area is hotter and brighter causing the dimness • strong magnetic field

7. Models of the Solar System • geocentric (Ptolemy) • earth at the center • stars are hole in a “bubble” that covers us • bright light behind it • could not explain retrograde motion • Heliocentric (Copernicus) • sun at the center • planets revolve around it • explains retrograde motion • orbital speeds differ throughout the year • us fast them slow • Retrograde

8. Planetary Motion • Brahe • Did research on motion • kepler (assistant) • noted that orbits were not round (elliptical) • Kepler’s three laws of planetary motion • 1st law • planets orbits are round with two foci not one like a circle • 2nd law • equal area law in equal time • do not travel a constant speed • closer equals faster

9. More Motion • 3rd law • harmonic law • p2=d3 • the square of the time it takes to travel in one orbit is equal to the cube of the mean distance from the sun • longer orbits = greater dist. • Greater dist = slower • Newton • Explained with gravity why • speeds change • orbits

10. Planets • Inner planets • mercury, venus, earth, mars • rocky bodies • iron core • outer planets • Jupiter, Saturn, Uranus, Neptune • gaseous giants • Rings • gas outer layer, liquid inner

11. Mercury • Revolution • 88 Earth days (shortest) • Rotation • 59 days • Diameter • 1/3 Earths • Temperature • Extreme • 450 C daytime –170 C night • closeness to sun • little to no atmosphere to hold heat • Surface • cratered surface • Impacts • do not burn up b/c of little to no atmosphere • cliffs • due to shrinkage • Gravity • 2/5 earth • cannot keep things in solar winds blow them away • distance from sun • 58 million km

12. Venus • distance from sun • 108 mill km • size mass gravity • about same as earth • Rotation • east to west • 243 days • Revolution • 224.7 days • Temp • 470 C • greenhouse effect • hottest in solar system • Atmosphere • thick gasses • carbon dioxide and sulfuric acid • allows in 2% of light • 90 times air pressure of earth • 300 km/hr upper level winds

13. Earth • distance from the sun • 150 mill km • the rest, well you know

14. Mars • Distance from the sun • 228 mill km • Rotation • About 24 ½ hrs • Revolution • 687 days • Size • just over ½ diameter of Earth • Gravity • about 2/5 Earths • Temperature • summer • up to 27 C • winter • down to –125 C • Atmosphere • Thin • gravity holds in some b/c solar wind not as strong • mostly carbon dioxide • air pressure 1% of Earth’s

15. Features of Mars • North • flat and smooth • Volcanic • Olympus mons • Largest volcano in the solar system • Over 500 km wide • 26 km high • South • Rugged • cratered • Channels • valles marineris • a canyon as long as the US • mars may have had water could be stored below the surface • water cannot exist there now it would boil, freeze, and evaporate all at the same time

16. Special Features • Axis is tilted about the same as Earths • Seasons • Ice caps • North • could be water • South • frozen carbon dioxide • very strong wind storms • diff in temp between poles and equator • sometimes cover entire planet • crust thickness • north 35 km • south 80 km • life on Mars • with the conditions of the past (atmosphere, liquid, etc.) it could have been possible

17. Moons Of Mars • Deimos • Phobos • Doomed orbit • 50 mill yrs

18. Jupiter • Rotation • 9hr 50 ½ min • Fastest • Revolution • 11.86 years • Distance • 778.3 mill km • Size • more than 11 X’s diameter of Earth • largest • Mass • more than twice • the total mass of all others combined

19. Specials of Jupiter • largest magnetic field • Auroras • radiates twice as much heat as it brings in • heat from original formation and gravity contraction • the great red spot • calm area in amongst turbulent area • Winds • colored bands that travel in opposite directions • 100 – 400 km/hr • Rings (all have them) • independent particles in their own orbits • inside the orbit of the moons • orbit over equator • Three layers • Mostly H & He

20. Moons of Jupiter • At least 28 of them (Galilean moons) • IO • active volcanoes • geologically active • heat caused by tidal forces of pull from Jupiter • atmosphere • Europa • has atmosphere • covered by a shell of frozen water • 100 km tick • smooth surface • possible geologic activity • possible ocean of water 100 km deep under surface • possible life from subsurface vents like on Earth

21. Moons of Jupiter • Ganymede • largest in solar • system • possibly salty ocean under surface • Callisto • most cratered objects • possibly oldest in solar system

22. Saturn • Distance • 1427 mill km • Rotation • 10 hr 14 min • Revolution • 29.46 years • Diameter • less than 10 times Earth • Surface • colored bands • Special • Density • floats in water • radiates more energy than it receives • Moons • at least 24 • Titan • Heaviest atmosphere of all the moons • 1.5 times earth

23. Uranus • Distance • 2869 mill km • Rotation • 17 hr 14 min • Rolls • possible collision with Earth sized object • Revolution • 84 yrs • Diameter • A little more than 4 times the diameter of Earth • Temp •   –200 C • Special • 370 times less sunlight • magnetic field is not tipped • Moons • at least 21 • Color • bluish • due to methane gas

24. Neptune • Distance • 4496 mill km • Rotation • 16 hr • Revolution • 165 yrs • Diameter • about the same as Uranus • Temp •   –225 C (coldest) • Special • magnetic field is tipped compared to its axis of rotation • Color • bluish due to methane • Winds • 2000 km/hr • sometimes ninth planet • switches with Pluto • feb 11 1999

25. Other objects • comets and TNO’s (trans neptunian objects) • orbit around the sun • most stay too far out to see • Parts • Nucleus • solid ice and dust • Coma • gas cloud • melting comet • points away from the sun • solar wind • Asteroids • in orbit around the sun • Meteoroid • same but not in orbit • Meteor • same but comes in contact with our atmosphere • Meteorite • Same but hits the planet