1. Lesson 19 The Jovian Planets

2. The Planets So Far Four Inner Planets – All found Inside of the asteroid belt – Mercury, Venus, Earth, Mars Four Outer Planets – All found outside of the asteroid belt – Jupiter, Saturn, Uranus, Neptune

3. The Planets So Far Four Inner Planets – All found Inside of the asteroid belt – Mercury, Venus, Earth, Mars Four Outer Planets – All found outside of the asteroid belt – Jupiter, Saturn, Uranus, Neptune

4. The Planets So Far Four Inner Planets – All found Inside of the asteroid belt – Mercury, Venus, Earth, Mars Four Outer Planets – All found outside of the asteroid belt – Jupiter, Saturn, Uranus, Neptune

5. The Planets So Far The outer planets are divided into two sub-categories: The Jovians – Jupiter and Saturn The Ice Giants – Uranus and Neptune

6. The Planets So Far Four Inner Planets – All found Inside of the asteroid belt – Mercury, Venus, Earth, Mars Four Outer Planets – All found outside of the asteroid belt – Jupiter, Saturn, Uranus, Neptune

7. The Jovians Are mostly gases (H, He, H 2 O, CH 4, NH 3 ); the rest = ice + rock Have no solid surface: gases --> solid at high pressure Have ring systems and many moons

8. The Planets So Far Four Inner Planets – All found Inside of the asteroid belt – Mercury, Venus, Earth, Mars Four Outer Planets – All found outside of the asteroid belt – Jupiter, Saturn, Uranus, Neptune 79 ceti b – an exoplanet the size of Saturn

9. The Jovians Form faster, and in a different way, compared to terrestrial planets: large enough to accumulate gas directly from the solar nebula They are far from the Sun (in the case of the solar system) So far, most extrasolar planets are gas giants, but they are all close to their parent star (why?)

10. The Planets So Far Four Inner Planets – All found Inside of the asteroid belt – Mercury, Venus, Earth, Mars Four Outer Planets – All found outside of the asteroid belt – Jupiter, Saturn, Uranus, Neptune Some exoplanets…

11. Jupiter Facts Jupiter’s diameter is 10x that of the earth’s Jupiter’s mass is 300x that of the earth’s Jupiter’s gravity is 2.36x that of the earth’s – If you weigh 180 lbs on earth’s surface, at the cloudtops on Jupiter you would weigh 426 lbs. Jupiter orbits at roughly 5 AU.

12. The Planets So Far Four Inner Planets – All found Inside of the asteroid belt – Mercury, Venus, Earth, Mars Four Outer Planets – All found outside of the asteroid belt – Jupiter, Saturn, Uranus, Neptune

13. Jupiter Facts All we can see on Jupiter are clouds – These clouds are in bright zones and dark belts – These are banded due to the rapid rotation of Jupiter. Jupiter rotates in roughly 10 hours, though each band rotates at different speeds. As you descend into Jupiter, the atmosphere transitions directly from gas to supercritical liquid, meaning that there is no “surface” on Jupiter.

14. The Planets So Far Four Inner Planets – All found Inside of the asteroid belt – Mercury, Venus, Earth, Mars Four Outer Planets – All found outside of the asteroid belt – Jupiter, Saturn, Uranus, Neptune

15. Jupiter Facts Jupiter should be purely white. – Its clouds are primarily water and ammonia, both of which form white clouds… They aren’t due to organic compounds that stain the cloud layers.

16. The Planets So Far Four Inner Planets – All found Inside of the asteroid belt – Mercury, Venus, Earth, Mars Four Outer Planets – All found outside of the asteroid belt – Jupiter, Saturn, Uranus, Neptune Three years ago, one entire band vanished….

17. Jupiter Facts Jupiter gives off more energy than it recieves from the sun. – Roughly 1.67x more than it gets. – Possibly due to heat generated when the planet formed – Or it could be due to radioactive decay That’s the process that keeps the earth nice and toasty!

18. The Planets So Far Four Inner Planets – All found Inside of the asteroid belt – Mercury, Venus, Earth, Mars Four Outer Planets – All found outside of the asteroid belt – Jupiter, Saturn, Uranus, Neptune

19. Jupiter Facts The winds that give Jupiter its storms and bands run deep…as far down as we can measure, in fact This is due to the huge amount of energy from the core If Jupiter was about 80x heavier, it would have become a dwarf star.

20. The Planets So Far Four Inner Planets – All found Inside of the asteroid belt – Mercury, Venus, Earth, Mars Four Outer Planets – All found outside of the asteroid belt – Jupiter, Saturn, Uranus, Neptune Taken by Cassini:

21. Jupiter Observations Pioneer 10 flew by Jupiter on December 1, 1973. Pioneer 11 flew by Jupiter on December 1, 1974. Voyager 1 flew by Jupiter on March 5, 1979. Voyager 2 flew by Jupiter on July 9, 1979. Ulysses, studies the poles of the Sun. Jupiter flyby February 8, 1992. Galileo Orbiter/Atmospheric Probe - 1995 – 2003. Cassini – flew by December 30 th, 2000 New Horizons – flew by February 28 th, 2007

22. Jupiter Observations Galileo atmospheric probe of Jupiter’s atmosphere - December 7 th, 1995 Depth of measurements ~200 km

23. The Planets So Far Four Inner Planets – All found Inside of the asteroid belt – Mercury, Venus, Earth, Mars Four Outer Planets – All found outside of the asteroid belt – Jupiter, Saturn, Uranus, Neptune Taken by Cassini:

24. Jupiter Observations Upcoming: Juno – launched in 2011, arrives in 2016

25. Jupiter, with its dark belts (where gases move down into the interior), and light zones (where gases move upwards). Also visible is the Great Red Spot, a huge hurricane that has been observed from Earth for ~ 350 years, and other more or less temporary surface features

26. The Planets So Far Four Inner Planets – All found Inside of the asteroid belt – Mercury, Venus, Earth, Mars Four Outer Planets – All found outside of the asteroid belt – Jupiter, Saturn, Uranus, Neptune Belt versus Zone

27. The Planets So Far Four Inner Planets – All found Inside of the asteroid belt – Mercury, Venus, Earth, Mars Four Outer Planets – All found outside of the asteroid belt – Jupiter, Saturn, Uranus, Neptune Jupiter Cloud Structure

28. The Planets So Far Four Inner Planets – All found Inside of the asteroid belt – Mercury, Venus, Earth, Mars Four Outer Planets – All found outside of the asteroid belt – Jupiter, Saturn, Uranus, Neptune Jupiter Cloud Structure

29. Jupiter Observations Some features in Jupiter’s dynamic atmosphere change just like weather on Earth. The 2 images are 10 hours apart.

30. Jupiter Observations Winds at top of atmosphere – travel in opposite directions at different latitudes

31. The great red spot

32. A giant cyclone. Twice as big as earth. Existed for AT LEAST 350 years.

33. The white spots Other cyclones (usually white) also exist, but none more than a few months or years

34. The rings Voyager discovered rings around jupiter in 1978

35. The rings Second only to Saturn's rings in size or complexity 182,000 km Moons inside ring system

36. Strength of the magnetic fields of the planets. Jupiter has by far the strongest magnetic field, because its interior is made of an excellent electric conductor (liquid metallic hydrogen), and because the planet rotates around its axis faster than any other (once in 10 hours). A strong refrig- erator magnet has a magnetic field of 100 gauss Object Strength of field (gauss) Inclination of magnetic axis relative to rotation axis (degrees) Mercury0.003<10 Earth0.3512 Jupiter4.22511 Saturn0.20.7 Uranus0.1 – 1.160 Neptune0.359 The strengths are given at the surfaces of mercury and earth, and at the cloud tops of the outer planets. Venus and mars have no detectable magnetic fields.

37. The Planets So Far Four Inner Planets – All found Inside of the asteroid belt – Mercury, Venus, Earth, Mars Four Outer Planets – All found outside of the asteroid belt – Jupiter, Saturn, Uranus, Neptune Aurora at poles of Jupiter – show that Jupiter has a strong magnetic field

38. Jupiter summary

39. Saturn: The ringed planet

40. Saturn was the Roman counterpart of the greek titan Kronos, father of gods like Jupiter (Zeus). He was also the god of agriculture. The ancient symbol of Saturn resembles a sickle. It is also the alchemical symbol for the element lead. Saturday was named after Saturn (dies Saturni, or day of Saturn).

41. Galileo Galilei Galileo first observed the rings of Saturn through his telescope in 1610. He first described them as “handles”. Later, because of the aberrations in his telescope, he thought they were blurred twin moons.

42. Christiaan Huygens Making his own telescope of far better quality than Galileo’s, the Dutch scientist Christiaan Huygens discovered in 1655 the first, and largest, moon of Saturn: Titan. Now a popular scientific tool, telescopes can be used to observe the rings of Saturn. The image below shows drawings of Saturn’s rings, made by several authors, from Galileo, Scheiner, Hevelius and Huygens, among others.

43. Christiaan Huygens In 1659, Huygens became the first to correctly interpret what Galileo’s mysterious “handles” were – a ring system. He also provided the first theory for the different shapes of the rings, as seen from Earth.

44. Giovanni Cassini Giovanni Cassini was contemporary to Huygens. In 1665 he discovered a gap in the rings of Saturn. It is still called the Cassini Division. He discovered four moons of Saturn: Iapetus, Rhea, Dione, and Thetys.

45. Voyagers 1 and 2 Voyagers 1 and 2 are spacecraft which have studied Saturn and returned incredible images. False color image from Voyager 2 (ultraviolet, violet and green), taken at a distance of 43 million km, in July 1981. Voyager 1 photo taken at a distance of 5.3 million km, in November 1980.

46. Multi-wavelength Saturn In September 2003, the Hubble Space Telescope took images of Saturn in ultraviolet, visible, and infrared light: Ultraviolet Infrared Visible

47. Cassini/Huygens On the 1 July 2004, the NASA/ESA mission Cassini/Huygens reached Saturn’s orbit, becoming the first “visitor” to Saturn since Voyager 2. Huygens was the European Space Agency (ESA) lander, which became the first man-made object to ever land on another moon of the Solar System – Titan.

48. The size of Saturn The planet Saturn is so large that it would fit neatly between the Earth and Moon:

49. Saturn’s inner layers Broken up into Four layers: Mantle (composed of water, ammonia, and methane ices) Molecular hydrogen Metallic hydrogen Rocky core

50. More Facts Saturn contains the most hydrogen of any of the planets That makes it the least dense It would float in water if there was an ocean big enough

51. More Facts Saturn rotates so fast that it has the largest equatorial bulge of any planet – 7000 miles … roughly 10% of its total diameter. Its rings are completely separate from the rest of Saturn The total mass of the rings are roughly equivalent to the moon Mimas. The rings stem from a medium sized moon being torn apart due to tidal friction.

52. Storms in Saturn In the South Pole of Saturn there are several vortexes, which form rings within rings. These are “locked” in the Pole. One of the most curious storms is in the North Pole, a hexagon shaped storm, revealed in this infrared image from Cassini. It is a clearing in the clouds, which extends deep below the visible clouds (about 75 km in depth).

53. Storms in Saturn Between February and March 2004, before its arrival at Saturn, Cassini observed the merger of two storms. The top four frames span 26 days, while the bottom four span only four days.

54. Aurorae Saturn has a magnetosphere similar to the Earth, which also reacts with solar activity. One of the most beautiful of these interactions are the aurorae, visible in ultraviolet in these images.

55. Ring features The rings of Saturn are the most prominent and distinctive feature of this planet. The image above is a mosaic of 45 different images, taken by the Cassini spacecraft on November 2008, and shows their main sections. C ring 17500 km B ring 25 580 km A ring 14 580 km Cassini division 65 700 km F ring

56. Multiple Rings! Encke GapCassini Division E Ring extends to 7.5 Saturn radii from cloud top

57. Ring features Spokes are dark patches seen in the rings, and are thought to be dust particles which scatter sunlight. Depending on the observing angle, they can appear darker (low angles, image below), or brighter (high angles) than the rings. The rings are formed by elongated clumps of ice, continuously forming, only dispersing when they bump into each other. The ice in the clumps rarely crashes, rather moving from one clump to the other.

58. Saturn summary