1 / 39

Announcements

Announcements. Online calendar has been updated – check it out Ch. 5 homework has finally posted Test 2 score have posted. If you did not have your ID, please see me after class Scores on Mastering Physics continue to be updated Expect to be fully updated by next week

lane
Download Presentation

Announcements

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Announcements Online calendar has been updated – check it out Ch. 5 homework has finally posted Test 2 score have posted. If you did not have your ID, please see me after class Scores on Mastering Physics continue to be updatedExpect to be fully updated by next week This week’s Power points and Movies will be posted online by tomorrow morning

  2. Why is Venus the hottest planet in the Solar System? A: It is the closest planet to the Sun. B: There is a lot of radioactive material in the crust. C: There is a large concentration of carbon dioxide in the atmosphere. D: The Russians left the lights on in the Venera 5 landing vehicle. E. Paris Hilton lives there. Clicker Question:

  3. Mars eccentricity = 0.093 Range in distance from Sun = 1.38 - 1.66 AU Rotation Period = 24.6 hours Orbital Period = 687 days Mass = 0.11 MEarth Radius = 0.53 REarth Density = 3.9 g/cm3 Average distance from Sun = 1.52 AU

  4. The Martian Atmosphere - 95% CO2 - Surface Pressure 0.006 that of Earth's atmosphere (thin air!) - Surface Temperature 250 K. - Dust storms sometimes envelop most of Mars, can last months. A “Reverse Runaway Greenhouse Effect”? During volcanic phase (first two billion years), thicker atmosphere, warmer surface, possibly oceans. Gradually most CO2 dissolved into surface water and combined with rocks, then atmospheric and surface water froze (creating ice caps and probable permafrost layer).

  5. Mars' Moons Phobos and Deimos Phobos: 28 x 20 km Deimos: 16 x 10 km Properties similar to asteroids. They are probably asteroids captured into orbit by Mars' gravity.

  6. From Mars, Deimos has an angular diameter of 140 arcseconds. Would colonists on Mars ever see Deimos produce a total solar eclipse? A: Yes, every day on Mars B: Yes, every new moon C: Yes, but rarely D: Never Clicker Question:

  7. The Martian Surface OlympusMons Tharsis Bulge Valles Marineris Southern Hemisphere ~5 km higher elevation than Northern, and more heavily cratered. South is like lunar highlands, surface ~4 billion years old, North like maria, ~3 billion years old. Valles Marineris - 4000 km long, up to 7 km deep. Ancient crack in crust. Reasons not clear. (Mars Global Surveyor radar data) Tharsis Bulge - highest (10 km) and youngest (2-3 billion years) region. Olympus Mons - shield volcano, highest in Solar System, 3x Everest in height. 100 km across.

  8. View From the Surface Dry, desert-like. Red => high iron content. Mars didn't differentiate as completely as Earth. Sky has butterscotch hue due to dust. Viking 1 site (1976) Sojourner robot from Pathfinder (1997)

  9. Opportunity panorama: inside Victoria Crater Deepest crater explored by far (230 feet) => apparently it was the top of an underground water table.

  10. Evidence for Past Surface Water "runoff channels" or dry rivers "outflow channels" South North teardrop "islands" in outflow channels standing water erosion in craters?

  11. Pathfinder site was an outflow channel Red arrows: rounded boulders indicating water erosion? White arrows: "conglomerate" rock, like in Earth's riverbeds? Blue arrows: sharp-edged boulders, volcanic rock?

  12. Did Mars once have a huge ocean? Long stretches along border are very even in elevation, like a coastline Ocean fed by outflow channels from higher elevation southern hemisphere?

  13. Evidence for "Permafrost" layer beneath surface "Splosh" craters suggesting liquefied ejecta.

  14. Evidence for Water on Mars Now subsurface ice Phoenix Lander (2008) Deployable arm

  15. Phoenix mission – icy soil at the poles! Phoenix analyzing scooped up dirt – was Mars ever favorable for microbial life? Organic compounds?

  16. Mars' History Smaller than Earth, Mars cooled faster. Atmosphere and surface water in first 1.5 billion years. Life? Most volcanic activity ended two billion years ago. Differentiation less complete than on Earth. No evidence for plate tectonics. Atmosphere mostly froze out into subsurface ice, polar ice caps and surface rocks.

  17. The largest mountain in our solar system is: A: Caloris Basin range on Mercury B: Gula Mons on Venus C: Mt. Everest on Earth D: Olympus Mons on Mars Clicker Question:

  18. Where is the water that once flowed on the surface of Mars? A: In the atmosphere B: In the polar caps only C: In a layer of permafrost below the surface and in the polar caps D: It was diverted to Los Angeles Clicker Question:

  19. Martian ‘Snick’ meteorite ALH84001 shows odd shaped features that are reminiscent of bacteria. General consensus is no life.

  20. Evidence for "Permafrost" layer beneath surface "Splosh" craters suggesting liquefied ejecta.

  21. Valles Marinaris flyover movie

  22. The Face on Mars Viking orbiter photos showed this:

  23. Newer, high resolution photo – Mars Global Surveyor 1998

  24. Isn’t this more disturbing???

  25. Spirit and Opportunity Rovers Scenes from “Roving Mars” (start at 15:10, skip to 20:27, skip to 26:16)

  26. The Jovian Planets Saturn (from Cassini probe) Jupiter Uranus Neptune (roughly to scale)

  27. Discoveries Jupiter and Saturn known to ancient astronomers. Uranus discovered in 1781 by William Herschel. Neptune discovered in 1845 by Johann Galle. Predicted to exist by John Adams and Urbain Leverrier because of irregularities in Uranus' orbit.

  28. Major Missions Launch Planets visited Jupiter, Saturn Jupiter, Saturn, Uranus, Neptune Jupiter Jupiter, Saturn 1977 1979 1989 1997 Voyager 1 Voyager 2 Galileo Cassini Basic Properties Mass (MEarth) Radius (REarth) Orbit semi-major axis (AU) Orbital Period (years) Jupiter Saturn Uranus Neptune 318 95 15 17 11 9.5 4 3.9 5.2 9.5 19.2 30.1 11.9 29.4 84 164 (0.001 MSun)

  29. Jupiter's Atmosphere and Bands Whiteish "zones" and brownish "belts". Infrared - traces heat in atmosphere, therefore depth Optical – colors dictated by how molecules reflect sunlight So white colors from cooler, higher clouds, brown from warmer, lower clouds. Great Red Spot – highest.

  30. Altitude 0 km defined as top of troposphere (cloud layer) (NH3) These molecules should all give white clouds. Molecules responsible for colors actually not clear! NH4SH Composition: mostly H, some He, traces of other elements (true for all Jovians). Gravity strong enough to retain even light elements. Mostly molecular. Spectroscopy of reflected sunlight reveals which molecules present.

  31. Other Jovian planets: banded structure and colors More uniform haze layer makes bands less visible. Reason: weaker gravity allows clouds to rise higher and spread out to create more uniform layer Blue/green of Uranus and blue of Neptune due to methane. Colder than Jupiter and Saturn, their ammonia has frozen and sunk lower. Methane still in gas form. It absorbs red light and reflects blue.

  32. - Zones and belts mark a convection cycle. Zones higher up than belts. • - Zones were thought to be where warm gas rises, belts where cooled gas sinks. Now less clear after Cassini, which found numerous upwelling white clouds in the dark belts. - Jupiter's rapid rotation stretches them horizontally around the entire planet. - Winds flow in opposite directions in zones vs. belts. Differences are hundreds of km/hr.

  33. Storms on Jovian Planets Jupiter's Great Red Spot: A hurricane twice the size of Earth. Has persisted for at least 340 years. Reaches highest altitudes. New storm “Oval BA”

  34. "white ovals" - may last decades "brown ovals" - only seen near 20° N latitude. Not known why. May last years or decades Neptune's Great Dark Spot: Discovered by Voyager 2 in 1989. But had disappeared by 1994 Hubble observations. About Earth-sized. Why do these storms last so long?

  35. Jupiter's Internal Structure Can't observe directly. No seismic information. Must rely on physical reasoning and connection to observable phenomena. (acts like a liquid metal, conducts electricity) Core thought to be molten or partially molten rock, maybe 25 g/cm3, and of mass about 10-15 MEarth . Other Jovians similar. Interior temperatures, pressures and densities less extreme.

  36. Rapid rotation causes Jupiter and Saturn to bulge: Gravity Gravity without rotation with rotation Jupiter and Saturn rotate every ~10 hours. Radius at equator several % larger due to bulge.

  37. Differential Rotation Rotation period is shorter closer to the equator: At equator Near poles 9h 50m 10h 14m 14h 12m 9h 56m 10h 40m 16h 30m Jupiter Saturn Uranus How do we know?

  38. Differential Rotation Rotation period is shorter closer to the equator: At equator Near poles 9h 50m 10h 14m 14h 12m 9h 56m 10h 40m 16h 30m Jupiter Saturn Uranus How do we know? Tracking storms at various latitudes, or using Spectroscopy and Doppler shift.

  39. Uranus' rotation axis is tilted by 98o Why? Unknown. Perhaps an early, grazing collision with another large body.

More Related