the In news: Moonquakes
In the news: Moonquakes
http://science.nasa.gov/headlines/y2006/15mar_moonquakes.htm?list802911
Four types of vibration
Deep 700 km below surface (tides) Vibrations (meteorites) Thermal expansion after deep freeze Shallow (20-30 km) below surface 1972-1977 (28 up to 5.5 on Richter scale)
Outline for 14 November (Tuesday)
Jupiter and Saturn
Orbit Surface Atmosphere Rings Moons
Atmospheres
gravity and escape velocity
Atmospheres
gravity and escape velocity
Atmospheres
The visible "surfaces" of Jupiter and Saturn are actually the tops of their clouds
How do we know this? The light "spots" are actually "holes" if we look in them (not with a telescope, but with a spectrometer), we see radiation that differs from the rest of the planet. That is, the sun sends out its nearly blackbody spectrum, and what we see reflected tell us about what is in the atmosphere.
The rapid rotation of the planets twists the clouds into dark belts and light zones that run parallel to the equator
The key difference between these two is ... Jupiter's rings are more disorganized. The key similarity is that they both have light and dark colored rings.
The outer layers of both planets' atmospheres show differential rotation
How do we measure rotation? On the Sun, we just watch a sunspot. The Sun is rotating and for this reason we see sunspots return to the same place with respect to our view every 27 days. Near the poles it takes up to 35 days. On Jupiter, the same thing. the equatorial regions rotate slightly faster than the polar regions. For Jupiter, the difference is a few minutes
For both Jupiter and Saturn, the polar rotation rate is nearly the same as the internal rotation rate
Atmospheres
The rapid rotation of the planets twists the clouds into dark belts and light zones that run parallel to the equator
Atmospheres
The visible "surfaces" of Jupiter and Saturn are actually the tops of their clouds
The chemical composition of Jupiter and Saturn is hard to measure. Why?
Atmospheres
The outer layers of both planets' atmospheres show differential rotation
The equatorial regions rotate slightly faster than the polar regions
Atmospheres
For both Jupiter and Saturn, the polar rotation rate is nearly the same as the internal rotation rate
Spacecraft images show remarkable activity in the clouds of Jupiter and Saturn
Storms
The colored ovals visible in the Jovian atmosphere represent gigantic storms Some, such as the Great Red Spot, are quite stable and persist for many years
Storms in Saturn's atmosphere seem to be shorter-lived
In the news: Hurricane on Saturn?
http://saturn.jpl.nasa.gov/multimedia/videos/video-details.cfm?videoID=136
vortex Hurricane-like at Saturn's south pole, where the vertical structure of the clouds is highlighted by shadows. Such a storm, with a well-developed eye ringed by towering clouds, is a phenomenon never before seen on another planet.
Both Jupiter and Saturn emit more energy than they receive from the Sun. What does this tell us?
The internal heat of Jupiter and Saturn has a major effect on the planets' atmospheres
If Jupiter and Saturn formed at the same time, which should be emitting more heat?
Saturn's atmosphere contains less helium than Jupiter's atmosphere This lower abundance may be the result of helium raining downward into the planet Helium "rainfall" may also account for Saturn's surprisingly strong heat output
Outline for 14 November (Tuesday)
Jupiter and Saturn
Orbit Surface Atmosphere Rings Moons
Saturn's rings are composed of numerous icy fragments, while Jupiter's rings are made of small rocky particles
The principal rings of Saturn are composed of numerous particles of ice and ice-coated rock ranging in size from a few micrometers to about 10 m Jupiter's faint rings are composed of a relatively small amount of small, dark, rocky particles that reflect very little light
Earth-based observations reveal three broad rings encircling Saturn
Why can't the rings be solid?
Roche limit
Images from http://en.wikipedia.org/wiki/Roche_limit
Something is Fishy
How can a planet be solid?
Saturn is circled by a system of thin, broad rings lying in the plane of the planet's equator This system is tilted away from the plane of Saturn's orbit, which causes the rings to be seen at various angl...