1. Friday October 14, 2011 (Quiz 6; The Oort Cloud)

2. The Launch Pad Friday, 10/14/11 What is the Kuiper Belt? The Kuiper Belt is a disk-shaped region beyond the orbit of Neptune that contains masses of ice and icy rock believed to be the source of comets with orbital periods of less than 200 years.

3. The Launch Pad Friday, 10/14/11 What is the Oort Cloud? The Oort Cloud is a hypothesized spherical cloud of comets which may extend to roughly 50,000 AU, or nearly a light-year, from the Sun. This places the cloud at nearly a quarter of the distance to Proxima Centauri, the nearest star to the Sun. The Kuiper belt and scattered disc, the other two reservoirs of trans- Neptunian objects, are less than one thousandth of the Oort cloud's distance. The outer limit of the Oort cloud defines the cosmographical boundary of the Solar System and the region of the Sun's gravitational dominance.

4. The Launch Pad Friday, 10/14/11 What is the Scattered Disk? The Scattered Disk is a distant region of the Solar System that is sparsely populated by icy dwarf planets, a subset of the broader family of trans-Neptunian objects. The scattered disc objects (SDOs) have orbital eccentricities ranging as high as 0.8, inclinations as high as 40°, and perihelia greater than 30 astronomical units.

5. Assignment Currently Open Summative or Formative Date Issued Date Due Date Into Grade Speed Last Day Quiz 5 Summative 10/7 10/1110/25 Lab - Comparing the Terrestrial and Jovian Planets Formative10/1110/13 WS - Trans- Neptunian Regions of the Solar System Formative10/1310/17

6. Latest News http://www.space.com/13276-sun-fires-furious- avalanche.html?utm_source=feedburner&utm_medium=feed&utm_campaign=Feed%3A +spaceheadlines+%28SPACE.com+Headline+Feed%29&utm_content=Google+Feedfet cher During a solar eruption, a growing mountain of plasma culminated in an avalanche-like fall back to the surface. NASA's Solar Dynamics Observatory was on hand to record the event.

7. Quiz 6

8. The Oort Cloud The Oort cloud is thought to comprise two separate regions: a spherical outer Oort cloud and a disc-shaped inner Oort cloud, or Hills cloud. Objects in the Oort cloud are largely composed of ices, such as water, ammonia, and methane. Astronomers believe that the matter comprising the Oort cloud formed closer to the Sun and was scattered far out into space by the gravitational effects of the giant planets early in the Solar System's evolution.

9. The Oort Cloud Although no confirmed direct observations of the Oort cloud have been made, astronomers believe that it is the source of all long-period and Halley-type comets entering the inner Solar System and many of the Centaurs and Jupiter-family comets as well. The outer Oort cloud is only loosely bound to the Solar System, and thus is easily affected by the gravitational pull both of passing stars and of the Milky Way Galaxy itself. These forces occasionally dislodge comets from their orbits within the cloud and send them towards the inner Solar System.

10. The Oort Cloud Based on their orbits, most of the short-period comets may come from the scattered disc, but some may still have originated from the Oort cloud. Although the Kuiper belt and the farther scattered disc have been observed and mapped, only four currently known trans-Neptunian objects (90377 Sedna, 2000 CR105, 2006 SQ372 and 2008 KV42 ) are considered possible members of the inner Oort cloud.

11. Continue Worksheet Trans-Neptunian Regions of the Solar System