MondayOctober 22, 2012

(WS - Trans-Neptunian Regions

of the Solar System)

The Launch PadMonday, 10/22/12

Identify

these object

s.

Pluto and

Charon

The Launch PadMonday, 10/22/12

Does our Solar System end at

the orbit of Neptune? Explain.

AnnouncementsHappy Week Before

Assignment Currently Open

Summative or

Formative?Date Issued Date Due Date Into

GradeSpeed Final Day

Quiz 6 S1 10/5 10/5 10/26

Quiz 7 S2 10/12 10/12 10/26

WS – Comets and Meteoroids F2 10/16 10/18 10/22

WS – Dwarf Planets F3 10/18 10/22 10/24

Quiz 8 S3 10/19 10/19 11/2

Recent Events in ScienceKeck Observations Bring Weather of

Uranus Into Sharp Focus

http://www.sciencedaily.com/releases/2012/10/121017153940.htm

Read All About It! In 1986, when Voyager swept past Uranus,

the probe's portraits of the planet were "notoriously bland," disappointing scientists, yielding few new details of the planet and its atmosphere, and giving it a reputation as a

bore of the solar system.Now, however, thanks to a new technique applied at the Keck Observatory, Uranus is

coming into sharp focus through high-resolution infrared images, revealing in

incredible detail the bizarre weather of the seventh planet from the sun.

The images were released in Reno, Nev. today (Oct. 17, 2012) at a meeting of the American Astronomical Society's Division of Planetary Sciences and provide the best look to date of

Uranus's complex and enigmatic weather.

Trans-Neptunian Regions of the Solar System

There are four basic regions of our Solar System.

Remember that the Solar system is defines as the area of space under the influence of the Sun’s gravitational field, and the objects

contained therein.

The four regions of our Solar System are:

• the Planetary Region

• the Kuiper Belt

• the Oort Cloud

• the Scattered Disk

The Kuiper BeltWe have already discussed the planetary region of

our Solar System, so let’s move on to the region known as the Kuiper Belt.

The Kuiper Belt is a region of the Solar System beyond the planetary region,

extending from the orbit of Neptune (at

30 AU) to approximately 50 AU from the Sun.

The Kuiper BeltThe Kuiper Belt is similar to

the asteroid belt, although it is far larger (20 times as wide and 20 to

200 times as massive.).

Like the asteroid belt, it consists mainly of small bodies, or

remnants from the Solar System's formation. While most asteroids are

composed primarily of rock and metal, Kuiper belt objects are

composed largely of frozen volatiles (termed "ices"), such as methane, ammonia and

water.

The Kuiper BeltThe classical belt is home to at least three dwarf

planets: Pluto, Haumea, and Makemake.

Some of the planetary region’s moons, such as Neptune's Triton and Saturn‘s, are also believed to have originated in the

region.

The Kuiper BeltThousands of icy objects orbit the Sun beyond Neptune in

a region commonly called the Kuiper Belt.

Credit: NASA/Johns Hopkins University Applied Physics Laboratory

Pluto Orbit Neptune Orbit

Credit: NASA, ESA, and A. Field (STScI)

Comparison of the Sizes of Some Kuiper Belt Objects to Earth

Figure 22.31

The Oort CloudThe Oort Cloud is a hypothesized spherical cloud of

comets which may lie 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 the Scattered Disc, the

other two reservoirs of trans-Neptunian

objects, are less than one thousandth of the

Oort Cloud's distance..

The Oort CloudThe outer limit of the Oort

Cloud defines the cosmographical boundary of

the Solar System and the region of the Sun's

gravitational dominance.

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.

The Oort Cloud

The Oort Cloud

The Oort CloudAlthough 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.

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.

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.

A View From The Oort Cloud

The Oort Cloud

The Scattered DiskThe scattered disc 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.

The Scattered DiskThese extreme orbits are believed to be the result of gravitational

"scattering" by the gas giants, and the objects continue to be subject to perturbation by the planet Neptune. While the

nearest distance to the Sun approached by scattered objects is about 30–35 AU, their orbits can extend well beyond 100 AU

This illustration shows two planets orbiting about a common star. The outer planet takes more time to complete an orbit than the inner

planet, so once per orbit the inner planet overtakes the outer planet. When the planets

are at a, the outer planet exerts a gravitational perturbation that accelerates the inner planet, advancing the body ahead of its normal path. When the planets reach b, the

reverse is true and the inner planet is decelerated. This perturbing influence is what

led to the discovery of the planet Neptune.

The Scattered DiskThis makes scattered objects among the most distant and cold objects in the Solar System. The innermost portion of the scattered disc overlaps with a torus-shaped region of orbiting objects known as the Kuiper belt, but its outer limits reach much farther away from the Sun and farther above and below the ecliptic than the belt

proper.

Worksheet

Trans-Neptunian Regions of the Solar System