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