Download The NEW Solar System

Name__________________________________________Date______________Period________
The NEW Solar System
Beyond Pluto
Kathy Svitil
Discover, November 2004
Meet the New Planets
Time, October 24, 2005
Michael Lemonick
Introduction
Since 1930 when Clyde Tombaugh discovered Pluto,
we have been taught the solar system had nine planets. For
better or for worse though, it might finally be time to throw this
model out in favor of a more complex yet more accurate view
of the solar system. As our astronomical technology continues
to develop by leaps and bounds, the decision of what exactly is
a planet and what is not begins to blur in light of recent
discoveries. Combined with confirmation of places like the
Oort Cloud and Kuiper Belt, our Sun’s neighborhood has now
become much more crowded.
1.
Provide a basic comparison of the Kuiper Belt and the Oort Cloud in terms of distance
from the sun, composition and astronomical significance.
2.
What are two frequent theories used to explain the often eccentric orbits of large outer
system objects (including Pluto)?
3.
Modern astronomical telescopes are able to peer billions of light years into the “past” and
across the universe. Why is it, then, so difficult to find such bodies as Sedna in our own
solar system?
Part 2: Where do all these objects go?
Somewhere along the line, you should have noticed that many (if not the vast majority) of
the smaller objects found in the solar system have wildly eccentric orbits. In addition, its seems
possible that early in the Sun’s own life, one or more partner stars may have been near enough to
cause gravitational problems for our solar system. Today, these objects are no longer ignored
like they were in the past due largely to the impact of Comet Shoemaker-Levy 9 in late July of
1994.
SL-9 was a short period comet (only discovered in 1993) with an orbital period of two
years that was centered around the planet Jupiter rather than the Sun. However, the Sun’s
gravitational influences caused enough wobble in the comet’s orbit that astronomers were able to
predict, observe and analyze a collision between a comet and a planet for the first time in modern
history. With the entire world watching, SL-9 broke apart into a string of 21 fragments and, one
after the other, crashed into Jupiter’s atmosphere at speeds over 60 km/sec. and releasing energy
on the order of 200,000 megatons of TNT each.
So, what was the effect on Earth? It scared us to death! Scientifically and politically,
attention was suddenly drawn to the very real possibility that Earth could be struck by one of
these wildly spinning rocks and end civilization as we know it. Collectively, these objects are
known as NEO’s or Near Earth Objects and they represent a huge number of potentially
dangerous rocks and iceballs with new ones discovered almost every day. For this part of the
assignment, go to the site http://neo.jpl.nasa.gov/neo/ as a start point and begin your research
there. (Information on SL-9 can be found at http://www2.jpl.nasa.gov/sl9/ if you wish to see
more on this historic event.)
1.
First, define the following important terms:
Semi-major axis
Ephemerides (orbital elements)
Astrometry
Perihelion/aphelion
Periodicity
2.
Now that you have some of the terminology down,, click on <orbit diagram> from the
main NEO page at the JPL and type in “Halley.” Once you have done this the search
engine will find several possibilities for unique objects...you want 1P/Halley (Halley’s
Comet). The screen will now show the ephemeride data for the famous comet. Answer
the following questions about the comet’s orbital characteristics. Do not forget units in
your answers and where appropriate, include answers to 3 decimal places. Note: By
clicking on <orbit diagram> from the data screen, a interactive 3D diagram of the comet’s
orbit can be seen.
Precisely how often does Halley’s Comet return?
__________
What is the maximum and minimum distance
the comet passes with regard to the sun?
__________
What is the distance of the comet’s semi-major axis?
__________
Given the orbital information above, what is the most likely
source (location) of Halley’s Comet?
____________________
3.
NEOs are catalogued according to specific aspects of their orbits. Consider each of the
following types of SSSBs (small solar system bodies) and define them according to their
main orbital characteristics. Note that multiple sources may be needed to describe all
object types. Note: Clicking on <NEO Basics> from the main NEO page will yield most
of the answers.
Object Type
Long Period Comet
Short Period Comet
(NEC)
Near Earth Asteroid
(NEA)
Atira asteroid
Aten asteroid
Apollo asteroid
Amor asteroid
Trojan asteroid
Centaur asteroid
Potentially hazardous
asteroid (PHA)
Orbital Characteristics
periodicity (p) > 200 yrs., aphelion (Q) much > Neptune
4.
The purpose of this portion of the lab is to familiarize yourself with the different types of
NEOs both by considering their orbital information and a visual representation of their
orbit. Ultimately, you will be expected to classify a NEO given its ephemeride data or an
orbital diagram. For purposes of the lab, use either the <Orbit Diagrams> link or <Close
Approaches> link to look at a minimum of five different NEOs or other SSSBs. When
you are finished, you will be given another example to serve as a quiz grade.
To add a level of “intrigue” to the object choices, consider an Internet search objects that
have made the news during their close approaches of even objects that have struck Earth.
This type of search can be done for almost any SSSB type whether it has the potential to
strike the Earth or not. Other events of historical importance can be charted from
information provided in Planets 5 notes.
For example, consider the article at http://neo.jpl.nasa.gov/news/news166.html and than
plot the object’s orbit to see the close approach outlined in the article.
Object Name:
Classification:
Perihelion/Aphelion (AU):
Periodicity (Yr. or Days):
Semi-major Axis:
Next Closest Approach to Earth (Date/Distance)*:
*Software can plot up to 2200 A.D.
Object Name:
Classification:
Perihelion/Aphelion (AU):
Periodicity (Yr. or Days):
Semi-major Axis:
Next Closest Approach to Earth (Date/Distance)*:
*Software can plot up to 2200 A.D.
Object Name:
Classification:
Perihelion/Aphelion (AU):
Periodicity (Yr. or Days):
Semi-major Axis:
Next Closest Approach to Earth (Date/Distance)*:
*Software can plot up to 2200 A.D.
Object Name:
Classification:
Perihelion/Aphelion (AU):
Periodicity (Yr. or Days):
Semi-major Axis:
Next Closest Approach to Earth (Date/Distance)*:
*Software can plot up to 2200 A.D.
Object Name:
Classification:
Perihelion/Aphelion (AU):
Periodicity (Yr. or Days):
Semi-major Axis:
Next Closest Approach to Earth (Date/Distance)*:
*Software can plot up to 2200 A.D.