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http:// www.youtube.com/watch?v=BYcTN8H7ysw. Good Planets are hard to find. Classifying Objects in the Solar System. Activity 1: Sorting the Solar System. Link to directions: http://www.astrosociety.org/education/publications/tnl/70/pluto.html#10 Link to images: - PowerPoint PPT Presentation
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http://www.youtube.com/watch?v=BYcTN8H7ysw
Good Planets are hard to find
Classifying Objects in the Solar System
Link to directions:http://www.astrosociety.org/education/publications/tnl/70/pluto.html#10Link to images:http://www.astrosociety.org/education/publications/tnl/70/solarsystemcards.pdf
ACTIVITY 1: SORTING
THE SOLAR SYSTEM
SURVEYDo you think Pluto should be a planet?
YES NO
Image: Hubble Space Telescope
Read this article
Hubble Observations of Ceres and Pluto• http://www.astrosociety.org/education/public
ations/tnl/70/pluto.html
There is a handout that goes with this article titled: Hubble Observations of Ceres and Pluto. You can find it in the folder titled Classifying Objects in the Solar System
The Original Definition of a Planet
Planet is derived from the
Greek word αστήρ πλανήτης(Wandering Star)
This was anything that wandered in the sky differently that the
fixed stars
How many planets are there?Geocentric Model (Early Greek)
Total Number of Planets = 7
Heliocentric Model (1550)Total number of Planets = 6
Due to Reclassification of Earth, Moon and Sun
This was all that could be seen by the unaided eye.
Then Uranus was discovered (1781)Total Number of Planets = 7
Then Astraea was discovered (1845)
Number of planets = 12
At this point the definition for planet is
still “Wandering Star”.
Moon diameter compared to the first 10 asteroids
to be discovered
Next came Neptune (1846)
Total number of planets = 13
Reclassification of 1851
• 1851 – 15 asteroids • A minor planet is an astronomical object in direct orbit
around the Sun that is neither a dominant planet nor originally classified as a comet.
• Minor planets can be dwarf planets, asteroids, trojans, centaurs, Kuiper belt objects, and other trans-Neptunian objects.[1]
• The first minor planet discovered was Ceres in 1801 (although from the time of its discovery until 1851 it was considered to be a true planet).
• The orbits of more than 570,000 objects have been archived at the Minor Planet Center.[2]
How are the planets spaced out?
Use your Pocket Solar System to roughly describe how
the planets in our solar system are spaced out?
Does the spacing seem to follow a pattern?
Just worth a note: Titus-Bode Law
What is a Planet???
Video (4:45 minutes)http://www.universetoday.com/13573/why-pluto-is-no-longer-a-planet/
Why Pluto is No Longer a Planet?
International Astronomical Union (IAU)
• Planets
• Dwarf Planets
• Small Solar System Bodies
RESOLUTION B5
Ceres and Pluto: Dwarf Planets as a New Way of Thinking
about an Old Solar SystemActivity Link:
DefinitionA planet is a celestial body that
1. Is in orbit around the Sun (or other star if speaking about exoplanets)
2. Has sufficient mass for its self-gravity to overcome rigid body forces so that it assumes a hydrostatic equilibrium
shape (round)3. Has cleared the
neighborhood around its orbit.
4. Is NOT a satellite
Examples
Planets ~ There are 8
DefinitionA dwarf planet is a celestial body that1. Is in orbit around the Sun2. Has sufficient mass for its self-
gravity to overcome rigid body forces so that it assumes a hydrostatic equilibrium shape
3. Has NOT cleared the neighborhood around its orbit
4. Is NOT a satellite
Examples: Ceres, Pluto, Eris
Dwarf Planets
Click the image to go to Mike Brown’s Dwarf planet page
Notable Dwarfs
Eris by Hubble Eris Orbit
Eris Orbit Eccentricity and Inclination
Eris Discovery (3 frames over 3 hours)
Notable Dwarfs
Haumea Sedna
DefinitionAn asteroid is a celestial body that:
1. Orbits the Sun inside the orbit of Jupiter
2. DOES NOT have sufficient mass for its self-gravity to overcome rigid body forces so that it assumes a hydrostatic equilibrium shape (IT IS NOT ROUND)
3. HAS NOT cleared the neighborhood around its orbit
4. IS NOT a satellite
Examples
Asteroids
Comparison of Astroids
Mars and asteroids: size comparisons
Click on the image to visit the NEAR mission webpage
Click on the image to visit the DAWN mission website
TNO’s are
any objects in the Solar System that orbits the Sun at
a greater average distance than Neptune.
Trans-Neptunian Objects (TNO’s)
A Plutoid (or ice dwarf) is 1. trans-Neptunian object 2. dwarf planet: that is, a
body orbiting beyond Neptune that is large enough to be rounded in shape.
Plutoids
Comets
Stardust
Click on the Image to link to the Deep Impact mission page
Definition • All other objects, except
satellites, orbiting the Sun
Examples• Most asteroids• Most Trans-Neptunian
Objects (TNO’s)• Comets• Other small bodies
Small Solar System Bodies
Pluto’s changing landscape• http
://hubblesite.org/newscenter/archive/releases/2010/06/video/a/
Pluto is:1. Dwarf Planet2. Kuiper Belt Object3. Trans-Neptunian Object4. Plutoid
Link here to PlutoToday.com http://www.plutotoday.com/
So What is Pluto?
Pluto’s fifth moon!
Click on the image to view a short video of the motion of the moons.
Click on the image to visit the NEW HORIZONS mission webpage
Originally You thought a Planet must have…
Atmospheres
Magnetic Fields
Moons
CoreLocation
OrbitsSize or Shape
GRAVITY
SURFACELAYERS WATER
Use the Internet to Research
Earth Ceres Vesta Pluto
1. www.nineplanets.org2. http://ssd.jpl.nasa.gov/
One Comparison
Earth has a relatively high density compared to the other three objects
The Earth is a planet and the other three are not, maybe density should be considered when classifying
planets/non planets.Question:
How does density affect the other characteristics of a planet?
Earth Ceres Vesta PlutoDensity (g/ 5.5 2.0 2.4 2.0
𝑫𝒆𝒏𝒔𝒊𝒕𝒚=𝑴𝒂𝒔𝒔
𝑽𝒐𝒍𝒖𝒎𝒆
Should Pluto be a Planet???
Conclusions
The International Astronomical Union has chosen one characteristic (the extent to which a body has
cleared its orbital neighborhood of other bodies) as the distinguishing characteristic of a planet versus a
dwarf planet, there are many other characteristics to consider.
Conclusions
Many planetary scientists would rather see a definition that focused more on characteristics of the body itself rather than where it is or what is near it.
The more that we learn about our solar system, the more our classification schemes are challenged to include
new discoveries.
New Horizons
IBEXNEAR
Neil Degrasse Tyson on Pluto
New York Public Radio (5:10 minutes)http://www.youtube.com/watch?v=4Rwe54vtvUA
PBS Movie (The Pluto Files 52:52 minutes)http://www.pbs.org/wgbh/nova/space/pluto-files.html
Allen Stern’s thoughts on Pluto (Planetary Scientist)
Nova Podcast (6:30 minutes)• http://
www.pbs.org/wgbh/nova/space/defense-pluto.html
Conclusion for Pluto – NOT A PLANET, NOT EVEN THE LARGEST OF THE DWARF PLANETS, BUT SITS A CLOSE SECOND!
Mike Brown – CalTech Astrophysicist
http://www.youtube.com/watch?v=C9pXpXAl8m8&feature=related
Facts and QuizzesInteresting Facts about our Dwarf Planetshttp://www.youtube.com/watch?feature=endscreen&v=Ho5FEyftFss&NR=1
Quiz on Plutohttp://www.space.com/16537-pluto-quiz-dwarf-planet-moons.html
Dwarf Planet Quiz1. http://www.astronomyquiz.info/dwarf-planets-quiz.html2. http://www.funtrivia.com/playquiz/quiz3249712533f30.html
QUIZ IMAGE 1
INFORMATION
a ) P l a n e t b ) D wa r f P l a n e t c ) S m a l l S o l a r Sy s te m B o d y
This object has not cleared out its neighborhood orbit.
Image 2
INFORMATION
This object is in an orbit around the Sun between the orbits of Mars and Jupiter.
Image 3
INFORMATIONThis object is in an orbit
around the Sun between the orbits of Mars and Jupiter.
Image 4
INFORMATION
This object orbits the Sun past Neptune’s average distance
from the Sun
Image 5
NFORMATION
This object contains more than 90% of the total mass in its
path around the sun
Image 6
INFORMATION
This object is in an orbit around the Sun between the orbits of Mars and Jupiter.
Image 7
INFORMATION
This object would be rounded but its extreme rotation causes
it to bulge.
Image 8
INFORMATION
This object’s orbit is highly eccentric.
Image 9
INFORMATION
This object orbits the Sun at an average distance of .3 AU
Image 10
INFORMATION
This object is the most distant of 8 objects in its classification.