Presentation Transcript
The Dwarf Planet Pluto http://en.wikipedia.org/wiki/Pluto : The Dwarf Planet Pluto http://en.wikipedia.org/wiki/Pluto Dr. Harold Williams
Montgomery College Planetarium
http://Montgomerycollege.edu/Departments/planet/
Clyde Tombaugh discover of Pluto: Clyde Tombaugh discover of Pluto
Lowell Observatory Astrograph: Lowell Observatory Astrograph
Lowell Observatory Blink Comparator: Lowell Observatory Blink Comparator
Ganymede (Jupiter), Titan (Saturn) and Callisto (Jupiter) Io (Jupiter), Luna (Earth), Europa (Jupiter), Triton (Neptune) and Pluto. : Ganymede (Jupiter), Titan (Saturn) and Callisto (Jupiter) Io (Jupiter), Luna (Earth), Europa (Jupiter), Triton (Neptune) and Pluto.
Asteroid Orbits: Asteroid Orbits Most asteroids orbit in a belt between Mars and Jupiter
Trojan asteroids follow Jupiter’s orbit
Orbits of near-Earth asteroids cross Earth’s orbit
Wikipedia Links: Wikipedia Links http://en.wikipedia.org/wiki/Minor_planet
http://en.wikipedia.org/wiki/Minor_Planet_Center
http://en.wikipedia.org/wiki/Minor_planet_number
http://en.wikipedia.org/wiki/Eris_%28dwarf_planet%29
http://en.wikipedia.org/wiki/Trans-Neptunian_object
http://en.wikipedia.org/wiki/Asteroid
http://en.wikipedia.org/wiki/List_of_asteroids_named_after_important_people
Slide15: Kuiper belt:
On orderly orbits from 30-100 AU in disk of solar system Oort cloud:
On random orbits extending to about 50,000 AU Only a tiny number of comets enter the inner solar system - most stay far from the Sun
How big can a comet be?: How big can a comet be?
Pluto’s Orbit: Pluto’s Orbit Pluto will never hit Neptune, even though their orbits cross, because of 3:2 orbital resonance
Neptune orbits three times during the time Pluto orbits twice
Is Pluto a Planet?: Is Pluto a Planet? By far the smallest planet.
Not a gas giant like other outer planets.
Has an icy composition like a comet.
Has a very elliptical, inclined orbit.
Pluto has more in common with comets than with the eight major planets
Other Icy Bodies: Other Icy Bodies There are many icy objects like Pluto on elliptical, inclined orbits beyond Neptune.
The largest of these, “Planet X” was discovered in summer 2005, is even larger than Pluto
Kuiper Belt Objects: Kuiper Belt Objects These large, icy objects have orbits similar to the smaller objects in the Kuiper Belt that become short period comets
So are they very large comets or very small planets?
What are the large objects of the Kuiper belt like?: What are the large objects of the Kuiper belt like?
HST’s view of Pluto & Charon: HST’s view of Pluto & Charon
What is Pluto like?: What is Pluto like? Its moon Charon is nearly as large as Pluto itself (probably made by a major impact)
Pluto is very cold (40 K)
Pluto has a thin nitrogen atmosphere that will refreeze onto the surface as Pluto’s orbit takes it farther from the Sun.
Other Kuiper Belt Objects: Other Kuiper Belt Objects Most have been discovered very recently so little is known about them.
NASA’s New Horizons mission will study Pluto and a few other Kuiper Belt object in a planned flyby.
Is “Planet X” a planet?: Is “Planet X” a planet?
Pluto and “Planet X”: Pluto and “Planet X” Pluto’s size was overestimated after its discovery in 1930
It was considered a planet, and nothing of similar size was discovered for several decades
Now other large objects have been discovered in Kuiper Belt, including “Planet X”
Some scientists consider all of those objects planets; others consider none of them planets.
Sedna in Green Circle http://en.wikipedia.org/wiki/90377_Sedna : Sedna in Green Circle http://en.wikipedia.org/wiki/90377_Sedna
What have we learned?: What have we learned? How big can a comet be?
The Kuiper belt from which comets come contains objects as large as Pluto.
What are the large objects of the Kuiper belt like?
Large objects in the Kuiper belt have orbits and icy compositions like those of comets.
Is “Planet X” a planet?
It remains a matter of opinion because scientists have not yet settled on a definition of the minimum size of a planet.
New Horizons Spacecraft: New Horizons Spacecraft http://en.wikipedia.org/wiki/New_Horizons
Major Contractors JHU APL, SwRI
New Horizons NASA’s Pluto-Kuiper Belt Mission http://pluto.jhuapl.edu/
New Horizons launched January 19, 2006 flyby Pluto July 14, 2015 : New Horizons launched January 19, 2006 flyby Pluto July 14, 2015
Spacecraft New Horizons: Spacecraft New Horizons
Thermal Space Battery: Thermal Space Battery
Antennas of New Horizons (HGA, MGA and LGA) : Antennas of New Horizons (HGA, MGA and LGA)