Is Pluto a Planet?

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Is Pluto a Planet?

• Dr John K. Davies
• Dr Suzie Ramsay Howat

UK Astronomy Technology Centre, Royal
Observatory, Edinburgh, Scotland
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The classical solar system
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Planet Uranus imaged from Voyager 2.
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Planet Neptune from Voyager 2.
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Percival Lowell
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Lowells Tomb, shaped like Planet Saturn
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Clyde Tombaugh and the Pluto Telescope.
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Discovery of Pluto, 1930
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Orbits of Pluto and Neptune.
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Nucleus of Halleys Comet
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Pluto is Shrinking
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Pluto is covered with ice.
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Pluto and Charon (Gemini Observatory)
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Pluto should have vanished by now!
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Mercury and Venus Planets without Moons
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9064 Johndavies. A minor planet

• Discovered 1993
• Status Main belt asteroid
• Diameter about 6km
• Brightness V17-18
• Composition Rocky
• Dist from Sun 2.1-2.7 AU

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243 Ida and Dactyl
Ida Size about 56 km long. Dactyl Size about
1.5 km.
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45 Eugenia and its moon.
Eugenia size 215km Satellite size 13 km
Period 4.7 days
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Eugenia, The Movie
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Pluto has an atmosphere
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Pluto Express Mission. 2020?
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Comets in the Oort Cloud
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Comet Hale-Bopp
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Comet Orbits
Interstellar comet (never seen)
Long Period Comet, like Hale-Bopp
Short Period Comet.
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Gerard Kuiper 1905-1973
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Kenneth Edgeworth. 1880-1973
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Jane Luu and Dave Jewitt
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University of Hawaii 2.2m Telescope
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Discovery of 1992 QB1
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The Classical Kuiper Belt
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The Plutinos
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1998 WW31 a Kuiper Belt Object with a satellite
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Some of the the largest known Kuiper Belt Objects
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Stop Press Sedna
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Sedna EKO or Oort Cloud Object?
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Sedna. Planet10?
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Orbital Elements and Stable Regions
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Comet Ring as predicted by Fred Whipple in 1964,
virtually what we today call the Kuiper Belt
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According to First Steps to Astronomy and
Geography, Hatchard Son, London, 1828 there
are 11 planets. Mercury, Venus, Earth, Mars,
Vesta, Juno, Ceres, Pallas, Jupiter, Saturn and
Herschel (Uranus)
Ceres
Sun
Venus
Pallas
Earth
Juno
Vesta
Mars
But 4 of these are no longer in lists of planets
published today
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Tradition in Astronomy
Lunar Sea!
Constellations
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What makes a planet?

• It goes around a star.

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Io and the Moon are not planets
because they dont go around a star.
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What makes a planet?

• It goes around a star.
• It does not generate heat internally.

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Jupiter is a planet.
since it is not heated by nuclear reactions.
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What makes a planet?

• It goes around a star.
• It does not make heat by nuclear reactions.
• It is spherical.

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So MOST asteroids are not planets
since they have not collapsed to spherical shapes.
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What makes a planet?

• It goes around a star.
• It does not make heat by nuclear reactions
• It is (more-or-less) spherical.
• It is bigger than 1000km in diameter

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Is Pluto a Planet?

• Please raise hands for yes

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Or not?

• Please raise hands for NO

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Pluto is a small icy planet
Like Neptunes moon Triton
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..and a member of the Kuiper Belt
Pluto
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Pluto could have dual status.
1000 Piazzi 2000 Herschel 3000 Leonardo 4000
Hipparcus 5000 IAU 6000 United Nations 7000
Curie 8000 Isaac Newton 9000 HAL 10000 Pluto?
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ATC Clapometer
Clap
Cheer
Standby Mode Quiet Please
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Clap for Yes, Pluto is a Planet
Yes
No
Cheer for No, Pluto is NOT a planet
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Clap for Yes, Pluto is a Planet
Yes
No
Cheer for No, Pluto is NOT a planet
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Clap for Yes, Pluto is a Planet
Yes
No
Cheer for No, Pluto is NOT a planet
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Clap for Yes, Pluto is a Planet
Yes
No
Cheer for No, Pluto is NOT a planet
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Clap for Yes, Pluto is a Planet
Yes
No
Cheer for No, Pluto is NOT a planet
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Clap for Yes, Pluto is a Planet
Yes
No
Cheer for No, Pluto is NOT a planet
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Clap for Yes, Pluto is a Planet
Yes
No
Cheer for No, Pluto is NOT a planet
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Clap for Yes, Pluto is a Planet
Yes
No
Cheer for No, Pluto is NOT a planet
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Clap for Yes, Pluto is a Planet
Yes
No
Cheer for No, Pluto is NOT a planet
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Clap for Yes, Pluto is a Planet
Yes
No
Cheer for No, Pluto is NOT a planet
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Clap for Yes, Pluto is a Planet
Yes
No
Cheer for No, Pluto is NOT a planet
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Clap for Yes, Pluto is a Planet
Yes
No
Cheer for No, Pluto is NOT a planet
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Thanks very much!
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Bye for now,Drive safely.
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Is Pluto a Planet?

• Presented by John Davies and Suzie Ramsay Howat.
• Written by John Davies
• Thanks to Jason Cowan, Chad Trujillo, Lowell
  Observatory archives , NASA, Yerkes Observatory,
  Dave Jewitt, Jane Luu, Martin Duncan and John
  Spencer

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For more information.
Published by CUP, get it from Amazon.
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Mutual Eclipses of Pluto and Charon