Is Pluto a Planet

1
Is Pluto a Planet?

• By Margot Newcomer
• Astronomy 007
• Prof. Verde

2
Why is this important?

• To many people this is an important issue. Some
  scientists feel that a solar system with
  everything classified nicely is too neat for the
  actual world. In actuality, the universe is a
  messy place.
• Also, it might be a decision with more than
  science involved, but popularity and status quo.

3
The History of Finding Pluto

• An amateur astronomer named
• Percival Lowell built an observatory in
• Arizona to look for a Planet X.
• It seemed as though Neptune wobbled, and it was
  assumed it was because of another Planet.
• After Lowell died, Tombaugh looked for Planet X
  and found it!
• And, for now, we have a ninth planet, Pluto!!!

4
Plutos Unusual Numbers

• Pluto is six times smaller than Earth, which is
  smaller than seven moons. 1413 miles in
  diameter.
• Plutos orbit is the only planet which crosses
  over another planets, Neptune.
• Its orbit is also titled 17 degrees from the
  rest of the solar system.
• Plutos composition is made of rock and ice.
• Plutos moon is very large and close.

5
Opposing Definitions of a Planet

• A planet has two rules.
• A planet must orbit the Sun.
• It must be large enough that its own gravity is
  strong enough to maintain a spherical shape.
  There are certain properties we expect to see in
  a planet such as an atmosphere and dynamic active
  surfaces at some stage in their history. (Pluto
  passes)
• A non moon, sun-orbiting body large enough to
  have gravitationally swept our almost
  everything else near its orbit. (Pluto passes)
• So, is Pluto a planet or not?

6
Arguments against Plutos planetary status

• Pluto is too small to be a planet.
• The solar system has two groups, the terrestrial
  and the gaseous outer planets.
• Plutos orbit is unlike a planets orbit.
• Plutos moon is too large, so if it is a planet,
  then it is a dual planet.
• Plutos origin was probably of a moon that got
  knocked off its orbit.
• A museum in New York has already taken Pluto off
  of its planetary display.
• Most children are aware of the Pluto debate, and
  many teachers are dismissing Pluto as a planet.

7
The Main Argument

• In the early 1990s, two astronomers, David Jewitt
  and Jane Luu, spotted objects outside of
  Neptunes orbit.
• They discovered the Kuiper Belt.
• The Kuiper Belt contains 100 objects that
  scientists believe are similar to the composition
  of Pluto, but smaller.
• The largest KBO found is 1/3 the size of Pluto.
• Some scientists feel that Pluto should be given
  the status of a minor planet.

8
Changing the Status of Pluto

• To change Plutos status, it would need to pass
  through the International Astronomical Union.
• A past incident with Ceres, gives a norm for
  changing Plutos status.
• Pluto was a media darling, which is why most
  people are resisting the change.

9
Scientific Arguments for Pluto as a Planet

• Pluto is much larger than known asteroids and
  comets.
• Plutos origin is really unknown, since it has
  never been studied close up. It could have the
  same origins as other planets.
• Simulations of Pluto and Neptune indicate that it
  is unlikely that Pluto was ever a satellite of
  Neptunes.
• The main difference between Pluto and the Kuiper
  Belt is that Pluto has enough gravity and mass
  for a tenuous atmosphere.

10
Non-scientific arguments to Keep Pluto a Planet

• Pluto has been a planet for 60 years. It is
  better to keep the status quo.
• If Pluto is decided not to be a planet, then
  funding to explore it will be lost.
• People in general like Pluto. Even if it is
  stated by the scientific world that Pluto is not
  a planet, people will still say it is
• According to a Levy, a scientist, This isnt
  about science, or things. Its about people.

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So, will the IAU ever change Plutos Status

• It is very unlikely that in the near future Pluto
  will be demoted from its planetary status.
• The IAU seems keen on keeping the status quo.
• From a statement from the IAU on Plutos state,
  It has been proposed to assign Pluto a number in
  a technical catalogue or list of such
  Trans-Neptunian Objects so that observations and
  computations concerning these objects can be
  conveniently collated. This process was
  explicitly designed to not change Plutos status
  as a planet.
• So, according to the main guys, Pluto is a
  planet, but the debate continues.

12
The IAU

• The mission of the IAU is to promote scientific
  progress in astronomy. AN important part of this
  mission is to provide a forum for debate of
  scientific issues with an international
  dimension. This should not be interpreted to
  imply that the outcome of such discussions may
  become official IAU policy without due
  verification that the above criteria are met The
  policy and decisions of the IAU are formulated by
  it is responsible bodies after full deliberation
  in the international scientific community.
• Johannes Andersen General Secretary, IAU

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References

• http//www.iau.org/IAU/FAQ/PlutoPR.html
• http//www.theatlantic.com/issues/98feb/pluto.htm
• http//science.nasa.gov/newhome/headlines/ast17feb
  99_1.htm
• http//www.lowell.edu/users/buie/pluto/planet.html
  
• http//www.studyworksonline.com/cda/content/articl
  e/0,,EXP666_NAV4-42_SAR920,00.shtml