August
9, 2015
Dear
Dr. Montmerle, Members of the IAU Executive Committee, Members of the
Secretariat, Members of the Commission on Public Outreach Information
Management, Commission on New Media, Working Group on Planetary System
Nomenclature, Working Group on Small Bodies Nomenclature, Working Group on the
Public Naming of Planets and Planetary Satellites, Working Group on
International General Assemblies, and Delegates to the 29th IAU
General Assembly,
I am
an amateur astronomer and freelance writer who is writing to respectfully
request the General Assembly officially reopen discussion on the issue of
planet definition for both our solar system and the countless others both
discovered and waiting to be discovered.
Please note that I do not represent any
government, space agency, space mission, company, or print or online
publication in writing this. These views are solely my own and those
shared by like-minded people who have signed petitions stating, “I agree that
Pluto is a planet, and a better definition is needed.”
The
last three years in general and the year 2015 in particular have been a time of
momentous, historic discoveries in planetary science. The Dawn mission’s orbit
of Ceres and the New Horizons flyby of Pluto have stunned the world, not just
with beautiful pictures, but with compelling evidence that these are complex
geological worlds undergoing active internal processes as we speak.
While
much data awaits from both missions, the information we have to date shows that
Ceres and Pluto are far more than spherical worlds. Ceres may have a thin
atmosphere and possibly a subsurface ocean. It could be one of the solar system’s
most active and prominent water worlds.
Pluto’s
lack of craters, its unusual variety of terrains, stunning mountains, and
flowing ices indicate it too is geologically active today and like Ceres, may
harbor a subsurface ocean. Like its larger planet counterparts, it seems to
have an internal heat source. Analysis of the orbital dynamics of the six-body
system (Pluto, Charon, and four small moons) reveals that its four small moons
do not solely orbit Pluto but orbit a barycenter between Pluto and Charon,
making the Pluto system a true binary, with Pluto and Charon acting much the
way stars in a double star system do.
Incredibly,
New Horizons has shown us that Pluto in many ways is more like Earth than
possibly any other solar system world. As NASA associate administrator John
Grunsfeld noted, “With flowing ices, exotic surface chemistry, mountain ranges,
and vast haze, Pluto is showing a diversity of planetary geology that is truly
thrilling.”
The
question of what constitutes a planet is about far more than Pluto. As
astronomer Dr. David Grinspoon pointed out, the current IAU definition
completely excludes exoplanets, of which we have now discovered close to 2,000.
It
makes no sense to have one definition for planets in our solar system and
another or none for the billions that orbit other stars or float freely in
space. Doing this privileges Earth and its parent star in a manner that runs
counter to the Copernican principle.
In
2006, the leadership of the IAU attributed the need to come up with a
definition of the word “planet” to the discovery of Eris and other large Kuiper
Belt Objects. New information frequently compels revisiting and revising our
classification systems. The discoveries of 2015 and of the last three years
once again compel a paradigm shift and revision in our understanding of planets
and planetary systems.
In our own solar system, scientists have been stunned to find that what we thought were dead worlds are much more akin to their larger counterparts, in spite of their size.
In other
solar systems, we have found a diversity of worlds in a huge variety of sizes
and orbits, many in locations and situations previously believed impossible.
These discoveries have often resulted in scientists noting a need to “go back
to the drawing board” to develop a new understanding of planet and solar system
formation.
At
the 2012 GA, the IAU approved electronic voting for members not able to be
physically present at the conference, a step forward I respect and applaud.
Now,
it is time to take the next step, to act with the flexibility and
open-mindedness that represents science at its best. No definition should ever
be final because we constantly learn more, requiring us to revisit concepts we
thought we thoroughly understood.
For these
reasons, I ask specifically that you reconsider and place for a new vote
Resolution 5b from 2006, which would establish “planets” as a broad, umbrella
category under which both classical and dwarf planets would be included and
that the definition of planet be expanded to include objects that orbit a star
or are free-floating in space, to accommodate exoplanets and rogue planets.
Additionally,
I ask that you remove all dwarf planets from the “Minor Planet” category,
remove minor planet numbers given to them, and remove them from the auspices of
the Minor Planet Center. The term “minor planet,” as noted by Dr. David
Weintraub, refers to objects now classed by the IAU as “Small Solar System
Bodies,” in other words, asteroids, comets, and centaurs, objects too small to
be in hydrostatic equilibrium. The newly-revealed complexity of dwarf planets
confirms they do not belong in this category.
I
also ask that you consider classifying complex spherical moons of planets,
which undergo the same processes as the terrestrial planets, as part of a new
category of “satellite planets.”
Continuing
to ignore these new developments will not make them go away and constitutes a
disservice to science. I am sure you are all aware that at a debate last fall
at the Harvard Smithsonian Center for Astrophysics, participants, including
scientists, educators, and students, voted overwhelmingly in favor of Pluto
being classified as a planet.
Other
polls, including those of professional astronomers, have shown similar results;
people with strong backgrounds in astronomy and planetary science have
overwhelmingly shown their support for dwarf planets being classed as planets
and for a definition that includes exoplanets.
If
you do not feel ready to put a resolution on the floor of this year’s GA, at
least set in motion a process of establishing a committee to revisit the issue
for the GA in 2018. I urge you to reach out to members of the New Horizons team,
the only people in the world who actually sent a probe to Pluto, as well as to
a broad cross-section of planetary scientists, both amateur and professional,
and even to the public for input.
Now
is an ideal time for such an effort, as the Dawn and New Horizons missions have
generated a revived interest in astronomy and space exploration worldwide.
Failure
to adequately address this issue based on new data will eventually result in
another organization or simply public usage taking it up and adopting a better
planet definition. If the IAU seeks to remain in a leadership role in terms of safeguarding
the science of astronomy, it is time to revisit this issue and allow the time
and deliberation necessary for the development of a genuine consensus, reaching
out to as broad a spectrum of people as possible through digital media.
Sincerely,
Laurel
E. Kornfeld, Highland Park, NJ, USAhttp://laurelsplutoblog.blogspot.com
http://laurele.livejournal.com
1 comment:
Great letter. I'd definitely second and would sign this too.
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