Geologists usually argue for a morphology-based definition of planet over the current IAU dynamics-based one. The definitions that Iām presenting are an extension of the geological/morphological framing. This reflects my background as a planetary scientist vs an astrophysicist.
Dynamicists and astrophysicists still tend to prefer the existing definitions. They are concerned about angular momentum budgets, orbital dynamics, and interstellar consequences. To them, Jupiter isnāt a star because it isnāt hot enough to impact interstellar space and it isnāt massive enough to cause the sun to do much more than wobble. On a galactic scale, Jupiter doesnāt matter compared to the sun. To them, Pluto isnāt a planet because itās too tiny and part of a larger debris cloud that damps its dynamical influence on the solar system. They are concerned with bigger things, and prefer to downgrade classifications to justify neglecting the influences of smaller bodies to make their math easier and less compute intensive. I want to be clear that this is still a valid and justifiable approach.
Geologists tend to prefer classifying objects based on what they are on the inside. Astrophysicists tend to prefer classifying objects based on their interactions in a larger system. As a result, geologists still usually refer to Pluto as a planet, and astrophysicists still usually refer to Jupiter as a planet.
āHow many planets are in the solar systemā is a question with a subjective answer based on your perspective, the story youāre trying to tell, and the problem you are trying to solve.
So youāre saying that the solar system actually only has seven planets?
Thatās a fuzzy number based on perspective.
Geologists usually argue for a morphology-based definition of planet over the current IAU dynamics-based one. The definitions that Iām presenting are an extension of the geological/morphological framing. This reflects my background as a planetary scientist vs an astrophysicist.
Dynamicists and astrophysicists still tend to prefer the existing definitions. They are concerned about angular momentum budgets, orbital dynamics, and interstellar consequences. To them, Jupiter isnāt a star because it isnāt hot enough to impact interstellar space and it isnāt massive enough to cause the sun to do much more than wobble. On a galactic scale, Jupiter doesnāt matter compared to the sun. To them, Pluto isnāt a planet because itās too tiny and part of a larger debris cloud that damps its dynamical influence on the solar system. They are concerned with bigger things, and prefer to downgrade classifications to justify neglecting the influences of smaller bodies to make their math easier and less compute intensive. I want to be clear that this is still a valid and justifiable approach.
Geologists tend to prefer classifying objects based on what they are on the inside. Astrophysicists tend to prefer classifying objects based on their interactions in a larger system. As a result, geologists still usually refer to Pluto as a planet, and astrophysicists still usually refer to Jupiter as a planet.
āHow many planets are in the solar systemā is a question with a subjective answer based on your perspective, the story youāre trying to tell, and the problem you are trying to solve.
My question was silly, and I appreciate the serious and thought-out response.