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The word planet comes from the ancient Greek word for "wanderer" which they used to refer to the wandering stars, the only stars that moved across the sky in re
by acqq 10y ago
The word planet comes from the ancient Greek word for "wanderer" which they used to refer to the wandering stars, the only stars that moved across the sky in relation the all other stars, only five of them visible, assigned to the gods and one goddess: Hermes, Aphrodite, Ares, Zeus and Cronus. Since then, the definition of the planet had to be modified as there are a lot of bodies orbiting the Sun known today. According to the latest precise definition, even Pluto isn't a planet anymore (but a dwarf planet).
In this light, I don't see the problem in making the difference between the planets (orbiting our Sun) and the exoplanets (orbiting other stars, see my other post here).
These guys however would like to remove the International
Astronomical Union's definition from 2006 and to introduce the new with which even the moons(!) of the planets would be called "planets":
https://arstechnica.com/science/2017/02/how-positively-peeved-pluto-people-plan-to-pluck-back-plutos-planethood/ https://arstechnica.com/science/2017/02/how-positively-peeve...
As the reporter cleverly summarized, their definition could be simpler stated as, "round objects in space that are smaller than stars." Then there would be around 110 such "planets" around the Sun, and the exoplanets would also be, of course, just "planets."
Their reasoning:
"In the mind of the public, the word
“planet” carries a significance lacking in other words
used to describe planetary bodies. In the decade following
the supposed “demotion” of Pluto by the International
Astronomical Union (IAU) [1], many members
of the public, in our experience, assume that alleged
“non-planets” cease to be interesting enough to
warrant scientific exploration, though the IAU did not
intend this consequence [1]. To wit: a common question
we receive is, “Why did you send New Horizons
to Pluto if it’s not a planet anymore?” To mitigate this
unfortunate perception, we propose a new definition of
planet, which has historical precedence [e.g., 2,3]. In
keeping with both sound scientific classification and
peoples’ intuition, we propose a geophysically-based
definition of “planet” that importantly emphasizes a
body’s intrinsic physical properties over its extrinsic
orbital properties."