Etymology of the word 'planet'

The less careful are always concerned about definitions and forget why celestial objects such as planets,among other things, are called that way and tend to fabricate contrived stories to force through debacles such as the current hype over the planet Pluto.

The etymology of the word planet should have halted the debacle insofar as planets are designated by that term by their motions and in the geocentric era this included differentiation with the motion of the moon and Sun -

"Moreover, we see the other five planets also retrograde at times, and
stationary at either end [of the regression]. And whereas the sun
always advances along its own direct path, they wander in various
ways, straying sometimes to the south and sometimes to the north; that
is why they are called "planets" [wanderers]. Copernicus

Nowadays it is easy enough to account for the wandering motions of the planets by splitting the perspectives between the inner and outer planets and their relative speeds to the Earth. Had academics enough common sense they would drop the definition stuff and revisit the etymology of the term planet and discover something really new and exciting.

We *know* that the word "planet" comes from the Greek πλανῆται, wanderers.

The stars stay in the sky in fixed patterns - the constellations - but the
five visible planets, Mercury, Venus, Mars, Jupiter, and Saturn move among
them.

While Uranus and Neptune are only visible through telescopes, it was
reasonable to include them among the planets.

We could have also included Ceres, Juno, Pallas, Vesta, and the other
asteroids, as they are also visible in telescopes, and move in the sky,
unlike the stars. It has been chosen, though, to exclude such objects from
those we normally think of as planets - even though asteroids are also
referred to as "minor planets", i.e., the "minor planet circulars".

Ceres, like Pluto, is also known as a "dwarf planet", based on the fact that
both are sufficiently large to be forced into a spherical shape by their
gravity.

Pluto _was_ recognized as the ninth planet of the Solar System after its
discovery. The IAU has proclaimed that it is officially not one of the major
planets; the basis for this is that another body, Eris, was discovered that
was larger than Pluto - _and_ that recognizing Eris as the tenth planet would
not have been an appropriate response, because Pluto and Eris are accompanied
by several other bodies of which we already know, although those are somewhat
smaller, and are likely accompanied by many more.

Thus, just as there are thousands of asteroids, there are likely thousands of
Kuiper Belt Objects.

Of course, what orbits the Sun is... what orbits the Sun. It is not for us to
decide what may orbit the Sun. But where is it unreasonable to say that we
will use the word "planet" to refer to only the largest and most important of
the bodies orbiting the Sun - and those shall be limited in number?

And that we will use the term in a reasonably consistent way, rather than one
controlled by history and sentiment?

John Savard

On Tue, 28 Mar 2017 00:44:57 -0700 (PDT), Quadibloc
wrote:
We *know* that the word "planet" comes from the Greek =
, wanderers.

The stars stay in the sky in fixed patterns - the constellations -
but the=

five visible planets, Mercury, Venus, Mars, Jupiter, and Saturn
move among=

them.

Actually, there were seven visible planets since
the Sun and Moon also were considered to be
planets. That's why we have seven days in the
week: Saturday, Sunday,. Mo(o)nday, followed
by Mars' day, Mercury's day, Jupiter's day and
Venus' day. Check the names of the weekdays
in French...

While Uranus and Neptune are only visible through telescopes, it
was
reasonable to include them among the planets.

We could have also included Ceres, Juno, Pallas, Vesta, and the
other
asteroids,

During the 38 years from 1807 to 1845 when there
were only four known asteroids, Ceres, Pallas, Juno and Vesta, they
were considered to be planets. Small
planets of course but still planets. Back then the solar
system had eleven planets. But from 1845 and on,
when more and more asteroids were discovered in
ever larger numbers, Ceres, Pallas, Juno and Vesta
were degraded to asteroids. This was some 150
years before something similar happened to Pluto,
and for similar reasons.

as they are also visible in telescopes, and move in the sky,
unlike the stars. It has been chosen, though, to exclude such
objects from=

those we normally think of as planets - even though asteroids are
also
referred to as "minor planets", i.e., the "minor planet circulars".


Ceres, like Pluto, is also known as a "dwarf planet", based on the
fact tha=
t
both are sufficiently large to be forced into a spherical shape by
their
gravity.


Pluto _was_ recognized as the ninth planet of the Solar System
after its
discovery. The IAU has proclaimed that it is officially not one of
the majo=
r
planets; the basis for this is that another body, Eris, was
discovered that=


was larger than Pluto - _and_ that recognizing Eris as the tenth
planet wou=
ld
not have been an appropriate response, because Pluto and Eris are
accompani=
ed
by several other bodies of which we already know, although those
are somewh=
at
smaller, and are likely accompanied by many more.


Thus, just as there are thousands of asteroids, there are likely
thousands =
of
Kuiper Belt Objects.


Of course, what orbits the Sun is... what orbits the Sun. It is not
for us =
to
decide what may orbit the Sun. But where is it unreasonable to say
that we=


will use the word "planet" to refer to only the largest and most
important =
of
the bodies orbiting the Sun - and those shall be limited in number?


And that we will use the term in a reasonably consistent way,
rather than o=
ne
controlled by history and sentiment?


John Savard

The empiricists are far too banal to deal with and I suppose this is why they find so much attraction is present social/political concerns however it shows up in their silly attempt to obliterate the context of a planet as it has always existed in astronomy. Acting like upstarts they try to justify an ancient term in terms of composition or size ,however, this wispy thinking was always going to end in failure.

The wandering or retrograde motion arises from two distinct perspectives, the outer planets are simply a consequence of a faster moving Earth causing them to fall temporarily behind in view -

https://apod.nasa.gov/apod/image/011...2000_tezel.gif


The inner planets Venus and Mercury run their circuits as one would see a car run around a racetrack and basically a Sun-centered version of the motion of Jupiter's satellites -

https://www.youtube.com/watch?v=FcrBAuLBXag

It is not conjuring up vapid definitions that moves astronomy forward but returning to the original term and reworking it with 21st century imaging, after all, astronomy is a visual exercise unless people have forgotten.

On Tue, 28 Mar 2017 10:16:02 +0200, Paul Schlyter
wrote:

Actually, there were seven visible planets since
the Sun and Moon also were considered to be
planets. That's why we have seven days in the
week...

That's unlikely. We have seven days of the week because it is natural
to break the lunar month into four division of seven days each. The
planets just contributed to our modern naming of those days.

I would have thought that over the years with the emergence of the two different perspectives as to how we see the outer and inner planets from a moving Earth that some sense of excitement and dignity would also light up the information.

It was just a perceptive bridge too far for the original heliocentric astronomers as they tried to merge the relative speeds which account for the orbital motion of the outer planets around the Sun using the faster motion of the Earth with Venus and Mercury's motions -


"Now what is said here of Jupiter is to be understood of Saturn and Mars also. In Saturn these retrogressions are somewhat more frequent than in Jupiter, because its motion is slower than Jupiter's, so that the Earth overtakes it in a shorter time. In Mars they are rarer, its motion being faster than that of Jupiter, so that the Earth spends more time in catching up with it. Next, as to Venus and Mercury, whose circles are included within that of the Earth, stoppings and retrograde motions appear in them also, due not to any motion that really exists in them, but to the annual motion of the Earth. This is acutely demonstrated by Copernicus . . ." Galileo


It is not a matter of putting academics in their place and forcing them to drop the stupid attempt to re-define a planet but rather those who strike the rich vein of perspectives which arise from the actual difference between the planets and Sun or moon as seen from a moving Earth

On Tue, 28 Mar 2017 07:56:32 -0600, Chris L Peterson
wrote:
On Tue, 28 Mar 2017 10:16:02 +0200, Paul Schlyter
wrote:


Actually, there were seven visible planets since
the Sun and Moon also were considered to be
planets. That's why we have seven days in the
week...

That's unlikely. We have seven days of the week because it is
natural
to break the lunar month into four division of seven days each. The
planets just contributed to our modern naming of those days.

If so, why not five divisions of six days each instead? Or three
divisions of ten days each? Those would be better approximations to
the synod in month.

And why is the seven day week so universal? Through all our calendar
reforms the weeks have run uninterrupted. And the Christians, the
Jews, the Muslims and the Atheists disagree strongly on a lot of
things, but they all agree on which day of the week it is.

In article ,
Chris L Peterson wrote:

We have seven days of the week because it is natural
to break the lunar month into four division of seven days each. The
planets just contributed to our modern naming of those days.

The origin of the week is probably that the days of new moon, full moon
and both quarters were considered not useful working days. The modern
names are translations of ancient names that were derived from the
names of planets that were named after certain gods. For example,
thursday was associated with god Marduk, called Zeus in Greek, Jupiter
in Latin and Thur or Thor in English.

Mikko

Paul Schlyter wrote:


If so, why not five divisions of six days each instead? Or three
divisions of ten days each?

There would go my vacations and days off.


-- It is not that I am lazy. I just don't like to work. ha ha ha

On Wed, 29 Mar 2017 10:09:12 +0200, Paul Schlyter
wrote:

On Tue, 28 Mar 2017 07:56:32 -0600, Chris L Peterson
wrote:
On Tue, 28 Mar 2017 10:16:02 +0200, Paul Schlyter
wrote:


Actually, there were seven visible planets since
the Sun and Moon also were considered to be
planets. That's why we have seven days in the
week...

That's unlikely. We have seven days of the week because it is
natural
to break the lunar month into four division of seven days each. The
planets just contributed to our modern naming of those days.

If so, why not five divisions of six days each instead? Or three
divisions of ten days each? Those would be better approximations to
the synod in month.

The lunar cycle falls very naturally (from a human perspective) into
four obvious lunar phases, separated by seven days.

And why is the seven day week so universal? Through all our calendar
reforms the weeks have run uninterrupted. And the Christians, the
Jews, the Muslims and the Atheists disagree strongly on a lot of
things, but they all agree on which day of the week it is.

All of this predates the existence of any modern religions by
thousands of years. The lunar calendar predates all other calendars by
thousands of years. In order for the number of days in a week to
change, there would need to be some compelling reason for making that
change, something that would be stronger than an ancient cultural
selection of seven-day weeks.

AFAIK, every known ancient lunar calendar consisted of seven-day
weeks. A great many used naming systems unrelated to the planets,
however.