[Pete Svarrior]

Kepler's laws of planetary motion

The moon is not a planet.

[Rama Set]

Kepler's laws of planetary motion

The moon is not a planet.

Fortunately the title of the laws are not exclusive.

[Pete Svarrior]

Kepler's laws of planetary motion

The moon is not a planet.

Fortunately the title of the laws are not exclusive.

We must be talking about very different things.

In astronomy, Kepler's laws of planetary motion are three scientific laws describing the motion of planets around the Sun.

• The orbit of a planet is an ellipse with the Sun at one of the two foci.
• A line segment joining a planet and the Sun sweeps out equal areas during equal intervals of time.
• The square of the orbital period of a planet is proportional to the cube of the semi-major axis of its orbit.

[Gulliver]

Kepler's laws of planetary motion

The moon is not a planet.

Did you have a point? I never claimed that the moon was a planet. I claimed that FEers too often ignore the Kepler's laws. Do you agree with Tintagel's inane 180^o statement or something?

[Pete Svarrior]

Did you have a point? I never claimed that the moon was a planet. I claimed that FEers too often ignore the Kepler's laws.

Ignoring the laws of planetary motion appears to be a sensible approach to things which aren't planetary motion.

[Gulliver]

Did you have a point? I never claimed that the moon was a planet. I claimed that FEers too often ignore the Kepler's laws.

Ignoring the laws of planetary motion appears to be a sensible approach to things which aren't planetary motion.

Nope. Those laws are a great result leading to understanding of the multiple-body problems and solutions. If an FEer wishes to build straw man, he or she should at least understand the basics of orbits instead of making wildly inaccurate claims about 180^o and such.

[Rama Set]

Kepler's laws of planetary motion

The moon is not a planet.

Fortunately the title of the laws are not exclusive.

We must be talking about very different things.

In astronomy, Kepler's laws of planetary motion are three scientific laws describing the motion of planets around the Sun.

• The orbit of a planet is an ellipse with the Sun at one of the two foci.
• A line segment joining a planet and the Sun sweeps out equal areas during equal intervals of time.
• The square of the orbital period of a planet is proportional to the cube of the semi-major axis of its orbit.

If you are trying to say that Kepler's laws are not applicable to other celestial bodies, satellites or any orbiting mass, you would be wrong. A brief Internet search provides a number of links to calculators and educational resources on the subject.

[Pete Svarrior]

If you are trying to say that Kepler's laws are not applicable to other celestial bodies, satellites or any orbiting mass, you would be wrong.

I would be absolutely correct, unless you're willing to demonstrate that the moon's orbit is an ellipse with the sun at one of the two foci.

Given that Gulliver's claim is a pedantic attack on the 10% amplitude in the RET moon's orbit's radius (which belongs to the same school of unnecessary points as but FE isn't really flat because hills exist lol! or RE isn't really round because it's actually an oblate spheroid hehehe), it's only fair that we call him out on his "obvious mistakes" too. He needs to learn that he will not be taken seriously if he behaves like this.

I also quite like how he keeps referring to the very non-specific "claims about 180° and such". He's not even capable of repeating what Tintagel said accurately, let alone construct a coherent response.

[Rama Set]

If you are trying to say that Kepler's laws are not applicable to other celestial bodies, satellites or any orbiting mass, you would be wrong.

I would be absolutely correct, unless you're willing to demonstrate that the moon's orbit is an ellipse with the sun at one of the two foci.

Given that Gulliver's claim is a pedantic attack on the 10% amplitude in the RET moon's orbit's radius (which belongs to the same school of unnecessary points as but FE isn't really flat because hills exist lol! or RE isn't really round because it's actually an oblate spheroid hehehe), it's only fair that we call him out on his "obvious mistakes" too. He needs to learn that he will not be taken seriously if he behaves like this.

I also quite like how he keeps referring to the very non-specific "claims about 180° and such". He's not even capable of repeating what Tintagel said accurately, let alone construct a coherent response.

I have no problem calling out other's mistakes but it should be acknowledged that Kepler's laws apply apply to orbits other than planets around the sun. You cannot use the general form of the law of periods but there is s more detailed equation that can and is used for the Earth-Moon orbit.

http://www.idialstars.com/kls.htm
Edit: Added a link to various implementations of Kepler's 3rd Law, including a comparison of the Moon's orbit around the Earth to Io's orbit around Jupiter.

[Pete Svarrior]

Sounds like you're just taking the concept of a Keplerian orbit and insisting that it necessarily requires the invocation of Kepler's 3rd Law of Planetary Motion. It doesn't. The two merely happen to have some overlap.

[Rama Set]

Sounds like you're just taking the concept of a Keplerian orbit and insisting that it necessarily requires the invocation of Kepler's 3rd Law of Planetary Motion. It doesn't. The two merely happen to have some overlap.

What I have clearly been saying is that Kepler's 3rd law can be used to calculate the orbit of celestial bodies other than planets.

[Pete Svarrior]

What I have clearly been saying is that Kepler's 3rd law can be used to calculate the orbit of celestial bodies other than planets.

Yes, erroneously. And I explained to you where the overlapping equations actually come from. You're welcome.

[Rama Set]

What I have clearly been saying is that Kepler's 3rd law can be used to calculate the orbit of celestial bodies other than planets.

Yes, erroneously. And I explained to you where the overlapping equations actually come from. You're welcome.

No no, that is you either ignoring research or not having done research or just basing your conclusion on something other than the math and observations. Kepler's 3rd law in its original and general form requires an extremely large center of mass relative to the orbiting bodies (e.g. The sun and the planets or Jupiter and the Galilean moons. There is a more detailed formula derived using Newton's work which can be applied to more equal masses like the Earth-Moon system.

[Pete Svarrior]

No no, that is you either ignoring research or not having done research or just basing your conclusion on something other than the math and observations.

No, I'm telling you you're using the right maths for RET. You're just calling it the wrong name, because the moons are not planets and the sun isn't the focus you want to use. This isn't hard.

[markjo]

No no, that is you either ignoring research or not having done research or just basing your conclusion on something other than the math and observations.

No, I'm telling you you're using the right maths for RET. You're just calling it the wrong name, because the moons are not planets and the sun isn't the focus you want to use. This isn't hard.

It doesn't seem to be anything other than needless pedantry either.  I bet that you also like to point out things like Panama hats come from Ecuador.

[Pete Svarrior]

It doesn't seem to be anything other than needless pedantry either.

Recall the original point of my objection.

Given that Gulliver's claim is a pedantic attack on the 10% amplitude in the RET moon's orbit's radius (which belongs to the same school of unnecessary points as but FE isn't really flat because hills exist lol! or RE isn't really round because it's actually an oblate spheroid hehehe), it's only fair that we call him out on his "obvious mistakes" too. He needs to learn that he will not be taken seriously if he behaves like this.

I also quite like how he keeps referring to the very non-specific "claims about 180° and such". He's not even capable of repeating what Tintagel said accurately, let alone construct a coherent response.

And the post that prompted it:

Also, I've repeatedly pointed out the straw man that FEers sometimes use that the moon orbits in a circle, ignoring Kepler's laws of planetary motion. They've been making that obvious mistake since EnaG.

If your side of the debate chooses to reduce a subject to absurdity, please do not act surprised when some of us respond in kind.

[Rama Set]

It doesn't seem to be anything other than needless pedantry either.

Recall the original point of my objection.

Given that Gulliver's claim is a pedantic attack on the 10% amplitude in the RET moon's orbit's radius (which belongs to the same school of unnecessary points as but FE isn't really flat because hills exist lol! or RE isn't really round because it's actually an oblate spheroid hehehe), it's only fair that we call him out on his "obvious mistakes" too. He needs to learn that he will not be taken seriously if he behaves like this.

I also quite like how he keeps referring to the very non-specific "claims about 180° and such". He's not even capable of repeating what Tintagel said accurately, let alone construct a coherent response.

And the post that prompted it:

Also, I've repeatedly pointed out the straw man that FEers sometimes use that the moon orbits in a circle, ignoring Kepler's laws of planetary motion. They've been making that obvious mistake since EnaG.

If your side of the debate chooses to reduce a subject to absurdity, please do not act surprised when some of us respond in kind.

Glad to see you are engaged in mutually assured destruction. You could have done what I did with you which is simply criticize your thinking, but I suppose this is more entertaining.

[Tintagel]

I have personally observed a full moon, at sunrise, where the sun is visible on the eastern horizon, and the moon ~30 degrees above the western (an estimate using they height of my fist at arm's length as ~10 degrees, which I understand is customary among amateur astronomers).  RET predicts that a full moon must occur when the angle between the moon and sun in the sky is 180 degrees.  I am aware of the alleged atmospheric phenomena that can cause full moon and sun to be visible at the same time, but I do not expect that this would predict the moon appearing 30 degrees above the horizon.  There were reasonably tall buildings in that direction; it was above them all. 

Just out of curiosity, are you sure that it was it the actual day of the full moon?  To me, at least, the moon's apparent fullness on the the day before, the day of and the day after the full moon all look pretty much the same.

Actually Tintagel already noted that his observation was the day after that full moon.

Also, I've repeatedly pointed out the straw man that FEers sometimes use that the moon orbits in a circle, ignoring Kepler's laws of planetary motion. They've been making that obvious mistake since EnaG.

Her observation, in fact. 

And yes, it was 24 hours after the actual full moon.  I know because the night before was a total lunar eclipse, one of those "rare" ones when the sun and moon are both visible in the sky, another violation of the RET moon model.  Moreover, if the moon's orbit subtends an arc of ~30 degrees in the sky in a mere 24 hours, then there should only be ~12 days between moon phases. There are photos elsewhere on the forum of this moon.

[Rama Set]

As I mentioned the only requirement for a full moon is 180 degree difference in their celestial longitude which you appeared to have observed.

[Tintagel]

As I mentioned the only requirement for a full moon is 180 degree difference in their celestial longitude which you appeared to have observed.

There was a lunar eclipse 24 hours prior.  How this can happen if the moon is so far away from the plane of the ecliptic?  I also doubt the existing model allows for a 30 degree discrepancy, ever.