Talk:Plane of the ecliptic

Article Title

The page title is "Plane of ecliptic" but the lead has plane of the ecliptic. Inclusion of the is surely grammatically correct? Or should the article be called Ecliptic plane as most of the links to it seem to take that form? Not a big deal, but a bit of a discrepancy. Also the first time I've really understood what this means, so thanks! Bigger digger (talk) 14:27, 12 May 2009 (UTC)

The "the" would be better, but I made it here by mistake and Plane of the ecliptic has revisions so only an admin can move it to that title. If one sees this, can they perform the move, please? Thanks! Densock|Dendodge^{in public} 11:33, 14 May 2009 (UTC)

As per Wikipedia:Requested_page_moves#Requesting_uncontroversial_moves I will tag the redirect and get it moved. Bigger digger (talk) 11:39, 14 May 2009 (UTC)

Moved. Dendodge _T\^C 15:34, 14 May 2009 (UTC)

Yep, I'll just pop off to see if there are any links that need fixing. Bigger digger (talk) 15:53, 14 May 2009 (UTC)

Which plane is the ecliptic?

I think the phrase 'which all the planets ... nearly share' in the first sentence must be incorrect. Surely it should read 'Plane of the Earth's orbit'? I'll go ahead (boldy) and make the change. --Chris Jefferies (talk) 23:22, 17 May 2009 (UTC)

From [1]:

Most objects in the solar system orbit in roughly this plane and in the same direction around the Sun as the Earth. There are exceptions such as many comets and a few minor planets which have high inclinations. Some comets even have retrograde orbits (e.g. Halley's comet) and orbit in the opposite direction to the planets.

So the original seems appropriate. OK to revert? Simões (^talk/_contribs) 23:42, 17 May 2009 (UTC)

Ooh, a good bit of WP:BRD, nice to see! I think that both are right. From looking at the sources (with my finger hovering over undo!) it seems that the PotE is defined by the Earth's orbit, but that the other major planets have similar orbital planes, which is actually what Chris Jeffries edit says. I think it's important that the first para states that the PotE is the plane of the Earth's orbit (currently relegated to the final para), so would favour incorporating the new edit rather than reverting it. Bigger digger (talk) 23:50, 17 May 2009 (UTC)

The total angular momentum of the objects orbiting the Sun (plus the Sun's and planets' rotations) is a vector, the sum of the angular momentum vectors of all the bodies that contribute. (By far the largest is Jupiter's.) This total angular momentum vector is strictly constant, except for tiny torques due to the Galaxy and passing stars, and a drag torque due to the outflowing Solar wind that is coupled to the Sun's rotation through its magnetic field, and is only important on a time scale of hundreds of millions of years. Perpendicular to this total angular momentum vector is the Fundamental Plane of the Solar System, which is similarly nearly constant, and nearly the same as the plane of Jupiter's orbit. The more massive planets dominate the sum, first Jupiter, then Saturn, etc. Smaller effects, the planetary perturbations, are due to the small exchanges of energy and angular momentum among the planets. They are easily measurable on time scales of centuries, and important over thousands to millions of years. The Fundamental Plane itself has probably changed very little since the birth of the Solar system. By definition the plane of the Earth's orbit at a given moment is the Ecliptic, and changes only very slowly with time, although the change over billions of years can be significant. Cheers Wwheaton (talk) 03:18, 18 May 2009 (UTC)

The total angular momentum of the system is indeed as you describe, and is much more consistent than the plane of the Earth's orbit. But like it or not, the ecliptic plane is defined to be the latter, not the former. Several of the article's references state this quite clearly.

I suppose the ecliptic is evidence that humans in the early 21st century still regard the Earth as the centre of the Universe :-)

The fact that the plane of the ecliptic varies over time is precisely why it's necessary to specify an epoch (as the article mentions). --Chris Jefferies (talk) 07:23, 18 May 2009 (UTC)

FWIW The Explanatory Supplement to the Astronomical Almanac, my goto book on this stuff, defines the ecliptic as "the mean plane (i.e. ignoring periodic pertubations) of the orbit of the earth around the sun". (p11) Fuchsia Groan (talk) 18:57, 15 August 2009 (UTC)

The plane of ecliptic is a relative term, and dependent on the point of observation. When observed from the Earth, it is the Earth's plane of ecliptic. Each planet would have it's own plane of ecliptic, which may or may not be similar to that of the Earth's. I think some note should be made that this is a relative term (with the earth being the typical relation). I will consider the wording and see if I can add something. T.Randall.Scales (talk) 17:37, 26 May 2010 (UTC)

Other solar systems.

Do other solar systems have something similar, where most planets orbit near the same plane? If so, maybe something about that should be stated here. --76.84.81.105 (talk) 01:20, 18 May 2009 (UTC)

Yes, in all probability, since we now observe newly forming stars to be surrounded by flattened disks. IMHO any extensive discussion here would take us too far afield. however, as the Ecliptic is by definition specifically the plane of the Earth's orbit. Wwheaton (talk) 03:22, 18 May 2009 (UTC)

Earth's orbit

"The plane of the ecliptic and the plane of Earth's orbit are the same". Isn't this because they are defined as the same, ie it is just an earth-centred perspective?--Grahame (talk) 01:41, 18 May 2009 (UTC)

Right. It is just historically the definition, and still universally used. Wwheaton (talk) 03:24, 18 May 2009 (UTC)

"How is the earth's orbit on this plane of the ecliptic influenced by the fact that the Sun itself is moving at over 200 km/sec? Does that suggest that the plane of the eliptic is somewhat perpendicular to the galactic plane? And if not (i.e. if the plane of the ecliptic coincides with the galactic plane), that suggests that the Earth's rotational speed around the Sun (relative to the centre of the galaxy) must vary quite dramatically depending on the Earth's angular position relative to the Sun and the centre of the galaxy (i.e. must go faster when moving in the same direction as the sun relative to the centre of the galaxy, and slower when moving against the movement of the sun, which seems unlikely). Does Nassim Haramein's visual of the sun and planets spiralling in a corkscrew shape through space offer a resolution here?" 123.50.150.132 (talk) 01:15, 11 July 2011 (UTC)

Redundant article?

There seems to be little here that isn't already in ecliptic. Any reason why we shouldn't merge the two? Astronomers make no distinction between "ecliptic" and "plane of the ecliptic", so I'm not sure why we do so here.

The two animated images here are somewhat confusing. I understand what they're trying to depict, but to the uninitiated they look like bugs crawling around a spider's web. Tfr000 (talk) 21:31, 13 March 2012 (UTC)

plane of the solar system

The remarkable fact that the plane of the solar system and the plane of the ecliptic are one and the same deserves its own article. The recent redirect should be reverted in my opinion. Tkuvho (talk) 07:41, 3 May 2012 (UTC)

I created a disambiguation page Plane of the solar system. Tkuvho (talk) 07:55, 3 May 2012 (UTC)