Talk:Orbit

Miscellaneous

where can i find information about earth's orbit around the sun? no link seems to lead to this information. -tom Are all planets orbiting the sun anti clock wise? -peg

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Most recent update was mine. My main intention was to fix the incorrect assertion in the previous version that inner planets has more circular orbits. This was in the introduction, so I placed the correction there. As a result the intro now looks a bit bloated with material duplicated below. -- Alan Peakall 17:03, 5 Sep 2003 (UTC)

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This page was moved to orbit (physics) and turned into a disambig page for a bit; this does not really make sense, since almost all inbound links were in the gravitational orbit sense. I moved the disambig page to orbit (disambiguation), and moved orbit (physics) back here. -- The Anome 00:10, 30 Aug 2004 (UTC)

You could also ask User:BenjBot to solve such a problem. I would not say that orbit in physics is the first thing for orbit. Tosha 04:00, 30 Aug 2004 (UTC)

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It's also a brand of gum... Someone should add that.

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Earth's orbit is neither clock wise nor counter-clock wise, and it is both. One cannot truely answer the question because it is relative to your perspective. The orbit is either clockwise or counter-clockwise depending on whether you look at it from the "top" (if it is truely the top), or if you look at it from the "bottom" (if it truely is the bottom).

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The equation of the orbit described by the particle is thus:

$r={\frac {1}{u}}={\frac {l}{1+e\cos(\theta -\phi )}}$,

Should the second :${\frac {l}{...}}$ be a :${\frac {1}{...}}$ ? Otherwise it doesn't make any sense, what would l be? DavidMcKenzie 16:00 21 July 2005

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Remembered what the l was: it's the semi-latus_rectum. Added a link to that and cleared up the ambiguity between the 1 and the L. DavidMcKenzie 16:51 21 July 2005

open orbits

Is it common for astronomers to call hyperbolic and parabolic motion orbits? To the layman, this is confusing. Orbits in common language implies periodic motion. If this is a common way for astronomers to speak, there should be an introductory sentence that explains this. Like this: "Astronomers commonly refer to any motion of one body relative to another as an orbit, even if the motion is not in a circular or eliptical path." It seems this article could use some translation into common English! -- Samuel Wantman 06:01, 30 July 2005 (UTC)

For astronautical engineers, spacecraft engineers and astronomers, I think it is common. Looking at the definition of "orbit" states that it is a "path" and I cant really see an implication of periodicity. The Greeks are probably the ones who coined the term "orbita" (path) for the wanderers (planets) as they probably did not observe open orbits (how could they have?). Open orbits were probably a mathematical result first before they were observed, hence the misnomer. Wicak 09:19, 3 August 2005 (UTC)

Kepler

I wonder if the statement "Kepler analyzed mathematically" is correct? As I recall reading, he made many many measurements over years, before arriving at a mathematical result. Empirical deductions would be a more accurate description. Wicak 09:12, 3 August 2005 (UTC)

Article Name

Shouldn't this article (Planetary orbit) be renamed Orbit (Astronomy) or Orbit (Celestial mechanics)? Planets are not the only thing that orbit. The star also orbits around the planet and two stars may orbit around eachother. Zhatt 16:40, 27 September 2005 (UTC)

Technically, that's not quite correct. The star does not orbit around the planet, nor does the planet orbit around the star. In reality, both the planet and the star orbit around the center of mass of the planetary system. In practice, however, the mass of the star is almost always many many orders of magnitude larger than the mass of the planet, so that the center of mass of the planetary system very nearly coincides with the center of mass of the star. So as a practical matter, the planet revolves around the star, not vice versa.

As an example, in our own solar system, the Sun makes up 99.85 percent of the total mass of the solar system, and Jupiter accounts for another 0.10 percent. The remaining eight planets account for only 0.04 percent combined, and comets, asteroids, and dust account for the balance. Source: Abell, Morrison, and Wolff, Exploration of the Universe, fifth edition (Saunders College Publishing, 1987), p. 234.

In a binary system, the two stars may have masses of similar order of magnitude, so that it is correct to say that each star orbits around the other, or more accurately, each star orbits around their common center of mass.

-- Metacomet 05:49, 30 December 2005 (UTC)

I agree that the article name is wrong though. Much of the focus is on satellite orbits; the common theme is gravitational orbits. Orbit (gravitational) is my suggestion. Joffan 23:25, 17 July 2006 (UTC)

I suggest either Orbit (astronomy) or Orbit (physics). The Land 00:10, 18 July 2006 (UTC)

you guys never sorted this out, but a name change is needed here.. what are we supposed to do with articles like Satellite orbit? it apparently doesn't fall under this one.. Mlm42 14:30, 4 October 2006 (UTC)

Example calculations

This section has been moved temporarily to another location while it is under development. -- Metacomet 05:51, 31 December 2005 (UTC)

Table of orbital data

This section has been moved temporarily to another location while it is under development. -- Metacomet 05:51, 31 December 2005 (UTC)

Stability of planetary orbits

My understanding is that the stability of planetary orbits, being an n-body problem, is a open question. Wasn't there a prize offered for solving this that was never claimed? --Michael C. Price ^talk 19:50, 22 September 2006 (UTC)

The following discussion is an archived debate of the proposal. Please do not modify it. Subsequent comments should be made in a new section on the talk page. No further edits should be made to this section.

The result of the debate was PAGE MOVED to Orbit (celestial mechanics), per discussion below. -GTBacchus^(talk) 03:38, 5 November 2006 (UTC)

Requested move

Planetary orbit → Orbit (physics) — This is a long overdue nomination. From the first line of the article, it is clear the name needs to be changed, and "Orbit (physics)" seems most appropriate. Mlm42 12:47, 30 October 2006 (UTC)

Survey

Add  * '''Support'''  or  * '''Oppose'''  on a new line followed by a brief explanation, then sign your opinion using ~~~~.

• Support - Although the article is clearly focused mostly on the orbit of bodies around the Earth or around the Sun, the article's information has more general applications (and it should include more information about the orbits of stars around each other and stars and star clusters around the centers of galaxies). George J. Bendo 14:43, 30 October 2006 (UTC)
  • After reading the comments below, I now think moving this to Orbit (celestial mechanics) is better. George J. Bendo 12:17, 31 October 2006 (UTC)
• Support (modified). Clearly not everything that orbits another entity is necessarily a planet (sorry Pluto). — CharlotteWebb 22:45, 30 October 2006 (UTC)
  • Orbit (celestial mechanics) was a more popular suggestion that I expected. Let's go with that. — CharlotteWebb 01:04, 1 November 2006 (UTC)
• Oppose except for a brief note on Bohr's analogies, this deals entirely with the celestial mechanics sense of orbit. That may be primary; and orbit would be defensible; but orbit (physics) would have to include orbitals. Septentrionalis 22:47, 30 October 2006 (UTC)
  • Orbit (celestial mechanics) would still be a better title than the current one. I would not particularly oppose moving it to Orbit as a primary topic, however. — CharlotteWebb 22:55, 30 October 2006 (UTC)
  • What do you mean by "would have to include orbitals"? do you mean atomic orbitals? i believe to use the term orbit instead of orbital in that case would be incorrect. Mlm42 08:57, 31 October 2006 (UTC)
• Oppose I would instead support the move to Orbit (celestial mechanics). WilliamKF 20:50, 31 October 2006 (UTC)
• Oppose I would support a move to Orbit (celestial mechanics). There are many things in physics that are orbits that this article fails to even allude to; giving it an unjustified general title would be wrong. linas 04:10, 2 November 2006 (UTC)

Discussion

Add any additional comments:

Orbit already redirects here. Why not simply move to that? siafu 14:50, 30 October 2006 (UTC)

As you can see in Orbit (disambiguation), there are many other uses, including Orbit (anatomy), Orbit (group theory) and Orbit (dynamics), which are fairly well used. Mlm42 16:50, 30 October 2006 (UTC)

Orbit (disambiguation) should be moved to Orbit, in that case. — CharlotteWebb 22:53, 30 October 2006 (UTC)

Would a move to Orbit (celestial mechanics) include content that could be in orbit (astrodynamics)? that is to say, is the term orbit in astrodynamics synonymous with orbit in celestial mechanics? if somebody is looking for information about orbits of satellites, like the International Space Station, should they check orbit (celestial mechanics) for the answer? Mlm42 08:58, 1 November 2006 (UTC)

No. Astrodynamics is rather different than celestial mechanics; it deals with rockets and mass change/mass ejection. By contrast, celestial bodies do not change or eject mass as a rule, which is why its called "mechanics" and not "dynamics". linas 04:17, 2 November 2006 (UTC)

It appears we have consensus to move this page to Orbit (celestial mechanics); i'm unclear with the procedure in how to proceed.. do i just move it, or do we still need an admin for something? Mlm42 08:56, 2 November 2006 (UTC)

Better to wait a couple days to see if someone else comes along; but then the page can just be moved. Septentrionalis 20:18, 2 November 2006 (UTC)

The above discussion is preserved as an archive of the debate. Please do not modify it. Subsequent comments should be made in a new section on this talk page. No further edits should be made to this section.