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22 votes
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Why do most planets remain within a few degrees from the ecliptic?

The ecliptic is the path through the sky along which the sun seems to travel during the year. If you flip your perspective around, that means the ecliptic is basically the path of Earth's orbit around ...
Darth Pseudonym's user avatar
22 votes

Why do most planets remain within a few degrees from the ecliptic?

As a single principle: Conservation of Angular Momentum Which means: The material that a star and solar system forms from inevitably has some spin to it. This spin is about some main axis and is ...
ScienceSnake's user avatar
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15 votes
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Why does Callisto only have eclipses every 3 years?

They do happen at certain points of every Jovian year. Jupiter's orbital period is approximately 12 Earth Years. the relative angle between the plane of Callisto's orbit and the plane of Jupiter's ...
notovny's user avatar
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12 votes
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Could there be an eclipse tomorrow if the Pleiades is covered by the Moon tonight?

Consider how far the pleiades are above the ecliptic, and how far the moon travels in a day. From this you can work the angle at which the moon must travel relative to the ecliptic, in order to cross ...
Dr Chuck's user avatar
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10 votes

Why aren't there eclipses every month when the moon's orbit is aligned with the ecliptic as a result of lunar precession?

There are few things here I think might be worth to state: The tilt of Earth is of no importance here. As the comment says what is of importance how much the Moon orbit is inclined to the ecliptic. ...
d_e's user avatar
  • 1,677
10 votes

Do all the planets travel along the same constellations?

The path of the sun would be very similar. The positions of the stars are almost exactly the same. They are so far away that moving to Jupiter won't change their apparent position in any way that you ...
James K's user avatar
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9 votes
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Why aren't there eclipses every month when the moon's orbit is aligned with the ecliptic as a result of lunar precession?

The precession of the moon's orbital plane does not align it with the ecliptic plane. The angle between those two planes is approximately 5.14° (it varies by ~±0.15°, mostly due to perturbation by the ...
PM 2Ring's user avatar
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8 votes

Why is the equinoxes only 2 days and not more?

First, don't think that equinox is when the day and night are the same. It is the moment, when the sun's declination is zero, or when the sun is directly over the equator. Let me explain ... Earth is ...
User123's user avatar
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8 votes
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How to find the local azimuth of the highest point of the ecliptic

Edit: Getting the exact value winds up being simple, but it was only later in the day that the answer occurred to me. All we need to do is ask for the altitude and azimuth of the Ecliptic’s south pole!...
Brandon Rhodes's user avatar
8 votes

How did the ancients know the constellation in which the sun is located?

They made star maps. They mapped the positions of stars on the imaginary celestial sphere - which they thought was an actual physical hollow sphere surrounding the Earth at some distance. Because the ...
M. A. Golding's user avatar
7 votes

Is the equinox Sun always at the same zodiac sign in the ecliptic belt?

As you said, the Sun takes a year to cycle the Zodiac, and it takes a year between two spring or autumn equinoxes. Both statements are true, but "year" in them means two different things. It takes a ...
Pere's user avatar
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7 votes
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How does the earth's plane of orbit (ecliptic) vary over time?

The position of the ecliptic does change, due to perturbation of other planets, but only very slowly. The invariant plane is the plane of angular momentum of the whole solar system. This is dominated ...
James K's user avatar
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7 votes
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Questions on apparent motion of superior planets

The planets do not orbit in the same plane as the Earth, they are inclined by a few degrees. This means that as they orbit the sun, they are sometimes above the plane of the Earth's orbit and ...
James K's user avatar
  • 126k
7 votes

Would an accumulation of dust in a planet's L1 Lagrange point plausibly obscure it from Earth?

No. The L1 point is unstable and dust doesn't accumulate there. A dust cloud could not be large and dense enough to obscure a planet without being so massive that it would contract under its own ...
James K's user avatar
  • 126k
7 votes

Why does the moon move within the zodiacal circle if its orbit is at an angle to the plane of the ecliptic?

The Zodiac isn't a circle, it's a band centred on the ecliptic. Traditionally, it extends ~8° north and south of the ecliptic. The inclination of the Moon's orbit is ~5.145°, so it's always within the ...
PM 2Ring's user avatar
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6 votes
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Why do some solar eclipses' umbra cross arctic/antarctic regions?

I wanted to ask this question even though I realized the correct geometry in the middle of typing it. So I will answer this myself. First of all, the sub-lunar point never exceeds 28.545 N/S. If you'...
DrZ214's user avatar
  • 1,980
6 votes
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Why is there free magnesium in the ecliptic (if there is) and why would some be orbiting within the ecliptic plane but retrograde?

Mg I does indeed mean neutral magnesium atoms, but May and his collaborators weren't observing magnesium atoms orbiting in the inner Solar System -- they were seeing absorption by magnesium atoms in ...
Peter Erwin's user avatar
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6 votes
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How did the Ancients understand the ecliptic using the Ptolemaic system

The ecliptic was understood to be the path of the sun relative to the sky. Ptolemy believed the sky rotated daily around the Earth. All the planets, including the Moon and the Sun, shared in this ...
James K's user avatar
  • 126k
6 votes

Why does moon's highest altitude change during the year

The moon's orbit around the Earth is inclined at about 5° to the ecliptic So as the Earth progresses in its own orbit around the sun, the moon's altitude also changes During summers the part of the ...
Danish 's user avatar
  • 381
6 votes

What objects (if any) are there above or below the ecliptic, or just vaccum/gases

There isn't much of anything. Firstly, if you go a long way out you eventually reach other stars, and these are distributed all round the sun, most aren't on the ecliptic, and those that are close to ...
James K's user avatar
  • 126k
5 votes

Why is the equinoxes only 2 days and not more?

Two further points to make are that: (1) because of the way we define sunrise and sunset as being when the entire Sun is below the horizon not just the centre of the Sun. (2) When the Sun is close ...
Science Geek's user avatar
5 votes

Why is the equinoxes only 2 days and not more?

The easiest graph to consider is the graph of day-length. If the day-length varies from 8 to 16 hours, there can only be two equinoxes: At the time of equinox, the day length changes at the fastest ...
predatflaps's user avatar
5 votes
Accepted

Orientation of local star map

By inspection of a star charting app, I'd say the circles lie in the celestial equator, ie declination equal 0 degrees. Stars above the circles are to the north and vice versa.
Dr Chuck's user avatar
  • 4,349
5 votes
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Galaxy plane and Earth's orbit. Connection to seasons?

I think you are asking whether there are any consequences for the Earth of the Sun and Solar System crossing the galactic plane$^1$? Yes, there have been a number of studies suggesting that their ...
ProfRob's user avatar
  • 156k
4 votes
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Oscillation in tilt of the solar system

The tidal field of the Galaxy does lead to the oscillation of the plane of very wide binaries. The mechanism of this oscillation is identical to the Kozai-Lidov mechanism (the only difference is that ...
J. O'Brien Antognini's user avatar
4 votes
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How to get the axial tilt vector(x,y,z) relative to ecliptic

Earth is a special case since the equatorial and ecliptic coordinate systems are defined in terms of its own rotation and orbit. Earth's north pole vector in equatorial coordinates is $$\vec N_{\oplus,...
Mike G's user avatar
  • 18.7k
4 votes

What is meant by sun's path through zodiac

The stars are not visible during the day, but they are still there (we just can't see them because of the brightness of the sun). We can't see the stars, but we can calculate where they would be if we ...
James K's user avatar
  • 126k
4 votes

What does Ptolemy mean by "a line drawn from the centre of the earth through the centre of the moon to a point on the ecliptic"

In his model, Ptolemy considered the ecliptic to be the path of the Sun—hence, a distinct circle than the path of the Moon. In modern terms, one could say that Ptolemy thus (rightly) considered the ...
Pierre Paquette's user avatar

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