Lunar and Solar eclipse - same times a year?

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Discussion Overview

The discussion revolves around the relationship between lunar and solar eclipses, specifically whether they can occur at the same times of the year due to the alignment of the Earth, Moon, and Sun. Participants explore the concept of eclipse seasons and the orbital mechanics involved, including the inclination of the Moon's orbit and its precession.

Discussion Character

  • Exploratory
  • Technical explanation
  • Conceptual clarification
  • Debate/contested

Main Points Raised

  • Some participants note that lunar eclipses can only occur during specific alignments when the Moon is behind the Earth, while solar eclipses occur when the Moon is between the Earth and the Sun.
  • There is a question about whether the positions of the Earth in its orbit are the same during lunar and solar eclipses, with some participants suggesting that there are specific positions where the orbital planes intersect.
  • One participant introduces the concept of eclipse seasons, explaining that these are the only times when eclipses can occur due to the inclination of the Moon's orbit.
  • Another participant mentions that the Moon's orbit undergoes precession with a period of approximately 18.6 years, affecting the intersection points of the Earth's and Moon's orbital planes.
  • There is a discussion about whether the Moon's precession is similar to the Earth's precession, with some participants suggesting that it adds complexity to the solar precession pattern.

Areas of Agreement / Disagreement

Participants express varying levels of understanding regarding the relationship between lunar and solar eclipses and the mechanics of eclipse seasons. There is no consensus on whether the specific positions of the Earth in its orbit are the same for both types of eclipses, and the discussion remains unresolved.

Contextual Notes

Participants reference the concept of eclipse seasons and the precession of the Moon's orbit, but there are unresolved questions about the implications of these phenomena on the timing and occurrence of eclipses.

christian0710
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Hi, Just wondering: The lunar orbit around the Earth is tilted 5.1 degree with respect to the Earth's orbit around the sun (as described in the video), so only at 2 times during the year the Earth is aligned with the sun such that lunar eclipses can happen IF the moon is behind the Earth (opposite the sun). So my questions is this: is true that on those same dates when lunar eclipse can occur, solar eclipses can occur to (if the moon is positioned between the sun and earth), because the lunar orbit crosses the Earth's' orbit around the sun and therefore is in perfect alignment to produce solar eclipse?
 
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Doesn't it take the moon some two weeks to get to the other side of the Earth ?
 
BvU said:
Doesn't it take the moon some two weeks to get to the other side of the Earth ?

Yes but I'm not asking if they can happen the same time. I'm asking if the position of the Earth on its orbit around the sun is then same when either solar eclipse or lular eclipse happens? So are there 1 or 2 specific positions on the Earth's orbit where the moons and Earth's orbital planes intersect, such that either lunar eclipse and solar eclipse could happen at that or those positions depeing on the position of the moon around the earth.
 
What you're asking about is known as an eclipse season: https://en.wikipedia.org/wiki/Eclipse_season

Eclipse seasons are the only times during a year eclipses can occur, due to the inclination of the Moon's orbit. Each season lasts for approximately 34 days and repeats just short of six months, thus there are always two full eclipse seasons each year. Two to three eclipses always occur each eclipse season. During the season the inclination of the Moon is low, hence the Sun, Moon and Earth become close enough in alignment (syzygy) for an eclipse to occur.
 
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Misunderstood Christian's question. Thanks for bailing me out, Drakkith !
 
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Drakkith said:
What you're asking about is known as an eclipse season: https://en.wikipedia.org/wiki/Eclipse_season

Eclipse seasons are the only times during a year eclipses can occur, due to the inclination of the Moon's orbit. Each season lasts for approximately 34 days and repeats just short of six months, thus there are always two full eclipse seasons each year. Two to three eclipses always occur each eclipse season. During the season the inclination of the Moon is low, hence the Sun, Moon and Earth become close enough in alignment (syzygy) for an eclipse to occur.

Thank you, This is much appreciated :)
 
christian0710 said:
Yes but I'm not asking if they can happen the same time. I'm asking if the position of the Earth on its orbit around the sun is then same when either solar eclipse or lular eclipse happens? So are there 1 or 2 specific positions on the Earth's orbit where the moons and Earth's orbital planes intersect, such that either lunar eclipse and solar eclipse could happen at that or those positions depeing on the position of the moon around the earth.

One thing you need to keep in mind is that the Moon's orbit around the Sun undergoes a precession with a period of ~18.6 years. This means that the points of the Earth's orbit where the planes intersect drift by ~18.6377 days per sidereal year.
 
Janus said:
One thing you need to keep in mind is that the Moon's orbit around the Sun undergoes a precession with a period of ~18.6 years. This means that the points of the Earth's orbit where the planes intersect drift by ~18.6377 days per sidereal year.

Interesting, you say that the moon undergoes precession with a period of 18.6 years, Does that mean it rotates like a cone just like the Earth 26.000 Year precession period?
 
christian0710 said:
Interesting, you say that the moon undergoes precession with a period of 18.6 years, Does that mean it rotates like a cone just like the Earth 26.000 Year precession period?

If it were the only effect, it would. Because you have precession due to the Sun, the lunar pattern just gets overlaid on top of the solar precession pattern. Kind of adding a "jitter" to the solar precession pattern.
 
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