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Lunar and Solar eclipse - same times a year?

  1. Aug 4, 2015 #1
    Hi, Just wondering: The lunar orbit around the earth is tilted 5.1 degree with respect to the earths 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 earths' orbit around the sun and therefore is in perfect alignment to produce solar eclipse?
     
  2. jcsd
  3. Aug 4, 2015 #2

    BvU

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    Doesn't it take the moon some two weeks to get to the other side of the earth ?
     
  4. Aug 4, 2015 #3
    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 earths orbit where the moons and earths 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.
     
  5. Aug 4, 2015 #4

    Drakkith

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    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.
     
  6. Aug 4, 2015 #5

    BvU

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    Misunderstood Christian's question. Thanks for bailing me out, Drakkith !
     
  7. Aug 4, 2015 #6
    Thank you, This is much appreciated :)
     
  8. Aug 6, 2015 #7

    Janus

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    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.
     
  9. Aug 6, 2015 #8
    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?
     
  10. Aug 6, 2015 #9

    BobG

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    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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