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Astronomy/Earth-Moon-Sun alignement

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Expert: - 2/6/2011


Question
Dear expert,


since Earth's and Moon's orbital inclination compared to ecliptic oscillates with time, what's the exact period when the Earth, the Moon and the Sun are exacty all on the same line, from heliocentric frame of reference?



Sincerely

Answer
To have a lunar or solar eclipse, all three objects have to be in line. At such times, it doesn't make any difference whether you are on the Earth, Moon, Sun, or anywhere else in the solar system; they would still be on the same line. So anytime there is a solar or lunar eclipse, the three bodies are on the same line from the heliocentric frame of reference.

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Courtney Seligman

Expertise

I can answer almost any question about astronomy and related sciences, such as physics and geology. I will not answer questions about astrology and similar pseudo-scientific rubbish.

Experience

I have been a professor of astronomy for over 40 years, and am working on an online text/encyclopedia of astronomy.

Publications
Astronomical Journal, Publications of the Astronomical Society of the Pacific (too long ago to be really relevant, but you could search for Courtney Seligman on Google Scholar)

Education/Credentials
I received a BA in astronomy and physics and a MA in astronomy, both from UCLA. I was working on my doctoral dissertation when I started teaching, and discovered that I preferred teaching to research.

Awards and Honors
(too long ago to be relevant, but Phi Beta Kappa and Sigma Xi still keep trying to get me to become a paying member)

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