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Astronomy/Earth-Moon relationship

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Expert: Jesse Martinez - 5/11/2010


Question
I've heard that the Moon created the gravitational relation that stabilizes the Earth. It was hinted the it might not be possible to have an Earth-like exoplanet without this symbiotic relationship. I feel that this is not necessary for an exoplanet to produce life. Your thoughts, please. Is Precession also a necessity?

Answer
Greetings. A few definitions are in order before I continue with the reply to this question. An exoplanet is a planet that is not in our solar system. Precession is a change in the orientation of the axis of rotation of a body, like the Earth. The Earth's axis of rotation is currently pointing towards Polaris.

See: http://planetquest.jpl.nasa.gov/
and
http://csep10.phys.utk.edu/astr161/lect/time/precession.html

Now to continue. There is a unique relationship between the Earth and the Moon. The two objects can be considered more of a binary planet system than any other known objects in the universe. The mutual gravitational attraction between these two objects cause the ocean tides on Earth. That in turn is considered one of the factors that causes the conditions for life on our planet. But it is not a requirement. Life would have developed without the moon's gravitational influence, albeit most likely different. So I do not think it is necessary for a planet to have a large satellite in order to be capable of supporting life. I agree with you on this point.

Precession is also irrelevant as far as affecting the development of life on a planet. Even fast precession rates would have no effect on life development, unless it was close to or shorter than the planet's period of revolution (year). That would be a rare situation.

Thanks for the opportunity to help. Do not hesitate to ask for further explanation if needed. Your humble expert, Jesse.  

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Jesse Martinez

Expertise

General and specific questions about the solar system and stellar and galactic astronomy, are what I can easily answer off the top of my head. For example, what is the largest planet in the solar system? How far away is the moon? Have there been any confirmed planets in orbit around stars other than the sun? How many stars are there? The tougher ones like explaining the big bang theory and black holes I will leave to the PhD’s. Even though I could muster an answer, I would have to research it more than I would like. I would also like to answer questions that involve Astronomy with other sciences, chemistry, biology, physics, geology and mathematics as long as they are not PhD level.

Experience

I have been into astronomy since I was 8 years old. I have kept detailed journals of my observations through small telescopes. Over the years I have participated in amateur observation projects for organizations like ALPO. My personal research has involved "discovering" the moons of Jupiter with a 4½-inch Newtonian reflector without any outside information like charts and tables. In a summer long project, I determined the existence of and plotted the orbits of the four major moons of Jupiter. From these observations, my data on orbital elements was surprisingly accurate (orbital radius and orbital period).

Education/Credentials
80 hours of college credits while studying physics and geophysics. Completed correspondence photography course while in high school. Took two semesters of electronics training at a community college. Studied computers and graduated from a technical school at the turn of the millennium, gaining A+ and Microsoft Certified Professional credentials. Hablo Español. Si quieres preguntar en Español, estoy a su servicio.

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