Question

Keplerian motion/Analemma

Does the earth actually alter speed or is it a result of the earth being closer to the sun at some points in its eliptical orbit or BOTH?

Additionally does anyone know where the value of the earth/sun analemma can be found. I read it is in a nautical almanac but it is not in mine!

Thank you

Mike


Are you talking about speed of rotation about the sun and/or rotation around its own axis? From what I know, there are changes in speed of rotation around the sun.

Since this is not my area of expertise, I searched Google under the key words "<I>earth sun analemma</I>" to get these possible sources:

http://members.aol.com/jwholtz/analemma/analemma.htm
http://imagine.gsfc.nasa.gov/docs/ask_astro/answers/970714.html
http://antwrp.gsfc.nasa.gov/apod/ap020709.html
http://www.seed.slb.com/en/scictr/lab/analemma/index.htm
http://en.wikipedia.org/wiki/Analemma

I hope this helps. Thanks for asking.