what speed are we doing

Hi Declan,

An excellent resource is the "Universe in the Classroom" series produced by The Astronomical Society of the Pacific. Your very question was answered in one of their newsletters at www.astrosociety.org/education/publications/tnl/71/howfast.html 8-)

The archive of previous newsletters is at www.astrosociety.org/education/publications/tnl/tnlarchive.html (I've used newsletter number 45 as the basis of a talk called "Where, on Earth, are we going?" :D ) I can't find the slides for it anymore but it had some humorous ones such as a clipping from the Weekly World News claiming Earth's rotation was going to stop soon.

Another cartoon was of two generals arguing over the definition of rotation and revolution ...

General 1: "It says here that the Earth undergoes one revolution every 24 hours"

General 2: "Surely you mean rotation?"

General 1: "Yep, one of them too." :lol: :lol: :lol:

All the best,

John

Another cartoon was of two generals arguing over the definition of rotation and revolution ...

You could make another out of libration & liberation

Ernst Mach (Think of "Mach 1") claimed that "Inertia" is a sign of the connectedness of "local matter" to the most distant matter in the universe.

After all, if something is "reluctant to move" (simplistically = inertia.) what is it reluctant to move relatively to, if not the whole of the Cosmos??

See:
www.spaceandmotion.com/Physics-Ernst-Mach.htm

so it is thought to have completed 20–25 orbits during the lifetime of the Sun and 1/1250th of a revolution since the origin of humans.

Amazings, thats nearly 1/3rd of a degree!