On 12/21/12 10:11 AM, Brad Guth wrote:
On Nov 28, 6:45 am, Sam wrote:
On 11/28/12 8:23 AM, Vilas Tamhane wrote:

Does motion depend on opinion? I thought it is acquired after
acceleration.

Mean velocity: v = ∆r/∆t

Instantaneous velocity: v = dr/dt

Whether a body is in motion (v â‰* 0) or at rest (v = 0) strictly
depend on the perspective of the observer. Not an opinion, but
an observation (measurement).
Are we accelerating or decelerating in any given direction relative to
other galaxies?

Use Doppler to measure the relative velocity to another galaxy. Do it
again some years later. Has the relative velocity changed?

On the larger scale, galaxies are rushing away from us in all
directions. And that expansion rate is increasing (acceleration).

No Center
http://www.astro.ucla.edu/~wright/nocenter.html
http://www.astro.ucla.edu/~wright/infpoint.html

Also see Ned Wright's Cosmology Tutorial
http://www.astro.ucla.edu/~wright/cosmolog.htm
http://www.astro.ucla.edu/~wright/cosmology_faq.html
http://www.astro.ucla.edu/~wright/CosmoCalc.html

WMAP: Foundations of the Big Bang theory
http://map.gsfc.nasa.gov/m_uni.html

WMAP: Tests of Big Bang Cosmology
http://map.gsfc.nasa.gov/m_uni/uni_101bbtest.html