Except for relativistic effects, which are pretty small, the earth has the same velocity from year to year, but it varies with the position in the orbit - or season if you choose. The effect is larger than one might think. The variation from perihelion to aphelion is on the order of around plus or minus 20 seconds. The cumulative effect is a lag of around plus or minus 15 minutes. The equation of time describes thie difference. This is all due to the ellipticity of the earth's orbit. The rotational speed remains constant, but the revolutional speed varies slightly. From: Josh M <mountaindrifter@gmail.com> To: Utah Astronomy <utah-astronomy@mailman.xmission.com> Sent: Friday, December 23, 2011 9:49 PM Subject: Re: [Utah-astronomy] From the funnies Does the earth have static points of minimum and maximum angular velocity in relation to the seasons? And how much time are we talking about?