I understand that tidal forces between two objects orbiting each other causes tidal stresses between the two objects, which results in a loss of energy, a change in the orbital distance, and a slowing of the objects' rotation. This is what makes sure the moon always has the same side facing Earth, and has slowed Earth's day significantly over the eons. It also has put Mercury in a metastable orbital resonance with the sun. My question is, what about the Earth's orbit around the Sun? I understand that the Earth would have next to no impact on the Sun, but has tidal forces with the Sun altered the length of Earth's year over the eons? I mean the absolute length of the year (I guess in Iternational Atomic Time), not the number of days (since the length of the day has changed itself this is a poor measure).