Space and time are nature quantities, they don't change at all. Despite Einstein's General Relativity that space and time can change with acceleration (but not gravitational field except gravitational acceleration), in fact, the "Dimension" and "Duration" of an object or event can change with the gravitational field and aging of the universe. The former causes Gravitational Redshift and the latter forms Cosmological Redshift.

According to Yangton and Yington Theory, Wu's Pairs, a Yangton and Yington circulating particle pairs is the building blocks of all matter in the universe. Also, Wu's Unit Length lyy (diameter of Wu's Pair) and Wu's Unit Time tyy (period of Wu's Pair) are dependent on gravitational field and aging of the universe. They both become smaller at lower gravitational field and longer aging of the universe (Wu's Spacetime Shrinkage Theory).

Furthermore, according to Wu's Spacetime Equation

tyy = γlyy3/2

Where γ is Wu's Spacetime constant.

In addition, based on "Principle of Correspondence" in which the amount of normal unit quantity maintains constant under equilibrium condition. Also, based on "Principle of Parallelism" in which the transformation factors between two units maintain constant

L = l m lyy

T = t n tyy

V = v mn-1γ-1 lyy-1/2

A = a mn-2γ-2 lyy-2

Where l, t, v and a are constants. m and n are the transformation factors between normal units and Wu's Units, they are also constants. For example 6 Saturn feet and 6 Earth feet twin brothers, both have the same amount "6". Also 6m Saturn Wu's Unit Length and 6m Earth Wu's Unit Length twin brother, both have the same amount "6m".

Despite General Relativity, Perihelion Precession of Mercury can be interpreted by Yangton and Yington Theory as follows:

For a moving object or event,

V = v mn-1γ-1 lyy-1/2

Where V is the velocity, “v” is the amount of normal unit velocity, γ is the Wu’s Spacetime constant, m is the ratio between the normal unit length of a normal object or event and Wu’s Unit Length of a reference subatomic object or event, n is the ratio between the normal unit time of the normal object or event and Wu’s Unit Time of the reference subatomic object or event. lyy is Wu’s Unit Length of a reference subatomic object or event.

Because Mercury circulation around the sun is a corresponding identical motion, so the amount of normal unit velocity “v” is a constant, also m and n are reference-dependent constants; therefore, the velocity “V” is proportional to lyy-1/2. When Mercury moves close to the sun, gravitational field becomes extremely large which makes lyy of the reference subatomic particle on Mercury much bigger and V much smaller based on “Gravity Effect Wu’s Spacetime Shrinkage Theory” caused by graviton radiation and contact interaction. As a result, Perihelion Procession is generated to maintain the structure coherency of Mercury. Based on the similar mechanism, Light Deflection can be also interpreted by Yangton and Yington Theory.