i i “230211*G*latex” — 2023/2/15 — 15:04 — page 1 — #1 i i i i i i Gravity’s ﬂuctuation derives from its speed— a constant to the absolute space presumed Wen-an Zhang ∗ ∗Retired civil engineer, Beijing, 100072, China Submitted to Proceedings of the National Academy of Sciences of the United States of America Newton’s equation of gravity implies gravity instantly attracting t- wo gravitating objects regardless of the distance they segregate in space. In other words, gravity working inﬁnitely fast was assumed to formulate the equation. If this is valid, there is no need for users of the equation to query what the dimension “r” therein really means; it is simply the relational distance between two gravitating objects. However, if gravity binds its inﬂuence with its gravitational ﬁeld out- put at ﬁnite speed, there is an additional eﬀect to account for. This additional eﬀect comes from the discrepancy between the relational distance and the true distance for the “r” to choose, because the instantaneous output of a gravitational ﬁeld needs time to approach its target, during which the ﬁeld-source of gravity has been moving farther and farther away from that ﬁeld’s starting point, meaning that the distance between the centers of two gravitating objects is not exactly the path in which the expanding ﬁeld radially chases its target, and the line joining the centers of the same is not precisely the route by which the gravity comes to pull its target. To reﬂect the said eﬀect in Newton’s model of gravity, this paper attempts to combine Einstein’s idea of ﬁnite speed gravity with Newton’s concep- tion of absolute space, from which the asymmetry of gravity (or the ﬂuctuation of gravity)and the meliorated radar wave measurement were mathematically derived. gravity ﬂuctuation | gravitational ﬁeld | gravitational constant N ewton’s equation of gravity soon came into use after the proportionality in his law of gravity was measured by the experiment. This equation is deemed applicable to any two gravitating objects of the universe in any scenario of rela- tionships. They may be in relative motion or motionlessness, in a small duo of one particle circling the other, or in a large group of celestial objects where the orbiting members revolve the central dominant while some of them have their own satel- lites, etc. Such diversiﬁed relationship scenarios demonstrate the more diversiﬁed motion status of those individuals by viewing them not just from the domestic member to member positions, but from the dynamic swarm to the outside references. Now the question is, if a celestial group, like our solar system as a whole, for instance, moves faster or slower than it currently does, or more generally, if an object’s motion in change through space, makes any diﬀerence to its gravitational ﬁeld strength? The answer, to Newton’s equation of gravity, would be “no”, because it implicitly postulates that gravity works inﬁnitely fast, which legitimates the equation to see the diversities as no more complex than the triadic relations between gravita- tional attraction, mass production and mass separation as the equation determines, because, to space, the speed of a gravity source, might be tremendous, but must not be limitless, thus leading the ratio of the latter to the former to zero. However, if gravity cannot strike its target in an instant, like a long and rigid rod transferring an applied force from one end to the other, which must require the continuous con- tact of solid particles full of the path along the force exertion route, but behaves inﬂuential only when its ﬁeld reaches its target through travelling at ﬁnite speed, to which, Albert E- instein, the most famous pioneer of physics in the twentieth century, already enlightened us one hundred years ago, the said eﬀect, though probably tiny, should take into account. To combine Einstein’s idea of ﬁnite speed gravity with New- ton’s concept of absolute space, this work proposes two ame- liorated gravi