Why Don't Some Objects Attract Each Other Despite the Existence of Gravity?

Gravity, one of the fundamental forces that govern the universe, may seem universal in its pull. However, certain objects can coexist without being attracted to each other, which raises a fascinating question: in a world governed by gravity, why do some things not stick together?

Gravitational Kinematics and Energy Balance

Gravity loses its grip when two bodies separate at a velocity high enough for the rapidly diminishing gravitational potential energy to become less than the remaining relative kinetic energy. This phenomenon is observed in gravitational assists, where objects (such as spacecraft) use the gravitational pull of a planet to change their direction or speed without being captured. This interaction can be understood as a balance between the kinetic energy of the moving object and the potential energy of the gravitational field.

Mass and Gravity: A Misconception

The idea that mass attracts mass can be misleading. If this were true, the Earth's center would be hollow due to the mutual gravitational pulls between the two sides canceling each other out. This misconception is often attributed to Aristotelian physics, where the concept of 'natural resting places' for objects influenced our understanding of attraction. Albert Einstein's theory of relativity provides a simpler and more accurate framework. It posits that massive bodies curve the fabric of spacetime, but mass itself does not directly attract other mass.

Max Planck and Quantum Theory: The Unseen Dynamics of Light and Matter

Max Planck's pioneering work on the behaviour of light significantly advanced our understanding of the quantum nature of the universe. While studying light, Planck discovered a key relationship between light and the energy levels of electrons. When a photon is absorbed, an electron jumps to a higher energy level; when a photon is emitted, the electron falls back to a lower level. The 'ultra violet catastrophe,' which Planck solved by proposing that light consists of discrete packets called quanta, marked the beginning of quantum mechanics.

These quanta of light are indivisible; an electron exists in distinct states with no intermediate levels, which results in the finite spectrum of colors we see. Light interacts with matter at angles, causing different wavelengths to bend at varying degrees (blue light bends more than red light). This phenomenon explains why, when light passes through a prism, it separates into a spectrum of colors. The difference in the angle at which light hits the glass produces varying wavelengths and thus different angles of deviation. This bending effect can be interpreted as a small modification in the path of light, influenced by the pressure within space itself.

Pressure, Heat, and the Expansion of Space

Space itself is not empty; it is under immense pressure from the constant expansion at the core of massive objects like the Earth. This core pressure causes the space within to rise, gaining kinetic energy and velocity. As this space expands, it exerts greater pressure on the core, maintaining the cycle of heat generation and gravitational force.

According to Einstein's theory of relativity, this pressure causes the fabric of spacetime to warp. The continuous motion of surface matter under pressure results in a cyclical exchange of heat and kinetic energy, with the core maintaining a high temperature. This dynamic interplay of forces creates a continuous flow of energy, sustainably powering the gravitational pull.

Gravity as a Change in Uniform Motion

At the heart of gravitational mechanics lies the concept of uniform motion. When an object is in free fall, its inertia strives to maintain its previous path. Therefore, as an object deaccelerates, its momentum continues to act in a uniform manner, influencing how it interacts with other objects.

In conclusion, while gravity is a pervasive force in the universe, it is subject to the complex interplay of energy, pressure, and the dynamics of space-time. Understanding these nuances deepens our comprehension of why some objects may not attract each other, even in the presence of gravitational forces.