Newtonian mechanics, pioneered by Sir Isaac Newton in the 17th century, serves as a foundational pillar of physics, offering a comprehensive framework for comprehending motion and forces in the universe. Its applicability spans a wide spectrum of phenomena, from the descent of apples to the orbits of planets, providing engineers and scientists with a reliable tool for predicting the behavior of diverse systems and driving technological advancements, including those pivotal to the Industrial Revolution. Moreover, Newton's introduction of calculus revolutionized mathematical analysis, profoundly influencing scientific and engineering applications and earning him historical acclaim as one of the greatest scientists in history.

The fundamental principles of Newtonian mechanics, encapsulated in his three laws of motion, elucidate the inertia of objects, the relationship between force, mass, and acceleration, and the concept of action and reaction. Newton's third law, in particular, asserts that the force exerted by one object on another is equal in magnitude and opposite in direction to the force exerted by the second object on the first. Mathematically, this principle translates into the conservation of momentum, wherein the total momentum of a system remains constant over time.

In exploring the implications of Newton's laws, particularly in the realm of weaponry, the concept of a photonic gun emerges. By harnessing photons with wavelengths approaching the Planck length, the smallest conceivable distance in the universe, as projectiles, a photonic gun promises unparalleled potency. Unlike conventional laser guns, which emit a continuous stream of photons without recoil, the photons in a photonic gun possess significant momentum, leading to noticeable backward reactions upon firing.

The characteristics of the photonic gun are remarkable: bullets travel at the speed of light and carry immense energy, making them nearly unstoppable and invisible to the naked eye. However, this formidable power comes with vulnerabilities, including sensitivity to gravitational fields and the potential for conversion into matter and antimatter to halt their progress. Addressing these weaknesses necessitates advancements in technology and energy control, along with the development of super dense materials capable of stopping photon bullets.

While the realization of a photonic gun presents formidable challenges, its conceptualization serves as a catalyst for scientific inquiry and technological innovation. By standardizing the principles underlying the photonic gun, researchers aim to advance defense systems and enhance our understanding of fundamental physics. Though the path to achieving such a feat remains uncertain, the pursuit of this concept represents a collaborative effort within the scientific community, aimed at pushing the boundaries of human knowledge and capability.