Definition of Universal Law of Gravitation
The Universal Law of Gravitation, formulated by Sir Isaac Newton, states that every mass attracts every other mass in the universe with a force that is directly proportional to the product of their masses and inversely proportional to the square of the distance between them.
Why is it Called Universal?
The term "universal" signifies that this law applies to all objects with mass, regardless of their size or location in the universe. Here are the key reasons:

• Applies to All Masses: The law governs the gravitational attraction between any two masses, whether they are planets, stars, or everyday objects.
• Consistency Across Distance: The gravitational force acts over vast distances, ensuring that even celestial bodies light-years apart are still influenced by each other.
• Foundation of Astronomy: This law is crucial for understanding planetary motion, the orbits of satellites, and the behavior of galaxies.
• Predictive Power: It allows scientists to predict the gravitational interactions between bodies, making it essential for space exploration and navigation.
• Not Limited by Environment: The law holds true in various environments—terrestrial, extraterrestrial, or even in a vacuum—indicating its universal nature.

Conclusion
The Universal Law of Gravitation is fundamental in physics, providing a comprehensive framework for understanding the forces that govern the motion of all masses in the universe. Its universal applicability makes it a cornerstone of both classical mechanics and modern astrophysics.

This gravitational constant is called universal because the value of G is equally applicable in whole universe. It doesn't depend upon the nature of the intervening medium or temperature or any physical variable. (short)