Final answer:
The gravitational constant (G) is a fundamental constant in physics, valued at 6.673 × 10⁻¹¹ N·m²/kg², used to calculate gravitational force and plays a crucial role in celestial dynamics. It is consistent throughout the universe and while small, is significant in determining the gravitational attraction between large masses like planets and stars.
Step-by-step explanation:
Understanding the Gravitational Constant (G)
The gravitational constant denoted as G, is a pivotal factor in the equations governing the universal law of gravitation. Defined by the equation F = G∗(mM)/r², it enables the calculation of the gravitational force (F) between two masses (m and M) separated by a distance (r). The value of G has been determined experimentally to be 6.673 × 10⁻¹¹ N·m²/kg², signifying that gravitational forces are inherently weak unless one or both masses are very large, like those of celestial bodies.
The universality of G implies that its value is consistent across the cosmos, independent of the mass composition involved in the interaction. Because of its consistency and reliability in the determination of gravitation, it is rightly known as the universal gravitational constant. Two common ways G is used in practice include calculating the weight of an object on the surface of a planet by equating F to mg (where g is the acceleration due to gravity) and canceling the mass m from both sides or in determining astronomical masses in satellite movements and Kepler's Laws.
Although the gravitational force is significant in astronomical scales, it's interesting to note that G is the least precisely determined among all fundamental constants in physics, due to the inherent challenges in measuring such a small quantity accurately. Nevertheless, G plays an essential role in understanding the dynamics of our universe, from the orbits of planets to the motions of galaxies.