Final answer:
Although gravity is the weakest of the fundamental forces, it is the dominant force on astronomical scales due to its ability to act over large distances and affect all objects with mass, which explains the Earth's orbit around the Sun.
Step-by-step explanation:
The gravitational force is considered a very weak force compared to the other fundamental forces. However, it is strong enough to hold Earth in orbit around the Sun due to the large masses involved. The disparity can be explained by understanding that at the level of astronomical distances, like the Earth-to-Sun distance, gravity is the strongest acting force. This is because other fundamental forces such as the strong and weak nuclear forces are negligible at this distance. Gravity's ability to act over large distances and affect all objects with mass explains why we experience weight and why planetary orbits occur, despite gravity being the weakest of the fundamental forces. While the entire mass of Earth is required to hold an iron nail to the ground, a simple magnet can overcome this gravitational pull, highlighting gravity's relative weakness. Nevertheless, on a large scale such as within astronomical systems, gravity dominates and determines the motions of moons, planets, stars, and galaxies. Additionally, the nature of space and time is also influenced by gravitational force, as we will see in the study of general relativity where space curves near massive bodies like the Sun.