Gravity is a phenomenon of space-time curvature. We all know of the tree dimensions, but introduce the fourth one and things become very complicated. Time is the fourth dimension, even though some have suggested that there are as many as nine dimensions, while others hold on to the assumption that there is an infinite number of dimensions. Whatever the true case is, let us stick to the four dimensions that have been proven to exist. The topic of dimensions is very important in determining the existence of substances and bodies. But why do bodies tend to “fall” towards the surfaces of more massive ones? This might imply that there exists a force which tends to pull on these bodies. Revisiting this topic about the warping of space brings back the notion of the existence of ether. During the time when the experiment about ether was being conducted, it was thought that it was a physical substance engulfing the surface of the earth, just like the atmosphere does. It had not been considered otherwise. These experiments concerned light. (We are not going to talk about ether and the Moley experiments here in this article. Read an article on “Space; what is it?”).
Suppose a body is travelling through space and it draws near a more massive body. Since both bodies warp space around them, they have a tendency to “fall” towards each other. The one with the greatest warping of space around it “pulls” greatest. The lighter one tends to “fall” into or onto the more massive one. This is due to the less warping of space created by the body with less mass. The lighter body is “attracted” towards the massive one. Under ordinary circumstances, this body would end up falling onto its counterpart. But there is a way that the body with a smaller mass redeems itself from annihilation; it revolves around the more massive one. This means that it has to maintain a certain angular velocity around the more massive body for it to survive. But where does get the energy to sustain its revolution, one may ask. The answer is quite simple but a little bit complicated. The trajectory described by this body is not a perfect circle. It is eccentric. More so, the “parent” body is not centrally located. This means that the orbit takes the shape of an egg; it is oval. This oval shape and the fact that the “parent” body is not centrally located are very vital in sustaining the revolution of a less massive body. The less massive body must have a certain angular velocity for it to maintain its orbit. It this value falls, it risks being annihilated; if it is too high above the limit, then it might fly away. For this reason, there is always a tug of war between centripetal and centrifugal forces (all these are apparent forces). Generally, less massive bodies tend to “fall” towards the surfaces of the more massive ones.
This analogy applies to the bodies in the solar system and the whole universe. They are “falling” towards each other but there exist very slim chances that they would ever collide, e.g. the moon and the earth, both bodies are massive and travelling at a certain angular velocity above a certain threshold.
Considering the above arguments, is it valid to still refer to gravity as a force? Force is carried by particles e.g. the magnetic force, nuclear force, electrostatic force etc. If gravity is to be treated as a force, then this implies that there are particles to carry it- gravitons, as some have suggested. Unfortunately, gravitons have not been found or discovered just yet. Maybe the current technology makes it very difficult to identify the gravitons- just may be. Meanwhile, gravity is just a field but not a force. But some may argue that fields are created by forces, and that this may imply that there might be a force responsible for gravity.
Picture this; let the portion of the universe containing the solar system be considered as a bubble (perfect sphere). The sun is at the center of this massive bubble and the planets and other bodies surrounding it. Due to the massive nature of the sun, it warps the space around it more than any other body in the bubble. This warping of space causes other bodies to “fall” into the sun, regardless of their position in space. If these bodies were stationery, then they would fall straight onto the surface of the sun and perhaps deeper since the surface of the sun is gaseous. But this is not the case, in most occasions. The planets and other bodies tend to maintain their orbits, and continue revolving around the sun. This observation can be explained from the time the sun and the planets were forming.
After the supernova explosion of a star which gave rise to the stellar dust from which the solar system and the planets were formed, this material was rotating and also moving through space. As the sun and the planets formed, these masses continued with their respective motions.