So, for a while people were content to believe that planets circled the Sun in elliptic orbits. However, there was more to learn for the diligent observer. By the end of the 19th century, it was known that the orbit of the planet Mercury could not be accounted for by Newton's theory of gravitation.
This issue was solved in 1915 by Albert Einstein (1879-1955) and his General Theory of Relativity. According to this theory, gravitational attraction between two masses warps the space time. Space time is difficult to perceive since it represents the three Euclidean dimensions plus the dimension of time.
In relativistic contexts time cannot be separated from the three dimensions because the rate at which time passes depends on the velocity of the object relative the speed of light and also on the possible presence of strong gravitational fields that slows the passage of time down.
General Relativity predicts and explain many observed phenomena. It provides the foundation for the understanding of so called "black holes" in space. General Relativity is also part of the framework of the Big Bang cosmology.
General Relativity theory does not, however, provide solutions for all questions either. It can for example not be reconciled with the laws quantum physics to produce a complete and self-consistent theory of quantum gravity. Relativity theory deals with the large scales whereas quantum mechanics deals with the atomic world.
I have included this study of gravitation for illustrating how new questions appear all the time as one move along in science. So far, there is no end in sight. This should make us restless and inquisitive.
Data from Wikipedia
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