Albert Einstein published his initial Special Theory of Relativity in 1905. And the universe he described placed a huge hole in Newton’s physics and left us with an enigmatic universe at the macro level

as well as micro.
Principal to Einstein’s Relativity was the idea that nothing was at rest in the universe. Hence, if everything moved, from where, in the universe, could we measure it? The answer was from wherever the observer happened to be. What he observed was relative to him. However, such an idea created a severe problem. Light seemed to travel at an exact speed – 186,000 miles per second – in a vacuum. But if the observer was moving relative to the speed of light, how could the speed of light always be constant? The answer, it seemed, was that time slowed down relative to the observer to allow the speed of light to remain the same.
Such an enigmatic concept changed science for ever. And it was to get worse in 1915 with his General Theory of Relativity. Einstein had proposed the concept of space-time, where space could not be considered without its place in time, and that this space-time curved. One of the geometrical outcomes of the concept was that space-time would be modified locally by the presence of a body with mass, such as a star or planet. In 1919, this was confirmed during an eclipse of the Sun, where light was observed to bend around it.
The general theory modified the movements of planets and meant there was no need for such a thing as gravity. A planet’s orbit around a sun arises from its natural trajectory in space-time. Although Newtonian gravitation is still used as an explanatory model, it is no longer correct. But just exactly how an exact mechanism works is still unknown.

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