The Copernican principle changed everything. It was not formulated by Copernicus, who in 1543 proposed only that the Earth was not the centre of the universe, and that the motion of the Earth around the sun could explain the irregularities in the heavens. At the time, ideas like that could get people condemned to the stake. But it was the start of a revolution. The modern working hypothesis known as the Copernican principle states that there is nothing special about our planet, our solar system, our galaxy, our place in the universe.
Nor is there anything special about now. The laws of physics have not changed in 13.8bn years. In some unimaginable cosmic future, the speed of light in a vacuum will be the same, and the mechanics of waves water, seismic and light will be as they were in the beginning. The properties of hydrogen and helium are the same, and the gravitational forces that shaped the solar system would be no different in Andromeda, or the Orion Nebula. The peculiar ways that different atoms and molecules absorb and radiate light at predictable wavelengths are the same in the corona of the sun as in intergalactic space 1bn light years away.
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