Nicolas Copernicus

1543, published On the Revolutions of the Celestial Spheres. This was considered the birth of modern astronomy. It presented the theory that the Sun is the centre of the solar system.

The Copernican Principle is that no particular location should be special.

In the perfect Copernican Principle, this idea is extended to time as well as space. In a relativistic universe, this makes sense since time and space are inextricably intertwined.

The Big Bang theory is not compatible with this principle, since it includes a very special event, the Big Bang some 13.7 billion years ago.

Further, according to the theory, we just happen to be living at a very special time, one where we can just see the earliest moments following the Big Bang.

In 100 billion years, if the theory is correct, the only galaxies we will be able to see will be those currently gravitationally bound to our galaxy.