Final answer:
The concept that all galaxies appear to be moving away from us supports the idea of a uniformly expanding universe where space itself is expanding, not the galaxies moving through static space. This phenomenon can be explained by Hubble's law and is in line with the Copernican Principle, which states that Earth's position in the universe is not central or unique.
Step-by-step explanation:
If Earth is not the center of the universe, then how can all galaxies appear to be moving away from us? This is a common question when interpreting the implications of the expanding universe and Hubble's law, stalwarts in the field of cosmology.
The observation that galaxies are receding from us, with those further away moving faster, does not imply that Earth holds a special place in the universe. Instead, it signifies that the universe is expanding uniformly—like dots on a balloon's surface moving apart as the balloon is inflated.
This expansion of space itself is described by the model of the universe that has galaxies embedded within it, not moving through static space. Thus, any observer, no matter their location in the universe, would perceive themselves to be at the apparent 'center' of expansion because all other galaxies would be moving away from them as well.
The Copernican Principle supports this, asserting that Earth is not at the center of the universe. Just as Galileo revealed that Earth orbits the Sun and is not its center, astronomy shows us that our solar position within the Milky Way galaxy is also not exceptional.
Edwin Hubble's discovery supports a model of the universe where the appearance of all galaxies moving away from one's own position cannot be used to determine a true center of the universe.