u/No_Woodpecker6948

Electromagnetism was successfully incorporated into quantum mechanics through quantum electrodynamics (QED), treating the electromagnetic field as a quantum field whose interactions are mediated by photons.

Why can’t we apply the same mathematical reasoning to gravity, quantizing the gravitational field and introducing gravitons?

What exactly breaks down when we try? Is it a fundamental incompatibility between general relativity and quantum mechanics, or mainly a mathematical problem we haven’t solved yet?

Consider a ship currently located at a distance of 1 light-year from earth, travelling in straight line at constant speed of 0.9999999999999999999c in relation to earth's frame of reference.

Consider that there is an intelligent alien inside the ship.

From the ship's frame of reference, the alien is stopped while earth is moving.

From earth's frame of reference, earth is stopped while the ship is moving.

So everything is symetrical.

Yet... If the alien would send a signal to earth, we would receive the signal 1 year later.

But... If we would send a signal to the ship, the alien would receive it about 2,2 billion years later.

What is the explanation for this, if there's no absolute frame of reference in the universe?

EDIT1: It would be 10 quintillion years, instead of 2,2 billion years.

EDIT2: The ship is travelling FARTHER AWAY from earth.