Hi, I read sean carroll book, "spacetime and geometry" and in the last chapter where he tries to derive unruh effect, he introduced the concept of Rindler coordinate. There is this part where he considers an accelerating observer in minkowski metric and introduce the trajectory blah blah. My question is, since the observer is accelerating, there must be some sort of fuel or energy propelling, so this energy by itself will actually result in curvature in the spacetime manifold. So isn't the consideration of accelerating observer in minkowski space invalid?? Thanks in advance for any response.