Reality Is Not What It Seems: The Journey to Quantum Gravity

by Carlo Rovelli

But it is not only space that curves: time does too. Einstein predicts that time on Earth passes more quickly at higher altitude, and more slowly at lower altitude.

Earth, like all masses, distorts spacetime, slowing down time in its vicinity. Only slightly—but two twins who have lived respectively at sea level and in the mountains will find that, when they meet up again, one will have aged more than the other

The atoms of our body, as well, flow in and away from us. We, like waves and like all objects, are a flux of events; we are processes, for a brief time monotonous. . . .

This permanent doubt, the deep source of science.

If you remember chapter 3, the answer is no. The watches that we usually wear on our wrists, or have on our mobile phones, are not sufficiently precise to allow us to verify this fact, but in physics laboratories all over the world, there are timepieces precise enough to demonstrate the discrepancy that occurs: the watch left on the floor is slow when compared to the one that has been raised above it. Why? Because time does not pass in the same way everywhere in the