A clock that is moving through space at a very fast speed does not tick at the same rate as a slow-moving watch gently attached to your wrist as you stroll on a tropical beach. The idea of a universal time - a godlike clock that could somehow sit outside our universe and measure, in one go, the movement of everything in it, how its evolution unfolds, how old it is and all that - does not exist.

— Christophe Galfard

Mankind has uncovered two extremely efficient theories: one that describes our universe's structure (Einstein's gravity: the theory of general relativity), and one that describes everything our universe contains (quantum field theory), and these two theories won't talk to each other.

— Christophe Galfard

Our image is here and will forever stay, and there is comfort in knowing that the memory of our lives will always be there, traveling among the stars.

— Christophe Galfard

The surrounding air is filled with floating atoms, sliding down the Earth's spacetime curve. Atoms first assembled in the cores of long-dead stars. Atoms within you, everywhere, disintegrating in radioactive decays. Beneath your feet, the floor - whose electrons refuse to let yours pass, thus making you able to stand and walk and run. Earth, your planet, a lump of matter made out of the three quantum fields known to mankind, held together by gravity, the so-called fourth force (even though it isn't a force), floating within and through spacetime.

— Christophe Galfard

Waking up in the same place in which you dozed off has never happened either to you or to anyone else. Ever. Earth does not stop moving when you sleep. Every hour that passes, Earth travels a little more than 800,000 kilometers around the center of our galaxy. And so do you. That's the equivalent of about twenty trips around the planet. Every hour. No one minds, though, as long as their bed stays still beneath their body.

— Christophe Galfard