“In this way, Edwin Hubble worked out the distances to nine different galaxies. We now know that our galaxy is only one of some hundred thousand million that can be seen using modern telescopes, each galaxy itself containing some hundred thousand million stars.”

“The immense distances to the stars and the galaxies mean that we see everything in space in the past, some as they were before the Earth came to be. Telescopes are time machines.”

“Whenever I saw the sun, I reminded myself that I was looking at a star. One of over a hundred billion in our galaxy. A galaxy that was just one of billions of other galaxies in the observable universe. This helped me keep things in perspective.”

“Some people think the Milky Way is a long line of stars, but it isn't. Our galaxy is a huge disk of stars millions of light-years across, and the solar system is somewhere near the outside edge of the disk.”

“The near side of a galaxy is tens of thousands of light-years closer to us than the far side; thus we see the front as it was tens of thousands of years before the back. But typical events in galactic dynamics occupy tens of millions of years, so the error in thinking of an image of a galaxy as frozen in one moment of time is small.”

“Our sun is one of a 100 billion stars in our galaxy. Our galaxy is one of billions of galaxies populating the universe. It would be the height of presumption to think that we are the only living thing in that enormous immensity.”