We in astrophysics we think of the universe all the time. So to us, Earth is just another planet. From a distance, it's a speck. And I'm convinced that if everyone had a cosmic perspective you wouldn't have legions of armies waging war on other people because someone would say, "Stop, look at the universe."

In five billion years, the sun will expand and engulf our orbit as the charred ember that was once Earth vaporizes. Have a nice day

While the Copernican principle comes with no guarantees that it will forever guide us to cosmic truths, it's worked quite well so far: not only is Earth not in the center of the solar system, but the solar system is not in the center of the Milky Way galaxy, the Milky Way galaxy is not in the center of the universe, and it may come to pass that our universe is just one of many that comprise a multiverse. And in case you're one of those people who thinks that the edge may be a special place, we are not at the edge of anything either.

Knowing how to think empowers you far beyond those who know only what to think.

I have thoughts every day that are themselves tweets.

Let us not fool ourselves into thinking we went to the Moon because we are pioneers, or discoverers, or adventurers. We went to the Moon because it was the militaristically expedient thing to do.

We're talking about a being whose very existence challenges our own sense of priority in the universe.