The photographs of Earth from space are changing how people think about the planet. I’ve been sitting with this since Apollo 8’s Christmas Eve broadcast and now, with the Apollo 11 images also out, I want to write about what I think is happening.

The Earthrise photograph from Apollo 8 — Bill Anders’s picture of the Earth appearing above the lunar horizon, blue and white against black space, with the gray lunar surface in the foreground — has become one of the most reproduced photographs in history. It’s on posters. It’s in textbooks. Time magazine ran it in multiple issues. It is, I believe, genuinely one of the most important photographs ever taken.

What does it do to you, this photograph?

It shows you your home from the outside. This is something no human being could do before December 1968. You could describe the Earth as a sphere orbiting the Sun — scientists have known this for centuries. But you couldn’t see it. You couldn’t hold the image in your mind of the actual planet, isolated in space, small, finite, vulnerable.

The photograph makes that visible. Here is Earth. This is all of it. The oceans and the clouds and every person who ever lived and every city and every nation — all of it in this small blue curve against the black.

Carl Sagan, who writes about these things for a general audience, has been describing the effect as a kind of philosophical shift — seeing the planet from the outside forces a confrontation with how small we are and how alone this world is in the dark. He hasn’t used the phrase “Pale Blue Dot” yet (that’s from a Voyager photograph decades away) but the idea is already here.

There are people who believe that the image will matter — philosophically, environmentally, politically — long after the space race is a footnote. That seeing the Earth whole will change how humanity relates to it.

I think they might be right. I hope they’re right.

Looking at that photograph: here we are. One world. All of us, together, on this.