One-Light-Day

One light-day, at your fingertips. Pinch, zoom, and scroll from everyday scales to the planets and beyond, all the way to Voyager 1.

One Light-Day is an app created to commemorate Voyager 1’s passage of the “one light-day point” from Earth.

But just how long is a “light-day,” anyway?

In this app, a variety of objects—from familiar things on Earth to the Moon, the planets, the edge of the solar system, and even Voyager 1—are arranged according to a single scale.

You can zoom in or out wherever you like. Of course, you’re also welcome to just scroll through it.

Space is filled with an astonishing amount of empty space.

“Aren’t we there yet?” “Just how far does it go?”

Experiencing that vastness for yourself is one of the joys of this app.

The purpose of this app isn’t to recreate space exactly as it is.

It’s about feeling its vastness and distance in a way that’s a little different from usual.

There isn’t just one “correct scale” for viewing the universe.

Zoom in. Zoom out. Scroll.

One light-day, right in your palm.