Penrose diagram

That may sound strange, but it gets stranger.

To really understand what this eternal black hole looks like, we're going to need to use a tool that we've already played with, the Penrose diagram.

To refresh your memory, in a Penrose diagram, the X and Y axes are redefined from space and time to merge space and time into new coordinates.

They compactify spacetime so that time bunches up towards the edges and the borders correspond to infinite past and future.

Also, lines of constant distance and time curve so that light paths always travel on 45-degree paths.

Any movement to the left brings you closer to that event horizon.

The event horizon itself is a 45-degree line.

In our weird Penrose coordinates, this represents a constant distance from the center of the black hole.