Space Expanding
Every galaxy not bound to ours by gravity is receding from us, faster the farther it is. From any other galaxy, the same pattern. There is no center because expansion happens everywhere at once.
What you're seeing
A grid of galaxies. As time advances, the space between them stretches. Every galaxy moves away from every other galaxy — no privileged center, no edge. Slide the observer slider to put yourself at a different galaxy, and the same pattern holds: everything moves away from you, faster the farther out.
This is the actual structure of cosmic expansion. The galaxies aren't flying through space — space itself is expanding between them. The distance grows because the metric is changing, not because anything is moving in the conventional sense.
Why atoms don't fall apart
Toggle "show bound objects" to see clusters of dots holding together while the larger grid stretches. These are atoms, planets, solar systems, galaxies, galaxy clusters — anything bound by a force stronger than expansion locally is. Within them, expansion is overwhelmed by gravity or electromagnetism by factors of 10³⁰ or more. Expansion still happens — it just doesn't win.
"Expansion only matters where nothing is holding things together. Inside an atom, the electromagnetic force wins by 39 orders of magnitude. Inside a galaxy, gravity wins. Between unbound galaxies, expansion wins."
This is why your body doesn't tear apart even though space is expanding through it. Every chemical bond, every gravitational pull within Earth, every binding force is overwhelmingly stronger than the local stretch. You are a knot of bound systems sitting in a stretching universe, and the knots stay tied.
No center, no edge
Move the observer slider. Every position sees the same pattern — galaxies receding, faster the farther they are. This isn't a bug; it's the central feature of homogeneous expansion. There's no "real" center because expansion isn't happening around a point, it's happening everywhere. A 2D analog: dots painted on a balloon as it inflates. Every dot sees every other dot moving away. No dot is special. The "center" of inflation exists in a higher dimension that no dot can reach.
Our universe might be like the balloon (finite but unbounded) or genuinely infinite. We can't tell from inside. What we can verify is that the math of expansion is symmetric: every observer is the center of their own observable universe. All of them are correct.
The receding horizon
One more thing the math forces: galaxies far enough away are receding faster than light. This doesn't violate relativity because they aren't moving through space faster than light — the space between us is stretching faster than light. Their light will never reach us. They are permanently outside our reachable universe.
And because expansion is accelerating, more galaxies cross this horizon every second. The observable universe is shrinking relative to the total. In ~100 billion years, observers in the Milky Way will see only a few gravitationally-bound galaxies. Everything else will have receded into the dark.
Future astronomers will have no evidence of the Big Bang. No evidence of expansion. No evidence other galaxies ever existed. The information will have left their light cone forever. We're living in a privileged epoch where the expansion is still visible.