If, as the data currently suggest, the accelerated expansion continues unabated, then as we encountered on floor 12, distant galaxies will disappear as if they have fallen over a cliff at the edge of space. That is, we are surrounded by a distant spherical horizon marking the boundary of what, even in principle, we can see. Everything more distant than the boundary recedes from us at greater than light speed, and so any light emitted from such distances will never reach us. Physicists call the distant boundary our cosmological horizon.
