Ethan Siegel in Forbes:
Perhaps the biggest surprise of all about the Universe came at the very end of the 20th century: the discovery of dark energy and the accelerated expansion of the Universe. Rather than being pulled towards us gravitationally, the most distant galaxies in the Universe are speeding away from us at ever faster-and-faster speeds, destined to disappear from our view. But does that create its own information paradox? Rob Hansen wants to know, and inquires:
The universe's expansion means our visible horizon is retreating; things faraway are vanishing continuously. (Albeit slowly, right now.) This would seem to imply we are losing information about the universe. So why is it the idea of losing information in a black hole's event horizon is so controversial, if we're constantly losing information to another horizon?
There's a lot to unpack here, so let's start with the accelerated expansion of the Universe.