[aeternum]

That's my understanding as well, but there are some well-established features of the universe that make this more plausible.

We know that our spacetime is in anti de Sitter space which is a type of hyperbolic geometry. In this geometry, infinity can be thought of as the edge of a sphere containing our universe.

Matter is equivalent not only to energy, but also to frequency and wavelength. Once all matter decays to photons and those photons hit infinity, there isn't anything remaining in the universe that provides any sense of scale. It could be argued that the concepts of frequency, wavelength, time, and length cease to exist.

Since you no longer can measure scale, all those photons at infinity look very similar to the photons in the primordial soup of the big bang. Furthermore there could theoretically be information transfer as the pattern of photons on the sphere vs. the pattern of the primordial soup (visible today as the cosmic background radiation) would be the same.

[galaxyLogic]

> those photons hit infinity

What does that mean "hit infinity"? I would think that could only happen after an infinite amount of time, in other words never.

[aeternum]

It is only from the reference frame of some physical observer inside the universe that it takes time for them to reach infinity.

From the reference frame of a photon, not only does it instantly arrive at infinity, but infinity and its original position one in the same since length is contracted to zero.

[galaxyLogic]

So photons are at infinity already?

[aeternum]

Yes, it can be looked at that way or that time & distance do not exist for photons.