Hi Penn, You quoted Brad Guth ( a Win_98 user ? ) saying:

Nothing ever runs into anything nor ever dies out there,
as it simply gets further and further away
no matter what your laws of physics have to say [snip]

According to our best observations
( WMAP, SNLS, Planck_Surveyor, SNAP, SDSS, LSST )
the universe has cooled from At_Least Planck_Temperature
( 10 ^ 32 degrees Kelvin ) to 2.7 Kelvin today,
....and Guth imagines that didn't kill anything ?
He must have thicker thermals than I do.
P.S. There's no limit to density/heat
just like there's no limit to vacuity/coldness.