In Brief
Assuming the universe exists in a state similar to how it is now, without the big rip, big freeze, big bounce, big slurp or any other proposed scenarios taking place,  what will our descendants see when observing distant sources of light? Or rather, what will they not see? How will the universe change over the next few trillion years?

Assuming the universe exists in a state similar to how it is now, without the big rip, big freeze, big bounce, big slurp or any other proposed scenarios taking place,  what will our descendants see when observing distant sources of light? Or rather, what will they not see? How will the universe change over the next few trillion years?

future of the universe infographic
Image source.