Relevant references and citations — with detailed annotations — provided to TED by Sean Carroll.
"The Universe: Hubble Ultra Deep Field," HubbleSite
Many images from the Hubble ultra deep field are here.
Sean Carroll, "Squelching Boltzmann Brains (And Maybe Eternal Inflation)," Preposterous Universe, May 5, 2014
My collaborators and I have recently proposed that, even though empty space has a temperature, it doesn't actually "fluctuate." If we're right, this could dramatically change how we think about ultra-long-term cosmology.