According to Wayne Hu here, http://background.uchicago.edu/~whu/intermediate/intermediate.html, the universe started hot and dense and then expanded and cooled. In the hot, dense conditions of the early universe, photons were tightly glued to matter. When the universe was about 300,000 years old the temperature dropped below 3,000K allowing atomic hydrogen to form and releasing the photons. These photons, which travelled freely through the universe as it expanded and cooled, make up the cosmic microwave background (CMB) we see today. Our eyes are at a specific point in the universe. A year after the universe became transparent, detectors would have measured the CMB as one light year away. The CMB which originated from matter close to us, is now long gone-it has traveled far away. At any point in time we are seeing photons from the surface of last scattering. But as time passes, we are seeing older and older photons- which originate from further and further away. And yet we think that the universe is expanding and that this expansion is accelerating. At some point the CMB should wink out of existence when the surface of last scattering becomes part of space that is moving away from us at faster than light speed. no?