About five billion years ago, an energy field that we call dark energy became important. Dark energy is a repulsive form of gravity, which means that the expansion of the universe isn't slowing down, it's accelerating.
After 9 billion years of the expansion of space slowing down, it's now speeding up.
The Cosmic Background Radiation from the birth of the universe that we are seeing now originated when the universe was a sphere with a 42 million light year radius.
However that light took 13.7 billion years to reach the earth because of a rapidly expanding universe.
We can currently see objects 46 billion light years away but we see them as they were in the distant past.
We will never see the light from objects that are currently more than 15 billion light years away, because the universe is still expanding.
We are losing 20,000 stars every second to an area that will forever remain beyond our future view.