The Deepest Time in the Deepest Space
This is the most distant object known to humans...
It's called MACS0647-JD. Its light took 8 billion years to reach us. The age of the universe is 13.7 billion years. The earth is 4 billion. Life is 3.6 billion. Humans, 200,000 years. And we are a life form that happens to be in the universe at the right time, because in the deep future the universe won't be filled with brilliant galaxies but a great emptiness that surrounds our one and only galaxy. This is the action of dark energy. It's pulling the distant galaxies apart at a faster and faster rate. And at one point in the future, light wont be able to cross the ever-expanding emptiness between the galaxies.
Indeed, if you were to fly into this future time, communicate with an intelligent life form in our now-isolated galaxy, and tell them that there are truly other galaxies in the universe, you'd be considered mad. No amount of science could prove the truth of your statement, could prove that other galaxies exist and that the universe was once filled with the galaxies we see all around us today. You would be right, the science would be wrong, but there would be no way of knowing or showing this fact.