Basically this is a term created to say we have no idea why our Universe seems to be expanding. I have a theory and would like it torn apart as much as possible....I request peer review. Dark energy is large scale Gravity. Our solar system and thus everything we observe is about 14 Billion years from the big bang event. we have no idea what someone 15 billion light years away sees. Perhaps our Universe is infinite and we only see our little part but gravity compounds, drawing everything outward. This would make us see unexplained expansion and in ways tackle dark matter as well. I would also point out that a Big Bang, like every explosion is a spherical event and this the most we will see at this point in our technology is the half between us and the Bang.