No one really knows how big the universe is exactly. The furthest star scientist have identified in ten billion light years away. One light year is 6 trillion miles so this means the star is 60,000,000,000,000,000,000,000 miles away. But the universe may extend further than this star. The earth is not at the edge of the universe so it must extend in the other direction as well. Stars extend in ever direction but we know the universe is at least 10 billion light-years across.