How big is the universe?

Ans Determining the size of the universe is a huge undertaking. Despite centuries of speculation and scientific exploration, the question of how big our universe really is or if it is, in fact, infinite remains unanswered and may be unanswerable. Even the most advanced instruments, which allow astronomers to observe galaxies 10 to 12 billion light years away, give no clue to what lies beyond the distance; light could have travelled since the birth of the universe, about 14 billion years ago.