Investigation into beginning of time or fiddling with nature

It has been called an Alice in Wonderland investigation into the makeup of the universe - or dangerous tampering with nature that could spell doomsday.

Whatever the case, the most powerful atom-smasher ever built comes online today, eagerly anticipated by scientists worldwide who have awaited this moment for two decades.

The multibillion-dollar Large Hadron Collider will explore the tiniest particles and come ever closer to re-enacting the big bang, the theory that a colossal explosion created the universe.