Scientists hope to fire the first beam of protons around a 27-kilometer (17-mile) tunnel on Wednesday in science's next great step to understand the makeup of the universe.

It is one of the biggest and most controversial experiments to be carried out in recent times. On September 10, a machine costing a staggering $7.75 billion (Rs 31,000 crore) will be fired up to recapture conditions not seen since the birth of the universe almost 14 billion years ago.

The machine, located at CERN, a Geneva-based nuclear research lab, will carry on the experiment inside a 27-km tunnel deep beneath the French-Swiss border.

The Large Hadron Collider -- built since 2003 at a cost of $3.8 billion -- will provide scientists with much greater power than ever before to smash the components of atoms in a bid to see how they are made.

The startup has been eagerly awaited by 9,000 physicists around the world who will conduct experiments here, though some skeptics have criticized the experiment, saying they fear the collisions of protons could eventually imperil Earth.

The skeptics theorize that a byproduct of the collisions could be micro black holes, subatomic versions of collapsed stars whose gravity is so strong they can suck in planets and other stars.

The news of the experiment has evoked resentment from some experts, who feel that such an experiment could cause the end of the universe.

In fact, scientists working on to recreate forces that occurred immediately after the Big Bang have received death threats.