Heads up, science fiends and night owls: The greatest science experiment ever built is set to switch on at around 3:30 A.M. Eastern time tomorrow.

After 14 years and $8 billion, the European Organization for Nuclear Research (CERN) plans to inject the first beam of protons fully around the Large Hadron Collider (LHC), the circular particle accelerator 17 miles (27 kilometers) long straddling the Franco-Swiss border near Geneva.

It will most assuredly not destroy the world.

What it will do is help researchers answer some big questions about the universe—why particles have mass; what dark matter may be made of, and why matter survived its brush with antimatter when the universe was young.

The LHC will accomplish all that by producing high-energy particle collisions—600 million per second—for detectors to scan for rare but telling debris. (See our special report, The Large Hadron Collider: Countdown.)

CERN estimates that in six to eight weeks it will steer the first proton beam into a head-on crash with a second beam circulating the other direction, for a combined energy of 10 trillion electron volts (TeV) per collision. The lab plans to shut down the accelerator for the winter in mid-November and prepare it to restart next year at its full energy of 14 TeV.

Scientists by now are sick of reiterating that they would not have built such a machine if they had the slightest fear that it would produce microscopic black holes capable of destroying the world. Nor do they appreciate the death threats.

Here's a list of LHC events around the country.

Image credit: CERN