As many of you may know, the ATLAS detector (and for that matter CMS) is physically huge. It weighs about 7000 tons, and measures approximately 45 meters in length and 20 meters in diameter. It is the size of a small ship, one packed with sensitive silicon sensors, sophisticated electronics, and powerful on-board computers.
When the proton beams start to collide at the LHC, we will be re-creating conditions that existed about 10-12 second after the big bang (of course, a lot of the interesting stuff had already happened in the first 10-37 second). All the heavy particles that we will create in these collisions existed freely in the aftermath of the big bang.
Although, these collisions will be taking place in the laboratory, one can imagine a ship travelling back to the beginning of time, and sending information about what is going on there.
— Vivek Jain, Indiana University