A Drawing of the ASCOT Experiment from the 1992 letter of intent. (Image: ATLAS Experiment/CERN)

This Tuesday, if all goes according to plan, will mark the end of a very long journey for many High Energy Physicists. The first 7 TeV Collisions will signal the end of the the commissioning period of the LHC and its experiments. That journey started many many years ago (before I had even entered High School). At that point in time ATLAS was a concept or, indeed, two concepts. Two proposals (ASCOT and EAGLE) were complementary enough that the physicists pushing them felt more convenient to join the effort and design a single, larger detector. After many conversations over coffee, and meetings, ATLAS become a coherent idea that was put down in paper. Then came the endless reviews, and discussions, and emails (and I could not imagine how this could ever be possible without the web). Finally the project got approval and construction could truly begin. Now we are ending this journey. The journey of designing and building one of the most complex and sophisticated instruments ever. We have checked that it works (as it was intended to work), and now it is time to send this ship out into the open seas.

EAGLE Experiment Design from the 1992 letter of intent. The EAGLE Collaboration and the ASCOT Collaboration joined forces to create the ATLAS Experiment. (Image: ATLAS Experiment/CERN)

However, The first 7 TeV collisions will also mark a new journey. The beginning of physics operations at the LHC. This is the journey that everyone has really been waiting for. At the instant that the first protons collide with a center-of-mass energy of 7 TeV, mankind will have stepped into a world that has never been seen before. At these energies we hope to find the secrets of nature that have been so well hidden from us. This world won't be revealed to us all at once though. It will take years, even decades, and painstaking efforts to analyze what we see. There will be endless, mind numbing shifts. There will be moments of interruption of the LHC operation (planned and unplanned). There will be countless sleepless nights for many physicists and graduate students to come. Only after many monumental efforts from many people will the fruits of our labor be reaped.