One short trip for a proton, one not-so-giant step for mankind, it turns out. On September 10 scientists at the Large Hadron Collider, near Geneva, successfully steered the first beam of protons around the accelerator’s 27-kilometer circular track. After entering the tunnel, the beam twice struck a scintillating screen, causing atoms in the screen to emit light. The first yellow spot in the screen grab at left was created just after the protons were kicked onto the correct trajectory by the injection system. The second spot was generated after the protons made one complete revolution, again striking the screen. But just nine days after this initial success, a faulty electrical connection in the tunnel led to a helium leak. Officials say the setback, combined with the closing of the accelerator during the winter to save fuel costs, means the long-awaited collision won’t be attempted until at least next spring.