Milestones

CROSSED. The edge of the solar system; by VOYAGER 1 , a 26-year-old spacecraft that has traveled farther than any other man-made object. Scientists differ on Voyager 1's precise location, but radio transmissions from the probe indicate that it has entered or is about to enter a turbulent border zone more than 13 billion kilometers from Earth called "termination shock," where matter from interstellar space slams into radiation emitted by the Sun. Data sent by Voyager 1 showed a marked drop in the speed of solar winds and a hundredfold increase in charged particles, some of which probably originated in deep space....