What milestone did Voyager 1 recently reach?

After 35 years of travel, NASA’s Voyager 1 space probe left our Solar System on Aug. 25, 2012, NASA recently announced. This makes Voyager 1 the first known man-made object to travel into interstellar space. The probe is now 12 billion miles from the sun and capturing sounds, and the first sound clip has been released by NASA. As of this year, the probe is traveling at a relative velocity to the sun of 11 miles per second. By 2025, the probe will not have enough energy to power any of its instruments.