大象传媒

Voyager 1 was launched into space in 1977 to study the planets beyond our own. But after passing them one by one, it just kept on going. And now scientists believe the probe left the edge of our solar system on the 25th August last year. It crossed a region known as the heliopause, where particles hurled out from the sun pile up against the matter and magnetic fields from other stars. Now, at nearly 12 billion miles from earth, it's in interstellar space - a cold, dark part of the Milky Way filled with gas and dust. Ed Stone is Voyager's chief scientist:

Ed Stone, Voyager鈥檚 chief scientist:
This is one of those journeys of exploration, like circumnavigating the globe for the first time, or having a footprint on the moon for the first time. This is the first time we have been exploring now, this new region of space, interstellar space.

As Voyager 1 ventures into the unknown it will send data back to Nasa. Eventually though, it will fall silent - its power supply is expected to run out in the next 10 years. But if the probe is ever happened upon by extraterrestrial beings as it floats through space they'll find a record containing pictures and messages. (RECORDING OF VOICES)