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First probe to leave our Solar System

First probe to leave our Solar System
Who
Voyager One
Where
Not Applicable
When
25 August 2012
Launched in 1977, Voyager 1 was sent to study the outer planets, but has now travelled beyond the edges of our solar system into interstellar space. Readings taken in April/May 2013 were compared with those taken in October/November 2012 and revealed a near-100-fold jump in the number of protons occupying every cubic metre of space. This was the clear indication scientists had been watching for to establish Voyager 1 had left the solar system. When the Voyager team compared the data together with information from the other instruments onboard, they calculated the moment of escape to have occurred on or about 25 August 2012.