A spacecraft launched from Earth is close to the edge of the Solar System.
Voyager 1 lifted off 33 years ago in 1977, and has been travelling through space ever since.
Now it's over 10 billion miles from Earth, space experts reckon it's nearly in an area called interstellar space - which is the space between the stars.
It will be a couple of years until the probe reaches right to the edge - but considering the huge distances involved, that's really quite close!
No one knows what Voyager 1 will find once it leaves our solar system - but it's already started recording some changes.
Voyager 1 set out to study planets like Jupiter - but kept going!
Not that it's easy to read - it's so far away that a radio message back to Earth takes 16 hours to arrive!
Voyager 1 was never designed to travel this far.
It set off way back in 1977 to record planets like Jupiter and Neptune, but just kept going!
And scientists didn't know it could travel the distance it has.
Edward Stone who works on the project said: "We had no idea how far we would have to travel to get outside the Solar System.
"We now know that in roughly five years, we should be outside for the first time."
And the big question is - what lies ahead on Voyager 1's amazing journey?