Last November, scientists debated whether Voyager had reached the so-called termination shock region.

BBC: Voyager impression (Nasa)

Also, changes in the speed and pressure of the solar wind cause the termination shock to expand, contract and ripple.

BBC: Voyager impression (Nasa)

Predicting the location of the termination shock was hard, the researchers say, because the precise conditions in interstellar space are unknown.

BBC: Voyager impression (Nasa)

Now, at the 2005 Joint Assembly meeting organised by the American Geophysical Union, space scientists say they are confident - and agreed - that Voyager has gone beyond the termination shock and is flirting with deep space.

BBC: Voyager impression (Nasa)

Louis Lanzerotti of Bell Laboratories and the New Jersey Institute of Technology said his team had found "compelling argument" that Voyager I was "in the vicinity of the termination shock" and had even passed briefly into the heliopause.

BBC: NEWS | Science/Nature | Voyager 'at edge of Solar System'

The most persuasive evidence that Voyager 1 has crossed the termination shock is its measurement of a sudden increase in the strength of the magnetic field carried by the solar wind, combined with an inferred decrease in its speed.

BBC: Voyager impression (Nasa)