WASHINGTON, Sept 12: Never before has a human-built spacecraft travelled so far. Nasa’s Voyager 1 probe has now left the solar system and is wandering the galaxy, US scientists claimed on Thursday.

The spacecraft was launched in 1977 on a mission to explore the outer planets of our solar system and to possibly journey into the unknown depths of outer space.

“This is the first time that humanity has been able to step outside of the cradle of the solar system to explore the larger galaxy,” Marc Swisdak, an astrophysicist at the University of Maryland, said.

The precise position of Voyager has been fiercely debated in the past year, because scientists have not known exactly what it would look like when the spacecraft crossed the boundary of the solar system -- and the tool on board that was meant to detect the change broke long ago.

However, US space agency scientists now agree that Voyager is officially outside the protective bubble known as the heliosphere that extends 13 billion kilometres beyond all the planets in our solar system, and has entered a cold, dark region known as interstellar space.

Their findings — which describe the conditions that show Voyager actually left the solar system in August last year -- are published in the US journal Science.

“Voyager has boldly gone where no probe has gone before, marking one of the most significant technological achievements in the annals of the history of science,” said a statement by John Grunsfeld, Nasa’s associate administrator.

The twin spacecraft, Voyager 1 and Voyager 2, were launched in 1977 on a primary mission to explore Jupiter and Saturn.

They discovered new details about the nature of Saturn’s rings and found volcanoes on Jupiter’s moon Io. Voyager 2 travelled on to Uranus and Neptune, before the duo’s mission was extended to explore the outer limits of the Sun’s influence.—AFP