NASA’s Voyager 2 probe, currently on a journey toward interstellar space, has detected an increase in cosmic rays that originate outside our solar system.
Launched in 1977, Voyager 2 is a little less than 11 billion miles (about 17.7 billion kilometers) from Earth, or more than 118 times the distance from Earth to the Sun.
Since 2007 the probe has been traveling through the outermost layer of the heliosphere — the vast bubble around the Sun and the planets dominated by solar material and magnetic fields.
Voyager scientists have been watching for the spacecraft to reach the outer boundary of the heliosphere, known as the heliopause.
Once Voyager 2 exits the heliosphere, it will become the second human-made object, after Voyager 1, to enter interstellar space.