Voyager 2 space probe appears to be approaching interstellar space

Voyager 2 space probe, which has been underway for more than 41 years, appears to be leaving the solar system. The probe has been in the outermost layer of the heliosphere for 11 years and now appears to be entering interstellar space, just as Voyager 1 did.

Voyager 2’s Cosmic Ray Subsystem instrument has observed a five percent increase in cosmic rays since late August, according to NASA. The Low Energy Charged Particle instrument detected a similar radiation.

Cosmic rays are fast-moving particles that originate outside the solar system. Some are blocked by the heliosphere, an area far beyond Pluto where the solar wind predominates and where the spacecraft is now located. Mission control believes the rise in cosmic rays is a sign that Voyager 2 is about to go beyond the solar system. Also just before Voyager 1 left the solar system, there was an increase in cosmic rays.

However, the rise in cosmic rays is not definitive proof that the probe will soon enter interstellar space, according to the Voyager team. Voyager 2 is in a different position than Voyager 1, and this may mean that it will take longer for the probe to reach interstellar space.

Also, the fact that Voyager 2 reaches the edge of the solar system six years after Voyager 1 is a relevant difference. The size of the heliopause, the outermost layer of the heliosphere, is influenced by the sun’s 11-year activity cycle. The Voyager team says there are clear changes in the Voyager 2 area and expects more to become apparent in the coming months.

Voyager 2 was launched in 1977 and is currently 17.7 billion kilometers from Earth. The probe was sent into space to study the planets Neptune and Uranus. Saturn was also visited. Voyager 1, launched a few weeks later than Voyager 2, has been in interstellar space since 2012, the part of a galaxy where there are no stars and planetary systems.

Voyager 1 and Voyager 2 locations – Image: NASA/JPL-Caltech