Voyager-1 Approaches Where No Spacecraft Has Gone Before

Saturday, June 09, 2012

Voyager-1 Approaches Where No Spacecraft Has Gone Before — The Edge Of The Solar System

By Tom Spears
The Ottawa Citizen
6-6-12

OTTAWA — New evidence from NASA suggests Voyager-1, launched in 1977, may finally be leaving the solar system — something no spacecraft has ever done.

For more than a month, the space environment around Voyager-1 has been changing. The little spacecraft is being hit by increasing numbers of high-energy particles, suggesting it’s in a region outside the sun’s influence where there are more cosmic rays.

Our sun sends out particles called solar wind that continue far past the most distant planets. It also has an enormous magnetic field. Astronomers generally define our solar system as the area where the solar wind and magnetic field extend.

NASA has been estimating for years that Voyager-1 will reach the edge of the solar system around 2014. It is 17.9 billion kilometres from Earth, just over 120 times the distance from the Earth to the sun.

Data from NASA’s Goddard Space Flight Center show that for most of the past year, Voyager-1 was being hit an average of 1.7 times a second by high-energy particles such as protons. Around the beginning of May, that rate started climbing steadily. It’s about two particles per second now.

The implication is that more cosmic rays are hitting the spacecraft because there’s less solar influence to deflect them, “in which case Voyager-1 has reached the magnetopause boundary (i.e. where the magnetic field ends) and thus the boundary of the Solar System,” astronomer Nick Suntzeff of Texas A&M University wrote in an email. . . .

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