Did the Voyager 1 spacecraft really leave the solar system?

Last year, scientists working with the Voyager I spacecraft excitedly announced that the craft had passed out of the solar system after 35 years of flight. Today, they are not so sure, but they are certain they are about to pass a final key milestone sometime soon.

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LOS ANGELES, CA (Catholic Online) - At 11.5 billion miles away, the Voyager I spacecraft has spent almost 36 years in flight and is still going strong despite its age and distance. Voyager I is the farthest man-made object from Earth and continues to sail at a stately 38,000 miles per hour.

Last July, scientists detected a sudden drop in the number of charged particles encountered by the satellite. This was one of the expected signs that Voyager had left the solar system. However, the drop in the particles, collectively known as the solar wind, was only temporary. The wind resumed days later, then dropped again in mid-August. Finally, on August 25 the solar wind dropped to zero, and has remained there ever since. However, this was only one expected sign the craft had exited the solar system.

Scientists expected the other sign would be a change in the orientation of the magnetic field from the customary Sun-oriented direction to something essentially unknown once the craft encountered interstellar space. Scientists expected the two events to coincide because the solar wind follows the sun's magnetic field.

Yet, despite the drop in the solar wind, the magnetic field persists.

This persistence makes it debatable whether or not Voyager has actually left the solar system. However, everyone agrees the craft is very near the boundary, if it has not crossed it yet.

One of the mission goals of the Voyager spacecraft is to determine what happens at the edge of the solar system, and to discern what it can of the nature of interstellar space - the space where no single star has influence.

Already the craft is so far away that if it were to photograph the Sun, it would appear as no more than a bright point of light against the vast stellar panorama of the Milky Way.

Engineers deliberately designed Voyager for this long-term mission into the void of space, complete with a plutonium power plant that is expected to power the craft at least until 2020, or perhaps much longer. Scientists intend to study data sent back by the craft as long as it remains powered.

The computer on board Voyager was state of the art in 1977. At launch, it featured a whopping 68 kilobits of memory on a ribbon like those used on 8-track cassettes. By comparison, an iPhone uses 512 megabytes of memory, an iPad over one million (1GB), and the latest smartphones two million (2GB).

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The spacecraft has used this ribbon of memory daily for almost 36 years, writing and rewriting as needed to carry out its mission. With this ribbon, Voyager has discovered moons around Jupiter, photographed the majestic rings of Saturn, and now breaks the barrier at the edge of the solar system.

When Voyager will encounter the last vestigial influence of the Sun remains to be seen, but scientists are expecting the news to come back any day now. They confess, the data does not perfectly match their predictions, yet they still expect the fateful measurement to register within the next several months to years, at the latest.

When that happens, Voyager will begin the final and most lengthy phase of its mission - its interstellar phase. That phase will last from 40,000 years to anytime beyond. At 40,000 years out, Voyager 1 will pass within 1.6 light-years of the star, Gliese 445 a red-dwarf star in the constellation Camelopardalis, near the more commonly recognized star Polaris, as seen from Earth.  No life is expected to exist around this star as it is thought to be too dim to support it.

Nonetheless, Voyager I has a mission. On board the craft is a golden record onto which photos and the sounds of life on Earth have been recorded. Any intelligent beings which locate the craft will discover a map, guiding them to Earth's location in the solar system and proof that intelligent life is out there, waiting for a response, in the great galactic void.

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