Godspeed you, Voyager 1

Farthest manmade satellite departs the solar system.

Voyager 1 has gone boldly where no man-made satellite has gone before. On September 12, NASA scientists announced that the thirty-six-year-old probe had finally exited our solar system, a first for any object man has launched skyward. Scientists have been hotly anticipating the satellite’s departure for over a year, the exact moment of which has been unclear up to now.

Since 2004, the probe has been expected to burst out of the sun’s magnetic influence, but uncertainty over the nature of the outer solar system has kept its followers on the edge of their seats. Our sun constantly emanates a stream of charged particles, known as the solar wind. The solar wind dominates the space around our planets and beyond, but is countered at the edge of the solar system by another force: cosmic rays. Each force carries with it a detectable magnetic field, but their interactions at the edge of the solar system was highly speculative. Last August, science journals were abuzz with the news that Voyager 1 had exited the sun’s solar wind field; had it finally escaped our solar system?

NASA concluded that it had not, because the magnetic field had not switched directions to coincide with the Milky Way’s cosmic rays. This change is still yet to be detected, but mission control recently reevaluated the last year’s data. NASA officially concluded that Voyager 1 had departed the heliopause, the outermost layer of our solar system, on August 25, 2012.

What has this deliberation taught us? Just how little we know about the outer reaches of the solar system. Longstanding theories and hypotheses concerning the interplay of particles, plasmas, and magnetic fields in the heliopause will have to be entirely re-evaluated. After all, Voyager 1’s encounter with this solar terminus is a first, and will pave the way for future exploration beyond our home sun.

This 1600-lb satellite is the farthest-reaching legacy of human civilization. As such it has a very special piece of cargo: a gold-plated audio-visual disc with a record of our species and home planet, directly intended for any intelligent life-forms that may find it aeons in the future. Inscribed on its surface is a star-map of Earth’s location and schematic of how to access its digital information.

Its contents were summarized by a message included from then-U.S. President Jimmy Carter, “This is a present from a small, distant world, a token of our sounds, our science, our images, our music, our thoughts and our feelings. We are attempting to survive our time so we may live into yours.”

It’s been decades since Voyager 1 was launched, and most of the world had all but forgotten it. Yet its media revival has reminded us not only of its contributions to science, but its legacy in human history. At this point it has an ambiguous trajectory, given the yawning emptiness of space beyond our solar system. By 2025 Voyager will slowly run out of its power reserves and we will lose all contact with it. Provided it doesn’t hit anything, overwhelmingly likely in inter-solar space, it could survive millions of years. Whether human civilization prospers or collapses, whether all trace of us on Earth is destroyed, Voyager 1 will remain, a cosmic message-in-a-bottle through space and time.

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