The Voyager probes: the ache for immortality
As of this writing, the two Voyager probes are between 15 and 20 billion kilometers from earth; transmissions, traveling over the Deep Space Network at the speed of light, take more than 15 hours to bridge the gap. And yet despite the distance they’ve traveled, the probes are still in the solar neighbourhood, mind-bogglingly far from other systems; Voyager 1 won’t pass within two light years of another star system for some 40 thousand years, and Voyager 2 will come within five light-years of Sirius in about 300,000 years. The probes are now moving through the heliosheath, the outer layer of the sun’s atmospheric influence, on the verge of interstellar space. Regardless of their speed relative to the Earth, in galactic terms they’re very nearly stationary, joining the vast dance of stellar and dark matter in its stately, 250-million-year orbit of the Milky Way. When the two Voyager missions launched from Cape Canaveral in 1977, embarking on a grand tour of the outer planets that ulti...