An uptick in a certain kind of deep-space cosmic particle on Voyager I’s detectors this week means that it is thiiiiiiiiiiis close to leaving the Solar System. The probe has been in transit from Earth since 1977, and now sits 17.9 billion kilometers from Earth. Its radio signals take seventeen hours to reach Earth at light speed!
It sits now at the border of the heliosphere, which is not really a border at all but more of a large fuzzy transition zone. This is the point at which hydrogen and helium carried by the solar wind are overtaken in force by interstellar cosmic particles. It’s the “outer” in “outer space”.
This humble hunk of electronics was built by us. We packed it with a golden message from Carl Sagan. We strapped it to a tube of fire and shot it to the edge of interstellar space (with the aid of a few complex math problems). What will happen when it enters the beyond? Like the marks we left on the Moon, will this be mankind’s footprint on the dusty surface of the unknown?
We don’t know what to expect. But I can’t wait to find out.
(More at The Atlantic)
