The Farthest
Excellent, accessible recounting of the Voyager I and II missions by the people who were/are there. Both probes are still going and some of the stats are amazing.
Voyager I travels at the speed of about 11 miles per second.
An AU is a unit of measurement that is equal to the distance from the sun to the Earth. About 93 million miles.
It took Voyager 40 years to travel 30 AU's. Approximately 2.7 billion miles or 30 AU'S to the edge of our galaxy.
When they were launched in 1977, a unique planetary alignment allowed the technicians to use the gravity of Jupiter, Saturn, Uranus and Neptune as slingshots for both probes.
By using this slingshot routine on one planet, they reduced the mission time by 20 years.
Approximately once every 2-3 years, a probe would come into contact with a new planet. Probes launched in 1977, Voyager II had last contact with Neptune in late 1989.
Both probes have entered interstellar space or the large, empty space between star systems and galaxies.
The Voyager probes had the same tech level as a common device in your pocket. Not your cell phone, the key fob for your car. Coupled with the fact scientists could delete and then rewrite flight and camera instructions as the probes went farther out into space, it's a pretty amazing journey.