How Fast Is Voyager 1?

Launched 1977, Voyager 1 crossed into interstellar space in 2012. It is now the most distant human-made object — over 24 billion km from Earth — still transmitting on a plutonium power source the size of a large grapefruit, over 47 years after launch.

Voyager 1 carries a gold record with sounds of Earth: greetings in 55 languages, music from Bach to Chuck Berry, and the song of a humpback whale.

• Signals take 22 hours to reach us
• Now in interstellar space