Voyager https://www.nasa.gov/mission_pages/voyager/index.html

time capsule: https://en.wikipedia.org/wiki/Time_capsule

on edit: some links to things that might cause someone to think it might be done anyway, whether or not it makes sense.

He isn’t saying it’s a probe. He says that it kind of looks like and acts like a discarded light sail. The probe it belonged to could be in a different part of the galaxy having dropped the sail long ago and we just ran into it or if it was aimed at us then the probe could still be decelerating and about to enter the solar system at a velocity that would allow it to be captured by the Sun’s gravity.

Blockchain.