When signals in space get a response
The Breakthrough Listen Search for Intelligent Life: Nearby Stars’ Close Encounters with the Brightest Earth Transmissions, Reilly Derrick and Howard Isaacson, 18 April 2023). The calculations are intricate, involving the trajectories of the spacecraft as well as the stars (the “ephemerides" of these objects). In this way, the study found that Pioneer 11 will “encounter" 411 stars in the GCNS, Voyager 2, 325; Voyager 1, 289; Pioneer 10, 241; and New Horizons, 142.
Most of these encounters are in the future, though. Voyager 1 will contact its first star only in 2044, New Horizons in 2119. On the other hand, transmissions to Voyager 2 and the Pioneers have already encountered a total of four stars.
Pioneer 10 was the first, in 2002. Voyager 2 had two encounters in 2007. Pioneer 11 had one in 2018.
And if by some chance there’s something out there listening and reflecting these transmissions, it’s the Pioneer 10 signal we can expect a response to soonest, in 2029. After that, from the two Voyager encounters, in 2031 and 2033. Two more this century, but decades later.
Of course, as the years go by, these probes’ signals will encounter more and more stars, as also any planets that orbit them and might harbour life. Still, the chances of a response are low. But even so, it’s getting to be time that we start listening.
Tell your children and grandchildren, and to tell their children and grandchildren. Once a computer scientist, Dilip D’Souza now lives in Mumbai and writes for his dinners. His Twitter handle is @DeathEndsFun.
. Read more on livemint.com
