In 2008, a radio message was transmitted from Earth toward Gliese 581c, a potentially habitable exoplanet located about 20.4 light-years away in the constellation Libra.

This message, part of a project to communicate with extraterrestrial life, was sent using a radio telescope, carrying digital data such as human messages and images.

Given the distance, the signal travels at the speed of light, taking approximately 20.4 years to reach Gliese 581c, arriving around 2028.

If intelligent life exists on Gliese 581c and responds immediately with a similar radio signal, their reply would take another 20.4 years to travel back to Earth, meaning we could potentially receive it by 2049 or 2050.

This assumes the recipients have the technology to detect and respond to our signal. However, Gliese 581c’s habitability is uncertain; later studies suggest it may be too hot or tidally locked, making life as we know it unlikely.

The endeavor reflects humanity’s curiosity and hope for interstellar communication, but the vast distance and uncertainties about the planet’s conditions make a response speculative.

Projects like this highlight both the ambition and challenges of searching for extraterrestrial intelligence.