The Voyager 1 probe has left the solar system and is still transmitting

Launched in September 1977, Voyager 1 crossed the heliopause — the boundary of the Sun's influence — in 2012, making it the first human-made object to enter interstellar space. As of 2024, it is more than 24 billion kilometres from Earth. Signals from Voyager 1 travel at the speed of light and take over 22 hours to arrive. The probe still operates on a nuclear power source and communicates data back to NASA's Deep Space Network. If it continues without a mechanical failure, it will reach the vicinity of another star system in roughly 40,000 years.

Source: NASA Voyager Mission Status