Humanity's farthest messenger: Nasa's Voyager 1 nears a one light-day milestone

Imagine sending a message into space and waiting 24 hours just for it to arrive. And if you expect a reply, be prepared to wait another full day.That's how far Nasa's Voyager 1 has travelled from Earth. Nearly 49 years after its launch, the spacecraft is approaching an extraordinary milestone that no human-made object has ever achieved, travelling one light-day away from our planet.When it reaches the mark on Wednesday, November 18, even a signal travelling at the speed of light will need an entire day to bridge the distance between Voyager 1 and Earth.More than 26 billion kilometres from Earth, Voyager 1 is travelling at approximately 61,000 km/h. To put that distance into perspective, one light-day is the distance light travels in 24 hours, covering nearly 25.9 billion kilometres.Even at the speed of light, a signal sent from Earth will take an entire day to reach the spacecraft.