On September 5, 1977, NASA launched Voyager 1, a space probe to study Jupiter and other planets beyond it. As of today, Voyager 1 is more than 20 billion kilometres away from us! But, it is still travelling at a speed of more than 60,000 km/h!

Voyager 1 is not a rocket. It is not burning any fuel. Then, how is it able to travel so fast on its own? Let's explore that now!