Yet, despite waves travelling a distance of 200 light years in all directions, they still have 118,800 light years to go until the entire Milky Way has heard the word.
In the photograph below, the small yellow dot - with the even tinier Planet Earth buried somewhere in its centre - reveals the limited extent of broadcasts since Marconi invented the radio in 1895. And, when you consider there are billions of galaxies like ours in the universe, the quest for extra-terrestrial life is not likely to end any time soon. Science blogger Adam Grossman, who created the diagram of ‘Humanity Bubble’ using a Nick Risinger’s famous image, quipped ‘This makes me feel small, sad and alone. Hold me.’