Earth calling… but not very far: The tiny yellow dot in our galaxy that shows the (comparatively small) distance radio broadcasts have travelled in a century of reaching out to aliens




Since the invention of radio more than a century ago, man has been broadcasting into space in the hope that any listening aliens could learn of our presence.

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.

A long way to go: The yellow dot shows the 200 light year radius of how far radio waves have reached into the Milky Way

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 on his site : ‘This makes me feel small, sad and alone. Hold me.’

Yet, given that it would take just four minutes to get to Mars when travelling at the speed of light, the distance of 200 light years is no small feat.