Researching a talk I gave recently, I came across this photo. It is of Earth taken in 1990 from Voyager 1 as it left our Solar System. At the time it was 6 billion km away – beyond the orbit of Pluto. Earth is the little blue dot centre-right of the image.
Voyager 1 was launched in 1977 and made a grand tour of the solar system through the 1970s and 80s. At the instigation of astronomer Carl Sagan it turned and took a final snap of home. This picture had no scientific value. But it is freighted with emotional meaning.
As Sagan said;
That’s home. That’s us. On it, everyone you ever heard of, every human being who ever lived, lived out their lives.
We exoplanet hunters are looking for specks of dust drifting in starlight. But some of these specks may turn out to be special.