Science Visualized Astronomy

To find ET, look at who’s (maybe) looking at us

map of stars in Milky Way that could see Earth in front of sun

EXTRATERRESTRIAL SURVEILLANCE  Eighty-two known stars (blue dots) within 3,500 light-years of Earth could host advanced civilizations that can see Earth cross in front of the sun.

E. Otwell, C. Crockett; Source: R. Heller and R.E. Pudritz/Astrobiology 2016

By Christopher Crockett

- More than 2 years ago

As Earth whips around the sun, it casts a shadow into the galaxy. If that shadow passes over cosmic neighbors that host reasonably intelligent aliens, they would see Earth the same way NASA’s Kepler space telescope sees some of them: as a periodic dip in the light from our sun.