Scientists estimate it is possible for nearly three dozen stars near our solar system to capture a partial or complete view of the Earth as it traverses the face of the Sun from their perspective. Some of those worlds could possibly detect signs of industrial civilization, such as the lights of cities or exhaust from factories.

“Even at the closest of these stars, Earth is just a small dot in front of an even smaller dot of the Sun. It’s going to be incredibly faint,” said Lisa Kaltenegger, associate professor of astronomy at Cornell University. “We are talking about the equivalent of taking a picture of a bumblebee standing in front of a car’s headlights from a distance of 100 miles.”

Kaltenegger and her team at Cornell mapped out the locations and viewing angles of potential alien worlds around the 1,715 stars within 100 light-years of our solar system. Their results were published Sept. 23 in The Astronomical Journal. They identified 2034 candidate exoplanets around those stars, a small percentage of which should be well-positioned to observe Earth over time, with some in the optimal viewing geometry multiple times. Of the likely observer stars, Kaltenegger said, the closest is expected to be only 11.9 light years away.