Stars that can see Earth transit

With thousands already detected, our search is entering a new era of discovery with upcoming large telescopes that will look for signs of 'life' in the atmospheres of transiting worlds. Previous work has explored the zone from which Earth would be visible while transiting the Sun.

However, these studies considered only the current position of stars, and did not include their changing vantage point over time. Here we report that 1,715 stars within 100 parsecs from the Sun are in the right position to have spotted life on a transiting Earth since early human civilization (about 5,000 years ago), with an additional 319 stars entering this special vantage point in the next 5000 years. Among these stars are seven known exoplanet hosts, including Ross-128, which saw Earth transit the Sun in the past, and Teegarden's Star and Trappist-1, which will start to see it in 29 and 1642 years, respectively.