The Milky Way could be teeming with interstellar alien civilizations, according to a new study. We just don’t know about it because they haven’t paid us a visit in 10 million years.

The study, published last month in The Astronomical Journal, posits that intelligent extraterrestrial life could be taking its time to explore the galaxy, harnessing star systems’ movement to make star-hopping easier.

The work is a new response to a question known as the Fermi Paradox, which asks why we haven’t detected signs of extraterrestrial intelligence.