Why our location in the Milky Way is perfect for finding alien life

Our arm of the Milky Way contains many older, metal-rich stars, which recent research suggests might offer favorable conditions for life on their planets.

All known life in the universe exists on Earth, a small planet in a minor arm of the Milky Way galaxy. Despite the billions of other potentially habitable planets out there, our understanding of life beyond Earth is still very limited.

So far, our exploration for extraterrestrial life has only covered a tiny fraction of the galaxy. “The area of space we’ve explored around our sun is minuscule compared to the size of the galaxy,” notes Jessie Christiansen, an astrophysicist at the California Institute of Technology. To date, we have discovered over 5,000 exoplanets—planets orbiting stars outside our solar system. Although some of these exoplanets are located across the galaxy and even in other galaxies, most are within a few hundred light-years from our sun, which is relatively close in cosmic terms.

Astronomers are investigating various types of stars within our galactic neighborhood to understand their potential influence on the habitability of their planets. We reside in the Orion Arm of the Milky Way, which lies within the galaxy’s thin disc. Our surroundings include the densely packed core of the galaxy on one side and the more sparse outer regions of other arms on the other.