The mysterious 'Great Attractor' pulling the Milky Way galaxy off course

No matter what you're doing right now – sitting, standing, walking – you're moving. First, because Earth is spinning around on its axis. This rotation is the reason we have days. Second, because Earth and other planets in our solar system are orbiting the sun. That's why we have years. Third, you're moving because the sun and the rest of our solar system is orbiting the center of the Milky Way galaxy at over 500,000 miles per hour. If all of that isn't nauseating enough, everything in the entire universe is expanding outward. All the time.

But in the 1970s, astrophysicists noticed something strange about our galactic neighborhood, or Local Group. The whole clump of neighboring galaxies was being pulled off course at over one million miles per hour, towards something we couldn't see — the "Great Attractor." This Great Attractor sits in the "Zone of Avoidance," an area of space that is blocked from view by the stars and gas of the Milky Way. Today on the show, host Regina G. Barber talks to astrophysicist Jorge Moreno about this mysterious phenomenon: What it might be and what will happen when we eventually reach it.

Curious about other cosmic mysteries? Email us at shortwave@npr.org.