It’s only once a year that you can experience almost complete darkness in the afternoon sky. This Sunday, the Western United States will experience a solar eclipse. But in a special path across Northern California, the moon will be almost fully enclosed by the disc of the sun, creating a “Ring of Fire” effect. To learn more about the science behind the spectacle – and another reason to look up later in May – KALW's Ben Trefny talked to our local expert, Paul Salazar. Salazar is a member of the San Francisco Amateur Astronomers and keeps a regular astronomy blog.