July’s double meteor shower could produce brilliant fireballs. Here’s how to see them.

Why do the meteor showers peak together?

Meteor showers occur when Earth passes through streams of rocky material left behind by comets. The particles strike the planet’s atmosphere at high speed, heating up and producing the streaks commonly called shooting stars.

“It is by complete happenstance that the debris trails from two different comets intersect where our planet passes through, creating the overlapping peaks,” says Devon Salasin, head astronomer at Stargazing Moab.

The Southern Delta Aquariids remain active from mid-July into late August, while the Alpha Capricornids run from early July into mid-August. That extended activity means meteors from both showers may appear well before and after the official peak.

Is there a visible difference between the two meteor showers?

“Besides originating from slightly different spots in the sky, what is known as the radiant of the meteor showers, the Delta Aquariids offer more frequent, faint streaks, while the Alpha Capricornids are famous for slower, dazzling fireballs,” says Alex Gianninas, an astronomy professor at Connecticut College.

(Here are seven night sky events to see in July.)