The host of NASA’s podcast “On a Mission” admitted in a recent episode that Earth is in the middle of a cosmic shooting gallery of buzzing asteroids. The host also noted that there are yet-to-be-identified monster asteroids in space that are big enough to wipe out cities, countries and even the entire planet.

Earlier this week, NASA released the first episode in the second season of its “On a Mission” podcast. In the episode, titled “The Sky is Falling,” the program’s host Leslie Mullen and guest astronomer Greg Leonard discussed the chances of asteroids hitting Earth.

According to Mullen, the planet gets pelted by hundreds of space rocks on a daily basis. Fortunately, these asteroids are too small to penetrate Earth’s atmosphere.

“The truth is, our planet is in the middle of a cosmic shooting gallery,” she said during the episode. “Asteroids often fly by, and the Earth is hit every day with hundreds of tons of dust grains and small rocks. Most of them burn up in the atmosphere, and sometimes, we see them as meteor showers or shooting stars.”

Mullen noted that NASA has not yet detected an asteroid that’s big enough to trigger a wide-scale mass extinction event on the planet. Although NASA is aware of a number of asteroids that are capable of leveling entire towns, cities or even countries, none of these are on a direct collision path to Earth.

Although Earth is safe from these large asteroids for now, Mullen noted that the public should be more worried about the mountains-sized space rocks that NASA has not yet detected or identified.

According to Mullen, there are real planet-killer asteroids lurking in the vastness of space. She believes that any one of these could take out the planet.

“The small rocks from space do little to no damage,” she said. “It’s the big ones we worry about. And there are big asteroids out there, monsters lurking in the dark, large enough to take us out.”

“Currently, none of the really big asteroids are headed for us,” Mullen continued. “But we haven’t found them all.”