Every year, millions of rocky shards from outer space burn up in Earth’s atmosphere, many briefly flaring and appearing in the sky as “shooting stars.” But how many survive their high-speed plunges to strike the ground?

Rocks from space that land on Earth are known as meteorites. Giant impacts, such as the one that likely ended the reign of the dinosaurs about 66 million years ago, caused by an asteroid or comet measuring about 6 miles (10 kilometers) across, are extraordinarily rare.

Instead, most rocks that fall to Earth are very small, and relatively few survive their fiery plummet through Earth’s atmosphere.

Scientists estimate that fewer than 10,000 meteorites collide into Earth’s land or water, which is a drop in the bucket compared with the moon, which doesn’t have an atmosphere and gets hit by varying sizes of space rocks: about 11 to 1,100 tons (10 to 1,000 metric tons) — the mass of about 5.5 cars — of space rock dust per day, and about 33,000 pingpong-ball-sized space rock collisions yearly,