Due to its larger target area and stronger gravity,
scientists estimate that Earth should be struck by twice
as many asteroids per square kilometer as the moon.
The evidence for this bombardment on the moon is obvious,
but evidence of these collisions on Earth is very scarce.
Compare the landscape in this photograph to the landscape
where you live. Notice the many small craters pictured
here, some as small as a few centimeters in diameter.
What do you think might happen to the object that created
one of these small craters if it were headed toward