If the atmosphere were absent, how would meteors reach the surface?

• A. Meteors would burn completely in the upper atmosphere.
• B. Meteors would be redirected by gravity.
• C. There would be no meteors at all.
• D. More meteors would reach the surface.

Answer: (A)

Atmospheric entry heating from drag and ablation is what usually causes meteors to burn up. The air around Earth heats and slows a meteoroid as it plummets through the atmosphere, so most of the smaller pieces burn away long before reaching the ground.

If the atmosphere were absent, there would be no air to cause that frictional heating. The meteoroid would lose very little energy to heating and would plow through with much of its original speed, reaching the surface largely intact. That means more meteors would reach the surface, not fewer, and they wouldn’t burn up in the upper atmosphere.

The idea that they’d burn completely or that there would be no meteors at all doesn’t fit the vacuum scenario, since gravity would still pull objects toward Earth and meteors would still enter. Without air, drag heating disappears, so burning up would not occur.