Which layer of the atmosphere is thick enough for meteors to burn up in?

Its the Mesosphere in this layer which extends from around 31 miles above the Earth's surface, the gases, including the oxygen molecules, are dense These gases in the mesosphere are thick enough to slow down meteors hurtling into the atmosphere, at this layer of the atmosphere is where they burn up, thus appearing like fiery trails in the night sky. 

Iam pretty sure it is c. 2000 bce