Why was an asteroid with only a 10-15 km (7-8 mile) width able to wipe out the dinosaurs and cause the extinction of 75% of all species on Earth?

Question

That width is less than the distance I drive from my house to the grocery store. Why was that size of an asteroid able to cause such catastrophic damage?

In: 21

Answer 1

Its not necessarily about the impact but the consequences of it.

One event can trigger volcanos to errupt, this leads to huge clouds of dust which will take months or years to vanish. This will cool down earth, killing plants and trees and basically food for animals. Its a cataclysmic chain reaction.