What if an Asteroid Hit the Earth?

Problem:
Suppose a cylindrical asteroid 10 km in height x 10 km in diameter impacted the earth at 30,000 mph. Calculate the energy dissipated, in megatons of TNT, and the rate at which it is dissipated, in watts.

Solution:
Let the density of the asteroid, , be five times the density of water, i.e.,

= 5000 kg/m³.

Then, the mass of the asteroid is

(5000 kg/m³) x (5000 m)² x (10,000 m) = 4 x 10¹⁵ kg

and the kinetic energy, traveling at 30,000 mph (= 1 x 10⁴ m/sec) is

Now, one megaton of TNT delivers 4.2 x 10¹⁵ joule, so that the required energy in megatons of TNT is

or 50 million megatons! The time for the asteroid to impact the earth is

so that the rate of energy dissipation in watts is

or 200 billion trillion watts!!!

Afterthought:
Such an object might have been responsible for causing the extinction of the dinosaurs at the end of the Cretaceous period. A layer of Iridium has been found in the Cretaceous-Tertiary (K-T) boundary, which appears to be world encircling (Alvarez, et. al.). Such a layer might have been deposited after an asteroid impact of great magnitude. In fact, the remains of a 65 million year old impact site have recently been found, providing an excellent candidate for the K-T event. From various geological survey data (originally intended to locate promising sites for oil drilling), the site is in the Yucatan.