To operate the calculator, enter desired values to describe an impactor and press the Calculate button. You may change any input value and recalculate.

To clear the input windows, press the Clear button.

diameter meters density grams/cubic centimeter velocity kilometers/second graze angle degrees from horizontal     Impactor Parameters volume cubic meters kinetic energy joules mass kilograms equivalent yield kilotons of TNT Crater Parameters actual diameter meters actual depth meters volume cubic meters apparent diameter meters apparent depth meters ejecta spread meters

Notes When an asteroid or comet impacts the Earth, the energy released mainly depends on the mass and velocity of the impactor. Mass is determined by the volume and density of the object. Below is a table of some information known about several of the largest asteroids. Asteroid name Density - g/cc Diameter - km 1 Ceres 2.05 ± 0.05 466 2 Pallas 4.2 ± 0.3 261 4 Vesta 4.3 ± 0.3 262.5 16 Psyche 1.8 ± 0.6 132 243 Ida 2.7 ± 0.4* 58 x 23 253 Mathilde 1.3 ± 0.2 28.5 x 25 433 Eros 2.67 ± 0.03 17.5 x 6.5 For comparison, the density of water is 1 g/cc, rock about 2 g/cc, and iron about 7 g/cc. For velocity of an object at impact, consider that the Earth's escape velocity is 11 km/sec. An object falling toward the Earth from a large distance (well beyond the moon) and starting from rest would be moving at close to this velocity on impact. Also, the Earth is moving at about 30 km/sec in its orbit about the sun; an object moving in the opposite direction might impact at more than twice this velocity. Try investigating the other components of the Earth's velocity through space. Some current information about actual threats to the Earth can be found here: NASA/JPL Near-Earth Object Program Copyright © 2004, Stephen R. Schmitt