Asteroid parameters:
Contents
About
This JavaScript program calculates the effects of the impact of an object hitting the earth. It was adapted from a BASIC program from the Astronomical Computing column of Sky & Telescope, November 1996.
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.
Source Code
The Java Script source code for this program can be viewed by using the View|Source command of your web browser.
You may use or modify this source code in any way you find useful, provided that you agree that the author has no warranty, obligations or liability. You must determine the suitablility of this source code for your use.
Discussion
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.
For comparison, the density of water is 1 g/cc, rock about 2 g/cc, and iron about 7 g/cc.
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 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
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