The N.E.A.R. project was begun with the realization of the catastrophic result of the collision of a large object with the earth. An object which is 3 km in diameter, composed of material having a density of 5 g/cc (5000 kg/m^3), and traveling at 10 km/s, would possess a kinetic energy of ½ mv^2 = 3.5 x 10^21 joules. The TNT_equivalent|energy yield of the largest nuclear weapons is about 5 x 10^15 joules so that one large asteroid possesses the kinetic energy of approximately one million large nuclear weapons.
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The N.E.A.R. project was begun with the realization of the catastrophic result of the collision of a large object with the earth. An object which is 3 km in diameter, composed of material having a density of 5 g/cc (5000 kg/m<sup>3</sup>), and traveling at 10 km/s, would possess a kinetic energy of ½ mv<sup>2</sup> = 3.5 x 10<sup>21</sup> joules. The TNT_equivalent|energy yield of the largest nuclear weapons is about 5 x 10<sup>15</sup> joules so that one large asteroid possesses the kinetic energy of approximately one million large nuclear weapons.