What if a grain of sand hit the earth going lightspeed?

1.Lets assume that the grain of sand can withstand travelling at that speed without breaking itself apart. In this case the energy can be calculated using the kinetic energy formula. E=1/2 mv^2. Substitute the values and you will get the energy at which it will hit the surface of the Earth. Won't be a Dinausar kid nightmare. 2. read more

Okay lets say the grain of sand hits earth at 99.9% light speed, i don't need to show you how kinetic energy is represented, so at 0.99c which is approx 6mc raise to power 2. With a grain of sand averaging 4mg the kinetic energy will be: 6 x 4 x 3 x 3 x 10 raised to power 10 joules. That's approx equivalent to 400 tons of TNT. read more