Question

Why explosions on other planets cannot be heard on earth waves?

Answer 1

The explosion on other planets can't be heard on earth waves because, there is no medium between earth and other planets through which the sound wave can travel. The earth atmospheric layer extends 500 to 1000 km and the atmospheric layer of other planets also exists  up to a limitation so, there is no contraction between the atmospheric layers thus, no path is created between the planets and sound needs a medium for its propagation.