P. Sometimes animals can actually hear the P waves of an earthquake before the waves are felt.

1566. Kilojoule is the preferred measure of energy preferred by the international community.

Moon. The moon is about 1/80th the size of the Earth in mass.

Interstellar. Interstellar space travel is unmanned or manned travel between stars.

Momentum. Momentum is conserved in all collision systems.

Sea. A sea is partially surrounded by land.