Longitudinal WaveA wave is a disturbance of a medium which transports energy through the medium without permanently transporting matter. In a wave, particles of the medium are temporarily displaced and then return to their original position. There are a variety of ways to categorize waves. One way to categorize waves is to say that there are longitudinal and transverse waves. In a transverse wave, particles of the medium are displaced in a direction perpendicular to the direction of energy transport. In a longitudinal wave, particles of the medium are displaced in a direction parallel to energy transport. The animation below depicts a longitudinal pulse in a medium.The animation portrays a medium as a series of particles connected by springs. As one individual particle is disturbed, it transmits the disturbance to the next interconnected particle. This disturbance continues to be passed on to the next particle. The result is that energy is transported from one end of the medium to the other end of the medium without the actual transport of matter. In this type of wave - a longitudinal wave - the particles of the medium vibrate in a direction parallel to the direction of energy transport.<span> </span>
Feldspar a common mineral found in rocks have two cleavage plane and can be cleaved in two directions nearly at right angle . Mica is a group of sheet silica that have perfect basal cleavage plane, and can be cleaved only in one direction.
An irregular galaxy is a galaxy which does not have a well-defined structure and is not identical to an elliptical or a spiral galaxy. Irregular galaxies do not fall into any class of the galaxies having a distinct size and shape.
These galaxies are rich in dust and gas and do not have a smooth appearance. They appear rough and chaotic in structure when observed through a telescope. Furthermore, these are the type of galaxies which are still not fully understood by the astronauts.