Molecules are simply a group of two or more atoms held by a chemical bond. These are primitive components of matter, whether they are gases or organic substances. Just like atoms, these molecules are a higher form of building blocks, the next step before a new form of matter is completely created. In the same way, molecules also greatly affect formation of stars and planets, as there are molecules in space, more formally known as interstellar, and at times, circumstellar molecules. These are formed and created by chemical reactions within clouds of gas and dust diminutively present in space.

The most common molecule and absolutely the most important in the universe is molecular Hydrogen, composed of two protons. This simple molecule is the primitive component of the first Stars, made up of clouds and clouds of gas, with molecules radiating energy. This only proves that there is a wider and more complex form of chemistry in interstellar space. Some of the molecules discovered are aluminum mono-chloride, hydrogen isocyanide, and methylenimine. There are about 130 neutral, and about 12 positively-charged, and just about 3 negatively-charged molecules in space. Studies of these molecules will allow new information about the activities in space to surface.