Matter in the Universe

Matter is generally considered to be anything that has mass and volume. The volume is determined by the space in three dimensions that it occupies. The mass is determined by its rest mass (or invariant mass), which is measured by the acceleration a body has when a force is applied. The greater the mass, the slower the acceleration for the same force. Matter is thus a general term for the substance of which all observable physical objects consist

The matter in the universe is created by the big bang, but not in the form that we see today. First, there is very strong evidence that most of the matter in the Universe is in the form of unseen or dark matter - matter that (at least so far) cannot be seen by standard astronomical methods, but whose presence can be inferred because it influences the Universe gravitationally. The nature of this dark matter is one of the most important unsolved problems in science.
Second, the big bang produces mostly the light elements hydrogen and helium (Here is a java applet illustrating big bang synthesis of the elements). The heavier elements must be produced later, by stars. Furthermore,

1. Many of the heavier elements cannot be produced by stars in the stable periods of their lives - they must be produced in violent explosions associated with the death of stars.
2. The heavier elements produced either in the stable portion of stellar evolution, or in violent explosions, can only be distributed through the universe by such explosions.

Thus, the existence of the heavy elements, and the biology built on them, depends crucially on violent processes taking place in stars and galaxies.