The solar system also contains over a million rocky fragments of at least 1km in diameter called asteroids as well as millions more with smaller diameters. Many of these asteroids are an asteroid belt between the orbits of Mars and Jupiter.

In the liquid state, molecules flow freely around each other and exist at a higher temperature range than the same substance in a solid state. Liquids maintain a constant volume but their shape depends upon the shape of their container.

A neutron is a subatomic particle found in the nucleus of an atom. It is neutral as it carries no electric charge.

A substance undergoes a phase transition when it moves from one state of matter to another, for example, when water freezes or boils.

Found in both animal sources (meat, fish, eggs, cheese) and vegetables (beans, nuts, some grains), proteins are important for the body's maintenance, growth, and repair.