In the context of chemical bonding, the concept of hybridization describes the mixing of atomic orbitals to form new hybrid orbitals. For a molecule such as ethylene (C2H4), it's essential to understand the types of hybrid orbitals involved in forming its double bond. This bond consists of one sigma bond and one pi bond. Given this information, which type of hybridization occurs in the carbon atoms of ethylene, and how does this relate to the molecular geometry and bonding characteristics?