What You Will Learn • Heat flow is the transfer of energy from a warmer object to a cooler object. • Energy from the sun, the major source of energy for phenomena on Earth’s surface, is transmitted to Earth by radiation.• Heat from Earth’s interior reaches the surface mostly by convection. Why It Matters The movement of energy through Earth’s systems is a major factor in most of Earth’s processes.hat You Will Learn • Heat flow is the transfer of energy from a warmer object to a cooler object. • Energy from the sun, the major source of energy for phenomena on Earth’s surface, is transmitted to Earth by radiation.