There are three main sources of heat in the deep earth: (1) heat from when the planet formed and accreted, which has not yet been lost; (2) frictional heating, caused by denser core material sinking to the center of the planet; and (3) heat from the decay of radioactive elements. CROSS SECTION shows Earth's structure.
â The operating margin was an especially useful metric or ratio during the meeting as we wanted the discussion to include revenue statistics.
What is an 'Operating Expense'. An operating expense is an expense a business incurs through its normal business operations. Often abbreviated as OPEX, operating expenses include rent, equipment, inventory costs, marketing, payroll, insurance and funds allocated toward research and development.