You are correct in stating the law of conservation of energy, which states that energy cannot be created or destroyed; it can only be transformed or transferred from one form to another. This principle applies to all known physical processes.
Energy comes from various sources depending on the context. In the case of our planet, the primary source of energy is the Sun. Solar energy is responsible for driving many natural processes on Earth, including photosynthesis, which converts sunlight into chemical energy in plants.
Additionally, there are various other sources of energy, such as:
Chemical Energy: Energy stored in chemical bonds. It is released during chemical reactions, such as when we burn fuels like wood, coal, oil, or when our bodies break down food.
Nuclear Energy: Energy released during nuclear reactions, such as those occurring in the core of the Sun or in nuclear power plants. Nuclear reactions involve the conversion of mass into energy (as described by Einstein's famous equation E=mc²).
Geothermal Energy: Heat energy derived from the Earth's interior, often used for geothermal power generation or heating applications.
Wind Energy: Energy harnessed from the movement of air masses, converting it into electricity using wind turbines.
Hydropower: Energy obtained from the flow of water in rivers or the gravitational potential energy of water held behind dams. It is converted into electrical energy using hydroelectric power plants.
Tidal Energy: Energy obtained from the gravitational interaction between the Earth, Moon, and Sun, resulting in the movement of tides. It can be converted into electricity using tidal power plants.
While energy cannot be created or destroyed, it can be transformed into different forms. For example, solar energy is converted into chemical energy through photosynthesis, and chemical energy is transformed into heat energy when fuels are burned. This principle ensures the overall conservation of energy in the universe.