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  2. Sun - Wikipedia

    en.wikipedia.org/wiki/Sun

    The Sun is the star at the center of the Solar System.It is a massive, nearly perfect sphere of hot plasma, heated to incandescence by nuclear fusion reactions in its core, radiating the energy from its surface mainly as visible light and infrared radiation with 10% at ultraviolet energies.

  3. Heat - Wikipedia

    en.wikipedia.org/wiki/Heat

    The molar heat capacity is the heat capacity per unit amount (SI unit: mole) of a pure substance, and the specific heat capacity, often called simply specific heat, is the heat capacity per unit mass of a material. Heat capacity is a physical property of a substance, which means that it depends on the state and properties of the substance under ...

  4. Solar core - Wikipedia

    en.wikipedia.org/wiki/Solar_core

    The core produces almost all of the Sun's heat via fusion; the rest of the star is heated by the outward transfer of heat from the core. The energy produced by fusion in the core, except a small part carried out by neutrinos , must travel through many successive layers to the solar photosphere before it escapes into space as sunlight , or else ...

  5. Thermal radiation - Wikipedia

    en.wikipedia.org/wiki/Thermal_radiation

    The primary method by which the Sun transfers heat to the Earth is thermal radiation. This energy is partially absorbed and scattered in the atmosphere, the latter process being the reason why the sky is visibly blue. [3] Much of the Sun's radiation transmits through the atmosphere to the surface where it is either absorbed or reflected.

  6. Solar energy - Wikipedia

    en.wikipedia.org/wiki/Solar_energy

    A heat pump is a device that provides heat energy from a source of heat to a destination called a "heat sink". Heat pumps are designed to move thermal energy opposite to the direction of spontaneous heat flow by absorbing heat from a cold space and releasing it to a warmer one.

  7. Heat transfer physics - Wikipedia

    en.wikipedia.org/wiki/Heat_transfer_physics

    Heat is transferred to and from matter by the principal energy carriers. The state of energy stored within matter, or transported by the carriers, is described by a combination of classical and quantum statistical mechanics. The energy is different made (converted) among various carriers.

  8. Laws of thermodynamics - Wikipedia

    en.wikipedia.org/wiki/Laws_of_thermodynamics

    The flow of heat is a form of energy transfer. Heat transfer is the natural process of moving energy to or from a system, other than by work or the transfer of matter. In a diathermal system, the internal energy can only be changed by the transfer of energy as heat: =.

  9. Second law of thermodynamics - Wikipedia

    en.wikipedia.org/wiki/Second_law_of_thermodynamics

    The second law of thermodynamics is a physical law based on universal empirical observation concerning heat and energy interconversions.A simple statement of the law is that heat always flows spontaneously from hotter to colder regions of matter (or 'downhill' in terms of the temperature gradient).