Post by NJtoTX on Dec 17, 2019 15:22:06 GMT
There are three physical Laws of Thermodynamics:
1. Heat cannot be created or destroyed but heat may be converted into other forms;
2. Heat flows from a hot body to a cold (or comparatively cooler) body;
3. Entropy increases with time.
There are also three mechanisms of Heat flow from a hot body to a cold (or comparatively cooler) body:
1. Conduction (Heat flow through a heat conducting material, such as a solid or an ideal/assumed non-moving liquid);
2. Convection (Heat flow through the movement of a liquid, gas or plasma);
3. Radiation (Heat flow through space, or a vacuum on Earth, or an ideal/assumed non-moving gas).
For discussion purposes of this question; only Laws 1 and 2 and the Radiation mechanism for Heat flow, are of most relevance.
The best mathematical theoretical model Physics has about how the Sun generates energy in various forms, including Heat, is through thermonuclear fusion. In stars like the Sun, most of the mass is made up of mainly Hydrogen, with some other chemical elements including Helium in relatively small quantities. The Sun has enough mass in its interior, generating a sufficiently strong gravitational force, that Hydrogen nuclei can go through the process of thermonuclear fusion.
Deep enough inside the Sun, 600 million tons of Hydrogen nuclei are forced together per second, to generate the energy, by thermonuclear fusion, that eventually takes 500,000 years to make its way through the dense hot plasma, from the interior to eventually escape from the surface of the Sun into space.
What happens to the 600 million tons of Hydrogen per second consumed by the Sun?
During the process of thermonuclear fusion, four Hydrogen nuclei (or protons) are forced together due to the strong gravitational force in the Sun’s interior, and as a result a great deal of energy in the form of two gamma ray photons are released. Two of the four protons release neutrinos and are converted into neutrons. The two neutrons and two protons form the nucleus of the element Helium. Essentially the Helium is the ash of the thermonuclear fusion reaction of the four Hydrogen nuclei.
The gamma ray photons are either scattered by the nuclei, making up the dense hot mainly Hydrogen plasma, as they make their way from the interior of the Sun to the surface, or the gamma ray photons are absorbed and re-emitted by the stray electrons in the hot dense plasma. The gamma ray photons are scattered as a result of collisions with stray electrons or predominantly Hydrogen nuclei and sometimes perhaps with much less abundant Helium nuclei. In Compton Scattering, a gamma ray photon interacting with a stray electron in an inelastic collision, will have some of the gamma ray photon energy absorbed by the electron, and the electron will re-emit the gamma ray photon at a lower energy.
By the time the photons reach the Sun’s surface (after countless interactions with the hot dense layers of Solar plasma and stray electrons), they escape with a range of energies or wavelengths, ranging from X rays to Ultra Violet to visible light to infra red. The heat energy from the sun is in the invisible infra red energy or wavelength region of the Sun.
Please note that the higher energy gamma ray photons escaping out to space, from the hotter Sun’s interior to the cooler surface, is consistent with the First and Second Laws of Thermodynamics. Also note that stars including the Sun, generating energy as a result of Hydrogen thermonuclear fusion, are referred to in Astrophysics as Main Sequence stars.
Approximately 174,000,000,000,000,000 watts out of the approximately 386,000,000,000,000,000,000,000,000 watts, reaches the Earth. The reduced amount of power happens because of the Inverse Square Law of the propagation of electromagnetic radiation, and not every part of the Sun is facing the Earth at the same time. Not all of the 174,000,000,000,000,000 watts reaches the ground because the Earth’s atmosphere is opaque to the X-ray to extreme UV and some of the infra red wavelengths.
According to some estimates 8% of the incident Solar energy is reflected back to space by air molecules, 17% is reflected back to space by clouds, and 6% is reflected back to space by the Earth’s surface. Out of the remaining 69% of the incident Solar energy that is absorbed by the Earth’s surface, 19% gets absorbed directly by dust, ozone and water vapor in the upper atmosphere, 4% gets absorbed by clouds, leaving 46% of the Solar energy making it to the ground.
Still, enough Solar energy reaches the ground to heat the Earth’s surface with an average power of 164 Watts per square meter, and to allow us to feel the Sun’s heat on our faces.
1. Heat cannot be created or destroyed but heat may be converted into other forms;
2. Heat flows from a hot body to a cold (or comparatively cooler) body;
3. Entropy increases with time.
There are also three mechanisms of Heat flow from a hot body to a cold (or comparatively cooler) body:
1. Conduction (Heat flow through a heat conducting material, such as a solid or an ideal/assumed non-moving liquid);
2. Convection (Heat flow through the movement of a liquid, gas or plasma);
3. Radiation (Heat flow through space, or a vacuum on Earth, or an ideal/assumed non-moving gas).
For discussion purposes of this question; only Laws 1 and 2 and the Radiation mechanism for Heat flow, are of most relevance.
The best mathematical theoretical model Physics has about how the Sun generates energy in various forms, including Heat, is through thermonuclear fusion. In stars like the Sun, most of the mass is made up of mainly Hydrogen, with some other chemical elements including Helium in relatively small quantities. The Sun has enough mass in its interior, generating a sufficiently strong gravitational force, that Hydrogen nuclei can go through the process of thermonuclear fusion.
Deep enough inside the Sun, 600 million tons of Hydrogen nuclei are forced together per second, to generate the energy, by thermonuclear fusion, that eventually takes 500,000 years to make its way through the dense hot plasma, from the interior to eventually escape from the surface of the Sun into space.
What happens to the 600 million tons of Hydrogen per second consumed by the Sun?
During the process of thermonuclear fusion, four Hydrogen nuclei (or protons) are forced together due to the strong gravitational force in the Sun’s interior, and as a result a great deal of energy in the form of two gamma ray photons are released. Two of the four protons release neutrinos and are converted into neutrons. The two neutrons and two protons form the nucleus of the element Helium. Essentially the Helium is the ash of the thermonuclear fusion reaction of the four Hydrogen nuclei.
The gamma ray photons are either scattered by the nuclei, making up the dense hot mainly Hydrogen plasma, as they make their way from the interior of the Sun to the surface, or the gamma ray photons are absorbed and re-emitted by the stray electrons in the hot dense plasma. The gamma ray photons are scattered as a result of collisions with stray electrons or predominantly Hydrogen nuclei and sometimes perhaps with much less abundant Helium nuclei. In Compton Scattering, a gamma ray photon interacting with a stray electron in an inelastic collision, will have some of the gamma ray photon energy absorbed by the electron, and the electron will re-emit the gamma ray photon at a lower energy.
By the time the photons reach the Sun’s surface (after countless interactions with the hot dense layers of Solar plasma and stray electrons), they escape with a range of energies or wavelengths, ranging from X rays to Ultra Violet to visible light to infra red. The heat energy from the sun is in the invisible infra red energy or wavelength region of the Sun.
Please note that the higher energy gamma ray photons escaping out to space, from the hotter Sun’s interior to the cooler surface, is consistent with the First and Second Laws of Thermodynamics. Also note that stars including the Sun, generating energy as a result of Hydrogen thermonuclear fusion, are referred to in Astrophysics as Main Sequence stars.
Approximately 174,000,000,000,000,000 watts out of the approximately 386,000,000,000,000,000,000,000,000 watts, reaches the Earth. The reduced amount of power happens because of the Inverse Square Law of the propagation of electromagnetic radiation, and not every part of the Sun is facing the Earth at the same time. Not all of the 174,000,000,000,000,000 watts reaches the ground because the Earth’s atmosphere is opaque to the X-ray to extreme UV and some of the infra red wavelengths.
According to some estimates 8% of the incident Solar energy is reflected back to space by air molecules, 17% is reflected back to space by clouds, and 6% is reflected back to space by the Earth’s surface. Out of the remaining 69% of the incident Solar energy that is absorbed by the Earth’s surface, 19% gets absorbed directly by dust, ozone and water vapor in the upper atmosphere, 4% gets absorbed by clouds, leaving 46% of the Solar energy making it to the ground.
Still, enough Solar energy reaches the ground to heat the Earth’s surface with an average power of 164 Watts per square meter, and to allow us to feel the Sun’s heat on our faces.