A new spacecraft called IRIS (Interface Region Imaging Spectrograph) has recently been launched to study the suns atmosphere. Material that travels
through the atmosphere, known as the solar chromosphere, heats up from about 10,000 degrees Fahrenheit
(5,500 degrees Celsius) at the sun's surface to temperatures as high as 3.5 million degrees Fahrenheit
(2 million degrees celsius) farther out.
The ultraviolet telescope will study "how solar material moves, gathers energy and heats up"
in the chromosphere on its way to the outer atmosphere, the corona.
The Sun is almost perfectly spherical and exists as a large ball of hydrogen. The hydrogen has
become so compressed by gravitational forces that 620 million metric tons of hydrogen fuse into helium each second.
The task of IRIS is not to study the interior, but to make sense of the layers of hydrogen on the outer edge
of the sun.
The ionization energy needed to remove an electron from a neutral hydrogen atom is 13.6 eVolts.
The Bohr radius of hydrogen has a value of 52.9 picometers (10^-11 meters).
The force holding a single electron to a single proton never grows higher then the value
calculated with coulombs law at this distance.
This value can be also computed in terms of other physical constants including the permittivity of free space,
the speed of light in vacuum and other constants found in nature.
At this distance, it takes 13.6 eVolts of energy to knock this electron away from the proton and it never takes
more then 13.6 eVolts of energy to ionize hydrogen no matter how close the electron is to the proton.
To properly model this, we use Newton's Shell theorem as support, and say that electrons do not feel an
attraction to the proton once inside the proton shell. Imagine. as many chemistry drawings show, a hydrogen proton
as a large gray shell and the electron as a small red dot.
Electrons and protons are attracted inversely proportional to the squared distance between them
if the electron is outside the proton shell of 53pm. Electrons feel no force from the proton while
inside the proton shell.
Bonding between hydrogen protons happens as one electron, trapped in a proton of one hydrogen,
gets trapped in a proton of another hydrogen, binding the two hydrogens together.
A proton and an electron combination (hydrogen) is neutral in charge. Although neutral, the proton acting as a shell of
charge with the electron close to the edge of the shell, will attract other neutral hydrogen atoms
until one electron (or perhaps 2 in the ortho form) is trapped in both hydrogen shells
binding them together.
The neutron is modelled in the same manner as the proton, but without the electric charge (white shell in figure). Protons and neutrons are
allowed to flow through each other, but only when the shells are very close, do they feel the effect of the strong
force. The strong force is a binding force that merges shells together if they are forced to be very close to each other.
A proton shell thickness is modelled as the charge radius of 0.88 femtometers. Elements are modelled as proton
and neutron shells, stacked on each other, binding together, with the neutrons acting as an insulators between proton shells.
Hydrogen Photon Emissions
Left alone, an electron falling into a proton (1), may pass through the shell with enough energy to emit a 10.2 eVolt photon,
equal to the difference of energy inside and outside the nucleus. The emission of the photon results
in the equivalent loss of the electrons kinetic energy (slows down), often trapping the electron
inside the nucleus. If an electron already exists inside the proton, then the falling electron drops to an even lower energy
level and emits a 12.09 eVolt photon.(2)
To model photon emissions, the energy of the photon emitted is determined by the energy level that the electron came from subtracted from
the energy level of where the electron ends up. The energy level is determined by counting how
many shells the electron is within, together with how many other electrons are within the same shell.
In a low density environment, most of the electrons in a hydrogen gas will only be within one or two shells.
Electrons entering this area will tend to emit a level 1 or 2 photon. In a higher density electron gas, many more
of the proton shells are overlapping each other and many more electrons are within each shell. In a high density gas,
electrons will absorb or emit higher level photons. Electrons are more likely to emit photons due to a
jump from energy level 8 to 9 when protons are more highly packed together.
Modelling the heat of hydrogen gas
Measuring the temperature of a hydrogen gas or liquid is fundamentally a measure of the movement
of the hydrogen proton. The electrons contributes to bonding and emissions, but since it has such a small mass
compared to the proton (some 1000 times smaller), the movement of the electon does not contribute in a
significant way to the heat.
Low density hydrogen gas can attain extremely high temperatures, due to the freedom of motion of the
molecules. The speed that the hydrogen molecule can attain is only limited by the speed of light
and the number of collisions with other hydrogen molecules.
As hydrogen gas is compressed
the freedom of motion is significantly impaired. At very high pressures, the hydrogen gas forms a liquid and the
motion of the protons undergoes a phase transition. The motion evolves from being relatively independent of other
molecules except for the case of collisions, into an ordered state where a molecule no longer flies around randomly
but now is so constrained by the other molecules and is only able to "vibrate in place". As in any other material,
the temperature that a gas can obtain, greatly exceeds the temperature a liquid or solid of that same material
can reach due to the constraint in motion of the individual molecules.
Modelling the Sun
|Solar Hydrogen Spectral Lines|
|0 to 2|
|0 to 1|
|1 to 4|
|1 to 3|
|1 to 2|
The sun is a very large ball of mostly hydrogen held together by its own gravitational force. This
force grows so large, that towards the center of the sun, hydrogen molecules are so compressed that the stong
nuclear force takes over and hydrogen is converted to helium.
Starting with the atmosphere, the outer layer of the chromosphere is extremely hot and emits photons
that have jumped into level 1 and 2 energy levels.
Photons with 10.2 evolts energy (0 to 1) are most common, with lots of 1.89 (1 to 2) and 12.09 (0 to 2) photons.
Indeed, the sun at the top of the chromosphere starts at a low density of 1×10^−12 kg/m³ and reaches
temperatures exceeding 15.7 million K°. The chromosphere consists of fast moving hydrogen protons and electrons flying around.
As you descend through the chromosphere the density rises up to 5×10^−6 kg/m³. The temperature drops as the mobility of
the hydrogen proton begins to be restricted by other protons in the neighborhood.
With significant overlap of the protons, we see a lot higher energy level transitions.
The phase transition from hydrogen gas to the hydrogen liquid on the surface of the sun (called the photosphere) occurs at
5,778 K°, where the density is 2×10^−4 kg/m³. Hydrogen protons cannot "fly around" anymore and hydrogen flows like any
Falling deeper into the sun, the density rises eventually to 1.6×10^5 kg/m³. The movement of protons and electrons
are so severely restricted that electrons bind with protons forming neutrons. This process is a reverse
beta-decay. In reverse beta-decay, electrons forced so close to a pole
of the proton, that through a w-particle, turn a proton into a neutron. Continued pressure eventully causes "layers" of proton
and neutrons shells to bind and become Helium, releasing enormous energy.