nuclear processing

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Checking my work with concentric circles.  I nailed it on the MacMurray wheel, but the rest have required some minor warping to get them to fit.  In all likelihood, these won’t be the final textures, but I wanted to make sure everything was centered and circular so they can provide a good starting point.  

Helium Fusion, How Carbon is Made, and the Triple Alpha Process.

@chemistry-official​ asked me to make a post on how Carbon is created, so here goes:

This process uses the helium in a star’s core. For a refresher on how helium is made,  click HERE for a detailed explanation and HERE for a simpler version.

As stars fuse hydrogen into helium, they eventually run out of hydrogen in their core to fuse. When the core is 100% helium, the star begins to collapse, since the outward push from fusion (which balances the inward pull of gravity) is no longer active. The star’s collapse heats up the core until the helium begins to fuse. The helium begins fusing very rapidly, and we call this the helium flash. It’s quite literally a flash too - the star’s brightness rapidly increases. The heat from this reaction heats up the outer layers of the star, which are made of hydrogen, which then begin to undergo proton-proton fusion to create helium.

Below is the reaction that occurs, turning helium into carbon:

This is how Carbon is formed - two helium nuclei combine to form Boron, followed by a third Helium fusing with the Boron to create Carbon. It’s called the triple-alpha process because this process uses three Helium nuclei, which are also called alpha particles. This process also releases energy, since Carbon nuclei are more stable than Helium nuclei. Since energy is released, the inward pull of gravity is then counteracted by the outward push from fusion, so the star is stable again.

When novices walk into a round
Some Astronomy: The Solar System

The Solar System is the Sun and everything that orbits it.  It formed about 4.56 billion years ago, from a spinning cloud of gas & dust.

There are three main regions.  1) The four rocky inner planets; 2) the four outer gas giants, separated from the inner planets by the asteroid belt; 3) an enormous region with small, icy worlds such as Pluto, and dormant comets.

The Solar System is about 15,000 billion km across (1.6 light years), but the smaller region of the Sun and planets is only about 12 billion km across.

The Sun

The Sun is about 1.4 million km across, and contains about 99% of the Solar System’s mass.

In its core, hydrogen is converted to helium through the process of nuclear fusion.  This releases enormous amounts of energy, which move outwards through the radiation zone, then the much smaller convection zone, to the photosphere (the visible surface), whence it escapes.

The photosphere has marks called sunspots (cooler areas of the surface).  Loops of gas arch above the photosphere - they are called prominences.

A solar prominence.

There are two more layers above the photosphere - the chromosphere and the corona.

The Inner Planets

The four inner planets are Mercury, Venus, Earth and Mars, and they have several similarities.  They are all (relatively) small, and have few/no satellites.  They have the same planet structure - an iron-rich core, mantle, and rocky outer crust.

They orbit the Sun in the same direction, and approximately the same plane.  Their orbits are elliptical in shape - Mercury’s orbit is very elliptical.

But there are very important differences.  Earth is the only planet with an oxygen-rich atmosphere, plenty of surface water, and a range of temperatures that keep most of the water in a liquid state.  These factors have been crucial to the development of life.

Mercury has almost no atmosphere, and its temperatures go to extremes.  Venus has a thick, carbon-dioxide-rich atmosphere, which creates extremely high pressures & temperatures on the surface.  Mars has a thin atmosphere and is cold; its water is beneath the surface, or locked up as ice at the poles.

The Outer Planets

The four outer planets are Jupiter, Saturn, Neptune and Uranus.  They also have many similarities.

They all have small, rocky cores.  The planets are composed mainly of hydrogen & helium.  However, Uranus & Neptune also have large amounts of chemical ices (made up of hydrogen compounds such as water, methane and ammonia).

Their atmospheres are gaseous, and often stormy; they are also composed mainly of hydrogen & helium.  However, Uranus & Neptune’s atmospheres also have 2-3% methane, which gives them their blue colour.

Like the inner planets, they orbit the Sun in the same direction, and approximately the same plane.  Their orbits are also elliptical in shape.

They each have a ring system, made of dust and ice, which is the fragmented remains of objects that got too close to their powerful gravity.  And they all have large numbers of satellites (Jupiter & Saturn have several dozen each).

Pluto

Pluto was reclassified as a dwarf planet in 2006.  It is composed mainly of rock & ice.  Its moon, Charon, is about half its size - much larger (relatively) than other planets’ satellites.

Pluto’s orbit is very elliptical, and at an angle to the orbits of the four gas giants.

Other Solar System Objects

There are billions of other small objects, left over from the Solar System’s early history.

Asteroids are rocky bodies, from a few hundred metres acoss, to several hundred kilometres.  Most are in the asteroid belt between Mars and Jupiter, but some travel close to Earth.

Comets are chunks of ice, dust and frozen gas.  There are many, many dormant comets in the Solar System - in the Kuiper Belt (beyond Neptune), or the Oort Cloud (a spherical-shaped shell of icy objects far out in the solar system).

When they get close to the Sun, they heat up, and frozen chemicals vaporize.  The coma (head) glows, and long tails of dust & ionized gas stream out behind it.

Meteoroids are smaller than asteroids - they are the remains of shattered asteroids, and comet dust.  Most that enter the Earth’s atmosphere burn up in it as meteors.  Those that reach the ground continue to be called meteorites.

one time my high school friends who play D&D style roleplaying games told me a story about a game they played where two groups were playing campaigns against one another with the same DM, and it all took place in one city, and my one friend was studying nuclear engineering at the time, so she secretly snuck into the city’s nuclear plant, described the process of causing a nuclear meltdown, rolled high enough that it worked, and without warning ended the game by destroying the city and killing all the characters in a nuclear explosion

Astronomers find dust in the early universe

Dust plays an extremely important role in the universe - both in the formation of planets and new stars. But dust was not there from the beginning and the earliest galaxies had no dust, only gas. Now an international team of astronomers, led by researchers from the Niels Bohr Institute, has discovered a dust-filled galaxy from the very early universe. The discovery demonstrates that galaxies were very quickly enriched with dust particles containing elements such as carbon and oxygen, which could form planets. The results are published in the scientific journal, Nature.

Cosmic dust are smoke-like particles made up of either carbon (fine soot) or silicates (fine sand). The dust is comprised primarily of elements such as carbon, silicon, magnesium, iron and oxygen. The elements are synthesised by the nuclear combustion process in stars and driven out into space when the star dies and explodes. In space, they gather in clouds of dust and gas, which form new stars, and for each generation of new stars, more elements are formed. This is a slow process and in the very earliest galaxies in the history of the universe, dust had not yet formed.

But now a team of researchers have discovered a very distant galaxy that contains a large amount of dust, changing astronomers’ previous calculations of how quickly the dust was formed.

“It is the first time dust has been discovered in one of the most distant galaxies ever observed - only 700 million years after the Big Bang. It is a galaxy of modest size and yet it is already full of dust. This is very surprising and it tells us that ordinary galaxies were enriched with heavier elements far faster than expected,” explains Darach Watson, an astrophysicist with the Dark Cosmology Centre at the Niels Bohr Institute at the University of Copenhagen.

Darach Watson led the project, with Lise Christensen from the Dark Cosmology Centre and researchers from Sweden, Scotland, France and Italy.

Lucky location

Because the galaxy is very distant and therefore incredibly faint, it would not usually be detectable from Earth. But a fortunate circumstance means the light from it has been amplified. This is because a large cluster of galaxies called Abell 1689, lies between the galaxy and Earth. The light is refracted by the gravity of the galaxy cluster, thus amplifying the distant galaxy. The phenomenon is called gravitational lensing and it works like a magnifying glass.

“We looked for the most distant galaxies in the universe. Based on the colours of the light observed with the Hubble Space Telescope we can see which galaxies could be very distant. Using observations from the very sensitive instrument, the X-shooter spectrograph on the Large Telescope, VLT in Chile, we measured the galaxy’s spectrum and from that calculated its redshift, i.e. the change in the light’s wavelength as the object recedes from us. From the redshift we can calculate the galaxy’s distance from us and it turned out to be, as we suspected, one of the most distant galaxies we know of to date,” explains Lise Christensen, an astrophysicist at the Dark Cosmology Centre at the Niels Bohr Institute.

Early planet formation

Darach Watson explains that they then studied the galaxy with the ALMA telescopes, which can observe far-infrared wavelengths and then it became really interesting, because now they could see that the galaxy was full of dust. He explains that young stars in early galaxies emit hot ultraviolet light. The hot ultraviolet radiation heats the surrounding ice-cold dust, which then emits light in the far-infrared.

“It is this far-infrared light, which tells us that there is dust in the galaxy. It is very surprising and it is the first time that dust has been found in such an early galaxy. The process of star formation must therefore have started very early in the history of the universe and be associated with the formation of dust. The detection of large amounts of solid material shows that the galaxy was enriched very early with solids which are a prerequisite for the formation of complex molecules and planets,” explains Darach Watson.

Now the researchers hope that future observations of a large number of distant galaxies using the ALMA telescopes could help unravel how frequently such evolved galaxies occur in this very early epoch of the history of the universe.

IMAGE….Atacama Large Millimeter/submillimeter Array (ALMA) in northern Chile consists of 66 radio telescopes that collectively observe the sky in the millimeter and submillimeter wavelength range. By observing the distant galaxy with the ALMA telescopes at infrared wavelengths, scientists could detect its dust. (Credit: ALMA/ESO)