Author's note. This book is one of a series originally published as Who the Hell are We? but extensively revised and updated.
Thank you for reading, voting, following and adding, 'Supernovae and Life' to your reading list or library.
Dunc MacPhun
In chronological order, you can find all of my work at:-
https://www.wattpad.com/myworks/234080674-supernovae-and-life
https://www.wattpad.com/myworks/238813918-we-eukaryotes
https://www.wattpad.com/myworks/244084318-neolithic
https://www.wattpad.com/myworks/247058691-our-sea
https://www.wattpad.com/myworks/249120741-migration
https://www.wattpad.com/myworks/251168052-middle-era
https://www.wattpad.com/myworks/254532133-disease
https://www.wattpad.com/myworks/256201647-atoms-light
https://www.wattpad.com/myworks/257785133-steam
I will be publishing more work in this series.
Thanks for reading. Dunc MacPhun. 2022 March 23
Except for hydrogen, the elements that make up every cell in our bodies were forged in an exploding star more than 4.6 billion years ago. And 3.8 billion years ago, life on Earth probably began.
The universe dates back to the beginning of space and time, about 13.7 billion years ago; an event known as the Big Bang.
This resulted in an enormous mass of expanding light elements (hydrogen-1, deuterium-2, helium-4 and lithium-7) and, as denser clusters of these gases and dust gradually coalesced, into huge swirling galaxies and gravitational fields became stronger until, about 13.4 billion years ago, stars began to form. (The number with the element is the mass number; the total number of neutrons and protons in the nucleus of the element. The total number of protons in the nucleus, known as the atomic number, defines the chemical properties of each element).
As the proto-stars grew larger, their gravitational fields compressed the hydrogen until it was hot enough and dense enough for the hydrogen nuclei to fuse together to form helium nuclei. In the process, this released an enormous amounts of energy.
(Each hydrogen nucleus has one proton and, in most stars, four of these are forced together to form a helium nuclei which has 2 protons and 2 neutrons and slightly less mass than four hydrogen nuclei. (In the process, two of the protons decay into neutrons). The lost mass is converted into energy according to Einstein's famous formula, E=mC2, where the lost mass is multiplied by the square of the velocity of light).
Most of the stars in the universe (about 90 %) are main sequence stars, like our Sun. These range from about a tenth of the Sun's mass up to 200 times as massive.
The Sun, the source of energy for almost all life on Earth, formed about 4.6 billion years ago from the gravitational collapse of a large molecular cloud possibly triggered by shock waves from one or more nearby supernovae. Gravity pulled about 99.86% of the total mass of the Solar System into the Sun, while the rest flattened into an orbiting disk that became the Solar System. At 1.39 million kilometres (864,000 miles) in diameter, the Sun is about 109 times bigger than Earth and its mass is about 330,000 times greater.
About 73% of the Sun's mass consists of hydrogen which is currently being converted into helium at a rate of 600 million tons of hydrogen every second. But not to worry. It has enough hydrogen to last for another five billion years. The rest of the Sun's mass is about 25% helium and the remaining 2% is mostly oxygen, carbon, neon, and iron.
A few stars collect even more hydrogen than main sequence stars and, in the greater gravitational fields, the heat and pressure rapidly convert the hydrogen into helium. The energy, needed to maintain the star's equilibrium against gravitational compression, diminishes and the star's core is further compressed until become hot enough to fuse helium into heavier elements releasing more energy in the process. As the helium is consumed to produce 6-carbon, 8-oxygen and 14-silicon the core is further compressed to make even heavier elements. (The number in front of the element is the atomic number; the total number of protons in the nucleus. For example oxygen has 8 protons and 8, 9 or 10 neutrons depending on the isotope).
(Hydrogen, deuterium, helium and lithium make up about 98% of the universe. Heavier elements make up only about 2%, and elements with atomic numbers greater than 26-iron are rare).
But the synthesis of element heavier than 26-iron consumes (rather than releases) energy and gravitational collapse begins. This brief and very violent explosion, known as a core collapse supernovae, produces an enormous shock wave that provides the energy to create all of the elements known to science and a brief burst of light that typically outshines an entire galaxy.(A supernova occurs on average about once every 50 years in our galaxy (the Milky Way) but in the entire universe one occurs every few seconds).
The supernova then either collapses to form an immensely dense, black hole or throws most of its mass into the universe leaving neutron stars or/and loose material that might be absorbed by other stars or planets. (Black Holes are so called because the massive gravity fields are so strong that the escape velocity is greater than the speed of light, which means no radiation, including light, can escape from the gravity field).
In 2017 astronomers observed the merger of two neutron stars. (Which can happen when two core-collapse supernovae, that had previously been orbiting one another, leave neutron dense stars as remnants). Spectroscopic examination suggested that most of the heavier elements may be synthesized by the creation of highly neutronized atoms (containing many more neutrons than are possible at low temperatures and pressures) that subsequently decay, by the conversion of the neutrons into protons, thereby creating stable elements with atomic numbers up to 92-uranium and 94-plutonium. (The numbers are the atomic numbers; the number of protons in each nucleus).Of the 94 elements, from hydrogen to uranium, that exist on Earth, all, except hydrogen, are extremely rare in the universe.
YOU ARE READING
Supernovae and Life
Non-FictionSpace and time began about 13.7 billion years ago but it consisted almost exclusively of hydrogen until some stars grew sufficiently massive to create the heavier elements in gigantic explosions called supernovae. The Sun formed about 4.6 billion...
