September 16, 2016 Friday
Bedtime Story
What the Alpher-Bethe-Gamow paper proposed
The idea postulated in the dissertation was that during the initial moments after the singularity (we are talking in terms of seconds), the temperatures were extremely high and all that existed then were a sea of neutrons (matter) and photons (radiation).
The neutrons then began to decay into protons and electrons by the now well known process of beta minus decay.
Alpher, Gamow and we apes were aware of only these subatomic particles then.
As per Alpher's calculations, the resulting ratio of protons to neutrons was 7:1.
Proton and neutron can stick together (due to the strong force that exists between quarks) and if they got electrons going around them, atoms form.
An electron going around one bare proton results in a hydrogen atom.
But electrons could not "stick" to the protons or to the neutrons as the universe then was incredibly hot.
High energy photons were knocking them out.
One proton could stick to a neutron forming deuterium, one of the stable isotopes of hydrogen.
Deuterium would have been stable 180 seconds after the singularity when the temperature had dropped down to 10^9 Kelvin.
All the neutrons then combined with protons to form deuterium.
2 deuterium particles can stick together to form an alpha particle which is the nucleus of Helium atom.
Some of the deuterium particles that did not fuse together and has got left over since then.
So by 17 minutes or so the universe had alpha particles and deuterium but no neutrons.
It remained that way for 350,000 years or so.
By then as the universe expanded the temperature dropped down so much that now it became possible for electrons to "stick" to the protons and alpha particles giving rise to elemental hydrogen and helium.
Alpher went down to calculate the ratio of elements that would be formed depending on their atomic weight.
He found the Helium mass fraction to be 0.2999.
This predicted roughly a quarter of the universe would be made up of helium atoms and three-fourth would be made of hydrogen by weight.
This prediction was proven true experimentally which made the paper so valuable.
This paper went on to predict that all the elements would have been produced during the Big Bang by this process of neutron capture.
This part turned out to be wrong as fusion beyond Helium is inefficient.
Stay tuned to the voice of an average storytelling chimpanzee or login at http://panarrans.blogspot.in/
Good night mon ami and my fellow cousin ape.
A detailed flowchart of the nuclear events in the first few seconds and minutes
The 4 different nuclei of elements that were formed in the first few minutes (note that electrons were unable to "stick" to them, not until 350,000 years had gone by)
Bedtime Story
What the Alpher-Bethe-Gamow paper proposed
The idea postulated in the dissertation was that during the initial moments after the singularity (we are talking in terms of seconds), the temperatures were extremely high and all that existed then were a sea of neutrons (matter) and photons (radiation).
The neutrons then began to decay into protons and electrons by the now well known process of beta minus decay.
Alpher, Gamow and we apes were aware of only these subatomic particles then.
As per Alpher's calculations, the resulting ratio of protons to neutrons was 7:1.
Proton and neutron can stick together (due to the strong force that exists between quarks) and if they got electrons going around them, atoms form.
An electron going around one bare proton results in a hydrogen atom.
But electrons could not "stick" to the protons or to the neutrons as the universe then was incredibly hot.
High energy photons were knocking them out.
One proton could stick to a neutron forming deuterium, one of the stable isotopes of hydrogen.
Deuterium would have been stable 180 seconds after the singularity when the temperature had dropped down to 10^9 Kelvin.
All the neutrons then combined with protons to form deuterium.
2 deuterium particles can stick together to form an alpha particle which is the nucleus of Helium atom.
Some of the deuterium particles that did not fuse together and has got left over since then.
So by 17 minutes or so the universe had alpha particles and deuterium but no neutrons.
It remained that way for 350,000 years or so.
By then as the universe expanded the temperature dropped down so much that now it became possible for electrons to "stick" to the protons and alpha particles giving rise to elemental hydrogen and helium.
Alpher went down to calculate the ratio of elements that would be formed depending on their atomic weight.
He found the Helium mass fraction to be 0.2999.
This predicted roughly a quarter of the universe would be made up of helium atoms and three-fourth would be made of hydrogen by weight.
This prediction was proven true experimentally which made the paper so valuable.
This paper went on to predict that all the elements would have been produced during the Big Bang by this process of neutron capture.
This part turned out to be wrong as fusion beyond Helium is inefficient.
Stay tuned to the voice of an average storytelling chimpanzee or login at http://panarrans.blogspot.in/
Good night mon ami and my fellow cousin ape.
A detailed flowchart of the nuclear events in the first few seconds and minutes
Difference between the Big Bang Nucleosynthesis and Stellar Nucleosynthesis
The 4 different nuclei of elements that were formed in the first few minutes (note that electrons were unable to "stick" to them, not until 350,000 years had gone by)
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