Dmitri Ivanovich Mendeleev (also romanized Mendeleyev or Mendeleef; Russian: Дми́трий Ива́нович Менделе́ев listen (help·info)) (8 February [O.S. 27 January] 1834 – 2 February [O.S. 20 January] 1907), was a Russian chemist and inventor. He is credited as being the creator of the first version of the periodic table of elements. Using the table, he predicted the properties of elements yet to be discovered.
This post was inspired by the “Poll: Do you believe in extraterrestrial life?“
I was thinking about Hoyle and CNO and of course about Lee Smolin. As you get older it is harder for me to retain all that proceeded each discussion, so linking helps to refresh.
Carbon is the 15th most abundant element in the Earth’s crust, and the fourth most abundant element in the universe by mass after hydrogen, helium, and oxygen. It is present in all known lifeforms, and in the human body carbon is the second most abundant element by mass (about 18.5%) after oxygen. This abundance, together with the unique diversity of organic compounds and their unusual polymer-forming ability at the temperatures commonly encountered on Earth, make this element the chemical basis of all known life.See:Carbon
It was necessary to recall the links from one to the other, to show how one’s perception “about Carbon was drawn” into the discussion about what life in the cosmos is based on.
I am partial to the allotropic expression on a physical scale by something that was understood as the Law of Octaves.
Carbon forms the backbone of biology for all life on Earth. Complex molecules are made up of carbon bonded with other elements, especially oxygen, hydrogen and nitrogen. It is these elements that living organisms need, among others, and carbon is able to bond with all of these because of its four valence electrons. Since no life has been observed that is not carbon-based, it is sometimes assumed in astrobiology that life elsewhere in the universe will also be carbon-based. This assumption is referred to by critics as carbon chauvinism, as it may be possible for life to form that is not based on carbon, even though it has never been observed.See:Carbon-based life
For sure each round of discussion on the topic leads too… and there are ideas with which one can ask. I am in no way advocating anything here in terms of AP other then to remember discussions about this very poll question before.
The triple alpha process is highly dependent on carbon-12 having a resonance with the same energy as helium-4 and beryllium-8 and before 1952 no such energy level was known. It was astrophysicist Fred Hoyle who used the fact that carbon-12 is so abundant in the universe (and that our existence depends upon it – the Anthropic Principle), as evidence for the existence of the carbon-12 resonance. Fred suggested the idea to nuclear physicist Willy Fowler, who conceded that it was possible that this energy level had been missed in previous work on carbon-12. After a brief undertaking by his research group, they discovered a resonance near to 7.65 Mev.See:Triple-alpha process
Mass spectrometers are analytical instruments that determine atomic and molecular masses with great accuracy. Low-pressure vapors of elements or molecules are hit by a beam of rapidly moving electrons. The collision knocks an electron off the sample atom or molecule, leaving it positively charged.
These newly-formed ions are accelerated out of the ionization chamber by an electric field. The speeds to which the ions can be accelerated by the electric field are determined by their masses. Lighter ions can go faster than heavier ones.
Ion’s path bent by external magnetic field
The beam of positively-charged ions generates a slight magnetic field that interacts with an externally-applied magnetic field. The net result is that the trajectory of a charged particle is curved to an extent that depends on its speed (determined by its mass). When the beam of a mixture of isotopes of different masses falls on a photographic plate, the different isotopes converge at different points, corresponding to the different radii of their semicircular paths.
The mathematical equation that describes this phenomenon is: m/e = H2 r2 /2V, where m is the mass of the ion, e is the charge of the ion, H is the magnetic field strength, r is the radius of the semicircle, and V is the accelerating potential.