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Author | Topic: Nuclear Fusion, Radioactive Decay, what is the starting point? | |||||||||||||||||||||||||||||||
Jesuslover153 Inactive Member |
In doing more research to learn and having come across the idea that everything came from hydrogen, I have to wonder if this is true?
Were there other elements in existance in the beginning? How is it that other elements come from other elements? This all makes me think of turning lead into gold or the other way around... Can anyone lead me to some simplified articles on this subject or give me some names of people whom explain this very well? or can anyone here explain this very well?
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frank Inactive Member |
Jesuslover,
The following link to NASA should be of help : http://observe.arc.nasa.gov/...th/stellardeath_contents.html An astronomy textbook such as Discovering the Universe (Kaufman I think) would also be a good source. Red Giants and White Dwarves (Jastrow) is also a good source, but is a little old. Hope this is of help. Frank
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Jesuslover153 Inactive Member |
thankyou very much, that was an interesting read.. a good starting place..
I heard someone in a different thread say that water is the ash of hydrogen, is this true? and how could that be? is there not three major elements in water being hydrogen, oxygen, and deterium?I can see the oxygen and the deterium as being the ash of hydrogen in nuclear fusion/burning, but how is it that the ash and the parent element react with each other? How does the periodic table of elements relate to nuclear fusion/burning? [This message has been edited by Jesuslover153, 04-10-2003]
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Coragyps Member (Idle past 765 days) Posts: 5553 From: Snyder, Texas, USA Joined: |
Frank's link may start a little later in time than you're asking, Jl. The Big Bang resulted in big bunches of hydrogen, smaller amounts of helium, and a little bit of lithium. After clumps of this gas got gravitationally drawn into the first stars ("Population III", they're called, and the first certified candidate for one was confirmed a couple of months ago) the processes that the link talks about started. Youngish stars like our Sun are Population I - they have lots of recycled starstuff in them.
The man who figured out that the 24% helium in the universe had to be "primordial" - not manufactured by early stars - was none other than Sir Fred Hoyle, dear to the hearts of many YEC's who haven't read much of his astronomy stuff. He did an energy budget on the universe back in the 1950's, and showed that not near enough energy had been liberated by the fusion of hydrogen to make that much helium.
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PaulK Member Posts: 17828 Joined: Member Rating: 2.5 |
Deuterium is a form of hydrogen - its an isotope not an element
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Coragyps Member (Idle past 765 days) Posts: 5553 From: Snyder, Texas, USA Joined: |
Water as the "ash" of hydrogen is a reference to chemical, not nuclear, reactions. The temperature in the center of a star, where the nuclear reactions happen, is much to high for the atoms that are formed to "stick together" chemically to make compounds like water. Even at the surface of the sun, at only 11,000 F or so, it's too hot for chemical compounds - just atoms.
So we're talking about two different sorts of critters - atoms, made up of protons, neutrons, and electrons, and molecules (like water or methane) that are made of atoms "stuck together" but not "fused" like in the nuclear case. The periodic table is just a handy classification of all the elements that gives us chemists reminders of how they interact with each other chemically. It doesn't really say anything about nuclear reactions. [This message has been edited by Coragyps, 04-10-2003]
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Jesuslover153 Inactive Member |
an isotope than is a similar element with the same structure but not weight? or ?
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Jesuslover153 Inactive Member |
the one part that really confuses me hear is how does the big bang model account for the creation of hydrogen?
where some links about this Fred Hoyle dude?
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NosyNed Member Posts: 9004 From: Canada Joined: |
quote: "Ash" is a nice poetic touch to describe this. But be careful when you are discussing both chemical reactions like the burning of hydrogen to produce water and also nuclear reactions. Don't mix them up. for information on deuterium see this site:Deuterium - Wikipedia Being a bit picky in one's definitions; deuterium is hydrogen. It is an isotope of hydrogen. But you'll note from the site that very little of the hydrogen in the water of the oceans is this isotope (1/7000) so it can usually be ignored.
quote:This is where you are mixing up chemical burning and nuclear reactions. You need to get a bit of background physics. Where did you go to school? My 16 year old is studying nuclear reactions this very week. The burning (chemical) of hydrogen and oxygen produces water (ash). It doesn't involve the nucleus directly at all just the electrons.The fusion (nuclear "burning" ) of hydrogen into heavier elements require temperatures at the centre of stars and high pressures. It is when the nuclei of atoms merge. The periodic table gives you the atomic number and weight of various elements. Fusing elements releases energy (up to iron). This is the energy of a hydrogen bomb and stars. Fissioning elements from above iron down to iron produces energy (this is the energy of an "atom" bomb (the Hiroshima and Nakasaki weapons for example) I hope this helps.
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NosyNed Member Posts: 9004 From: Canada Joined: |
An isotope of an element has the same number of protons (the atomic number) but more or less neutrons. The protons are positively charged and so the number of electrons (negitively charged) is (usually) the same as the number of protons. It is the structure of the electrons that gives an element most of it's chemcical properties.
There are affects of the differing atomic weights in chemical reactions.
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NosyNed Member Posts: 9004 From: Canada Joined: |
I don't know the detailed calculations but I think I can give a not wrong high level overview.
You've got to have seen the E=Mc**2 equation. The big bang released a humungous amount of very dense energy. Energy turns into matter under those conditions. One way to describe the process is that hydrogen "froze" out of the quark soap as the universe cooled. If you want a lot of details you might quickly get into physics that requires more math than I can remember (or maybe ever learned). A good, small (but old now) book is "The First Three Minutes" which describes what went on during the first three minutes of time after the big bang.
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Dr Cresswell Inactive Member |
quote:In that if you burn hydrogen in an oxygen atmosphere you get water, I suppose calling water the ash of hydrogen isn't too bad a description. But that's chemistry not physics ... physics is much more fun, especially the nuclear variety quote:The periodic table is an organisation of elements according to their chemical properties, which depend on the number of electrons in the neutral atom - which in turn is the same as the number of protons in the nucleus. Hydrogen and deuterium are different isotopes - the same number of protons (1 in this case) but different numbers of neutrons (0 and 1 respectively in this case). Apart from some very minor second order effects, all isotopes of the same element behave the same chemically. The Big Bang produced mostly hydrogen and some helium, with very small quantities of heavier elements such as lithium. All other elements are produced by nuclear fusion ("burning") in starts. Main sequence stars burn hydrogen through a series of steps to produce helium-4; with some deuterium, tritium and 3He as steps along the way which survive the burning in small amounts. If there are small quantities of heavy elements (carbon, nitrogen, oxygen etc) then this can occur at relatively low temperatures and pressures allowing small long lived stars like our Sun to exist, in the early universe gas clouds would have continued to collapse further before hydrogen burning started generating super-massive short lived stars that rapidly collapsed to super-novae ejecting the heavier elements formed into space where it was incorporated into later stars and solar systems (like our own). As a star uses up its hydrogen fuel in the core it collapses again, and when the core temperature and pressure reaches sufficient levels it starts burning helium into heavier elements (by a "fortunate" coincidence a resonance in 12C allows the production of large quantities of carbon), and then as the helium is used up there's further collapse each time reigniting the nuclear furnace until iron is produced. Elements heavier than iron need more energy to create by fusion than they release, and the collapse of the star becomes critical. Eventually, in a process that is not entirely understood (yet), the core of the star rebounds with a flood of neutrons and neutrinos. The neutrons fuse with the outer layers of the core forming elements heavier than iron in profusion and the outer core and outer layers of the star are blown off into space in a supernova. The remains of the core collapses into a neutron star, or if it's heavy enough a black hole. The "ashes" of the star spread into the galaxy, and eventually seed other clouds of hydrogen with the heavy elements you and I are made of - we are all in truth star dust. Alan(guess who has a PhD in Nuclear Physics )
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joz Inactive Member |
Look up in the sky...
See that bright thing... Actually don't you'll hurt your eyes... Its bright like that because as I type this it is busy converting hydrogen atoms into helium atoms, millions of the little buggers. To be precise 4 times as many hydrogen atoms are needed to produce each helium. Each of these reactions gives off a little energy, in the 20 KeV range I seem to remember, and by virtue of there being a lot of these reactions occurring the energy released ads up to be an absolute shit load.... Does it seem a little less like alchemy now? *edit fixed missing K in KeV" [This message has been edited by joz, 04-10-2003]
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Percy Member Posts: 22508 From: New Hampshire Joined: Member Rating: 5.4 |
Hi JL,
All the other answers were good, but there was one question you asked that caught my eye:
Jesuslover153 writes: How is it that other elements come from other elements? Maybe something you've read has already answered this for you, but in case not... An atom consist of a nucleus of protons and neutrons surrounded by a cloud of electrons. As a visual aid you can imagine a miniature solar system where the electrons are planets and the protons and neutrons in the nucleus are the sun. Protons have a positive charge, electrons a negative charge, and neutrons no charge at all. The number of protons in the nucleus determines the element. Hydrogen has 1 proton, Helium has 2 protons, Lithium has 3 protons, and so forth up through Uranium with 92 protons and so forth. An electrically neutral atom will have as many electrons as protons. The number of neutrons can vary from one atom to the next, but is usually somewhat close to the number of protons. An atom of one type can change to an atom of another type by losing or acquiring protons. Losing protons is called fission, and acquiring protons is call fusion. Fission is what happens naturally to Uranium as it decays to Lead, and you can detect the emitted protons with a Geiger counter. It's also the process used by commercial nuclear reactors and atomic bombs. Fusion is what happens in hydrogen bombs and in the cores of stars. Elements coming from other elements is a natural process that happens all the time, and of course scientists have figured out how to make fission and fusion happen artificially. --Percy Added by edit: Good grief, take your time composing your message and 97 other people will beat you to it! Sorry for the redundancy. [This message has been edited by Percipient, 04-10-2003]
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Jesuslover153 Inactive Member |
seems alot less like alchemy now... thanks for the info this will help alot...
got to love knowledge. |
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