APOD and General Astronomy Discussion Forum
https://asterisk.apod.com/
Note that as of 2012, 114-ununquadium has been given a permanent name: fleroviumjohnnydeep wrote: ↑Mon Jan 09, 2023 2:13 pm The most detailed periodic table I've yet found is the one from https://www.vertex42.com/ExcelTemplates ... ments.html. There are both PDF and Excel format versions. Here's the color PDF - https://www.vertex42.com/Files/pdfs/2/p ... _color.pdf.
Ha - only you would have noticed that!Cousin Ricky wrote: ↑Mon Jan 09, 2023 8:30 pmNote that as of 2012, 114-ununquadium has been given a permanent name: fleroviumjohnnydeep wrote: ↑Mon Jan 09, 2023 2:13 pm The most detailed periodic table I've yet found is the one from https://www.vertex42.com/ExcelTemplates ... ments.html. There are both PDF and Excel format versions. Here's the color PDF - https://www.vertex42.com/Files/pdfs/2/p ... _color.pdf.
Such are the pitfalls of a static jpeg compared to a dynamic site like Ptable (which does have that update). <sigh> Still, the new name is over 10 years old, so I would have hoped the Vertex42 site would have been updated by now. Oh well.Well, given that most estimates suggest that only a few percent at most of the Universe's hydrogen has ever been in a star, and most of the hydrogen in stars is still there, as hydrogen, I think that it is reasonable to say other sources of the element aren't "appreciable", representing only a very, very tiny fraction of all hydrogen.javachip3 wrote: ↑Tue Jan 10, 2023 5:47 am "The hydrogen in your body, present in every molecule of water, came from the Big Bang. There are no other appreciable sources of hydrogen in the universe."
Really? Many fusion and fission reactions produce free neutrons. Neutron star mergers, supernovas, relativistic jets from black holes, and other cataclysmic events also produce free neutrons. Free neutrons decay with a half life of 10 minutes into a proton, an electron, and an electron antineutrino. A proton is a new hydrogen nucleus. After 13.7 billion years, might not this account for some percent of all existing hydrogen?
Huh. So, 95% or more of the hydrogen in the universe is just floating around as gas in interstellar and intergalactic space? If the following graphic is still accurate, it would imply that about 0.5% / 4% = 1/8 of the hydrogen in the universe is in stars, which would be about 12 percent.Chris Peterson wrote: ↑Tue Jan 10, 2023 2:42 pmWell, given that most estimates suggest that only a few percent at most of the Universe's hydrogen has ever been in a star, and most of the hydrogen in stars is still there, as hydrogen, I think that it is reasonable to say other sources of the element aren't "appreciable", representing only a very, very tiny fraction of all hydrogen.javachip3 wrote: ↑Tue Jan 10, 2023 5:47 am "The hydrogen in your body, present in every molecule of water, came from the Big Bang. There are no other appreciable sources of hydrogen in the universe."
Really? Many fusion and fission reactions produce free neutrons. Neutron star mergers, supernovas, relativistic jets from black holes, and other cataclysmic events also produce free neutrons. Free neutrons decay with a half life of 10 minutes into a proton, an electron, and an electron antineutrino. A proton is a new hydrogen nucleus. After 13.7 billion years, might not this account for some percent of all existing hydrogen?
There is a lot of uncertainty in the numbers because there's a lot of uncertainty about how many stars there are. However, even allowing for something on the order of 10% of the hydrogen being in stars, we need to consider that most of the stars that have ever existed in the Universe still do, and are still in their hydrogen fusing phase, and have only fused a tiny fraction of that hydrogen. So compared with the amount of primordial hydrogen, that created as a fusion byproduct remains very tiny.johnnydeep wrote: ↑Tue Jan 10, 2023 3:49 pmHuh. So, 95% or more of the hydrogen in the universe is just floating around as gas in interstellar and intergalactic space? If the following graphic is still accurate, it would imply that about 0.5% / 4% = 1/8 of the hydrogen in the universe is in stars, which would be about 12 percent.Chris Peterson wrote: ↑Tue Jan 10, 2023 2:42 pmWell, given that most estimates suggest that only a few percent at most of the Universe's hydrogen has ever been in a star, and most of the hydrogen in stars is still there, as hydrogen, I think that it is reasonable to say other sources of the element aren't "appreciable", representing only a very, very tiny fraction of all hydrogen.javachip3 wrote: ↑Tue Jan 10, 2023 5:47 am "The hydrogen in your body, present in every molecule of water, came from the Big Bang. There are no other appreciable sources of hydrogen in the universe."
Really? Many fusion and fission reactions produce free neutrons. Neutron star mergers, supernovas, relativistic jets from black holes, and other cataclysmic events also produce free neutrons. Free neutrons decay with a half life of 10 minutes into a proton, an electron, and an electron antineutrino. A proton is a new hydrogen nucleus. After 13.7 billion years, might not this account for some percent of all existing hydrogen?
Thanks. Points taken!Chris Peterson wrote: ↑Tue Jan 10, 2023 4:57 pmThere is a lot of uncertainty in the numbers because there's a lot of uncertainty about how many stars there are. However, even allowing for something on the order of 10% of the hydrogen being in stars, we need to consider that most of the stars that have ever existed in the Universe still do, and are still in their hydrogen fusing phase, and have only fused a tiny fraction of that hydrogen. So compared with the amount of primordial hydrogen, that created as a fusion byproduct remains very tiny.johnnydeep wrote: ↑Tue Jan 10, 2023 3:49 pmHuh. So, 95% or more of the hydrogen in the universe is just floating around as gas in interstellar and intergalactic space? If the following graphic is still accurate, it would imply that about 0.5% / 4% = 1/8 of the hydrogen in the universe is in stars, which would be about 12 percent.Chris Peterson wrote: ↑Tue Jan 10, 2023 2:42 pm
Well, given that most estimates suggest that only a few percent at most of the Universe's hydrogen has ever been in a star, and most of the hydrogen in stars is still there, as hydrogen, I think that it is reasonable to say other sources of the element aren't "appreciable", representing only a very, very tiny fraction of all hydrogen.
Beautiful !johnnydeep wrote: ↑Wed Jan 11, 2023 4:37 pm Just thought I add this recent relevant comic from XKCD - https://xkcd.com/2723/
https://imgs.xkcd.com/comics/outdated_p ... ble_2x.png
I had heard that story as well. All the more reason to accept/approve Sweden's NATO membership request post haste!MarkBour wrote: ↑Sat Jan 14, 2023 5:37 pm Thanks for the periodic table reference, johnnydeep! I like it very much.
And one more note on the origins of the elements, which I saw in the news today. ("Where we get them in a different, not-very-scientific sense.)
Sweden has just reported the finding of a large deposit of some valuable rare earths. Perhaps Ann can start supplying us? They had not yet reported details on what all is in the deposit, but apparently good quantities of neodymium and praseodymium.
https://www.npr.org/2023/01/13/11491358 ... -in-sweden
Ha ha! Yes, maybe if they offered some Neodymium to Turkey.johnnydeep wrote: ↑Sat Jan 14, 2023 8:56 pm I had heard that story as well. All the more reason to accept/approve Sweden's NATO membership request post haste!
