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Tangentially related, but I think this is an interesting fact, all the atoms in our universe/galaxy/solar system with a mass up to that of iron are formed in th
by eklitzke 4y ago
Tangentially related, but I think this is an interesting fact, all the atoms in our universe/galaxy/solar system with a mass up to that of iron are formed in the core of stars in stellar fusion. Hydrogen fuses into helium, and as a star nears the end of its lifetime you get heavier elements like lithium, carbon, and so on. Under normal stellar fusion no elements heavier than iron will be produced, and iron is only element number 25. If you just looked at nucleosynthesis through the lens of stellar fusion, it isn't obvious that there should be any heaver-than-iron atoms at all in the universe.
These heaver-than-iron elements are created in a very interesting and exotic process. When a large enough star dies it explodes in a supernova, and a huge amount of energy and neutrons are released in a very short period of time. This supernova generates enough energy and neutron material that small amounts of heavier elements like gold, platinum, etc. are created through exotic nuclear fusion reactions, even though these heavy fusion reactions are energy-absorbing.
It's interesting to think when you're wearing jewelry made from gold or platinum, all of those atoms in your jewelry were created during the death of a star.
- b33j0r 4y agoIt’s funny that alchemy was kinda onto something, but underestimated the energy requirements by orders of magnitude of orders of magnitude
- BizarroLand 4y agoTrue, all you need to turn lead into gold is a moderately powerful collider and some hydrogen. The conversion is also very slow. And expensive. To make it this way it would cost a Quadrillion dollars an ounce. https://www.scientificamerican.com/article/fact-or-fiction-lead-can-be-turned-into-gold/ https://www.scientificamerican.com/article/fact-or-fiction-l...
- unnouinceput 4y agoQuadrillion now, but costs will drive down and once is turned to gold, it stays gold. In the far future where all gold was mined this will be the only process left to get more. Or explode stars and capture gold from them.
- kennend3 4y agoI joke with my Son all the time about turning Mercury into gold (He works in the nuclear industry). Once you get past the enormous energy costs to do this you have a secondary problem, all the gold produced this way is radioactive and it beta decays to.. Mercury.
- hgsgm 4y ago
- ajross 4y agoActually current modeling has supernovae as being only a small contributor to the measured abundance of heavy nucleii. These guys tend to come from a more exotic source still: material thrown off as a neutron star is tidally disrupted during a merger event with another neutron star or black hole. The wikipedia page is pretty good, as always: https://en.wikipedia.org/wiki/Nucleosynthesis https://en.wikipedia.org/wiki/Nucleosynthesis Almost everything with mass of 90 or above comes predominantly from neutron star mergers, basically.
- Mistletoe 4y agoGood Lord the universe is old. To think of how rare all that must be and how it had to have time to somehow get here to our planet.
- clavalle 4y agoIf they weren't here, we wouldn't be able to talk about it. I'd be interested to know if we're in an element rich vein of the wider universe or if all the good stuff is more or less evenly distributed?
- Mistletoe 4y agoI'm not sure but this has some interesting info such as- >Some whole galaxies have average metallicities only 1/10 of the Sun's. Some new stars in our galaxy have more metals in them than the original solar nebula that birthed the Sun and the planets did. So the amount of "metals" like oxygen and carbon can vary by a few orders of magnitude from star to star, depending upon it's age and history. https://www.reddit.com/r/askscience/comments/9tujxn/are_the_elements_distributed_evenly_throughout/ https://www.reddit.com/r/askscience/comments/9tujxn/are_the_...
- moloch-hai 4y agoPhosphorus is supposed to be rare in the wider world. Considering how central it is to everything important, life might find it very difficult to start in our temperature range, without.
- 867-5309 4y agowe are all made of star stuff
- maerF0x0 4y agoor as I like to say to encourage myself that small things matter "Stars are made of quarks"
- rhacker 4y agoWhat are quarks made of? https://static.wikia.nocookie.net/memoryalpha/images/d/d9/Quark_as_Lumba.jpg/revision/latest?cb=20100106000630&path-prefix=en https://static.wikia.nocookie.net/memoryalpha/images/d/d9/Qu...
- pishpash 4y agoStar stuff sounds like some German element.
- emmelaich 4y agoExactly what I thought! I checked with google translate. star stuff = sternzeug. stern stoff = star fabric
- hibbelig 4y agoStoff had more than one translation into English. One is cloth. Another refers to substances. Eg hydrogen is called Wasserstoff in German: water-stuff
- dejj 4y agoSee “waterstuff” in the Uncleftish Beholding: https://www.ling.upenn.edu/~beatrice/110/docs/uncleftish_beholding.html https://www.ling.upenn.edu/~beatrice/110/docs/uncleftish_beh...
- agumonkey 4y ago
- stock_toaster 4y ago“The nitrogen in our DNA, the calcium in our teeth, the iron in our blood, the carbon in our apple pies were made in the interiors of collapsing stars. We are made of star stuff”. – Carl Sagan
- steam_raven 4y agoWe have calcium in our bones, iron in our veins, carbon in our souls, and nitrogen in our brains. 93 percent stardust, with souls made of flames, we are all just stars that have people names" Nikita Gill
- fknorangesite 4y agoOh wait I can play this game: You and I are complicated but we're made of elements Like a box of paints that are mixed to make every shade They either combine to make a chemical compound or stand alone as they are - They Might Be Giants
- gretch 4y agoI understand this is a poem that is focused on artistic expression and not scientific accuracy, but I find the line about “carbon in our souls” to be out of place. I guess the rest of the poem is incidentally correct (when not abstract)
- ok_dad 4y agoOne who is a materialist could argue that your "soul" comes from the stuff you're made out of, so your "soul" probably has carbon it somewhere.
- dr_dshiv 4y agoSure, the word “soul” comes from the proto Germanic “saiwiz” (for sea or ocean). But not because “you are like a drop in the ocean,” but because “you are like an ocean in a drop.” The idea of soul can be objectionable when it is based on an immortal being or on a vitalist life-force (like “anima” of the Latin). But it seems fine when it is based on the psyche (like the “Psuche” of the Greek). I embrace taboo words like soul because they 1. are common 2. are useful for referring to things that seem pretty important (like avoiding soulless companies or products or buildings) and 3. are challenging to my normal (scientific) understanding of the world. Still, I’d be more comfortable if the poem referred to the “carbon of our souls” rather than “carbon in our souls.” Hmm…
- 29athrowaway 4y agoIt is also interesting that the Milky Way will collide with Andromeda and then we will be invaded by zerg.
- jmartrican 4y agoSo that means that for life to form, we probably need a star to die so that the heavier atoms used in complicated life forming chemical reactions (correct me if i am wrong here as what I'm about to say depends on it), hence it could be the case that if the universe is 13.5 billion years old, then we humans are appearing in the universe at the earliest possible time. 13.5 billion years seems like the time required to create a star, have the star die and blow up, have all that material settle and create a new star, then the planets are formed, than enough time on one of those planets needs to pass for life to form, then complicated life.
- matt-attack 4y agoI have zero ability to answer your question but I would love to know about about this. If life (like we know it) requires the explosion of aged stars, what is the earliest it would take. What is the minimum time needed to form, grow and explode a single star? Has there been time for this to occur 10s, 100s of times since the Big Bang? (obviously they can happen in parallel, but I'm thinking about how many in series).
- caf 4y agoThere's a large range of stellar lifetimes, from a few million years up to trillions of years.
- short_sells_poo 4y agoI'm just a layman but I believe by the time our sun has formed, we've gone through multiple star cycles. The early stars were very pure - made basically purely of hydrogen (maybe some helium?). They were huge, burned very bright and died comparatively quickly. Each time stars died, more heavy elements (and heavier elements than before) were produced. Over time the heavy element content (called metallicity) has increased in all stars. I believe there are also theories of white dwarf mergers undergoing runaway fusion and a lot of heavy elements being generated during the explosion. You raise an interesting question though: what is the earlier point of time where the heavy elements were abundant enough for life (as we know it) to form? Just because we started existing at +13.5 billion years, it doesn't mean carbon based life couldn't have formed much earlier.
- SiVal 4y agoIron is always spoken of as the dividing line, but I'd like to know whether iron is exactly on the line, on one side (which?), or it depends. IOW, does fusion of iron atoms release energy (hydrogen side of the line), absorb energy (uranium side of the line), neither, or either (depending on conditions)?
- eropple 4y agoAs I understand it, iron is the first element that absorbs energy under fusion, and therefore won't fuse further. Could be wrong, though.
- moloch-hai 4y agoIt will happily fuse further. It just won't support the outside of a star against gravity, while doing it. So the star collapses, fuses lots more stuff even heavier than iron, and then explodes. Most of the iron and heavier stuff fuses into the core of a neutron star, the ultimate in energy-consuming fusion.
- kennend3 4y agoNone of this is accurate. Iron will not happily fuse further because this NEEDS energy and where would that energy come from? "heavier than iron" elements are produced when a star explodes because that collapse produces enormous amounts of energy. During the collapse, the outer edge of the star is accelerated to something like 20% of the speed of light, that is an ENORMOUS amount of energy slamming down on the core. Lastly, neutron starts don't produce energy, they are the incompressible remnants of a dead star.
- moloch-hai 4y agoYou answer your own question: the energy for further fusion, all the way to neutron degeneracy, is provided by gravitational collapse. The outer layers fusing provide energy for the explosion.
- schiffern 4y ago>all the atoms in our universe/galaxy/solar system with a mass up to that of iron are formed in the core of stars Note that this is not, strictly speaking, true. Roughly 90% of the helium atoms in the universe were created via Big Bang nucleosynthesis. https://en.wikipedia.org/wiki/Big_Bang_nucleosynthesis https://en.wikipedia.org/wiki/Big_Bang_nucleosynthesis
- blibble 4y ago> all the atoms in our universe/galaxy/solar system with a mass up to that of iron are formed in the core of stars in stellar fusion. all is a strong word for example: the nuclear fusion experiment in the article, that would have produced a few atoms heaver that hydrogen (not to mention all the nuclear bombs that had a fusion stage)
- eru 4y agoIf I understand this right, I think some of the lighter than iron elements are also created in those exotic processes. But yes, unlike for the heavier-than-iron elements, the lighter ones are _also_ created in normal stellar fusion.
- qbrass 4y agoHeavier elements supposedly come from two neutron stars colliding because even a single star exploding isn't enough energy. So think about two stars killing each other to make your jewelry.