How the Universe Made the Elements in the Periodic Table

I'm Matt Baker, I'm an associate dean here in the College of Science, and we're excited to bring you this year-long lecture series on frontiers in science in honor of the one hundred and fiftieth birthday of the

periodic

table

, so in 1869, Dmitri Mendeleev discovered, formulated the

periodic

table

of chemical

elements

and since then it has had a tremendous impact on science and we join the international celebration of this with a series of events, we have some entertaining events, we have already had a sporting event. and we will have some arts related events and a scavenger hunt and some other fun things throughout the year so you can go to the periodic table dot got techy D U and see all the things we have planned, but the academic core of our celebration this year it is a series of seven lectures on different aspects of the periodic table, so there are many different schools within the Faculty of Science and we are trying to show how the periodic table not only influences chemistry but has also impacted everything kind of things all over the world. of science and even beyond, we even have a lecture on geopolitics and the impact of rare chemical

elements

on the geopolitics of the world today, but we also have a talk on the mathematics of the periodic table, we have a talk on global warming and chemistry of the oceans and we will have a historical talk about discoveries related to the periodic table and some kind of fun anecdotes and trivia next month we will have a conference about silicon, its past, present and future in the different ways that silicon impacts our daily life, so I hope that all of you will attend all the events, not just today's, and help us celebrate this year, so without further ado, I'm going.

Oh yes, thank you. I forgot the most important thing, which is that there are t-shirts available for ten lucky winners. after the Q&A session, so stay for that, we'll also have a reception with some food and refreshments out here after the Q&A after the lecture, so stay for that and you might be a lucky winner now without further ado. will present dr. Pablo Laguna, who is the president of the School of Physics here at Georgia Tech and will introduce today's speaker. Thanks for coming. I am delighted to introduce you to our first distinguished speaker, Dr.

Jean Sawa Jame came to Georgia Tech thirty years ago. He was the first astronomer at Georgia Tech. He earned his bachelor's and master's degrees from Binder Vanderbilt and a PhD from Michigan. He does research in observational stellar astronomy and is the director of the observatory here in Georgia. Technology that is on Howie's roof. He has also been teaching introductory courses in astronomy and of course a more advanced course in stellar astronomy for many years and is strongly committed to outreach and education for kindergarten through 12. Hopefully he will have these monthly public lectures. Some of you have attended and it has been a great success.

There are hundreds of people who come every semester, so join me in welcoming Dr. Tsao, who is going to tell us how the

universe

created the elements of the periodic table, can you hear me? Okay, okay, I just need to get my bearings a little on where everything is. Thank you for coming tonight. I appreciate it, I hope. Tonight you will find in this whole series not only education but also entertainment and you will be very glad you came, so I will talk to you like Dr. Laguna said about how the

universe

created the elements. I haven't necessarily researched this.

I just taught it a lot, so I feel pretty comfortable and I want to tell you the story, so I show you some of the steps that we're going to follow. We're going to have to look at the Big Bang, low-mass stars, high-mass stars, supernova explosions, and a new mechanism that our department is associated with, which is a neutron star collision, which I'm NOT going to talk about. It's from the periodic table. I am NOT going to talk about its structure, the periodic table is largely based on chemical reasons and we will mainly look at the nucleus.

I'm also not going to talk about man-

made

elements, okay, so let's stick with what the universe

made

and not necessarily humanity. Well, before we continue because I know we have a very varied audience, let's review the definitions that we are going to have to deal with, so the first atoms consist of nuclei that have a positive charge surrounded by bonded electrons that have a negative charge and this It is the electromagnetic force that keeps those two nuclei together, which is what I am going to spend most of my time on, it consists of protons and neutrons united, the protons have a positive charge, the neutrons have no charge, they are neutral, these two are about 2000 times more massive than electrons and the nuclei are held together by a different force called the strong force, think about it, we're going to talk about all these positively charged protons being held together.

Protons and neutrons are made of bonded quarks and can change in the fourth force of nature the weak force and we will have to touch a second so that atoms, nuclei, protons and neutrons and then some other terms, an element be defined by the number of protons, so hydrogen is one, helium has two and is the charge, but isotopes are elements that have a variety of numbers of neutrons, so hydrogen could be just one proton, but there is also something called a deuterium proton plus a neutron. and then there's the trinium proton plus two nucleons and I'm going to look at these various isotopes for certain elements too okay, so let's start from the beginning a long time ago, not necessarily in a galaxy, but certainly from the beginning. and here is a simulation, this is the universe that is approximately as big as an atom and these are photons, imagine that they are photons and quarks that flow through some are made of matter, so I do not have antimatter, protons do not exist yet . and neutrons and electrons, but the early universe is just this boiling cauldron, it's made up of quarks and photons, it's extremely dense, okay, it consists of both matter and antimatter and I've talked about that and there are the four forces of nature because the ones we passed, including gravity like the fourth, all right now, this is what it feels like when T equals about a millionth of a second.

Well, now we go down to approximately T equals one ten-thousandth of a second. We've got a couple of things going on, it's a wonderful balance now. I'm purposely NOT going to show you any equations, but I'm going to show you some reactions along the way, but I'm going to talk about some things and you've all heard of e equals MC squared, okay? and what that says. is that energy and matter can transform back and forth and this is a diagram showing two gamma rays. Gamma rays are tons. A unique feature of photons. The shorter the wavelength, the more energetic they are, so here you have two Mac trucks hitting each other when that happens, now they can create two particles, in this case, although it's a mass particle and an antimatter particle and yeah , antimatter is real, it's not just for Star Trek warp engines, okay, it really exists in the universe and mainly in a few. reactions in the nuclei of stars, but this is a reversible process in that sense, an antimatter, if a proton and an antiproton come together, they can annihilate each other, so they don't get along and will create two photons, so in that first millionth of a second, this is what is happening, it would be a wonderful balance in some ways, except that there is one important change: the universe is expanding and it is expanding rapidly.

Chemistry students will touch on that, it's okay if you have a volume of gas and you increase the volume to the temperature. Low for physicists and chemists temperature means speed, okay, so if it's cooling, things are slowing down, that's for particles, what we need to look at are photons, photons of light travel. I love using this expression and, by the way, most physicists do. in the audience they are ready to strangle me because I am giving them something very classical, something inaccurate, but I am trying to convey the image accurately enough, but the photons move through the structure of space.

Think of space as something other than matter, literally. You could think of it as a leaf and like the leaf the fabric of space is expanding it will stretch the photons the photons are getting longer so the energy is decreasing okay the photons are changing but the particles no, so the reaction occurred. balanced a millionth of a second ago to a ten-thousandth of a second it is no longer balanced the only thing that can happen is that you can destroy particles, then they became particles and suddenly they are being destroyed because the photons do not have the energy, the equivalent mass to create new ones particles, so in about a ten-thousandth of a second all the protons and neutrons that could form have been created and about t is equal to one second, now you have all the electrons, okay, there are problems and One of the problems I know that I can't solve the question of what happened to all the antimatter in the universe because the best thing is that it should have been the same amount and we have some ideas, but none of them are really like that.

Well, I'll just have to say that somehow it happens that the antimatter is completely gone and I'm not going to worry about this, okay, now we're stuck with matter particles. Time is about one second so what is the condition of the universe now give me a second to review my notes okay in a second this is the periodic table we have protons okay and technically this is not a periodic table yet because there is no periodicity and second these are not atoms okay, they are just The nuclei of an atom, remember, they have the electron tied around them, so there is no chemical aspect at this point.

Well, can we do more than this? Can we make better heavier elements to make heavier elements? What are we going to have to do? It's taking protons and smashing them into protons and making them fuse together making the strong force work to hold them together now. I think you've all done this activity before where you take two magnets and take the two north ends and try it. to put them together and they repel each other, it just doesn't stick well, that's the electromagnetic force and that's the atomic force, we want to get down to the nuclear level so that the strong force, which is very strong but very short, can capture this.

What we have to do is have the universe send out the protons at a very fast speed so that the strong force can catch them and get close enough before the electromagnetic force rejects them. The only way to do it is to have a high temperature and a very high speed so the question is whether the early universe had a high enough temperature and a high enough speed to do this well. I am not going to talk to you for a moment about a time equal to one second. I'm going to tell you right now this is an image and this is the evidence that most people use to say that the Big Bang seems to be the correct theory this is an image of the temperature throughout the universe now it seems very scattered but the deviation From red, which would be the warmest, to blue, which would be the coldest, the deviation is one thousandth of a degree, so if you showed this as a variation of one degree, everything would be one color, this It is called three-degree fund. radiation that is in all directions of the universe and the reason scientists love this for the Big Bang is because it is isotropic, no matter where you look there is this glow, well if you take this radiation from three degrees of the background and you say, "okay." I have an idea of ​​how big the universe is right now and as I look at it it seems to follow what physicists call a blackbody curve.

You see how beautifully the curve fits here and here's a case where we take something that we know in the lab very well and apply it to the universe this mathematical equation. I'm not showing you the equation just the graph and if you put it back to that T equals one second, the first early epoch of the universe we see that the temperatures are high enough. for the fusion of helium so that helium is created, then we believe that the early universe also creates helium and further verification on this is when we finish tonight and I'm talking about abundances, people who work in this field use oxygen, yes, done in stars iron, yes, made in stars, uranium, okay, there may be two mechanisms, but when it comes to helium, they work, there is too much.

We couldn't have created the amount of helium in the universe that we see in stars, so that's great evidence that the early universe had. have also created helium, so how long did it produce helium well? for a long time, maybe fifteen minutes, okay, and here's our periodic table at about 15 minutes into the age of the universe again, these aren't atoms, they're just the nucleinow once now this is the easiest to do to make heavier elements even heavier higher temperatures will be required and the universe is cooling and so what happens now? Well, the universe continues to cool for about 400,000 years, okay, so we jump from 15 minutes now to 400,000. years, this is when it's cold enough that the protons and helium can start grabbing the electrons, the electrons start to stick together and you actually have atoms and at that time, even though this soup that was hot was photons and particles, now the Photons can pass because atomic spectra can only capture certain wavelengths and now they pass and that is what forms that three degree background radiation that was produced when light was decoupled from most of the matter that is at 400,000, the universe is cooling and to merge we have to have some hot spots.

We have to make some furnaces, we have to make some stars, so now there's a big question: when did the first stars start forming? Fortunately, we have a person in our department, Dr. JohnWeiss, who works in the early universe, so I had some conversations with him and they were interesting conversations because 25 years ago he was a student at Georgia Tech and took some of my courses, so now I ask your advice on some of these issues. The first star probably formed between 400 and 500 million years of the age of the universe. Again we are taking a giant step and this is an image of some of the oldest stars in these globular clusters, but we really don't know anything. about these first stars, these first stars should have been made of hydrogen and helium and I forgot to mention this, so the amount of helium that was created in the first 15 minutes is about 12 particles of hydrogen per one particle of helium, so It is approximately abundance.

As we see, we have never found a star that only has hydrogen and helium. Well, that tells us that even the oldest stars we have, if history is correct, are not first generation stars. Well, then how did a star form? So grab your favorite proton. Okay, look at it, and for about half of its life it will be on a star, a planet, a human being, or a cat, something like that, and then the other half of its life it will be in the interstellar medium, it will be outside. there as a cloud of gas and the interstellar medium is produced by the death of stars and that is where newer elements are created, so the original cloud is just hydrogen helium, the next cloud will have some other elements and then the next , after that, other elements. and then I was asking dr.

Wisely, look at the abundance of elements in the Sun right now and our Sun is five billion years old, we think the universe is about 14 billion years old, so the Sun formed when the universe was about 9 billion years old. of years, so what happened between those first? stars to get to the abundance we have today, so how many generations did it take for stars to start forming, die, create enriched material, then that forms a new star and build the periodic table and our back, calculating the wrapper is that? our stars may be tenth generation, but we don't know about those stars, we don't know now.

I understand fusion reactions, you're going to see them, they've changed, but the evolution of the universe over the first, you know, eight billion years. As far as creating the elements, I mean, we have a good idea, but if the star is different than what it is today because the mass of the star determines its evolution, I think this would be the most challenging part of what we are talking about this night, but Also, if I had to do it again, I might consider spending some time and I think this would be a very interesting aspect to study the elements.

The other thing about stars is that they are a microcosm of the universe, the war in the universe and there is a war between gravity and pressure, is there enough pressure in the Big Bang to make it unique or will gravity slow the expansion and the universe will contract and in the stars we have self-gravity? pulling down on the material and we have fusion reactions that create energy, a pressure temperature that fights against that and most stars there is a lull at the moment and that's good in the case of our Sun, that's fantastic because it doesn't We want the Sun to change honestly, our bodies can't adapt fast enough and this is what's happening inside the star and that's why we want to see the fusion reactions right because the fusion reactions are creating this energy and they're also causing us giving the elements we want here. it's a model of our Sun and a typical star and a great way to model this is if you could imagine a spherical egg, a bird egg, there's a shell and then there's a big region of that mucus.

I don't really know what you would use. call it and then there is the yolk and for us the yolk is the core and the Sun everything is well mixed so even in the core which is the only place where fusion reactions occur, the existing hydrogen and helium are already fine mixed and the new helium that is produced is also mixing well and this is about 30% of the diameter of the Sun. Well now I also have to add that for a moment there are two types of stars when it comes to stellar richness , its mass, and there are low mass stars. and high-mass stars and live their lives differently just as the rich and the poor live their lives differently the Sun is a low-mass star that reaches approximately four times the low-mass stars. mass of the Sun and then the high mass stars can reach up to fifty times the mass of the Sun, but there are not many of them, while there are zillions of low mass stars, including those smaller than us, the lower mass stars They have approximately 8% of the mass. of the Sun Jupiter has a thousandth the mass of the Sun, so there is a big jump between planets until you can get to the smaller stars, so we will look for just these low mass stars for the moment and make some helium.

Okay, so I'm going to show you some reaction rates, so this is one of the ways to make helium, so we're going to start with two hydrogen protons colliding with each other, they're fast enough that the strong force wins and I mentioned. Quickly, the weak force of one of the protons transforms into a neutron and in the process emits this exotic particle called a neutrino. I thought I'm going to go back to that and emit a positron in which that unfortunate positron has been born as antimatter. a universe of matter travels about a centimeter before being annihilated with an electron, so we get a little extra energy from that and then the next step is to hit this, this is deuterium, we hit the deuterium with a third proton, like this there's not much difference here.

Well, now everyone is thinking, Well, I know what you're going to say, so you get it with a fourth proton and we make helium. That's not what happens, apparently it takes two of these helium Tannis, so here's a case of an isotope and by the way. You see, the number tells how many protons and neutrons are in the nucleus and it creates helium four, which is the common stable helium and then two protons are returned, so if you're in my class, the answer is it takes. four to make a helium, okay, although in the end you see six involved, it takes one or two to get here and then a third to get here, so it's three here, three here, we get four and we get two back, so this one is the step. now there are all kinds of side branches and you can create some more elements that have a little bit more mass and our periodic table can go all the way up to lithium, beryllium and boron, but these guys don't live long, they just fall apart.

Other reactions occur and that is why their abundances, although they are so close to these two that are so abundant, their abundances are some of the smallest in the universe. Well, I want to tell a good story but I also want to give you facts, so I showed you. You aspects the three-degree background radiation from the Big Bang so you can believe that story when it comes to understanding how the insides of stars work. We still have a problem. We can't get it out. We can't go down to the core. Let's say we got it absolutely right and the problem with the light being created in the nucleus is that the light also only travels about a centimeter and then it gets involved in another reaction and a new photon is created and goes in a different direction.

So your favorite photon might take a million years to get out and that doesn't tell you what's going on in the nucleus, but that little neutrino I mentioned passes through almost everything and here's the first look at the neutrino detector . in size compared to men and this was full of dry cleaning fluid this is from the 1960s and this is from the days when groups were not one hundred and fifty people but three and one of the three was professor here at Georgia Tech, who unfortunately passed away a few years ago and I said this is known as the Ray Davis experiment.

Don Harmar was number two and I said Don, so here's this picture, which you and him look at and say, "That's Ray." Davis, here's the third guy. I am the one who took the photograph. This is a mile deep in a gold mine and I would love to tell you these stories, but there is a problem here with this detector and all the other neutrino detectors are just picking up. About a third of the number of neutrinos we say come from the Sun, so there's a chance that the story I just told you about what happens in the Sun we don't quite understand, but most scientists believe which is because the neutrino can change. in three different flavors and that only one of those three causes the correct reaction, but because of a connection with Georgia Tech I wanted to mention this and I could spend a whole hour talking about it, so let's continue, let's go back to the Sun and so I said that everything It is well mixed and one day the sun will wake up and go away.

A wonderful change has occurred: the heavier helium has rushed to the very center of the star and at this point this is a good five billion years from now, but the Sun will be a red giant and now has an extra layer . The most central region of helium does not react. It's still not hot enough because now you have two positive charges and two positive charges that you have to put together, that's a lot harder. than the two protons, so this will take a while, the hydrogen shell is no longer the nucleus, it continues to burn, it continues to dump more helium into the nucleus, but someday this finally kicks in and we have helium created, okay, and here are the Steps.

So again I'm not just going to show you some, check the math, so helium has two protons, two neutrons, so it's a four, and carbon has six protons, six neutrons, so 3 times 4 gives us carbon, this is known as triple alpha. process, but you can also make oxygen, it's pretty easy, in fact there is more oxygen in the universe than carbon and you can even go a little further and get some neon. Neon is pretty abundant so far, something you'll notice and maybe hear. another talks about the periodic table, there is definitely a difference if it is even or odd.

You can see that the even species are being created and not the odd numbers, not to the same extent and it goes back to helium, which is kind of the building block as we go here so that the Sun and the low mass stars will eventually have it was Yogi Berra, someone who said deja vu over and over again, so exactly the same thing about a nucleus in this case it is carbon and oxygen that are not yet burning surrounded by helium. a burning shell surrounded by a burning shell of hydrogen, so we've definitely been creating elements heavier than lithium, beryllium and boron, but unfortunately low mass stars just don't have enough gravity to make that happen this fusion reaction and whenever I say, the nucleus can Then that means that the death of the star is coming and unfortunately we still have a lot of periodic table to do, so we have a death and periodic table problem.

Now, when low-mass stars die, they do so in a very non-violent manner. but it is not necessarily a well understood process in which the outer part, which is the suns, can be 20 to 50 times larger than what it is now. It has a very low density, it just peels off this outer layer and this would be a three dimensional layer, but from our perspective it's only shiny when you look through the thickest part, so it ends up looking like a ring and that's the name of this object, the ring nebula, and has been gently detached and left behind what is called a white dwarf, it is that inert.

Carbon and oxygen nucleus that could never fuse. It is a very dense core. It's much denser than a diamond, but it just didn't work. Now we have a little problem here: this is whereThey find most of the heavier elements. We just created that there aren't as many planetary nebula remnants, so it's not the most efficient way to increase the abundance of the heavier elements, but how do we see this happening? We can do spectroscopy on these guys and we see. the heavier elements and by heavy I only mean a slight rise, these low mass stars can take us up to carbon, nitrogen, oxygen and neon, fluorine doesn't really develop that's why it's bad color wise with these two others, so these are the most abundant elements and that's what low-mass stars can do for us.

High mass stars. There is a big difference between 10 and a star with 10 times the mass of the Sun and the Sun, the core of the Sun. the temperature is about 15 million degrees, okay, the core temperature of the star of 10 million, 10 masses and 10 solar masses is probably closer to a billion degrees. These guys have heat. They make a much bigger bonfire. Not that they both have. We have 15 million dollars. the bank and they have a billion and they can live much longer, they spend it much faster, they live less time than a lower mass star because they are just burning and eating, but at least that cauldron is extremely hot, so I'll pick it up where there are the low mass stars, the high mass stars will quickly fuse hydrogen with helium they will quickly fuse helium with carbon and oxygen and then continue with the carbon and the oxygen here is the carbon burning now remember that your environment is basically pure carbon and oxygen, so there's not a lot of other stuff there, so you can't really have a carbon plus helium reaction, it has to be itself against itself and now you have a positive charge of six against a positive charge of six, so the temperatures do have to be huge and we do, we can make magnesium and this is a Raymond and you can make some others as long as you balance this, this is 24 on this side of the equation, this side has to be 24 and you can play the games. and you can see magnesium and neon and this one is also quite popular, but this is the one of interest, but there is also a lot of oxygen and its reactions. we can produce sulfur and a little bit of phosphorus and silicon and silicon is the one that interests me a little more and finally we are going to burn silicon so that silicon more silicon produces nickel and nickel is a little unstable the nickel disintegrates, which happens as you see, the 56 does not change, but nickel has two protons, two more protons than iron and two of those protons change to neutrons, so their charge, their number changes, the number of protons decreases, the number of neutrons increases, etc. the dough stays the same because of the way silicon is so important next month's speaker is going to be all he talks about so I'm going to give you a little push for that so I hope you come back to hear it so we're moving forward and look what we're doing and then the star at this point and now this is a more massive star to begin with, it also extends, I mean, it can reach the orbit of Jupiter, the single star, and this region is extremely De fact, low density, the outer edge is probably less dense than the best vacuums we can make on earth, okay, it's very thin, but the core, if you made a density profile, this is where everything is and it looks like this of onion peel. the different elements are being created and then the next one starts and we're here at this point with the iron core and I paused for a second, let's see where our periodic table is, so now we're up to these high mass stars. they've taken us to iron and again we highlight magnesium and silicon, okay, and you say, why did you stop?

Okay, so the next thing is you take iron and iron, smash them together and you're just going to fill in the rest of this and the problem is mother nature changes the rules, okay? So how's that for a teaser? Now we have our intermission and during intermission and I do this with my classes. I need everyone to stand up and start stretching and take another sip of coffee, check the basketball score, reintroduce yourself to the person next to you. Well, I hope that my president institutes this in all our colloquiums. Well, because I can certainly use it.

Thank you. I hope that helps. I'll try to talk to this side. a little too, it's just that my grades are way down so sometimes if I go back I have to make sure I'm telling the story right so like I said mother nature changes the rules when we get to clear the reason for that merger. reactions work is because the two things you want to crush weigh more than the final product, okay, even iron, this is true now, scientists don't want to see something unbalanced, correct conservation laws, so how do you balance well this? is that e is equal to MC squared there was a little bit of mass.

I can't see my pointer now a little bit of mass here turned into energy and that's the energy that the star is releasing on the court to fight gravity, okay? Fusion reactions are not only building our periodic table, they are releasing energy, they are fighting the gravity of stars, but now, if I were to try to break down iron to make Rhenium Teller, I think they don't weigh that much. It's okay to balance it. this we would have to put some energy here, a star doesn't want to do that, the energy in the core goes in this direction and if you suddenly say no, no, you have to put some energy this way, you go the same way than gravity, a star is not going to do that and then we are faced once again with the star facing its death because its core is not going to want to do what we have to do and we still have to have half the table periodic so that our high mass stars inside can become iron, but now what we have to do is that in a minute we will have to do a supernova explosion, but first I have to tell you.

A little bit more scientific diagram, what's being plotted here is how strong the attraction of the core is, or if you want to think about how strong the pool is, the best way is to say it and then these are the various elements, so, what is happening? is that if you were to take a helium four and get the two protons out, how much energy did it take to get the first one out and get the second out? That energy and since there were two, I divided it by two and yes, do the same with the iron.

I have to get twenty-six. Take that total energy divided by twenty-six and I'll see that iron is the most tightly bound nucleus, so until the fusion of iron you see that iron is the most tightly bound nucleus and these begin. to disintegrate, this is also a dividing line, if you want energy to be released you use fission on this side as the elements are moving towards a more compact state. Well, that's the actual physics that's happening, so like I said, we need a supernova to come now and create. which we can't do, so let's learn about supernova right now, you know everything you need to know about super, okay, here's a supernova explosion.

I'm going to explain in a second how it happened, but this is the remnant of a The supernova doesn't look like that beautiful planetary nebula, it's very violent, it's very confusing and mixed, and this is where the elements higher than iron form. It also has a blue glow hidden in the center, there is a neutron star that acts as a pulsar with a jet illuminating this and we are getting into the scope of our department as we get to these very dense objects, like neutron stars and black holes, and then that's a close-up view of this supernova that the Crab Nebula is in.

In our galaxy, many of the supernovae we have studied are found in other galaxies. This star is actually a member of this galaxy. You can see that a single supernova vent can become almost as bright as the entire galaxy and we can watch the brightness change and fade. over time and we can see the effect of radioactive decay of certain elements, certain elements have maybe a decay half-life of 77 days and we can see that there is a plateau and then after the 77 days, maybe a radioactive element different come into action again, how? we know this happens, we take spectra and we can see the elements that are in the supernova remnant, the material and we have elements higher than iron now.

I didn't say how that supernova explosion happens, so let me go over this myself. quickly because I don't want to go into this too much, but in that supergiant there was an iron core that was forming correctly and it's extremely dense and think about the early universe, extremely dense and extremely hot, and this core gets very hot in about a day, it only lasts about a day before this event occurs, it gets so hot that the photons being created now have enough energy, they are like a hammer, they can break an iron nucleus and split a single iron nucleus into thirteen helium and four. neutrons and if you ever have neutrons in a reaction like this you think it's a bomb and this is an explosion okay so you have to have those free neutrons and then there's enough energy for even helium to decay back into protons and neutrons and there are all these free electrons that are always nearby because it has to be electrically balanced and the electrons and protons collide with each other and that creates even more neutrons and some neutrinos, suddenly a volume the size of the Earth's neutrons in everywhere, but where did the energy come from in words and gravity is relentless and suddenly you have this implosion and these neutrons collide with each other at a speed of about one tenth the speed of light and we think that a neutron star will stop that one neutron density. star, a neutron star is the size of Atlanta, okay, the density, if you were to take a sugar from a neutron star material, because it's just a giant nucleus, there's no space, well, that's equal to Mount Everest, okay, sugar cube, so now you have this extremely difficult. object much harder than a diamond again and you have all this other material that suddenly realized, hey, we're falling like this, well, it's like a fastball pitch at 100 miles an hour, you hit it right with a bat even though it's going in this direction.

Suddenly it goes in that direction and you have this gigantic bounce and then this material, the innermost region, is what goes through the star and creates that bright supernova and this is where all those elements are created, but I haven't told you how correct it is this. It happened but I said we can't make iron with iron now we're going to change and we're going to use neutrons, neutrons have no charge so we can put them together, we don't have to worry about the electromagnetic force is so much so I'm going to show you a different type of periodic table.

Technically, this is not a periodic table because there is no periodicity and I realized about a week ago while I was preparing this talk, you know it's called the periodic table. table of elements is not called table of elements chemists have a periodicity because they see that there are chemical properties this metal and this metal and this metal all behave the same that is why it is a periodic table this table shows the number of protons going here Number of neutrons going this way and the color code is black are the stable isotopes right here this is hydrogen this is a free neutron so this is helium and then lithium and as you go up you get so high and then We'll start here and we'll go on and you can see that there is a wide variety of non-stable isotopes.

Remember that the isotope is a number of neutrons. Switch and then we get to about uranium over here and then these become natural and man-made. There's too much information to look at there, so I'm going to zoom in on a region that looks something like this because we see two different processes happening. You see many symbols. Let's look at the S and the S. "Slow" means "fast" in a supernova, it's just "fast", well, "well, fast", well, here's a silicon core that's now being hit by this neutron explosion. and maybe silicon goes from having 14 neutrons to 114 neutrons total once.

It was very fast and then this is very unstable, so one neutron changes to a proton and then another doesn't and another does and in this type of graph, when you get hit by the neutrons, you go this way and when you change to a proton the protons are in this direction, then you start going down and that's what these wavy lines are, these are these isotopes that are not stable until you get to a point on the periodic table, this table of isotopes that is stable and then you have your isotope form, but notice there are also some guys back here, well this guy is a blocker, so a supernova technique could create this isotope, but for this element it can't, so what is the slow process that we think What happens in some stars where?

A neutron hits you, it takes time, it disintegrates with another neutron, it takes time for it to marry,so it's a very slow walk, the rapid supernova explosion will give us this large amount of very heavy elements being created, well, notice another thing about this. Remember I talked about the odd-even effect. Well, this is an odd element. It's not five even stable isotopes, just one, five even, odd times one, so we're still seeing this odd-even effect with the isotopes and it will go. Back up a bit because helium is involved in many of these reactions. This is a simulation and I will tell you about another mechanism in a second, but this simulation shows a value of 39 seconds, so here are its stable isotopes and fast processes. it just happened, so let me go ahead and start it and I'll talk about it, there we go, and in 39 seconds all these isotopes are being created and they're decaying and they're getting closer and closer to stable time. and at the end they're going to go fast and then look at what happens on the top right and then those that have a very short half life decay into uranium, let me show you this and I don't know if I can show you.

For the second time I think you saw it correctly, then they are really the elements superior to iron. Now obviously you can make more of the lower ones, but the elements higher than iron are going to require something like a supernova explosion, so that gives us the full table. I'm not done with the story yet, but I am a complete table. By the way, I went by uranium because when this table was made, the farthest known planet in the Solar System was Uranus and when the next element was found they discovered I decided to name it after the next planet.

The timing was right at the time when Pluto was discovered, this is called Neptunian and then here is the evil plutonium named after Pluto, which then was the last one and I've read articles that it's not that evil, okay? We don't have to worry so much about it, but this is not the only story. This is not the only way to do this. And this is a woman from our department. I'm going to play this video in a second. but a few years ago with the gravity wave studies carried out in our department they found a neutron star colliding with a neutron star and they believe that this can also create heavy elements above iron and that simulation that I showed you was based on this phenomenon that I am about to show you stars that were left behind a star with most of its fuel and locked under their own weight 135 million years ago in a galaxy far, far away called NGC or 993, two stars of neutrons were in a spiral, they revolved around each other. its closest distance between Atlanta Nashville as they began to merge as they spiraled faster and faster they stretched and compressed space-time produced a gravitational wave signal that continued to travel under which it was and then merged as they merged introduced in a fireball of gamma radiation That light also traveled to us and the receiving matter that was left behind began to fuse in nuclear reactions in this process is called Q Nova and they produce heavy elements like and that's only like two and a half. years, right, I mean, this is the first one, so new scenarios are being discovered and there are some other theories out there.

I saw one about primordial black holes devouring neutron stars and maybe the reactions that can occur there, you know, the problem is that we can. I won't replicate them in labs, so they are a little harder to study. Well, I'm getting close to the end, so here's a graph that shows the abundances of the elements in the universe as best we can tell at the moment. Well, and different again. type of scientific graph to get all this information here, this axis is logarithmic, which means that if you go from nine to eight, which you think is just one, it's actually a factor of 10 to 1 to go from 9 to 6, a difference of 3 is 10 to the third power or one thousand and this is going down and these are not even plotted hydrogen is always set at 12 and then helium is at about ten point nine those are by far the two largest and we see that oxygen is third and neon fourth and nitrogen beats carbon and then look at some of these.

I talked about magnesium and silicon and it's jumping and falling until we get to the iron which has a big spike again and then it goes through the iron, a little bit of nickel and then the bottom just falls out. and that's partly because what creates these events is much rarer, since we had helium-hydrogen created in the Big Bang and we have many stars creating these elements in this particular region, again you can see the even effects and odd. the two effects of the saw, the pairs are going to be higher of the particular group here is lithium, boron, beryllium, it's right here.

I don't know why I didn't plot it really rare and then you can see that these are all rare gold. 79 on this graph, so it's down here somewhere in the same region, so this is where we are today, now we can talk about the future and how things will change, but we'll have to go many billion years before that we'll see that happen, so I'm coming to the end, what are some of the flaws in the story? Well, the first one we talked about is true, I mean, I know what to do with antimatter to handle that problem, really, how much hydrogen was it?

Helium was produced in the Big Bang, maybe there was a little bit of lithium too, but to get a handle on that, we think we have a good idea of ​​how long before the first stars appeared, and really everything about the first stars. If they had instead of 10 solar masses, I mean. Today's stars are the most massive or 50 times the mass of the Sun. What would happen if these stars were 250? They would live perhaps a thousand years. I am the calculation and the gigantic supernova explosion, so perhaps the first part of the in and was much denser. maybe this cycle could happen much faster, so we're just not sure what happened there and this relates to how many generations there were between them we really think we know our stellar interiors well out of all the ones we think we know that and we think We know that some of these supernova processes are pretty good.

We have opened the door to these other mechanisms. We need to worry about frequency right now. We have a detection. Just because we haven't detected them doesn't mean they aren't. It doesn't happen all the time, but you know it's wonderful to see these other ways of doing this and in astronomy that's the best thing we can usually see is that you can get a result in more than one way and hopefully you're consistent and then finally I didn't even talk about this topic but Dark Matter we can say that for every particle that you can see in the universe there are probably 10 particles of equal mass 10 whatever and we don't know what it is because it's dark.

I haven't been able to detect it anyway apart from gravity and a favorite theory is that there are these other particles and the nickname is "wimps" means weak interaction so you can't detect them as massive particles, maybe they're not big. Deal, you know, maybe there are a lot of pink elephants in this room, we just don't see them until someone shouts fire and everyone is trying to get through those doors and the pink elephants are stopping you from flowing that way, so it could be that these are on the way inside the Sun and that's why we don't have as many reactions or maybe these massive particles have their own reactions or they decay into something so if you want a Nobel Prize answer that question, okay, and that will be a great day when we understand it, so should we really worry about this?

Well, the answer is yes, there are some heavy elements in our body. Do you know which one is the heaviest? Think about it for a second, so I chose an image of people feeling the sunlight and here. They are some of the heaviest elements, oh there is iron, so everything above iron was created in a supernova or neutron star collision, where is it going to stop what is the object with greater mass than our body human must have in order to live and that is iodine and that is? According to Wikipedia, there could be something even heavier that we have to have, so this is very important and therefore, if all of these elements are created by supernovas, then you have supernova dust on you, which we all have to have the life we ​​have. have these particular elements so I'm going to show you the periodic table again and again thank you for coming and I'll answer some questions explain that it doesn't work it works oh yes it works oops so you said that gamma rays come together to make matter and antimatter and then when you were talking about making things like magnesium and silicon and all that jazz, carbon or oxygens come together to form that atom and a gamma ray, how does that work?

So those are two different things, matter and antimatter. They come and go, okay, so they'll destroy each other and we'll forget about it for the rest of the universe after the first second, so inside stars you want to know how a fusion reaction would occur, not like where that gamma occurs. Okay, back from OK, so if you were in chemistry in high school and you had to balance charge in a reaction, you had to have the same number of positives and negatives on both sides in these physical reactions, there are several other charges that you put several other conservation laws and MC equals square is one of them, so if you can calculate how much mass is at one end and then you get the final product and the two don't match, then that could be a gamma ray, well, that is a possible way out, if a proton changes to a neutron, then you will always have that antimatter and the neutrino, but if they are just collisions and they don't change, then you will usually get a gamma ray, okay?

So Jim, the example you gave was a core collapse supernova. Yes, the abundances are approximately the same as those produced by a type 1a supernova or are similar. Therefore, the type 1a supernova is a white dwarf that acquires too much mass and collapses when the white supernova the dwarf collapses, we think that everything fuses, but it starts with carbon and oxygen, so fusion reactions maybe are produced at most, so you won't get higher levels. I'm just thinking about the downside of supernovae. although no one has ever made a graph that says if it's a solar mass of 10, this is what you get and if it's 12, this is what you get.

At this moment it is not yet known what the reactions are, what the final would be. exit we have a question from Miami Florida and the question is what are the elements that exist naturally on earth and if it does not include all the elements, how are the other elements formed? Okay, so all the elements we were showing are on the ground and you're raising my level of experience here. I think there is an element that is very radioactive and is difficult to find. I think it starts with an S, okay, and then once you get to this range, although everyone thinks uranium apparently there may be some. of these from other decay processes, but there are very few of them on Earth, but they probably exist, but everything I have shown you is fine on Earth and it is distributed fairly evenly in our solar neighborhood, there are no big changes .

There will not be one star that is full of barium and another that is full of iron, so it is quite homogeneous, the abundance is quite well distributed, you have the same thing in all the stars and then that is what is left for the system, this type of follow up. To this question, I think you said that Novas, supernovae are neutron stars, they are quite rare, how do you get the distribution of all these elements that they produce throughout the universe, assuming that they are well distributed? I have some gravitational astronomers. There are astrophysicists here who can answer your question.

That's what I was saying and people are starting to split into two camps. Oh, no supernova can do it. Oh no, colliding neutron stars can do it. Both have their advantages and both have their own. The downside is that colliding neutron stars have a lot of neutrons right there, a very dense environment, so a gigantic rapid process could occur. On the other hand, it took two supernova explosions to produce those two neutron stars, so you know which one it has. was the one that contributed the most, but right now with colliding neutron stars, which were very well studied once the first observation came out, it's in its infancy, but that's what a lot of people are jumping into now and I hope so we can get a better feel for Altima, but I think we're too new to this to start answering your kind of questions, but I'll take you to someone who understands, ask a question, okay, then say like edit Caron and that Superstar. would collapse into a supernova as it will in the next million years when that happens, is it possible that the supernova would release enough energy and have a high enough temperature to produce elements we have never seen before?

Is there still a possibility of discovering them? stable elements that we are outside the scope of the periodic table, so the elements that are down here I thinkSo the answer is yes, it is possible for them to form, but because of the strong force and the weak force there is sort of a limit to how big a nucleus can get because the strong force can't get to the other side very well and From what I understand, these elements will have half-lives on the order of milliseconds, so there is some sort of limit that even if it was created, it's not so unstable that you wouldn't see it collapse, so you mentioned that when you were building the table periodic that's something right now, that they're not actually atoms, they're just the nuclei, so where do those electrons come into play? so in the early universe, when T is equal to one second, all the electrons have been formed because now the universe is cold enough that even gamma rays to produce electrons don't have enough energy, but there are always electrons out there also because we have to be electrically balanced, we don't have half the universe positive and half negative, so they are always mixed there, not necessarily united, you have protons doing this and electrons doing that in a time of approximately 400,000, that's what cold enough that the protons You could start grabbing the electrons and they stick together and now you have an atom, okay, but when you go back inside the stars, they are and they are not atoms, they are nuclei and free electrons are swarming around, so which is not atomic in the nuclei.

Adain the cores of stars I think we're going to have enough two more questions and that's all we have time for, okay? Now, at the higher limiting numbers, there are hypothetical islands of stability at about one hundred thousand two hundred and fourteen protons. So my question would be with the new evidence on neutron star collisions, is there any evidence that, for example, a rhodium isotope with a higher neutron count comes out of something that we can't really produce in the lab, but we can get some kind of special scopic evidence that, although I can't answer the question that way, I don't think enough would be created for A to be able to see it in a spectrum and B for us to know what the spectrum looks like, in fact there wouldn't be made. a spectrum because you wouldn't have any spectrum of life without first creating it in the lab.

Okay, we couldn't identify it and some of these supernova remnants are still plasmas, they don't have all the electrons yet. being bound and creating the spectrum, they are pretty, they will be weak, so it is difficult what the processes are that bring this to us, the Earth, from the core of the stars in the universe and therefore how it reaches a planet. Okay, so yes, in a certain volume of space there should eventually be some supernova explosions and there should be a lot of planetary nebulae, so you get a mixture of gases and eventually there will be enough self-gravity for these gas clouds to start to contract. and you will form a new generation of stars and you will tend to form clusters like the first diagram I showed you, they will live their lives and then depending on their mass they will die at different times, so it will be the same process.

So in a way I'm saying that following your favorite proton, it's going to get trapped in a star or a stellar environment or it's going to be ejected back into the interstellar medium, but as you do this over and over again, the elemental abundances grow because the Stars have been creating heavier elements and especially with supernova explosions, if you have them in your environment then it's just in your environment, so when our solar system formed the abundance that we see in the Sun, we felt the same abundance on Earth. abundance on Jupiter now the Sun has changed it due to fusion reactions, but basically whatever the Sun started with, we had the same thing here, but the iron sank towards the core and we lost hydrogen and helium, helium, well, got me talking about how helium was first discovered in the Sun, not the Earth, and was named after the Sun, Helios, and eclipses like we had a year.

A year and a half ago, there is a relationship between the elements and astronomy and where they are found. Here was a case where we did it the other way around with the celestial object before finding it on Earth. I hope I have answered your question well in this regard. note I would really like to thank Jim for this amazing lecture once again and Jim, we have a little gift for you from the Faculty of Science to thank you for giving this lecture. Thank you very much and I would like to mention our interim dean David color, who has a very important announcement to make, so it is a real pleasure to serve as interim dean of the Faculty of Sciences, especially as a chemist, this special year that is the International Year of the Periodic Table and you know it.

The Faculty of Science celebrates this special year for a year and everyone needs to know who Moines Ruhi is where Maureen is. He's in the lobby so everyone can meet Maureen. She really is the driving force behind this entire series of events. not only the monthly lecture series that Matt is really taking a leadership role in, but we also have concerts, we have a party during the summer for the summer students and the first day of school in the fall will be a special day for we. with lots of activities based on elements in place on the periodic table so the most important thing at the moment is probably the food, but before the food there are t-shirts, thanks Julia, so how are we going to get the t-shirts out?

I don't see any. T-shirts in the room so I was wearing one, where are the t-shirts? If you look under your chair there may be a shirtless envelope that gives you a shirt on the bag table and if you are sitting next to an empty chair you have two chances to win a shirt and with that again I would like to say thank you to dr. Come out for an enlightening lecture to kick off this series and I hope we can continue the conversation in the lobby where you can talk some more with Jim and each other about the elements and the periodic table.

Thank you for coming tonight.