This is an automatic transcription so there may be errors.


Hello, everybody. Welcome back to the math and physics podcast. I'm your host Parker. 

And I'm Ray and we welcome you to episode number 48. Where today, once again, we have a very special guest on we have Mr. Paul Delaney. So Mr. Delaney has has been so quite a history that we have. I met him originally three years ago, doing a co op program at at my high school. And he was basically supervising me, I was, you know, playing around with the telescopes at York University and stuff like that. So anyways, Mr. Delaney is a lecturer, senior lecturer, professor at York University, where he is in the department of astronomy and astrophysics. So before I started talking too much, Mr. Delaney, maybe you want to give a small introduction on you know, what you do it York And, yeah. 

Thank you very much, Rayhan. And thank you to Parker for inviting me onto the podcast. This is really great. Absolutely. I met Rayhan three years ago, as he indicated from a co op experience. And we had a great six months at York during that time. And then of course, you know, we've sort of hung out together, so to speak from afar, ever since. What I do at York, as you indicated, I'm in the Department of Physics and Astronomy, I look after the Allen Caswell observatory on campus have been in that role for about 35 years now, I'm gonna retire this year.


Yeah, when I look back on that, I go, Wow, gee, 35 years, whoa, hey, right God, apart from the obvious, you see the telescope in the background, that's how one meter telescope there, we've got a variety of both permanently mounted and portable telescopes, which we utilize for our undergraduate astronomy courses. So if you're doing sort of the astronomy stream at York, every year of that degree, you will have a laboratory experiment that is requiring the use of the telescope. So we integrate that into the astrophysics program there. But outside of that, of course, there is research, we do a lot of variable star research with these telescopes, we've got a variable star research program that has been running now for 25 years, one of the longest running for this particular type of star anywhere on the planet, in fact, and then of course, we've got our outreach programs are Monday and Wednesday night online public viewing our

YouTube, teletube, I stumbled on one of them. And of course, normally, when you have the opportunity to come onto campus, there's lots of tour activity. So high schools, cub packs, various community groups all have the opportunity to come up and look through our telescopes engage with students like right hand. I mean, remember, you gave that presentation to the astronomy club. 

Yeah, yeah, I was I was actually just gonna say so in, in my co op experience, right. At the end, I gave a give a presentation to the astronomy and physics club of York on like Einstein, Einstein's field equations, and gravitational waves and stuff like that. And oh, my that was that was, that was an amazing opportunity for me. So obviously, thank you for that. And that was, I think, the best thing that I've ever done in physics. So like, that was definitely a really cool, really cool. 

You blew them away, mate. I mean, of course. 

Yeah. Thank you. Thank you. 

Yeah, it was really, really impressive. I mean, it was such a big opportunity for me, because I was 16 years old at that time. And imagine telling my friends, Hey, I just presented to a bunch of university students. And I'm like in grade 10-11. These guys. It's amazing. It's amazing. So once again, obviously, thank you for that. And before we do get into like fully fledged into the podcast, I do want to mention some quick news and some information. So last week's episode, we forgot to mention the comment of the week, which is kind of sad. And because we just started it the week before that, and the first week we forgot. So anyways, we're going to continue it. And this week, we have a very, very nice comment. I'm not going to read the whole thing because it's quite long. It's by Emma. I'm not going to pronounce the last name because I'm not sure how to, but it's by Emma. She sent us a message on Instagram. And the idea. I'm just going to kind of sum up the idea is basically that she started listening to the podcast. She is inspired to go to University of Toronto, but she lives in America. So you know, all sorts of complications. The interesting thing about this comment is, I'm planning on taking AP Physics next year, something I would have never considered a few months ago. listening to you guys is something I look forward to every day, you guys break down concepts in a way that is not only easy to comprehend, but intriguing at the same time. And I think I think this comment was amazing. And this is the point of our podcast, you know, to share our love of math and physics, and to inspire others to get into this field. You know, that's, that's the whole point. So thank you, Emma. And yeah, 

Thank you so much. Yeah, absolutely. Yeah. Other than that, we do have just a little update for you guys. We have officially gone over 4600 followers on Spotify, and also 250 subscribers on YouTube. So if you're listening to this on Spotify, or Apple or anywhere else, where you're just listening to the audio, make sure to check out the video version of this podcast on YouTube.

Other than that, in terms of downloads, we are over 60,000 total downloads. So we are on our way to 100,000 very soon. Mm hmm. I think that's I think that's about it. Yeah, so I was just saying to those viewers that are probably well, viewing the YouTube video, or from Spotify, came on to the YouTube video, once again, might be able to notice I am not at my house. I am in fact, in Niagara. And the Falls is right next to me, unfortunately. So the plan, the plan of this podcast was so that the the falls would be in the background. And that would just be a beautiful sight. But very unfortunately, and I kind of thought this would happen. There's too much light coming from there, right. So if the light from the back I just, I'll just be completely, you know, exposed or like dark. So I guess that didn't work. But I just wanted to mention it to those people watching it. Because they must be like this guy always is in a new place. Where is he? So yeah, here I am. Hey, at the end of today's podcast, turn the computer around, that can be your fade out. I can do that. I can do that. That's actually a smart idea. That might be that might be nice. That might be nice. So yeah. So Parker, you were just summing up all the places that they can go and follow us. So sorry, I kind of cut you off. Right. So if you have any questions or comment your comments, you can email us at math dot physics Or you can check out our Instagram where we post our updates. And when I when we post our episodes or any kind of news at math or physics podcasts. Also on Tick tock, same same handle and on Twitter, we're starting to post tic tocs. Now, we we said we said that two weeks ago. Yeah. And we did not do anything. Yeah, but I think now we're gonna start. No, we will. We will start we will start. Well, I guess continue. Yeah, we will continue continue. Yeah, for sure. Yeah. So we can start off with, with the classic question that we have for every one of our guests that come on the podcast, what first got you or inspired you into the field of astronomy, Math and Math and astronomy. If you go all the way back to when I was about nine years old grade three, my grade three teacher wrote in the report that went home to my parents, that Paul had a great knowledge of the planets in our solar system. That's the earliest moment that I can recall a passion for astronomy, why it manifested itself in grade three, don't remember. But from that point forward, there was never any doubt in my mind that I wanted to be an astronomer. Now, this worried my parents a lot because they didn't know anybody who was an astronomer, they were terribly worried that, you know, he wasn't getting any job. I mean, who who employs an astronomer, and so on. And my parents were not scientists in any way, shape, or form. So they had no idea about the progress from elementary school to high school and beyond. If this guy, their son wanted to be an astronomer. So I think it was both an exciting revelation from their point of view, as well as great trepidation. But from my point of view, there was never any doubt from that day forward, I consumed everything I could about astronomy, I started reading science fiction, because of course, I was learning to read at that point in time and science fiction seemed a really natural outlet. There were lots of people who were running around the space. That's what I like looking at. So there was no aha moment. But from, as I say, age nine, there has never been any doubt about what I wanted to do as a profession, both as an amateur and as a professional.

And in high school, did the math and the physics like all of the concepts that came easily to you, I wouldn't say it came easily to me, but I enjoyed it. And if you enjoyed it

When you put in the time, invariably success follows. So yes, you do the math and the chemistry and the physics. I took them all the way through high school from the moment I arrived in high school right through to the end. And that's what I graduated with from high school. Yeah, I,

yes, I I don't think coming easily to me. I'm just not naturally gifted in that regard. But because I enjoy doing it. I never had an issue, putting in the time to hone the skill. And as a consequence, yeah, my math and physics chemistry worked out pretty well. And I carried that into the university environment. But no, I wouldn't say it came easily. But I really did enjoy it. And that's perhaps one of the takeaway messages for whatever discipline people are going to engage in. If you like doing something, it's not work. And then generally speaking results in Well, we're talking about grades, if successful grades, good grades, and that opens up opportunities, choice for you with respect to your future endeavors. So I guess, because you already knew since age nine, but when you came into university, did you ever, I don't know, like, explored different subjects? and were like, hey, that's kind of interesting. That's kind of interesting, or did you always simply stick to the astronomy mindset that you were you were comfortable with? Very good question. I mean, back then, when I entered university, because we're talking 1974. Here, gentlemen. Yeah, even then there are breadth requirements for a university degree, to give students the opportunity to explore areas outside of the outside of their comfort zone, if you will, to make sure that the decision they're making about their future academic pathway is in fact, the correct one. So yeah, I took geology. When I came into university, along with the math and the physics and the chemistry. I knew I wanted to be a science that there were, you know, I wasn't about to become a poet. I wasn't about to become a stage dancer or anything like that. So it was gonna be science, stone, yeah, math, physics, chemistry, but I took geology. And I always thought during that year with geology, that, you know, I could really get into geology and archaeology, instead of astronomy. I didn't go that path. Why? Because I just wasn't as good to be one. But it was something that really didn't excite me. So yeah, I did look around a little bit I, I wanted to be in science, biology, never turned me on to biology, zoology, those sorts of things. I just wasn't that type of a scientist. So it had to be in the physical sciences. I thought astronomy was where I wanted to be, I was pretty sure. But I did take geology. And I really did enjoy my chemistry. I took chemistry through second year, in fact, because I enjoyed my chemistry, but the love of astronomy, certainly one out, which is what I was expecting, but breadth requirements at a university, really, really important, don't just left them off, because you never know what door they may open. And in my case, as I say, geology and archaeology was the door that I nearly reached out to.

In a sense, geology is kind of a subset of astronomy, because you're studying a planet. Quite great. Oh, and let's face it, when we go to the moon, when we go to Mars, when we go to any of the other bodies in our solar system, geology is an essential ingredient. Yeah. So you're right. It wasn't a big stretch to think about geology and archaeology compared to straight out astronomy. That's right. Yeah. And I just had a comment from what you said earlier, about, you know, when you like what you're doing, it's not work. And a lot of people ask, they asked me about my courses, and I tell them, I'm doing astrophysics. They're like, Oh, aren't your courses like, super difficult? Like quantum physics? calculus? I'm like, yeah, it's, it's difficult. But it's not. It's not hard for me to do the work. The work is hard. But it's easy for me to just, you know, learn and get lost in all of the interesting concepts that are coming quite Yeah, I think like, that's where passion comes in. Right? Like your passion kind of substitutes for any difficulty. Because a lot of times, like when there's a really difficult problem, you're like, Oh, no, like, I can't wrap my head around it. But if you're really passionate about the subject, like if you really enjoy it, then you will simply keep working on that question, because you like to work on that question. Not because you have to or not, because you need to, but because you'd like to, and I think that's that's what, that's what's more important. That's absolutely correct. And so, you know, when when you're a student doing studies at, you know, Senior High School, in university or indeed, graduate school, there's a lot of time, effort and energy that is required to become good at whatever it is that you're studying. Don't be afraid to spend the time you know, sometimes you look at your friends and you go, gosh, they got the answer far quicker than I did. You know, they only had to spend an hour or two studying for filling the gap, midterm test or an assignment. I had to spend three or four hours. Doesn't matter if if you're

spending the time to be successful, and you're enjoying it. The time commitment is just, you know, there, it's not a big issue. Don't worry about the fact that it takes you more time than your friend to get to a certain point, tortoise and the hare type stuff, right? You'll always get to the finish line doesn't matter how rapidly What matters is getting there. And the quality result, once you get there was the most inspirational words that any any aspiring university student right there. Well.

question I had was, were you interested in observational astronomy? Like before that you were interested? Like, let me formulate this better? Did you like astronomy? Because you're like, hey, the stars are cool, the planets are cool, or did you like it? Because you're like, I can see these things. And I can make comments on their observations. Basically, like were you more of a visual astronomer or like a practical like a theoretical astronomer, like which stream Did you enjoy it? I think it'd have to be the visually observational astronomer I remember going to so Khalili when I got my first telescope. I was 16. And again, my parents were very worried because I had never bought a telescope before and this was a major investment. Yeah, what did the look for in a quality telescope. I remember I even named Robbie was my first telescope. It was a four and a half inch attorney and reflector and taking it out into the backyard and looking at Alpha Centauri and looking over the Large Magellanic Cloud I was it was magic was gorgeous. I always like looking at the night sky, the moon. Let's face it, everybody looks at the moon. And you get excited over the moon grab a pair of binoculars don't have to have a telescope look at the moon with binoculars experience lunar eclipses. And so yeah, I got bitten by the observational bug very early on in the southern hemisphere with the Milky Way high overhead. Remember, I lived at a time when light pollution wasn't as big a problem as it is today. So my skies in my backyard. Even though I lived in downtown Adelaide city of about a million people, the skies were still quite dark. You could see the Magellanic Clouds with the naked eye. Well, you can't anymore because I go back to Australia still on a regular basis. So yeah, I was an observational astronomer from the outset. And I loved and I still love being at the telescope, I get a great joy out of looking at a star field, even though other people will go it's just stars. Yeah, no, but look at them. They're beautiful. I really do enjoy the stars. And of course, the nebula, the galaxies. I also enjoy, of course, teasing apart the stories that they have to tell. They're giving us information about their histories, their lives. And I really do enjoy that now as well. But back when I was starting out, certainly it was the observational side of astronomy that drew me ever closer to it. You know, theory goes along hand in hand with the analysis of starlight. But I always put for collecting the data and looking at the objects more than actually analyzing. That's awesome. And this, this next question might be a little packed. But I heard a while back that neutron stars were very, very spiritual. And there are almost perfect spheres and they rotate very, very quickly. So can you comment on that and say, maybe explain, like, Why are neutron stars? So like, perfectly spherical? Yep, sure. I mean, a neutron star is a stellar remnant. It's the end stage of stellar evolution. So when you're looking at stars that are, you know, generally speaking three, four times the mass of our sun or larger, they end up their lives as either a neutron style or indeed potentially a black hole. Its mass dependant stars like our own Sun couple of times the mass of ESA, they're going to end up creating what we call white dwarfs. But once you go further up the mass scale for stars, the more massive the star, the more shall I say Titanic is the death throes. So when we're talking about stars with sufficient mass as at least four times the mass of our Sun, we're talking about stars that in their lives in a supernova explosion, that leaves behind a stellar remnant. And again, depending upon mass, we're talking about leaving behind either a neutron star, or a black hole. Now you can create neutron stars and black holes in other ways, with white dwarfs that end up creating too much mass tripping over the genre, cycle limit, and so on. But, generally speaking, we're talking about these objects, which are only a few 10s of kilometers in diameter. Very, very compact with enormous densities. What has happened there is that the mass that is left over in the cause of these dying

Stars, or in the case of white dwarf that accretes too much mass, there is now so much matter that the gravitational force literally overwhelms regular matter, which of course, is atoms, you know, protons, neutrons and electrons. And the compaction is so fierce pulling in so tightly that literally, the atom becomes a bowl of neutrons. When you're talking about such phenomenal gravitational pull, the only type of object that is going to be able to resist further that compaction process is a sphere, where all points are equally distant from the surface so that there is no a typical or a severe asymmetric gravitational pull. So you've got this ball of material that stands out being a few 10s of 1000s of kilometers in size, but the mass has generated such a gravitational pull, that it overwhelms matter in the regular atomic format, crushes them to become basically neutrons. And it keeps compacting, compacting, compacting down until it can compact no more what we call neutron degeneracy rules. And that generally ends up being an object that is a few 10s of kilometers in diameter. And as I said, the only object that can result from that level of gravitational compaction is a sphere. And it's rotating. Good to see the conservation of angular momentum, all stars are rotating, even our own Sun is rotating, does about once every 25 to 30 days. It's a pretty slow kind of guy. But nonetheless, it's one and a half million 1.4 million kilometers in diameter. If you now sort of shed most of that matter and compact to the core, angular momentum must be retained. And so smaller radius for a higher mass ends up with a faster rotation rate. So take 1.4 million kilometers sphere spinning, bring it down to say 30 4050 kilometers, do the math, you're talking about a phenomenal increase in spin rate associated with the neutron star. Of course, it's not a star.

Yeah, because I'm also assuming like any asymmetries in the actual star would simply be pulled in by gravity. Right? So like, it would kind of like balance out that way. Like, that's actually pretty interesting. Well, you might have heard of, again, it's a bit of a misnomer. A stock, like, some neutron stars do change their rotation rate ever so subtly, and we think it's associated with their sort of surfaces cracking a little bit. And the rearrangement, if you will, to get rid of that back crack, so to speak. So the change in rotation rate is associated with some type of defamation that may have taken place on the surface. I read somewhere that also in your in your past, you were a nuclear physicist. Now, what what is the, what is the connection there? Between that and well, this year is drawn? Well, the short answer is it was a job.

Oh, okay, pleated my master's degree, I decided that I wanted to reach out to the real world I had just gotten married, I decided that I wanted to spend more time with my wife rather than with my PhD. So I decided I made a deliberate decision not to do a PhD. So I took my master's degree in observational astronomy, and started applying for jobs. And while I applied for a few astronomy positions, without a PhD in astronomy, those positions are there, but they're few and far between. But being a master's student in astronomy basically means that you have a very high quality physics degree. Now I'm taking graduate level e&m graduate level, modern physics, and so on and so forth. So my physics qualifications are pretty darn good. Well, there's a lot of jobs out there for physicists, both in the energy industry, oil and nuclear, and there was a position available at the atomic energy of Canada. Looking after a nuclear reactor in Manitoba, a little place called Pinilla, it was a research reactor that was doing material testing, and was utilizing organically cool, organic coolant rather than water. And so this was an experimental reactor running from Oh, give or take a bit. 1962 1963 sounded an interesting position. I applied, I went through the whole interview process, they like my credentials, I like them. So I worked for the atomic energy of Canada for three years. wonderful opportunity, really a very different aspect of physics because it was very practically oriented as you can well imagine. But it was a blended a little bit of teaching because I had to help train the reactor operator

Those who are monitoring this reactor on a day to day basis had to create fuel loadings for the reactor so that it was balanced for all the various experiments. Really, really neat job. But I did get a little bored with looking down into the ground at this nuclear reactor rather than looking at the stars, despite the quality skies in Manitoba, you know, my professional day to day activity wasn't associated with astronomy. And after three years, I found that I was missing that connection. And so that's what I turned back into astronomy as a full time profession. So where was your transition between Australia and Canada? Because like, all this time, you were in university and masters with Australia? No, no, no doing a nuclear job in Oh, okay. So let me give you my full history here. That's okay.

I didn't I did my I did my undergraduate degree at the Australian National University in Canberra. So that was from 74, to 78. So that was a Bachelor of Science with Honors in experimental physics, I was playing with beam line technology and was sort of slamming atoms into metals and looking at ablations. And that that was my master's that my what we call our honors thesis in Australia, which is very similar to a one year master's thesis up here. At the end of that, I applied to do graduate studies, which in Australia would have been a PhD up here in North America, it was applying for a master's degree. And so I applied to a number of different locations, to do an honest, sorry to do graduate studies. And it worked out that the University of Victoria was the group that I latched on to for doing my master's degree in astronomy. So I was out at the Dominion Astrophysical Observatory, the University of Victoria, which is still one of the very best astronomy groups anywhere in the country, it's a great place, and a lovely place to, to live as well. So I came up to Canada in September of 78. The plan was to do a two years master's degree. problem was, and it wasn't a problem at all. But the issue was, I met my wife to be and Well, I haven't made it back to Australia permanently.

So I did my graduate studies here in Canada. And because I had married my wife here, we decided that Canada was going to be our collective home. And so I'm now a dual citizen. And that's why I got picked up a job at the Atomic Energy Canada, because that was important. And then why I became an astronomer in this country. And what was your specialization for your graduates, I collected data with my supervisor from a satellite that is no longer operational, the International ultraviolet explorer satellite, it was launched in 78. And I had data from it. Six months later, I actually went to NASA in Washington, DC, Greenbelt, Maryland, in particular, to actually observe on that satellite, which was really neat experience. And so I was looking for the signature of the element boron in stars. boron is a light element that might have been produced in very small quantities at the Big Bang, hydrogen, helium, and a dash of lithium. But there's theories out there that talk about beryllium and boron, the next slide is the elements being formed that really, really small levels. And we went looking for signs of boron in a variety of stars. And so I was doing spectroscopy in the ultraviolet region of the electromagnetic spectrum, looking for signs of the element boron, try to put thresholds on how much boron was or what well, how much more was present into these stars. And how do you differentiate between boron that was that originated from the Big Bang and boron that's being created. Now. boron isn't created now. That's the point.

So if you find that it's primordial. Okay, so what what were your findings from that? Like? Did you find like a certain threshold for boron? Or did you did you find what you were looking for it? I guess the answer is we didn't find what we were looking for. Because there was no significant quantity above threshold levels. I don't remember what the threshold level was that we determined. But basically, we could not find evidence down to the level of resolution that the IE satellite was delivering us, we could not find evidence of boron in the status. So there was a threshold that we could put, don't remember what that was. Now, that was like 40 years ago, guys. But yeah, that's what we were looking for signs of boron in the stars. And we were looking across a variety of different stars so that we could differentiate between, you know, the more long lived stars versus you know, the more recent stellar populations couldn't find the stuff but it was nonetheless interesting to look at the spectrums. We found lots of other stuff in there, which we commented upon, but boron itself, no, we were unsuccessful in

finding any significant quantity in those stars? And let me know if this is just like a quick answer. But what is it about boron that makes it a primordial element?

Basically, because, well, yeah, the short answer is hydrogen, helium, lithium, beryllium, and boron are the simplest elements. And there's no naturally occurring process in still a nuclear synthesis that generates those particular elements. Well, let me rephrase that hydrogen converts into helium, of course, but there is no stellar nucleosynthesis process that generates lithium, beryllium, and boron. And to the best of my knowledge, there is no process at the supernova end, or the merger of neutron stars, black holes, and so on, that generates light elements down there. So there's no known unless something has popped up in the last 40 years. And I must admit, I haven't been keeping tabs of it. But to the best of my knowledge, there's no known process that can generate lithium beryllium Oberon. So the only stuff that we can create it in humanity, yeah, we can create those elements. However, naturally occurring sources. Not.

So when you deal with like your variable star research, because I mean, we haven't actually got into like the research that you conduct right now, right? Like, because you're kind of variable star astronomer, does? Does I guess, does any of this does any of this knowledge from like your graduate school? Like come into, like, play? Like, have you ever have you ever done something in your graduate or undergrad, which you use to this very day, in your observational variable star research, one of the things that I did while I was doing my master's degree studying spectra and looking for boron is that I was also working with one of the other professors in the department looking at eclipsing binary star systems. So they are not what we call intrinsically variable, they are extrinsic That is to say, because of their continuous Eclipse processes, they are changing their overall light output. So it's similar to intrinsic variable size, where they're sort of pulsating as a result of, you know, nuclear still at processes. I for the three summers that I was in Victoria, was a research assistant. And we look at these binary star systems every clear night that was possible during the course of the year at the campus Observatory, we also used the spectroscopic capability of the Dominion Astrophysical Observatory to measure the radial velocity of some of the stars. Bottom line to it is, I was knee deep in variable style research, right from the get go, even though my primary thesis was associated with spectroscopy and looking for boron, but sort of 50% of my time was spent, I'm pretty close to 50% analog, looking at collecting the data for the other types of variable stars, these binary star systems, and analyzing that data. And in fact, I ended up with more papers out of that work than I did out of boron. That's just the way it worked out in this particular case. So variable stars became a part of my life as a master's student, the fact that I'm looking at, you know, intrinsic variable stars, stars that are very similar to scifi variables as x Phoenicia stuff, that's just happen to be the the branch if you will, that I ended up you know, developing most at your I didn't come to your with the plan of how we're gonna do Essex finish your stuff. Yeah, I came to York doing a variety of different things, including just, you know, training undergraduates and graduate students on data collection processes. But it worked out that sX vinnytsia stars have got all the right attributes to observe on a university campus anywhere on the planet. So we adopted that project. And we continue to observe every clear night looking at a subset of those stars to this day. Awesome. Yeah. And I just remembered a question that I had when we were talking about neutron stars. And so apart from knowing that they exist, what do astronomers have to learn from observing these neutron stars? Well, neutron stars, as I said, are the end products of stellar evolution. And so it gives us a little more insight into, you know, the start in process the life cycle of a star. neutron stars, of course, are also pulsars, if we've got the right orientation. Those intense objects intense from a gravitational field perspective, are also intense from a magnetic field perspective. And they can with the right environment, sweep a beam of radiation across the earth on a really, really regular basis. The Crab Nebula, for example, has got one of the brightest pulsars in the night sky.

It's sweeping across us, you know, 30 times a second. So when we are seeing poses that gives us more insight into the magnetic field composition that is associated with those stars. It talks to us about, you know, as I said, the end state of a stellar evolutionary process. So learning more about neutron stars. And now of course, with gravitational waves being detected neutron stars, merging with white dwarfs, neutron stars, merging with black holes, and so gives us another insight into these particular objects and what they can do with during the merger process. So, if I think of the universe very much like a jigsaw puzzle, you know, if you've got a 1000 piece jigsaw puzzle, with every single piece face down, every object in the universe, every wavelength band in the electromagnetic spectrum represents a piece of the puzzle, until you turn over that piece of the puzzle, hoping to gain insight into the picture as a whole. The only problem is, we don't know what the picture looks like, like a regular jigsaw puzzle, you've got a photograph, and you know what you're working towards. In our case, in astronomy, and astrophysics, all the pieces are facedown, and we're not real sure what the final picture looks like. We've got ideas, but we're not certain. And so neutron stars and their analysis, just another piece of the bigger puzzle that talks to us about the operation of the universe. And the bigger puzzle might be infinite. Probably is, yeah, 1000 pieces might be a big enough puzzle. It might be 10,000. Yes. Yeah, I think given this job security, okay.

Talking about like, the the infinite the infinite puzzle, right, like I was, I was just, I was just wondering, and I would just like looking up these, you know, these questions, you know, before before, like, we had this conversation here, and I was just and a very common question was, and something that I was just, you know, just continuing to think about is, can we ever, ever estimate the true size of the universe because we are constricted by the observational universe, right, and we can estimate it to a, to a very reasonable degree, obviously, it's not exact, because it keeps increasing. But we can, we can estimate it. But my question is, will we do you think we would ever be able to like humanity as a civilization would ever be able to estimate the true size of the universe? Or do you think is just infinite? If we really do believe that the speed of light is the ultimate speed limit? I think the answer has to be No, we'll never really know. You will be able to develop theories, models, that you can test experimentally and have confidence that the predictions of your model suggests that it is this big. But because, you know, we have been, we're existing 14 billion years ish, since the beginning since the Big Bang. And because the expansion, right is occurring, and because we're limited by, as you say, the horizon, the speed of light, we never really will know for certain the extent. And that's putting aside the question of multiverses. I mean, yo, are we the only universe that is out there? The perhaps the only way we will ever really know is if in fact, an old theory, which we don't believe is true anymore. If we're eventually going to stop expanding, and begin to contract back towards a Big Crunch if we're in an oscillating universe, you know, now fast forward, he attends of billions of years, guys, because this is not gonna happen anytime soon. But I guess technically,

we could if we are in a collapsing universe, we could, quote, determine the extent of the universe if we're in this oscillating Big Crunch type scenario. But that to last I heard cosmologically speaking, that is not believed to be the correct analysis, the correct state of our universe, we do think were in a continually expanding universe. And if that is really the case, then you know, we will not necessarily know the true extent of our universe. And does that have any significance in terms of the mass density of our universe, if it just keeps on expanding? Eventually? Well, back 20 years ago, we thought the the critical density of the universe was really important to try and determine whether or not we were in our forever expanding or adjust expanding or indeed, the crunching type collapsing universe, the critical density of our universe was really, really important, given the findings associated with dark energy, and the repulsive force that is associated with dark energy than the critical density of the universe. As I understand remember, I am not a cosmologists, okay, but as I understand it now, dark energy

He has overwhelmed the concept of the critical density. There is now simply not enough matter in our universe, even when we stop factoring in dark matter, dark energy, overwhelms that and continues to push outwards. So I don't think critical density, total mass of our universe is nearly as important as it once was, as a 20 or so years ago, when we weren't aware of dark energy, if I'm not mistaken dark energy, because I'm actually not too sure about it either. But dark energy does, is that continuously created and is expanding the universe like how do we believe that the universe is expanding via dark energy? Do we believe that more and more dark energy is being created and therefore expanding the universe? Or, like, what is the exact or like, I guess we don't have an exact answer, but what is the estimated answer that we have for why dark energy is expanding our universe? Okay, so I'm gonna put the caveat here, you need to speak to one of my colleagues who deal with this sort of stuff, because this stuff keeps changing. When I went to university, none of this stuff exists. So I'd be learning it like you on the fly.

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