Journalist: Omer Choudhry
Omer Choudhry: Welcome to the show. Today we are joined by a very special guest, a professor at McMaster University in the Department of Physics and Astronomy, Dr. Laura Parker. Dr. Parker is not only a great astronomer, but also someone who inspires her students. And I'm very excited to do this interview because I believe that the field of astronomy is something that a lot of us have questions about. And this interview will hopefully help answer some of those questions. And so without further ado, would you mind telling us a little bit about yourself?
Dr. Parker: Sure. So I am, as you mentioned, a professor at McMaster. So I arrived at McMaster in late 2007, after having done my PhD in 2005, at the University of Waterloo. So those in between 2005 and 2007. I was in Germany doing research as what's called a postdoctoral fellow for a couple of years. So I have had lots of time in Ontario between McMaster and Waterloo, but I'm originally from the east coast of Canada. So I'm from the Maritimes. But that's been a long, long time ago.
Omer Choudhry: Awesome, So my first question was, surrounding your research interests. Would you mind telling us a little bit about your field of research as well as what within astronomy has interested you the most? And why?
Dr. Parker: Maybe I'll start with the second part, if that's okay, so I was a student in university that was interested broadly in science and astronomy didn't really pique my interest until second year, when I had my first exposure to astronomy in in one of my courses, and I really found it interesting. And from that point onwards, I was interested in some of the really big questions about the origin of the universe and the evolution of the universe. And so that's the direction I went in, we call that field of astronomy “cosmology”. So I was always fascinated by the big questions trying to understand cosmology. But then by the time I got towards the end of my PhD, and thinking about what to do next, I actually pivoted a little bit. And these days, I don't work on cosmology so much anymore, I now try to understand the complexities of these things called galaxies. So you may have heard of the Milky Way galaxy, the one that we live in, but there are billions of galaxies, and they have a diversity of properties. And I'm trying to understand how galaxies form and how they evolve, and a little bit less about how the universe formed and evolved, because I think we've answered some of some of those big questions. And now I'm getting into the messy details of how these beautiful objects called galaxies form and evolve.
Omer Choudhry: That sounds awesome. So my next question is kind of surrounding galaxies, and more so within our own Milky Way galaxy, in relation to the sun. And so many people know that the sun is a star. But would you mind explaining to us how stars exist? And maybe what determines their lifespan? And why is this information useful for us when we're looking at galaxies.
Dr. Parker: So our galaxy, the Milky Way, is made up of about 100 billion stars. So the sun is just one out of billions of stars in our galaxy, and our galaxy is one of billions of galaxies in the universe. So in that sense, we're not all that special. So there are lots and lots and lots of stars. So clearly, whatever form stars has to be pretty common. So within a galaxy, you've got gas and dust. And if you have enough that accumulates in one spot, gravity can make it collapse and form stars. And so when a cloud of gas collapses, it can form one star, or it can form multiple stars at one time. And also we think it forms planets at that same time. So a cloud of gas and dust goes into making stars and planets. And that happens at different spots in our galaxy over time. And our own Sun, this happened four and a half billion years ago. But there are stars in our Milky Way that are much older, and there are stars that are still being born today. So at a rate today, the average star from star formation rate in the Milky Way galaxy is one star per year. So on average across our entire galaxy, we make one new star each year.
Omer Choudhry: Wow, that is definitely really cool to think about, especially kind of focusing on how other stars in our galaxy work because we all see the sun on a daily basis. But definitely, I think that's a great point to mention how there's billions of stars in our galaxy. So using the information that we've gathered in relation to our stars that's close to us, we can definitely begin to understand more of the things that we didn't know before about our galaxy. And so my next question is kind of, pertaining to media portrayal of science. And so the concept of dark matter and energy is often framed in a certain way in cartoons or comics, or however, I was wondering, can you explain the concept of dark matter and energy to us because a lot of us see it when we're growing up. I mean, Looney Tunes is a common show that tends to use darkness, matter and energy and space to pique interest in children, but would you mind explaining this?
Dr. Parker: Sure. So again, these are big, big concepts, and I teach courses on these topics. So it's not super easy to explain quickly. But the overall picture is the universe is made up of regular stuff like you and me. And we're made up of atoms and molecules. So I call that regular matter. And then there seems to be a whole lot of extra matter that is not made up of atoms and molecules, but it still has gravity so we can detect it. So regular matter, atoms and molecules, dark matter, is something else, but we can detect its gravity. One way we found it is by measuring how fast galaxies rotate. So galaxies rotate pretty quickly. And if there wasn't a lot of dark matter there, the galaxy would be rotating too fast. So there has to be dark matter there, or else all that stuff would just spin off out into space. So something's holding it together, there's extra gravity. And that was, that was work that was pioneered by astrophysicist Vera Rubin and collaborators back in the 1970s, measuring how fast galaxies rotate, finding, they rotate really fast, which is evidence for extra mass. And that extra mass we call dark matter. So that's one piece of evidence for dark matter. There are a whole bunch of others. And they all point to exactly the same story. Most of the mass, most of the gravity in the universe is due to stuff we cannot see, that we call dark matter. Now, dark energy, on the other hand, that was discovered more recently. So the first evidence for dark energy came in 1998. And actually, the Nobel Prize for the work that led to that discovery was awarded in 2011. So we're pretty recent Nobel Prize in Physics, dark energy is a little different. It's not matter with gravity, the evidence for dark energy comes from seeing that the expansion of the universe is actually speeding up. So if you've heard the words, the Big Bang, before, you might picture a universe that started sometime in the past, and it's getting bigger, it's expanding. But you would kind of expect a universe filled with gravity, that the expansion should slow down over time. But for the last two decades, we've seen evidence that the expansion is speeding up. And we don't actually know precisely what's causing it. But we've given this whatever it is that's causing the expansion, we've given it the name dark energy. So to go back to your original question, dark matter and dark energy are things we can see observable evidence for, we still don't know exactly what they are. But we see really clear evidence that these things are there. And I think where sometimes media stories or cartoons get it wrong is they make it seem like we know nothing. But we know a lot, you know, 20 years ago, we didn't know dark energy existed 50 years ago, we didn't know Dark Matter existed. So we've learned a lot about the universe. It has opened new questions, but that's exciting.
Omer Choudhry: Yeah definitely, that was an amazing answer. I think I know a lot of these concepts. Definitely, there's way more than we can fit into this interview to talk about, which is what makes it so amazing. But I think that was a great explanation, and definitely kind of helped clear some of I guess you could say the previous information that we had, I think that was a great answer. And I definitely found that an interesting point. So my next question is relating to Jupiter, one of the planets within our solar system, and its many moons. So the fourth largest, I believe, is the moon Europa. And it's often spoken about because of some evidence that scientists have discovered of liquid water existing beneath its icy surface. So my question is actually relating to what a lot of scientists began to ponder about was whether or not there are possible forms of life on this moon. And my question to you would be, do you think that it's possible that there could be life in certain cases where we do find something similar about a planet that's kind of like water being compared to Earth? Do you think it's possible that there's life beyond Earth?
Dr. Parker: So do I think it’s possible there's life beyond Earth? Absolutely. Whether there's life in our solar system is a much narrower question. And I'm not sure the answer to that one. Obviously, there's a life here on earth. I don't know if there's life elsewhere in the solar system. Statistically, given that there are billions of stars just in our own Milky Way and billions of galaxies, I think probability says it's likely there's life elsewhere. But for anyone who has ever taken a statistics course, it's very dangerous when you have a sample size of one, which is we know there's life in one place here on Earth. Extrapolating from a sample size of one is really, really difficult to do. So although there's a huge sample of possible planets out there, that probability of there being life seems high. We don't actually know probably enough about how life evolved on earth to know how common that process is. So that's kind of the big picture, the picture of our solar system. There are a few places that are promising where you could imagine life might be able to evolve. So life here on Earth, DNA base life needs access to liquid water. And so the natural place to look in our solar system is for places that have liquid water. And that includes in the past, certainly Mars, and even today, there's evidence that there's occasionally liquid water on the surface. And that also includes some of the moons of the outer planets. And in particular, Europa is one that's very exciting. It has a thick layer of ice around it. And beneath the ice, we think there's a slushy ocean. And so there's a proposal to send a mission to Europa, to drill down through the ice, kind of like researchers do on Earth, drilling down in Antarctica to take ice core. So deliver it to drill down into the ice on Europa, and to take a sample of that water. Now, we're not going to find humanoid life forms there. But maybe there's simple microbial life that exists somewhere else in the solar system. So this is an exciting prospect, and something that I think there's a lot of excitement about future missions to look for simple forms of life in the outer solar system.
Omer Choudhry: Awesome. Once again, that's really interesting. And so the next question that I have kind of ties in with the previous one, it's more about characteristics of how, how we would define a planet or a moon or an area outside of earth as being heritable. Do you think that, or, in your own opinion, would you think that instead of us looking for like the best exact copy of earth that we could possibly find that we should look for certain things and that along the way, humans now possess the ability to help make the planet heritable for themselves in the future, as long as the core elements are there?
Dr. Parker: So kind of two separate things. So one, what makes a place habitable, and then could we make it habitable for humans, so the second one is a little bit like colonizing, colonizing something else in space. And, and there, I think, there's a lot of ethical concerns, to debate and to sit and consider, even within our own solar system, we have to be really careful about not contaminating other solar system bodies with bacteria from Earth, for example. So you want to be really careful about doing that. So I think that's sort of a messy, a messy situation. Also remember that the idea of ever traveling outside of our solar system to inhabit somewhere else that is beyond our current capability. So the very, very, very, very closest star to us outside the solar system would still probably take thousands of years to reach by the fastest rocket ship we have. And so at the moment, we certainly don't have the technology to travel to another, another planet elsewhere. Now, the other part of the question was, what makes the planet habitable? And could you imagine changing that. So at the moment, we're kind of narrow in what we look for, we're looking for places where liquid water could exist. And the reason for that is we know liquid water is necessary for life on Earth. But that's probably a pretty narrow definition. So I think as we have more planets that we're discovering, and we can study their properties in more detail, there'll be lots more than looking for just water, we'll be looking for signatures of other molecules that we think are produced by biology. So we know once there was life on Earth, the Earth's atmosphere was absolutely transformed. We now have lots of oxygen molecules we didn't before there was life. And so we will also be doing that for other planets looking for these signatures of biological molecules. So that's one thing. And the other thing, of course, is, you could also search other planets for signs of intelligent life. So we have not just bio signatures that there's life on Earth, we also send out repeating patterns into space, like lasers and television signals. So if there's other intelligent life out there, that's another way to look for it is to to look for these repeating signatures that nature.
Omer Choudhry: Awesome. Yeah. That's very interesting. That's all the questions that I have today. But it was very nice having you to speak about this topic. And thank you so much for your time. I think we all kind of learned a lot more about astronomy and cleared up some of the big concepts and questions that we had, many of which we had when we were young. And we really just needed to ask why and how and so I really appreciate the time you've taken to help us understand more about our solar system within this 10 to 15 minutes that we had. Do you have any final comments?
Dr. Parker: No, I just wanted to thank you for the opportunity and also to highlight that it is true. I think that for a lot of people their interest in science sometimes starts with astronomy. For me, that's where it stayed. I stayed in astronomy, but I think it's a nice gateway to pique the interest of kids and students of all ages and then you find out that there's all these different bits of science that are also really, really fascinating. But it's quite a privilege to work in a field, which I think is inspiring to a lot of young people starting out in science.
Omer Choudhry: For sure, and from personal experience, it's definitely been inspiring, but I know that I can speak for others when I say it's definitely one of those things where like you said, it's a great gateway to kind of figuring out what questions we should ask. And so I definitely appreciate you taking the time to meet with us and for our listeners, if you have any questions, you can always leave it in the comment section. And we will see you next week for our next interview.