Show Notes

Can we look into the past? Does the universe have an edge? What’s so great about a total solar eclipse? Have we been visited by aliens? Astrophysicist and educator Alex Filippenko joins Editor-in-Chief Pat Joseph live onstage to discuss eclipse chasing, dark energy, and the abiding mysteries of the universe. 

 

Further reading: 

• Watch the full live conversation with Alex Filippenko on YouTube
• Buy your tickets for “Enthralled: What Explains Our Unshakeable Fascination with Cults?” with Poulomi Saha on March 27 

This episode was produced by Coby McDonald. 

Special thanks to Alex Filippenko, Pat Joseph, and Nat Alcantara. Art by Michiko Toki and original music by Mogli Maureal. Additional music from Blue Dot Sessions.

Transcript: 

LEAH WORTHINGTON: 

Hello, and welcome back to The Edge! It’s been a minute, but we’re cooking up some exciting new episodes for your hungry ears.

In the meantime, we’ve got a little something different—but equally delicious—for you this episode. 

Just over a year ago, we launched our series, “California Live!” (exclamation point included), featuring live, in-person conversations with Berkeley experts about hot, buzzy, often controversial topics in the modern zeitgeist. 

For our inaugural event, Editor-in-Chief Pat Joseph sat down with astrophysicist and educator Alex Filippenko to discuss, oh you know, just “Life, the Universe and Everything.” Onstage before a packed audience at the Berkeley Art Museum and Pacific Film Archive, Pat and Alex talked about the mysteries of dark energy, recent findings from the James Webb Space Telescope, as well as the Great American Total Solar Eclipse of 2024. Safe to say it was wildly entertaining and mind-expanding.

Today we bring you that conversation—audience oohs and aahs included. Enjoy! 

Oh, and mark your calendars for our next California Live! event on Wednesday, March 27. Pat will be joined by Professor Poulomi Saha to talk about cults—and our enduring obsession with them. Link in the show notes. Ok, here’s the episode.

[MUSIC OUT]

PAT JOSEPH: We couldn’t be happier to have as our guest tonight Alex Filippenko, one of the world’s most celebrated astronomers. Alex’s accolades and accomplishments are really too lengthy to list here, but I’ll give you a small sample. So he’s a fellow of the California Academy of Sciences, the National Academy of Sciences, the American Academy of Arts and Sciences, and the American Astronomical Society.

In 2015, he shared the Breakthrough Prize in Fundamental Physics with fellow members of the Hi Z Supernova Search Team and the Supernova Cosmology Project, both of which were recognized once more for their Nobel Prize winning discovery that the expansion of the universe is accelerating. Alex, who had the privilege of announcing that discovery to the public in 1998, also had the distinction of being the only scientist who was on both teams that were competing to make that discovery.

In addition to being a Nobel quality scientist, Alex is an educator of the very first order, he’s been voted best professor at Berkeley by Cal students a record nine times. He was also, Yeah.

He was also named professor, National Professor of the Year in 2006, and winner of the American Astronomical Society’s Education Prize in 2022. He’s also a really nice guy, which kind of paradoxically makes him hard to like. I should confess that the title of tonight’s discussion was my idea. I didn’t even confer with Alex.

Sorry, Alex. Uh, I’m kind of surprised you guys went for it. Life, the universe, and everything. We won’t get to everything. Of course, I stole the title from the late, great Douglas Adams, author of The Hitchhiker’s Guide to the Galaxy. And it was Adams who wrote what I take as a rallying cry for the evening.

He wrote, Let’s think the unthinkable. Let’s do the undoable. Let us prepare to grapple with the ineffable itself and see if we may not eff it after all. Ha, ha, ha. So my strategy tonight, because I don’t know that much, is to ask stupid questions that I trust will yield brilliant and profound answers. Like all great teachers, Alex insists there’s no such thing as a dumb question, but I intend to put that assertion to the test.

So let’s begin, shall we? So folks, please join me in welcoming Alex Filippenko.

ALEX FILIPPENKO: By the way, Patrick, I can already tell you the answer to life, the universe, and everything. 

PAT: I bet you can. Everyone here can. 

ALEX: 42, right? So, so there we go. We’re, we’re done. Right. Right. So, right. Well, our first slide here. Oh, yeah. So, I think Douglas Adams said the answer is 42, but nobody knows what the question is.

PAT: Yeah, yeah, that’s right. There you go. Right? Yeah. Yeah. Do you think the universe is trying to show us, tell us something? Yeah. 

ALEX: Well, you know, yeah. By the way, this is not Photoshop. This is something that somebody spotted on an image from deep space taken by the James Webb Space Telescope recently. Yeah, it’s just a small part of a much bigger image.

Uh, you know, the sky is pretty big out there, and if you look in many, many, many different spots, you will find pretty much any pattern that you might be looking for. So,  I doubt the question mark there is truly of cosmic significance. It looks to me like  the top part is a pair of interacting galaxies, kind of gravitationally,  sort of moving past each other and attracting each other.

And then that third one, which is the dot at the bottom, is probably another third galaxy. But galaxies are often found in pairs, triplets, quadruplets, that are gravitationally interacting this way. This just is a particularly interesting configuration of them. Yeah, I have my own theory. 

PAT: Okay, what’s that?

ALEX: It’s actually the the ghost of Douglas Adams. Oh Okay, f***ing with us from beyond. There you go. Yeah, or maybe it’s a portal to another universe or something like that, right? You know, I actually I looked up this word because I knew there was a word for this. Okay, do you know it? Maybe scientists use this all the time.

That’s pareidolia. P-a-r-e-i-d-o-l-i-a. The tendency for perception to impose a meaningful interpretation on a nebulous, nebulous stimulus, usually visual, so that one sees meaning where there is none. 

PAT: Aha. Yes. I’ve heard the word, but I did not recognize it when you mentioned it. Would you like the card?

ALEX: Well, I would, like, afterward there, you know. Unless you’ve got other notes that you need on this card, I will,  

PAT: You know, one of my mottos is learn at least one new thing each day. And so there we go, pareidolia. Thank you. 

ALEX: Done. Okay. Yeah. All right. 

PAT: Okay, so,  Alex’s class that everyone wants to take who comes to Berkeley is Intro to Astronomy, which I think is Astro C10.

ALEX: Yeah, that’s right. 

PAT: Um, and you’re teaching it. 

ALEX: Yeah, yeah, 930 students. Down from 960 because the second homework assignment is due tomorrow and already some students have realized it’s a pretty hard class. 

PAT: So,  how do you remember all their names? 

ALEX: I don’t. Oh. I only choose to, you know, call on students by name if I happen to know their name. But then many students will assume the wrong thing. They think that I know all their names, right? That’s a bad deduction from a limited sample of,  of,  you know, students on whom I call. Yeah. 

PAT: So a lot of professors and scientists at your level wouldn’t welcome teaching a survey class, an intro class. Um, I take it you’re different. How many years have you been? Oh, I love it. 

ALEX: Yeah, this is my 37th time. I do it once a year. I started on the faculty in 1986. I didn’t teach that course then. They assigned me some, you know, lighter load as a new faculty member. But then, starting fall of 87, nearly every fall, sometimes in the spring instead if I’m traveling in the fall.

But yeah, so I, I love that class because it’s a chance to bring science in general, and astronomy, astrophysics in particular, to students, many of whom, most of whom, are not already interested in science. Now some, some tens are. You know, 20, 30, even percent might be  you know, science oriented already. The class will be interesting and fun for them, but it’s not designed specifically with them in mind.

It’s designed to get science to students who aren’t already interested, and to see them, to show them that it’s a noble and an exciting profession. Yeah, and so I really enjoy doing that. Do you find that in the age of, the screen age, that it’s getting more difficult, you’ve been teaching it so long, so things have changed, students are different, and now, I mean not just the students, but all of us are locked into our screens.

Yeah. Is it more difficult to, to talk to an audience of students and engage them? Yeah, to some degree, there’s no doubt about that. Um, you know, I don’t have a no laptop or no electronic device policy in my class. Um, You know, they may have reasons for,  being on their devices. So I, I have to be particularly interesting and energetic and dance around and do demos and things like that so as to capture their attention so that they’re not glued to their screens.

So it’s incumbent upon me to be more interesting and informative and entertaining. Then whatever they can find on the internet or chatting with the person next to them, you know, yeah Yeah, you’ve all seen these photographs of teenagers right sitting on a street corner and they’re texting whom they’re texting each other, right?

Or they’re texting someone else but not paying any real attention to the people with whom they’re sitting which is a bit weird Yeah I’ve heard you even throw things. I do throw things. Yes. Why? Well  you know, there are like balls and stuff that I throw, because if I illustrate transitions of electrons and atoms, you know, one, one jump of an electron from here to here in an atom might require a certain amount of energy to be released, and then another jump might require a different amount of energy to be released.

And so the energy is released in little packets called photons, quanta. And different colors of light represent those different energy packets. And so I’ll throw green balls or yellow balls or red balls out to the audience. And similarly as a way to engage the students, I’ll have them throw some of the balls back at me.

And I will then undergo the corresponding transition to a higher energy level when catching the ball. Yeah. Alright. Or I ask them to kick me or something like that. And that illustrates how sometimes electrons collide with atoms. And they will knock an electron off completely. That’s called collisional ionization.

So how many professors ask students to kick them, right? You know, not too hard, of course. But,  yeah. I did bring some things. Oh, you want to throw Yeah? Yeah. Oh, oh, oh, there we go. I’ll do that. So let me show you. I’m an electron. By the way, we didn’t rehearse any of this. I don’t know what questions Patrick will ask me.

But suppose, suppose I’m an electron in a higher energy level. Yeah. And I’m kind of lazy. I want to go down to a lower energy level. So I’ll do that, and I’ll throw that ball out. There you go. And also, it keeps the students awake, you see, if there’s a chance that I,  And then, if I catch it, I have to go back up to here, right?

And then, you know, you, I see you have some other ones there and stuff, but,  Yeah, I do, if you know, so, if I were down here, so throw the purple one at me. Okay, the purple one. The purple one has a higher energy. And so now, you ionized me. You effectively kicked me off, but with a photon, not with your leg.

And so now, I’ll just kind of go running around. I’m a free electron. Okay, and I’m gonna grab one of these other balls. Um, let me grab a blue one. I’m a free electron, and then I see a positively charged atom there. Not necessarily the one from which I came, but just one that’s missing an electron. And I jump down, right?

I should have been running up here, but I can’t walk on air. And in jumping down, I had to release some energy, so already, I will do that. And then I’ll jump down to the ground state, and I’ll release some more energy. So, you see how it keeps students engaged and,  and,  entertained. You see? There you go.

PAT: I like it. Alright. He’s not lying. We didn’t rehearse any of that, so. Have you ever heard of the Five Minute University? 

ALEX: The Five Minute University? Boy, they must speak pretty quickly. 

PAT: Any of you out there know about the Five Minute University? So this was, if you remember the comedian  uh, Father Guido Sarducci the persona.

Yeah. So he proposed the five minute university and the idea was that he would give you a degree after five minutes and the way he was going to do that is he was only going to teach you what the average student remembers five years out of college. 

ALEX: Oh, wow. Yeah. Five minutes. 

PAT: Yeah, so, for economics, all you needed was supply and demand.

ALEX: Yeah, I still remember that from my microeconomics class,  in college. 

PAT: There you go. 

ALEX: Which was some time ago. 

PAT: Yeah. So the question that I’m, I’m working up to is,  obviously your, your intro to astronomy students, unless they become astronomers, are not going to keep all that information in their heads. So, five years out, what do you hope that they will have retained? 

ALEX: Yeah. Yeah. So there’s, there’s a few topics that I actually tell them and I emphasize. You know, here’s a few things I want you to understand and remember forever. Um, one of them is that we are made of star stuff, as Carl Sagan used to say so eloquently.

And what’s meant by that is that, you know, the universe started out with hydrogen and helium and a smidgen of lithium. All the other elements, you know, the carbon in your cells, the oxygen that you breathe, the calcium in your bones, the iron in your red blood cells, those were all built through nuclear reactions deep in the cores of stars.

And some of those stars blew up, liberating those elements and creating some new ones along the way. But the point is liberating them into space, where they could then collect up into clouds and gravitationally collapse, forming new stars. And after several generations of stellar birth and death, you have enough heavy elements that you can build an Earth like planet, made out of, you know, rocks and iron and things like that, and, and then, you know, life, right?

So that’s a pretty amazing thing. We’re not just in the universe, we’re a product of the universe in this very visceral sense, okay? Uh, another concept is looking back in time. We can do that by looking progressively farther away. You look at galaxies, which are giant gravitationally bound collections of stars, a billion light years away, and five billion light years away, and nine billion light years away.

And you’re seeing them as they were one, five, nine billion years ago. The non infinite speed of light provides a movie of the history of the universe. It’s kind of like, you know, geologic strata in the Grand Canyon or something for geologists then one other one is, they’ve got to go see a total solar eclipse.

Okay, and there’s one coming up April 8th, 2024, folks. Don’t go just anywhere in Texas, whatever you look it up online, just Google it or whatever your favorite search engine is. Find the path of totality and go within that path. If you’re close but not within that path. No cigar. Okay. It’s not the same thing.

98 percent total. That’s like, it’s an interesting curiosity, but it’s not total, right? And so I joke with them that I find, if I find out that they had a chance to go to see the total solar eclipse, and especially if they were close, but didn’t make the effort to go, I will retroactively fail them, and their whole careers will have been messed up thereafter.

So, you know. There’s a few of the things that I tell them to learn and remember. 

PAT: Yeah, so eclipses Is it interesting to you, are eclipses interesting to you on a scientific level or more of just visceral? 

ALEX:  Yeah, just visceral for me. There’s no doubt that there’s scientific utility to observing total solar eclipses.

That’s not the astrophysics that I personally work on. I go just to experience it. And in fact, we’ve had several trips,  with Cal Discoveries Travel, right? In the California Alumni Association and stuff. So, uh It’s, it’s always been fun. Now, mind you, there’s what’s called an annular eclipse coming up this October 14th, where the moon is too far away from Earth to fully cover the sun, because it looks a bit too small.

Some news media will say that that’s total. That’s not total. The bright part of the sun will still be visible as a ring. So that’s a special case of a partial eclipse. It’s an interesting curiosity, but it’s not that big a deal. So if you go on October 14th, because someone told you that was the date of the total eclipse in the USA, it’s not.

The date of the next total solar eclipse is April 8th, 2024. And that’s the last one in the U.S. for 20 years thereafter, okay? So You know, be there or be square. 

PAT: So, yeah, you and I first met, I think, at the Oregon eclipse. 

ALEX: Yeah, 2017, August 21st. Yeah, I remember most of the dates. We had a group of 400 Cal alumni, families, friends up in Oregon.

And it was kind of a scary experience because, you know, there were all these wildfires going on for the two days prior to the eclipse. Even at two or three o’clock in the afternoon, the sun was this blood red. There was also the issue that, you know, we had Sun River Resort, which was a beautiful place, but it was not on the Path of Totality.

So we had to take people to the Path of Totality that morning. And, you know, it’s just some two lane road or something. What if some big old truck gets, I don’t know, blocks the whole road? So we left at two in the morning. For what should have been and turned out to be a one hour journey, but we allowed eight hours for the journey.

Just in case. Okay, I see Jojo back there. She was there, right? 

PAT: Some of us never forgave you. 

ALEX: Well, there you go. Right. But no, people, people didn’t mind. They knew that eclipse chasing. You have to put some skin into the game, right? You know? 

PAT: Yeah, it was. It was. And you know, I stayed there and camped. And the next day, if it had been a day later, we wouldn’t have seen anything.

ALEX: Yeah, yeah. There was a lot of smoke. 

PAT: The smoke was so bad I had to flee. 

ALEX: That’s right. Yeah, Oregon was on fire. Yeah. 

PAT: How many eclipses have you seen so far? 

ALEX: Nineteen total solar eclipses. Yeah. And, you know, If you don’t go specifically to a place which is going to have one, right, if you just sort of wait around, on average, you have to wait 380 years for one to visit you.

Now, I am not 380 times 19 years old, okay? And so, clearly  you know, I’ve made an effort to go see them, but it’s a very, very memorable experience. There’s really no way to describe it. You just have to go there and experience it yourself. The photos, even the videos, don’t really come close to the experience.

Telling you what the experience will really feel like emotionally, so, you know  I know it’s, I sound a little bit like a nutcase. Let me call me a, you could call me a lunatic, ha ha, pun intended, right? Yeah, but um, but really, you will thank me. Students who came back or emailed me after 2017 said, First of all, I can’t retroactively fail them.

Second of all, I undersold the experience of everything. And that’s partly because I didn’t want to make it, You know, I didn’t want to ruin it for them, right? So I said it’ll be really great, but they were like it was mind blowing, you know, yeah I’m not easily moved and I yeah, I moved a little. I’m just curious how many of you How many of you here have seen a total solar eclipse?

Okay, probably because of 2017 August 21st, right? Prior to that one, how many of you would raise your hands? Just a few, right? Okay, and was it life changing, or at least, you know, psyche changing for you? Okay, I’ve got 20 bucks for each of you. 

PAT: Yeah, no, joking aside, it was fantastic. And what I remember is going around with a notebook and a recorder afterward and asking people about the experience and most of the people I talked to were crying.

They were wiping away tears. And uh, I was a little embarrassed before them, but made for a good story though. Um, so you’ll be in Texas? 

ALEX: Yeah, yeah, this time actually I uh, I’m not doing anything with Cal Discoveries Travel. Not that I didn’t want to in principle, but the event in 2017 was organized by you know, lots of us at Cal Discoveries Travel Plus.

Myself and my wife, who sort of conceived the trip. And with 400 people, that was a factor of 20, bigger than the typical Cal Discoveries travel trip, which is, you know, maybe 20 participants. And the stress of the whole thing nearly broke up our marriage. And so, we’re still happily married. But it was a close call there, right?

So we just decided this time we’re not doing anything with anyone really, no travel agency or anything like that. And so then people say, okay, but where are you going to be? And we’re not telling you. We’ll be somewhere in Texas between Dallas and Austin. Okay. If you want to try to find us, be my guest, but it’s just our family and a couple of very close friends this time.

PAT: Yeah. I remember that  my impression of you,  Well, you did seem to have an entourage there. Um, there was like a little group of people that would follow you everywhere. Family and, and friends. Um, so that seemed odd for an astronomer to have an entourage. But also you were so energetic. And maybe you were just trying to get away from those people.

Um, but you were always running. 

ALEX: Running away, right? 

PAT: Running, running, running, running. And I’ve noticed that when I communicate with you by text or email. Uh, usually by text  I get a response from the ski lift, or I get a response from you running in Grizzly Peak, or I get a response from you on a boat to Darwin, Australia, or in Darwin, Australia to go see an eclipse.

ALEX: Yeah, that was just a few months ago. 

PAT: Yeah, and before we started tonight, you had to go walk around the block. 

ALEX: Yeah, that’s right, yeah, because I was in meetings all day, you know, I needed some exercise. I needed to get my 10,000 steps. Because, just as a brief aside, right? Lockdown March of 2020. I decided not to become a couch potato and I would walk and run quite a lot before that, but I decided to get at least 10, 000 steps each day for three and a half years.

Now, I have not missed a single day. Yeah. So once you have a long streak like that, it’s very motivating because If your streak is only three or four days long, right, then you miss a day, and you’re all, ah, big deal, no big deal. And then the next day, you’re all like, well, I already broke, I already messed up my streak, so I don’t have to block it.

But, you know, when you’re out six months, a year, two years, something like that, then you realize that, hey, if I don’t make it, it’s like 11 o’clock at night, I’m only at 5,000 steps, I gotta get there by midnight. It’ll be two years before I’m at this point already again, right? So it’s very motivating. Try it.

You’ll like it. I did one, have one surgeon mandated break this past January when I had hernia surgery. And, you know, we wanted to go on some international trips shortly thereafter. So my surgeon said, Alex, you can’t do your 10,000 steps. But, so that’s not, or you won’t go on these other trips. So that wasn’t my fault.

I give myself a pass on that. 

PAT: So I, while we’re on how energetic you are,  I texted you once for,  uh, we thought it would be nice to have in the magazine when the comet, is it Neowise? Yeah, Neowise was a few years ago, right? Neowise was in, in the sky, and we thought Lick Observatory, which I know is near and dear to you.

Yes. I thought, why don’t we get a picture of Neowise and Lick Observatory in the foreground. And I texted you, and you texted me back, running. And then, before I knew it, I had five or six different astronomers and astronomers assistants sending me photos. We had so many photos of the comet Neowise over,  Lick Observatory.

And we don’t get that kind of response, usually. Other professors who are in here take note. Um, But, and so my designer said, you know, damn, if you want something quick, ask an astronomer. Mm hmm. Yeah. I don’t know if it’s true, but we were impressed. Depends. Yeah. Right. Yeah. Um, all right. So that’s the life section of what we were talking about.

We’re going to try to get to everything. 

ALEX: Oh, yeah. Life, the universe, and everything. Right, right. Let’s go to the universe. 

PAT: Okay. So let me give you my  naive conception of the universe. When I see these, these images from the space telescope, especially ones like this one, if we had the full one, you’d see how large a chunk of space you’re looking at. In my mind, it’s, it’s all moving. Like everything is spiraling, wobbling, orbiting, rotating. Is that true? And is there anything in the universe that’s just standing still? 

ALEX: Yeah, pretty much everything is in motion. You know, I mean, it used to be thought that Earth is the center of the universe, and that we’re neither rotating nor moving through space.

And you know, that all turned out to be wrong. And basically  lots of things are in motion in part because there’s gravity, which never ends, right? You know, you have things that could be quite far apart from each other, but there’s still a gravitational attraction between them. So that’ll make them move, right?

If I were to drop this glass, which I won’t right now, but it would move because of the gravitational attraction induced by Earth. And, and then on sufficiently large scales  you know, you have galaxies that are moving apart from each other. So these big gravitationally bound clumps of stars. a billion to a hundred billion, even a trillion stars in some cases.

They’re moving apart from each other because of, you know, something we still don’t completely understand, the Big Bang, the birth of the universe, in this expanding state, 13 or 14 billion years ago. So, it’s very difficult to have something that’s completely motionless, just because of the interactions with all of its neighbors, and because of the motion imparted by the Big Bang.

PAT: So, to your discovery  in 1998, which, I mean, your discovery with all the other people who were involved—the implication of a universe that’s not only expanding, which I assume we knew it was expanding? 

ALEX: Yeah, we knew,  from the time of Hubble around 1929 or so. 

PAT: Okay. Yeah. But to find out that it was accelerating. That was…

ALEX: That was the weird part. Yeah. Right, because Well, again, you know, gravity, right? I’ve got this ball here, right? And if I drop it It falls, but even if I were to toss it up, the mutual gravitational attraction between the ball and Earth slows it down, right? And if gravity is strong enough, as it is here, and I don’t toss the ball very fast, it’ll stop and come back.

Um, if I toss it faster, it’ll go higher, right? If I toss it fast enough, and you would neglect air resistance and technical difficulty of a ceiling here. It will escape from Earth, right, as rockets do, but there’s still a gravitational pull induced by Earth, and so the rocket should still slow down, right?

Um, but with attractive gravity, that’s what you would expect, right? And either the thing will come back again, or it goes away. So, similarly with all the galaxies, they’re pulling on each other. And so what we wanted to find out, starting around 1990 or so, was are they pulling on each other enough that the universe will someday stop expanding and then re-collapse?

So that would be Big Bang, Big Crunch, or you could say Big Bang, Gnab Gib, which is Big Bang backwards, right? Big Bang, Gnab Gib. Or was the universe launched at a speed greater than its escape speed? Sort of like, you know, the rocket that’s launched. So to figure that out, which universe we live in, we have to look at the past history of expansion.

And that means looking far away and hence long ago, right? That concept I told you about, you know, 15 minutes ago or so. Um, and we could trace the expansion history. And we wanted to see if it’s been slowing down a lot, then it’ll someday stop and come back. If it’s not been slowing down a lot, then it’ll expand forever.

Well, much to our surprise, we found that in the past four or five billion years, it’s been speeding up, not slowing down. So that’s like, wrong answer, right? Multiple choice exam in my class. You know, universe is doing what? A, B, C, D, E. Accelerating? No, for many of the years that I taught the course, that would have been the wrong answer.

But it looks like it’s the right answer. It’s been verified in a number of ways, and so we dream up this repulsive dark energy that is  the explanation for why the universe is accelerating over the largest distances, but we don’t know what the dark energy is. We don’t see it, so it’s dark. And we don’t know what it is, so it’s mysterious, so it’s dark in that sense as well.

PAT: Had any physicist ever theorized the existence of dark energy before? 

ALEX: Yeah, yeah. Einstein in 1917 thought the universe was static, neither expanding nor collapsing, as did most astronomers and physicists at the time. And yet, you know, gravity should collapse the universe down, so Einstein essentially came up with this thing that he called the cosmological constant.

Which of unknown physical origin, but basically it pointed in the up direction and gravity points in the down direction. And they’re of equal size, and so the net force, so to speak, was zero, right? It’s not may the force be with you, it’s may the net force be with you, because the force may be with you, but if some other force is against you, you’re going to lose.

So, may the net force be with you, alright? There you go, we should correct the movies there. But anyway, so he had these things. Conspiring, in a sense, for no apparent reason, and that was, you know, something that he didn’t like, how finely tuned this had to be, but whatever. Somehow, this anti gravity and gravity balance each other, and you get a static universe.

Twelve years later, when Hubble and others discovered that the universe isn’t static after all, the whole physical and philosophical motivation for a static universe vanished. And Einstein called this cosmological constant, Greek uppercase lambda is how it’s usually denoted, the biggest mistake of his career.

Because, you know, he could have been famous. He could have been, he could have predicted that the universe is in some dynamic state. Well, so he renounced it as having been the biggest blunder that he had ever made. And then, you know, some better part of a century later, what we did is we resuscitated, we resuscitated the idea, not to give a static universe, but one which over the biggest distances You know, the up arrow dominates over the down arrow and the thing expands faster and faster.

So, it, he had the right idea for the wrong reason. Uh, and now we still don’t know whether it’s really the cosmological constant or some more generic dark energy. The, the cosmological constant would be a property of the vacuum itself. It just has the property of being, you know, in a sense gravitationally repulsive.

Um, dark energy more generally is some sort of an energy that flies around through the universe. It’s not a property of space itself. That’s a subtle difference, but it’s like light going through this room But it’s not light. It’s something different that has a gravitationally repulsive property And we’re still trying to figure out you know which model for the dark energy is more correct more likely to be correct and the the data seem to suggest that the energy of the vacuum is fine.

It’s a fine hypothesis. It has not been negated by the data. Um, but that’s not to say that someday we won’t find a slightly different answer. So, you know, we’re still searching. We don’t have all the answers. 

PAT: So, it’s interesting  when I, when you talk about dark energy and dark matter and I think about outer space. But what I’m hearing you saying is that these things are here locally. 

ALEX: Yeah. There’s the dark energy here. It’s just that, you know, we’re held together as humans by electromagnetic forces, you know. We’re electrically neutral. But to give an example, the, the water model molecule has, you know, an oxygen and two hydrogens, and the oxygen wants a couple of extra electrons.

And the hydrogens are fine with giving up their electrons. So what they do is they share their electrons with the oxygen that makes the oxygen atom more negatively charged. That side of the water molecule and the hydrogen mickey mouse ears on top if you want, are the more positively charged. And so then.

Water molecules line up with the negatively charged part of one molecule being attracted by the positively charged part of another molecule. And so it’s these residual electromagnetic forces of that sort that hold our bodies together, and they’re much, much stronger than any tendency for empty space to expand.

Similarly, Earth is held together by gravity, and you’re held to Earth by gravity, and that’s a much stronger force. than the tendency of empty space to expand. So, it’s like a spring that’s so strong that you can’t stretch it at all. I forgot all of my, I forgot all of my little  bag of tricks as I call it.

You know, I forgot my bag of tricks. But, you can imagine a spring that you, it’s so tight, you can’t stretch it. Okay? But, when you go out to, you know, tens of millions of light years, and certainly by a hundred million light years, and a light year, is the distance light travels in a year. It’s an awfully long way. Six trillion miles. You know, six million million miles. So, if you go out that far, a hundred million of these light years, and it’s mostly empty space in terms of, you know, being devoid of stars and galaxies, but everywhere there’s the dark energy, as there is here, but here it’s dominated by all these other things.

Out there, there’s nothing else to dominate it. And so it dominates, and that’s what then causes the universe’s expansion to accelerate. There’s a quiz on this tomorrow. I want to go back to this idea that you were talking about driving home with your students, which is  uh, so trippy to think about.

That when we look into space through a telescope, we’re looking back in time. Yeah, it’s beautiful. It’s crazy. If light traveled infinitely fast we would see the whole universe as it is right now. We wouldn’t have this window into the past. 

PAT: So, but here, this disturbing thought I had, what happens, well, is it possible that it’s all ended out there and the news just hasn’t reached us?

ALEX: Yeah, maybe, but if so, the news won’t reach us for a while, you know, so I wouldn’t—not before the next election or anything like that, right, so, you know. Yeah, it’s possible it has all ended, but, you know, the current dark energy appears to be still repulsive. And there’s no evidence that it’s different out there somewhere, that it has become gravitationally attractive, which it could become someday, since we don’t know what it is.

There’s certain hypotheses that it’ll change sign, S I, you know, G N at some point, and start collapsing in the universe. But there’s no evidence that it’s any different out there than it is here. And so, the odds are, are very good that the whole universe is still expanding, and at an accelerating rate.

But someday, the dark energy could become gravitationally attractive. It’s not inconceivable. And so, it’s still conceivable that the universe will end in a big crunch, a gnab gib. You know, ending in fire, so to speak, right? Hot, compressed, dense. Not that fire is dense, but, you know, it’s at least hot. So in 1923, the famous American poet, Robert Frost, had a, this poem.

And he didn’t know any cosmology or any astronomy. Um, but he had a poem, which is,  amazingly Uh, relevant to today’s work, right? The poem, many of you know it, I’m sure, have heard of it, “Fire and Ice.” It goes, “Some say the world will end in fire. Some say in ice. From what I’ve tasted of desire, I hold with those who favor fire. But if it had to perish twice, I think I know enough of hate to say that for destruction, ice is also great and would suffice.” So, Frost would prefer the re-collapsing universe ending in fire, but if the universe and he had to perish twice, then eternal expansion, becoming colder, more dilute, ending in ice, that would be okay with him, and that’s perhaps, appropriate, given his name, Robert Frost, right?

PAT: I hadn’t thought about that. So, in an expanding universe—this is something that I also struggle with—everything is moving away from us.

ALEX: Everything. Except us. We’re held together by Earth here and all that. Right. So, you really have to go out past ten million light years or so. Okay. To see the expansion of the universe.

PAT: I am now going to risk the dumbest question that I could. 

ALEX: No, they’ve all been good so far. 

PAT: Okay, good. Okay? Um, if we get.

ALEX: By the way, the quickest way to turn off your students Is to make the student feel like they just asked a crappy question, you know, that was just so obvious to everyone, you know. 

Um, so you never want to do that. Okay, so here we go. So even if you ask a stupid question, I won’t admit it. Yeah, exactly. 

PAT: You won’t be honest with me. So if we can This is really dumb. 

ALEX: No, it’s not. Trust me. 

PAT: If we can look into the past.

ALEX: Yeah, we can. 

PAT: And the universe is expanding, meaning there’s some edge of the universe out there, time is either stretching or new time is being made? 

ALEX: Yeah, time, you know, as the universe proceeds. 

PAT: Yeah. Why can’t we look out there into the future? 

ALEX: Well, because it took time for light to go from there to us, so you’re necessarily looking into the past. Right? 

PAT: Yeah. 

ALEX: How do you look into the future when it took some time for the light to reach us?

And that’s always the case. We’d love to look into the future. But we don’t know of any way of doing that. You know  by the way, you said it has an edge. Let me just comment on that. 

PAT: I assume it has an edge. 

ALEX: Well, it doesn’t necessarily have an edge there. There’s an observable edge that’s that boundary from beyond which light has not yet had time to reach us. So that’s the observable boundary of the universe. But the universe may be infinite beyond that, or it may be finite. Okay, we just don’t know. And, and I don’t know that we will ever know, because we don’t want to get too much into the weeds here.

But to um, To really know what’s out there beyond our observable horizon, you have to make certain assumptions that the rest of the universe is exactly like this little part that we’re seeing, supposing it’s much, much bigger in total. And that’s kind of like saying, well, any cubic centimeter of air in this room is exactly like every other cubic centimeter, and that’s manifestly false.

You know, for example, there are sound waves traveling through here, there are pockets that are more dense, there are pockets that are less dense, and so, how do you know that the pocket you’re looking at, is in fact our pocket? is representative of the universe as a whole. And so  I’ve thought about this long and hard, and I don’t know that we will ever have a way of knowing whether the universe is infinite or finite.

So you see, your question was very deep. Dumb questions, profound answers. 

PAT: So one last one about the universe. Does it have a center? And I guess to me it seems like the center should be the Big Bang itself. The singularity that it all starts from. But I’ve read that’s not the case. 

ALEX: Right. So that’s a very natural thing to think.

Um, the glib answer was that the, The explosion, or the big bang, was everywhere, including where you are, where I am, and all that. But to understand that a little bit more deeply think of, think of the following. And this actually goes to how you can have a finite universe as well. And again, I apologize, I forgot my bag of tricks.

But most of the tricks are easily imaginable. So suppose you have a, a balloon that I’m blowing up. Not too much, otherwise I might get a little bang, okay? But I’m blowing it up, and this hypothetical universe is just, A two dimensional universe, so I’m only restricting my attention to the, to the rubber itself.

So I’m, I’m a creature that lives in the rubber, and I can go forwards and backwards, left and right, or any combination of those two motions. But I can’t go into the balloon or out along the radial dimension. So this is a two dimensional universe, this hypothetical universe, okay, and the laws of physics only operate within the rubber.

And  It’s two dimensional because I only have, you know, x and y, or any combination of them. I can mathematically describe the z direction, or, you know, like, you know, the equation for a sphere is x squared plus y squared plus z squared equals the square of the radius. Okay, so x, y, z, three variables. And yet, I’ve only got a two dimensional surface that’s curving through them.

Or, in different coordinates, polar coordinates, there’s r, the radius. And then theta and phi, the angular coordinates, those describe a sphere as well. So again, you have r, theta, and phi, but you are living in only two of those dimensions. So, that creature could realize that there is an r equals zero, right?

The center of the balloon. But that’s not part of the universe that I just described, right? That’s in a mathematically describable But physically inaccessible dimension, right? So that’s where the center is. All parts of the balloon are expanding away from all other parts. Put little stickers on the balloon, not, not dots, by the way, because the dots would expand and galaxies don’t expand because they’re gravitational altogether.

So stickers are a better analogy. If you’re in one sticker, you see all the other stickers moving away. You think, oh, I’m at the center. Then you call up your friend in another sticker, and they say, No, all the stickers are moving away from me. So you’re wrong, I’m at the center. So to break the tie, you call up another friend, and that friend says, You’re both bozos, okay?

They are, they’re, all the other stickers are moving away from mine, so I’m at the center. And then you think about it, you get together for a beer or something, if you, you know, are able to traverse that space, and at some intergalactic,  bar, and you realize that the center Is that R equals zero, but you’re at R equals 10 centimeters or whatever.

So the center is not in any physically accessible location and that from your perspective, yes, the expansion was and is everywhere, right? And even when the balloon was very small, it wasn’t actually a point. It was always topologically a balloon, right? It was never a mathematical point. It was always this little structure, no matter how small, that expanded.

And so, the expansion did occur everywhere. The Big Bang was everywhere. None of us can, can claim to be in the galaxy that was at the center, because there is no galaxy at the center. And by the way, just to finish my thought, without becoming too long winded, our universe might be a three dimensional volume.

Wrapping itself around, so to speak, “a fourth radial dimension,” right? 

PAT: Yeah, that makes perfect sense. 

ALEX: Yeah, well, there you go. Quiz on that tomorrow, too. So with that discussion, we’ve probably guaranteed that your audience will drop to one half the next time you have one of these. But, it’s like Hawking wanted to put one equation in his book, A Brief History of Time, and his publisher said, with every equation, Stephen, Your readership, your, you know, buyership will drop by, you know, to 50%.

He said, okay, I’m, I’m willing to do that for, you know, e equals mc squared. Yeah, . But I, but I won’t put in Newton’s second law F equals ma ’cause that’ll drop buyership to only 25%. Right. And so, uh. So,  I hope I didn’t ruin things for the future. No, no. Maybe, maybe some I’m gonna go blow up a bunch of balloons.

Yeah, there you go. There you go. Blow up the balloons, okay? 

PAT: Hawking once wrote that Einstein was undaunted by common sense. And I love that he meant that as a compliment. 

ALEX: Mmm, there you go, right, yeah. 

PAT: Okay, so we’re going to ask some of your questions. Thank you for submitting them. Um, this first one mentions Stanford, but we’ll let that go.

It says, “20 years ago I was listening to an astronomer at Stanford who was asked, ‘As you peer through your telescope night after night, what do you think it’s all about?’ And he replied, ‘It’s about physical representations of ideas.’ Does that resonate with you?” What would you reply? 

ALEX: Yeah  it does actually.

Because, you know, you can ask for the meaning of life and the meaning of it all and all that and maybe the answer is 42. You know, and um, you know, each of us has to find meaning in our own lives and there are many, many ways, you know, helping people, being a volunteer, being a medical doctor, you know, writing computer software, whatever, you know.

There’s no, as long as you’re finding happiness and meaning in what you’re doing, that’s a well lived life. But in a broader perspective, you can say that, you know, if the universe were filled only with inanimate objects, you know, planets and rocks and stars and black holes and things like that,  none of those things has the capacity, to our knowledge, to think.

And to be inquisitive, to ask questions, and then to attempt to answer those questions through experiments and observations and logical reasoning and things like that. We, homo sapiens, can do that. And so, in a sense, we’re, we’re the only way, right now, that we know of. Maybe there are intelligent aliens out there, you know, probably, but not many, if that’s another question.

But I think we’re not alone, but we’re pretty rare at this level, I think. But anyway, we’re the, we’re one way, perhaps one of very few ways, in which the universe has to, to know, to understand itself. Right? And so, we’re, we’re the explorers of the universe, the conscience of the universe, the, the  you know, the, the brains of the universe.

And, it’s beautiful to me that Homo sapiens have reached this level, you know, through language and all that. I mean, they weren’t dumber back then, it’s just now we have lots of things, written and spoken languages, things like that  easier ways to learn, to transmit information. But anyway, at this level now.

We can explore our very origins. Where did the elements of our body come from? Where did the,  you know, how did the Big Bang happen, maybe even, right? Why are there stars? Why are there galaxies? And so, no rocks, no stars, no planets themselves, we think, can come to that kind of an understanding. But we can.

So, in the bigger picture, you know, Homo sapiens have this larger ideal to which to aspire. Even though, I’m quick to point out that not everyone needs to be an astrophysicist. We don’t need too many of us in the world at a given time, okay? Uh, any way in which you explore the world and, and help out in some way and, and live a meaningful life, that can give all the meaning that, that you need.

But as humanity, in a sense, this physical understanding of the universe, I think  gives us a sort of a, a collective purpose. Yes. Yeah. 

PAT: That’s a great answer. Um, okay, next question. “My 92 year old mother wants me to ask, if you think extraterrestrials are currently visiting Earth.” Well, there you go.

ALEX: So, I don’t think they’re currently visiting Earth. I think the various data that have been in the news recently and the declassified documents and all that, they don’t come close to meeting the standards of evidence that science demands. These days. Okay. Uh, so, so they might be out there somewhere.

I have various reasons of thinking that they’re rare. I don’t think we’re unique, but they’re, they’re probably rare. Um, I doubt they visited us if they have the capability of interstellar travel. We are of little interest to them. Um, and especially peering at us in such, in such ways like, right, the images are always really fuzzy and for 50 years they’ve been really fuzzy.

If they’re that advanced, why aren’t they either completely invisible to us, or why haven’t they, you know, shown up and said, okay, not, not just even take me to your leader, but we’re gonna be your, your, your new leaders, you know, and stuff, right? We’re, we’re not of great interest. I think it’s like, most of us are not entomologists interested in ants.

Some of you are. But, you know, it’s like, you know, if there’s an ant on the sidewalk, you just, like, don’t pay attention. If there’s an ant in your kitchen, you might kill it. But we’re not in anyone’s kitchen, right? And if they’re that advanced to be flying around and traversing interstellar space and all that  I don’t know.

I just don’t buy it. The evidence for 50 years now has really not gotten better and, you know, the tick tock and the various things that have been publicized lately. There’s a fellow named Mick West who goes into great detail trying to find more mundane explanations of a non extraterrestrial Sort and he can usually find them as and again, quoting Sagan again, you know, extraordinary claims require extraordinary evidence.

You don’t just go jumping to some conclusion and claiming that’s the right answer just because you have not yet found, you know, a more mundane answer. And for most of the. UAPs, the Unidentified Aerial Phenomena, is the new PC way of referring to UFOs. Um, they do have more mundane explanations, and there’s a small percentage where that explanation has not been found yet.

But that does not mean that it’s intelligent extraterrestrials visiting us and abducting our kids and, you know, whatever. Getting them pregnant or something. Why isn’t the baby ever made out of kryptonite or anything? Why is it always human DNA and stuff? You know, right? Show me the bar of kryptonite, right?

Why isn’t there ever physical evidence that’s clearly not human made or something that occurs on Earth? And so, I’m sorry if some people here disagree, but I don’t think the evidence is very good and, and I think far too much is being made out of all this. That’s not to say we shouldn’t investigate the unidentified phenomena.

I’m all for investigating them. 

PAT: Yeah. Would it be fair to say you’ve, you’ve just never seen an example? 

ALEX: No, I’ve never seen a, a good example.

PAT: Even for someone else to investigate? No, even some—

ALEX: Well, no, no, it’s just I choose not to do it. I think these investigations are interesting.

But life is limited. You’ve got to choose what it is you’re going to do, and I’m sufficiently pessimistic that they have the capabilities of visiting, and if so, have actually visited, that I choose to spend my scientific career on more li on problems that are more likely to give an interesting answer.

PAT: Well, back to Douglas Adams. Do you remember who the aliens were? 

ALEX: Yeah, they were the dolphins. 

PAT: That’s right. Thanks for all the fish. See you later. And thanks for all the fish. 

ALEX: I like to think that they’re just minding their own business. 

PAT: Let’s see. Is there water on the moon and should space programs focus on exploring our solar system or beyond it? 

ALEX: So, there is some water on the moon. Um, there’s a place, there’s a couple of craters in particular at the South Pole, which are deep enough that sunlight does not reach them. And comets, which are dirty ice balls or icy dirt balls, depending on the relative amounts of ice and dirt.

They sometimes crash into the moon, sometimes earth as well. Made in part of water, so that water then remains on the moon and some of it evaporates away if it landed on some random part of the moon that’s exposed to the sun. But the parts that land near the South Pole there could land in a crater there and that water then would collect up there.

So that would be an interesting place to have a source of water if you were to have some sort of a lunar base. There’s very little water on the sunlit side because  There’s no atmosphere to keep it in, and the temperatures are really high during the 14 12 days that a given spot is illuminated by the sun, followed by 14 12 days of darkness.

And so, you know, the stuff evaporates away. But  so it’s only in very small regions of the moon that there might be water. Um, as a base, it’s an interesting place. It’s not a particularly hospitable environment. It ain’t gonna be cheap, okay? But it could be used as a launching point. for going further out.

And there’s a big debate, you know, do you need human astronauts or can you do it all with robots? I happen to be of the opinion that you can do most of it, if not all of it, with robots. Cheaper, faster, better, and without risking loss of life. However, having said that, human space exploration is exciting to people, to the general public.

I mean, I remember I was 11 when Apollo  Eleven landed on the moon, you know, and I was already cut out, I think, to be a scientist. But I know of several friends of mine who said, Yes, I’m going to become a scientist because they were just so thrilled by this landing. And I still look at the moon and I’m thrilled with the knowledge that fellow Homo sapiens have been there, you know.

So I understand the appeal of human space exploration. 

PAT: Would you like to take a trip to space? 

ALEX: I would, but  you know, it’s still pretty dangerous. And, you know so I would have to have greater assurances that I would come back and alive and in good shape. Also there’s a lot of training that goes into it. You can’t just say, okay, I might just do it and then go up the next day, right? And that training takes a lot of time, and so I decided early on to become an astrophysicist, not an astronaut. There’s a big difference, okay? And tip my hat to the astronauts. It takes years and years of training. 

PAT: I believe there’s a Cal alum in space right now. 

ALEX: Yeah, yeah. There’s been, there’s been several. I mean, we, we had one graduate student, Tamara Jernigan, who was pursuing a PhD here several decades ago. And then she got a call one morning from NASA. And she was recruited to the space program. And she went up the space shuttle several times. That was fantastic achievement. But usually, right, it’s hard to do too many things at one time and do them well. So, you know, most astronauts are not PhD astrophysicists. There’s very few examples that are. 

PAT: Well, I think that’s all we have time for unfortunately. This was fun. I hope you enjoyed it. 

ALEX: Well, a great pleasure. Thank you, Patrick.

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LEAH: This is The Edge, brought to you by California magazine and the Cal Alumni Association. I’m Leah Worthington. This episode was produced by Coby McDonald, with support from Pat Joseph and Nat Alcantara. Special thanks to Alex Filippenko. Original music by Mogli Maureal.

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